United States

Department of

Agriculture

Animal and

Plant Health

Inspection Service

Veterinary

Services

National

Animal Health

Monitoring

System

August 2010

Beef 2007–08

Prevalence and Control of Bovine Viral Diarrhea

Virus on U.S. Cow-calf Operations, 2007–08
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USDA:APHIS:VS:CEAH

NRRC Building B, M.S. 2E7

2150 Centre Avenue

Fort Collins, CO 80526-8117

(970) 494-7000

Email: NAHMS@aphis.usda.gov

http://nahms.aphis.usda.gov

#587.0810

Cover photo courtesy of Dr. Dave Dargatz
USDA APHIS VS / i

Items of N ems of Note

The cattle industry has made significant efforts

in recent years to control Bovine Viral Diarrhea

Virus (BVDV) in cattle. These efforts have been

facilitated by a more complete understanding of

the epidemiology of BVDV in cattle and

wildlife populations, enhanced availability of

diagnostics for detecting animals persistently

infected with BVDV, and a better idea of the

economic impact BVDV has on cattle herds.

These advancements have made it clear that in

some groups of cattle the impacts of BVDV can

be substantial. Furthermore, the knowledge

gained in the epidemiology of BVDV and the

improvement in diagnostics tools have made the

control of BVDV feasible.

Based on the NAHMS 2007-08 Beef Cow-calf

study, only 12.3 percent of cow-calf operations

had not heard of BVDV, and 64.0 percent of

operations knew some basics or were fairly

knowledgeable about the virus. These results are

likely a reflection of the substantial coverage the

agriculture media has devoted to BVDV in the

past few years. While producers are generally

aware of BVDV, relatively few (4.2 percent) had

done any testing of calves for persistent

infection with the virus in the past 3 years.

Larger operations (200 or more beef cows) were

much more likely than smaller operations to

have tested calves for persistent infection with

BVDV in the past 3 years (15.6 percent of

operations). The low overall rate of testing

might indicate that most producers do not

believe their herd is at risk. Producers might

also believe that the cost-benefit ratio for

controlling the disease is prohibitive.

Information on the economic impacts BVDV

has on a herd is relatively new; therefore, it is

The ear-notch testing done during the Beef

2007-08 study confirmed, as have other studies,

that animals persistently infected with BVDV

are relatively infrequent within a herd and that

most operations might not even have any

persistently infected calves in any particular calf

crop. Of the 205 cow-calf operations that

submitted ear-notch samples for BVDV testing,

only 8.8 percent had one or more persistently

infected animals identified. Among the 44,150

possible that the majority of producers had not

yet received the information by the time of the

interview or that they had not had time to fully

assimilate it. This premise might be supported

by the finding that 46.6 percent of cow-calf

operations did not know if removing calves that

tested positive for persistent infection with

BVDV would affect the value of the remaining

calves in the herd. Larger operations were more

inclined than smaller operations to believe that

removing persistently infected calves would

increase the value of the remaining calves.

Among operations that vaccinated any cattle for

any diseases, 80.7 percent vaccinated at least

some calves at 22 days of age through weaning

and 61.2 percent vaccinated weaned

replacement heifers before breeding. While

some of these herd owners might believe that by

vaccinating these animals they are effectively

controlling the development of animals

persistently infected with BVDV, the high-level

use of vaccines could also be a reflection of the

widespread belief by producers that BVDV can

have significant animal health impacts; overall,

66.7 percent of producers believed that BVDV

was a significant problem for the U.S. beef

industry.
ii / Beef 2007-08

ear-notch samples collected and tested, only 53

(0.12 percent) were positive for the BVDV

antigen. While it is tempting to ignore such a

small fraction of the total calf crop, these

animals have a tremendous capacity to transmit

the infection to other animals in the herd or to

other groups of cattle in which they come in

contact. Although such transmission rarely

results in the creation of another animal

persistently infected with BVDV, it can and does

result in disease related to acute infection with

BVDV, such as respiratory disease or

reproductive disease. A number of feedlots have

noted the substantial impact of animals

persistently infected with BVDV on in-contact

cattle and have instituted screening programs to

remove them at arrival. In some cases it appears

that groups of calves that test negative for

persistent infection with BVDV sell at a higher

price than comparable groups that have not been

tested.
USDA APHIS VS / iii

Selected Highlights ed Highlights

Only 12.3 percent of producers had not heard of

BVDV.

Only 4.2 percent of operations had tested any

calves for persistent infection with BVDV in the

previous 3 years.

Overall, 46.6 percent of producers were unsure

if removing calves that tested positive for

persistent infection with BVDV would affect the

value of the remaining calves in the herd.

Overall, 33.1 percent of operations vaccinated

calves against BVDV at 22 days through

weaning; 25.1 percent vaccinated weaned

replacements heifers through breeding; and 28.1

percent vaccinated cows.

Of operations that vaccinated at least some

cattle against BVDV in 2007, more than 8 of 10

used a vaccine that included both type 1 and

type 2 BVDV on all cattle groups vaccinated.

A higher percentage of operations used a killed

virus vaccine than a modified live virus vaccine

on bred replacement heifers precalving, on cows

precalving, and on bulls.

Overall, 8.8 percent of operations had a calf

persistently infected with BVDV.

Only 0.12 percent of calves tested were positive

for persistent infection with BVDV.
iv / Beef 2007-08

Acknowledgments ledgments

This report was a cooperative effort between two U.S. Department of Agriculture (USDA)

Agencies: the National Agricultural Statistics Service (NASS) and the Animal and Plant Health

Inspection Service (APHIS).

We want to thank the NASS enumerators who contacted beef producers and collected the data.

Their hard work and dedication were invaluable. The roles of the producers, area veterinarians in

charge, NAHMS coordinators, veterinary medical officers, and animal health technicians were

critical in providing quality data for the Beef 2007–08 reports. Recognition also goes to the

personnel at the USDA-APHIS-Veterinary Services’ Centers for Epidemiology and Animal Health

for their efforts in generating and distributing this report.

Additional biological sampling and testing for the Beef 2007–08 study were afforded by the

generous contributions of collaborators, including:

• USDA Agricultural Research Service (ARS)

–Bovine Functional Genomics Laboratory, Beltsville, MD

–Bacterial Epidemiology and Antimicrobial Resistance Research Unit, Athens, GA

–Environmental Microbial Safety Laboratory, Beltsville, MD

–Virus and Prion Research Unit, Ames, IA

• USDA:APHIS:VS National Veterinary Services Laboratories, Ames, IA

• IDEXX Laboratories, Inc., Westbrook, ME

All participants are to be commended, particularly the producers whose voluntary efforts made the

Beef 2007–08 study possible.

Larry M. Granger

Director

Centers for Epidemiology and Animal Health
USDA APHIS VS / v

Suggested bibliographic citation for this report:

USDA. 2010. Beef 2007–08, Prevalence and Control of Bovine Viral Diarrhea Virus on U.S. Cowcalf Operations, 2007–08

USDA:APHIS:VS, CEAH. Fort Collins, CO

#587.0810

Contacts for further information:

Questions or comments on data analysis: Dr. David Dargatz (970) 494-7000

Information on reprints or other reports: Ms. Abby Fienhold (970) 494-7000

Email: NAHMS@aphis.usda.gov

Feedback

Feedback, comments, and suggestions regarding Beef 2007–08 study reports are welcomed. Please

forward correspondence via email at: NAHMS@aphis.usda.gov, or you may submit feedback via

online survey at: http://nahms.aphis.usda.gov (Click on “FEEDBACK on NAHMS reports.”)
vi / Beef 2007-08

Introduction 1

Terms Used in This Report 3

Section I: Bovine Viral Diarrhea Virus 6

A. Disease Agent/Disease 6

1. Overview 6

2. Surveillance strategies 8

B. Control of BVDV 11

1. Identifying and eliminating persistently infected animals 11

2. Preventing entry of persistently infected animals to the herd 11

3. Vaccination 16

4. Industry concern 17

Section II: Population Estimates 18

A. BVDV on U.S. Cow-calf Operations 18

1. Producer familiarity with BVDV 18

2. Producer testing practices 20

B. Producer Expectations of the Economic Returns and Health

Effects Provided by Testing for BVDV Persistent Infection 26

1. Effect on calf value of testing for persistent infection with BVDV 26

2. Effect on cattle health of testing for persistent infection with BVDV 30

C. BVDV Vaccination 34

1. General practices 34

2. Vaccination by cattle group 39

3. Timing of vaccination for replacement heifers 41

4. Vaccination frequency 44

5. BVDV booster injections 44

6. BVDV vaccine type and genotype 46

7. Vaccination and familiarity with BVDV 50

8. Vaccination and reproductive outcome 51

9. Use of vaccination and testing 52

D. Types and Management of Herd Additions 53

1. Cattle brought onto the operation 53

2. Quarantine of cattle brought onto the operation 57

3. Testing of herd additions 60

Table of Cont able of Contents
USDA APHIS VS / vii

Section III: BVDV Persistent Infection Testing 62

1. Study methods for biological sampling for persistent infection with BVDV 62

2. Operations that submitted ear-notch samples for testing 63

3. Sample testing results 67

4. Characteristics of positive operations 69

Section IV: Conclusions 72

Section V: Methodology 75

A. Needs Assessment 75

B. Sampling and Estimation 76

1. State selection 76

2. Operation selection 76

3. Population inferences 76

C. Data and Sample Collection 77

1. Data collectors and data collection periods 77

2. Biological sample collection and testing for BVDV 77

D. Data Analysis 78

1. Phase I: Validation—General Beef Management Report 78

2. Phase II: Validation—VS Initial and Second Visit Questionnaires 78

E. Sample Evaluation 78

1. Phase I: General Beef Management Report 78

2. Phase II: VS Initial Visit 80

3. Phase II: VS Second Visit 81

Appendix I: Sample Profile 82

Responding Operations 82

Appendix II: U.S. Beef Cow Population and Operations 83

Appendix III: References 84

Appendix IV: Study Objectives and Related Outputs 87
USDA APHIS VS / 1

Introduction

Introduction oduction

The National Animal Health Monitoring System

(NAHMS) is a nonregulatory program of the

U.S. Department of Agriculture’s (USDA)

Animal and Plant Health Inspection Service.

NAHMS is designed to help meet the Nation’s

animal health information needs and has

collected data on cattle health and management

practices on cow-calf operations through two

previous studies, the 1992–93 Cow-calf Health

and Productivity Audit and Beef ‘97.

The Beef 2007–08 study was conducted in the

24 States (see map next page) with the largest

beef-cow populations and provides participants,

stakeholders, and the industry as a whole with

valuable information representing 79.6 percent

of U.S. cow-calf operations and 87.8 percent of

U.S. beef cows. Parts I and II of the study

contain information from the 2,159 cow-calf

operations that participated in Phase I of the

Beef 2007–08 study. Part III provides

comparisons among population estimates from

all three NAHMS beef studies: Beef 2007–08,

Beef ’97, and the 1992–93 Cow-calf Health and

Productivity Audit.

Of the 2,159 operations participating in Phase I

of the Beef 2007–08 study, 1,033 consented to

be contacted by a veterinary medical officer

regarding participation in Phase II of the study.

Of these 1,033 operations, 567 completed the

Phase II Initial Visit Questionnaire. Data from

the Initial Visit Questionnaire are reported in

Part IV of the Beef 2007–08 study. Of the 567

operations that completed the Initial Visit

Questionnaire, 470 agreed to continue in

Phase II of the study and completed the Second

Visit Questionnaire, data from which are

reported in Part V of the study.

Producers participating in Phase II that met

inclusion criteria were given the option to

submit ear-notch samples from their calf crops

to be tested for bovine viral diarrhea virus

(BVDV) persistent infection. Participation was

limited to spring calving herds in which

70 percent or more of the calves were born from

November 1, 2007, through June 30, 2008. Of

the 567 operations participating in Phase II, 472

were eligible based on meeting the criterion of

being a spring calving herd, and 306 ordered

kits to collect and submit ear-notch samples.

(Based on 2007 calving information, 272 of

these operations were eligible for BVDV

persistent infection testing and 34 operations

were not.) A total of 205 operations actually

submitted samples, of which 190 were eligible

based on 2007 calving data, and 15 were

eligible based on 2008 calving data or other

available information.

Section I of this report provides an overview of

BVDV and control of BVDV, including testing

and surveillance strategies.

Section II contains population estimates from

management data collected during Phase I and

Phase II of the Beef 2007–08 study and

provides population inferences on general

BVDV management practices.

Section III of this report provides test results

from the 205 operations that submitted ear-notch

samples for BVDV persistent infection testing.
2 /Beef 2007–08

Introduction

Data in items 3 and 4 of Section III are not

weighted to represent the U.S. beef population.

Rather, they describe the management and

production practices of the 205 operations that

participated in the voluntary BVDV sampling

study.
USDA APHIS VS / 3

Introduction

Terms Used in This Report

Antigen capture: An enzyme-linked

immunosorbent assay (ELISA) that binds

(captures) BVDV antigen for detection.

Beef cow: Female bovine that has calved at

least once.

Beef heifer: Female bovine that has not yet

calved.

Congenital defects: Abnormalities present at

birth, including defects of the brain, eyes, hair,

skeleton, and lungs. Defects may result from

BVDV infections at 100 to 150 days of

gestation.

Cytopathic biotype: A strain of the BVDV that

kills epithelial cells when cultured in vitro.

Enzyme-linked immunosorbent assay

(ELISA): A laboratory method that can detect

either BVDV antigen or antibody.

Herd size: Herd size is based on October 1,

2007, cow inventory. If there were no cows on

October 1, 2007, then July 1, 2007, cow

inventory was used.

Immunocompetence: The ability of a calf to

produce an immunologic response to an

infection.

Immunohistochemistry (IHC): A method to

detect BVDV antigen in formalin-fixed skin

samples.

Immunotolerance: Failure of a calf to

immunologically respond to an infection, which

results in the calf never eliminating the

infection.

Noncytopathic biotype: A strain of the BVDV

that does not kill epithelial cells when cultured

in vitro.

Operation: Premises with at least one beef cow

on October 1, 2007, or July 1, 2007.

Operation average: The average value for all

operations. A single value for each operation is

summed over all operations reporting divided by

the number of operations reporting. For

example, operation average dollars per head

(p 29) is calculated by summing reported dollars

per head over all operations divided by the

number of operations.

Persistent infection: A calf infected with

noncytopathic BVDV from about 40 to 125

days of gestation. Calf is immunotolerant and

persistently sheds large quantities of BVDV for

the rest of its life.

Population estimates: The estimates in this

report make inference to all of the operations in

the target population (see Section V:

Methodology, p 75). Data from the operations

responding to the survey are weighted to reflect

their probability of selection during sampling

and to account for any survey nonresponse.
4 /Beef 2007–08

Introduction

Precision of population estimates: Estimates

in this report are provided with a measure of

precision called the standard error. A 95-percent

confidence interval can be created with bounds

equal to the estimate plus or minus two standard

errors. If the only error is sampling error, the

confidence intervals created in this manner will

contain the true population mean 95 out of 100

times. In the example to the right, an estimate of

7.5 with a standard error of 1.0 results in limits

of 5.5 to 9.5 (two times the standard error above

and below the estimate). The second estimate of

3.4 shows a standard error of 0.3 and results in

limits of 2.8 and 4.0. Alternatively, a 90-percent

confidence interval would be created by

multiplying the standard error by 1.65 instead of

2. Most estimates in this report are rounded to

the nearest tenth. If rounded to 0, the standard

error was reported (0.0). If there were no

reports of the event, no standard error was

reported (—).

Polymerase chain reaction (PCR):

A laboratory method used to generate numerous

copies of specific genetic segments to allow

detection. In the context of BVDV testing, the

PCR method can be used to create copies of the

genetic material (RNA) of BVDV. This allows

detection of the virus in a sample even if it is

present in very small quantities.

Regions:

West: California, Colorado, Idaho, Montana,

New Mexico, Oregon, Wyoming

Central: Iowa, Kansas, Missouri, Nebraska,

North Dakota, South Dakota

Southeast: Alabama, Arkansas, Florida,

Georgia, Kentucky, Louisiana, Mississippi,

Oklahoma, Tennessee, Texas, Virginia

Sample profile: Information that describes

characteristics of the operations from which

Beef 2007–08 data were collected.

Transient infection: An animal infected with

either biotype of BVDV (cytopathic or

noncytopathic) following birth, sheds low
USDA APHIS VS / 5

Introduction

quantities of BVDV for a limited period, and is

immunocompetent with a normal immune

response to clear the virus.

Type 1 genotype: A grouping of BVDV based

on gene sequences of the virus. Type 1 BVDV

may be of the cytopathic or noncytopathic

biotype.

Type 2 genotype: A grouping of BVDV based

on sequences of the virus. Type 2 BVDV may

be of the cytopathic or noncytopathic biotype.

Virus isolation: A laboratory method used to

grow BVDV on cell cultures, which provides

virus to perform genotype and biotype tests.
6 / Beef 2007–08

Section I: Bovine Viral Diarrhea Virus—A. Disease Agent/Disease

Section I: Bo Section I: Bovine Viral

Diarrhea Virus

A. Disease Agent/Disease

1. Overview Bovine viral diarrhea virus (BVDV) was first

recognized in 1946 as a cause of diarrhea and

ulcers on mucus membranes in cattle and

abortion in cows. Today, it is known that BVDV

is associated with a variety of cattle diseases.

The majority of disease from BVDV in a cowcalf herd is associated with reproduction

(Grooms, 2004). The presence of BVDV in a

herd may cause decreased fertility in breeding

cows, abortions, congenital malformations in

calves, and the birth of calves persistently

infected with BVDV. Signs of disease may also

include increased rates of diarrhea and

pneumonia in suckling or weaned calves (Baker,

1995). Persistently infected individual calves

may show signs of severe, bloody diarrhea and

ulcerations on mucus membranes.

There are two biotypes of BVDV—cytopathic

(CP) and noncytopathic (NCP) (see Terms Used

in This Report, p 3). Both biotypes can cause

disease (Donis, 1995).

There are also two genotypes of BVDV—type 1

and type 2. Both types have been associated

with clinical disease, including respiratory,

digestive, and reproductive diseases. Type 2

BVDV has sometimes been associated with

more severe clinical disease in adult cattle,

including thrombocytopenia (low number of

blood platelets) [Donis, 1995].

While infection with BVDV can manifest in a

variety of ways, the most significant effects of

BVDV occur following infection of a cow

during pregnancy. A cow infected with BVDV

rarely shows any signs of disease, but the effects

on its fetus can be devastating.

The effects of BVDV during pregnancy vary

depending on the stage of pregnancy at infection

and the BVDV biotype (Grooms, 2004). Note

that the time categories below overlap because

there is biological variation and lack of clarity in

the effects of BVDV infection in the progression

of gestation.

• Days 0 to 45 of gestation: Embryo or fetal

death due to either CP or NCP biotype.

• Days 40 to 125:

 CP biotype rarely results in fetal death

and abortion, or mummification.

 NCP biotype results in infection of

calves and immunotolerance to BVDV.

Calves infected during this period

become persistently infected and shed

large quantities of the virus throughout

their lives. Brain and/or eye defects may

be present in some cases.

• Days 100 to 150: Beginning of

immunocompetence. Either CP or NCP

virus can cause congenital defects (brain or

eye) in calves, but not persistent infection.

Abortions can also result from infection at

this time.

• Day 125 to term: Birth of normal calves

with evidence of an immune response, but

may also have abortions and weak calves.
USDA APHIS VS / 7

Section I: Bovine Viral Diarrhea Virus—A. Disease Agent/Disease

Persistent infection occurs when a cow infected

with the NCP biotype of BVDV during

approximately 40 to 125 days of gestation

passes the virus to her calf. Persistently infected

calves may or may not have congenital defects,

but do shed large quantities of BVDV in nasal

and oral secretions, and in feces. Typically,

calves persistently infected with BVDV are poor

performers; however, some will gain and grow

relatively well, sometimes well enough to be

retained as replacement heifers. Persistently

infected calves are the major source of

continued infection for the herd (Baker, 1995;

Houe, 1995; Larson et al., 2004b). Persistently

infected cows always produce persistently

infected calves. However, more than 90 percent

of persistently infected calves are the result of

transient BVDV infections of their dams

(Wittum et al., 2001).

Persistently infected calves

• Shed large quantities of virus which can be

transmitted to other members of the herd;

• Usually perform poorly, but not always;

• Usually have increased sickness and death

loss; and

• Occasionally perform well enough to be

incorporated into the breeding herd.

Normal calves born with serum antibody to

BVDV are the result of infection after 125 days

of gestation. These calves are not a problem.

They have been exposed to BVDV and have

eliminated it by an active immune response.

Normal calves can be infected with BVDV

following birth. Known as transiently infected,

these calves shed relatively low quantities of

virus for a limited time (up to 7 to 14 days), but

then clear the infection and cease shedding the

virus. Calves transiently infected with BVDV

may show few signs of disease but may also be

immunosuppressed and more susceptible to

other infections. Symptoms of transient infection

in calves may include either diarrhea or

pneumonia (Baker, 1995).
8 / Beef 2007–08

Section I: Bovine Viral Diarrhea Virus—A. Disease Agent/Disease

2. Surveillance

strategies

Optimal surveillance strategies for BVDV and

persistent infection with BVDV should

incorporate the epidemiology of the disease

agent, the attributes of the herd, and current

knowledge of diagnostic tests and testing

methods. While basic information about each of

these areas has been incorporated in this report,

producers and their veterinarians are advised to

seek out the most current information before

tailoring a specific plan for an individual herd.

Signs of BVDV presence within a herd include

increased sickness and death in calves from

birth to weaning, decreased pregnancy rates,

increased abortion rates, and the birth of calves

with congenital malformations. Available data

suggest that most herds do not have persistently

infected animals within the herd (Wittum et al.,

2001). If an operation does have one or more

persistently infected animals, testing to identify

and remove these animals may be necessary to

stop transmission. Since cows or heifers

persistently infected with BVDV will always

produce persistently infected calves, testing all

calves in the herd is an efficient way to identify

positive calves and potentially positive cows or

heifers. Additionally, all cattle in the herd not

represented by a calf (replacement heifers not

yet calved, bulls, etc.) should be tested.

BVDV would not be suspected in a cow-calf

herd in which a high percentage of cows

exposed to a bull wean a calf and in which no

laboratory evidence exists of transiently infected

or persistently infected animals.

Four possible surveillance strategies to detect

BVDV are outlined in Larson et al. (2004a).

1. Surveillance Strategy I—monitor production

and health

• Low-cost/low-sensitivity strategy.

• Slow introduction to persistent infection

through diagnostic testing (production must

be negatively influenced before presence of

persistent infection is detected).

• Monitor overall pregnancy proportion and

percentage of pregnant animals in first

21 days.

• Monitor stillbirths, neonatal morbidity,

neonatal mortality, and weaning percentage.

• Necropsy and submit tissues (thymus,

Peyer’s patches, spleen, skin, blood) for

laboratory analysis on high percentage of

abortions, stillbirths, and mortalities.

• If unexplained suckling calf losses occur

(pneumonia, scours, etc.) send appropriate

samples to diagnostic laboratories to

identify transiently infected and persistently

infected calves.

• Positive test results should be confirmed

with other supporting evidence.

2. Surveillance Strategy II—serology (type I and

type II) of herd subset

• Low-cost/low-sensitivity strategy.

• Serology of nonvaccinated, sentinel animals

has been used to identify persistently

infected animals in dairies.
USDA APHIS VS / 9

Section I: Bovine Viral Diarrhea Virus—A. Disease Agent/Disease

• Differentiation of titers due to vaccination

or field virus exposure (height of serologic

titers) is difficult, subjective, and must

include consultation with laboratory

diagnosticians for interpretation.

3. Surveillance Strategy III—pooled PCR of

blood (entire calf crop)

• High-cost/high-sensitivity strategy.

• Identifies persistent infections prior to

breeding season if done before bull turnout.

• Delayed response to persistent infection

introduction if done after breeding season.

• Pool samples of 20 to 30, with repooling

and rerunning of positive pools.

• Positive PCR does not differentiate between

transient infection and persistent infection;

therefore, additional confirmatory testing is

needed.

4. Surveillance Strategy IV—IHC or ELISA on

skin samples (entire calf crop)

• High-cost/high-sensitivity strategy.

• Identifies persistent infections prior to

breeding season if done before bull turnout.

• Must confirm positive tests if BVDV is not

suspected because of poor positive

predictive value in herds with no prior

evidence of persistent infection.

In cow-calf herds in which BVDV infection is

suspected because of poor reproductive

performance, high calf morbidity or mortality, or

laboratory confirmation of animals transiently

infected with BVDV, an appropriate diagnostic

plan will help determine if persistently infected

animals are present in the herd (see figure, next

page). To optimize its value, the diagnostic

effort should be done before the start of the

breeding season to ensure the timely removal of

persistently infected animals before the next

crop of persistently infected calves would be

created— i.e., days 40 to 125 of gestation. A

structured or planned approach to testing will

minimize the number of tests necessary to obtain

the most information about the herd. All animals

in the herd do not have to be tested to know the

herd’s persistent infection status.

Three groups of animals should be selected for

testing:

• Group 1: All calves—since a persistently

infected cow will always produce a

persistently infected calf, neither the cow

nor the calf are persistently infected if the

calf tests negative. However, a persistently

infected calf does not necessarily mean that

the cow is persistently infected, since a

transient infection in the cow can lead to a

persistently infected calf.

• Group 2: All cows without calves.

• Group 3: All bulls and replacement heifers

(purchased or raised) because these animals

are not represented by testing of the other

two groups.

Test results from these three groups of animals

will determine if other testing is indicated. For

example, if a persistently infected calf is

identified, its dam should be tested to determine

if she is also persistently infected. Test results

can then be used to determine the appropriate

course of action for control/elimination of

BVDV from the herd.
10 / Beef 2007–08

Section I: Bovine Viral Diarrhea Virus—A. Disease Agent/Disease

Cow-Calf Herd (BVDV-Suspect Herd)

BVD is Suspected (High Risk)

• Poor reproductive performance despite good nutrition and bull fertility

• High calf morbidity / mortality despite good sanitation and nutrition

• Laboratory confirmation of BVDV transient (acute) infection (TI) or BVDV PI animals

Appropriate diagnostic testing to determine

if Persistently Infected (PI) with BVDV

Testing Must Occur Before Start of Breeding Season

• All calves (IHC test is appropriate for calves of all ages)

• All cows without calves (open or calf died) (IHC, Ag-capture ELISA, VI, PCR)

• All replacement bulls and heifers (purchased or raised) (IHC, Ag-Capture ELISA, VI, PCR)

Test Negative Test Positive

Retain in herd

• High NPV* of tests Calves

• Remove calf and dam from breeding herd 

• Euthanize calf 

• Test dam

Test Dams

Test Negative

• Return dam to breeding herd 

Test Positive

• Sell to slaughter

Safe for human consumption

Heifers, Bulls & Cows

• Sell PI animals to slaughter

Safe for human consumption

• All cows still pregnant at time of testing must be removed from breeding herd because fetus 

is of unknown BVDV PI status

• Absence of confirmed PI calves does not guarantee absence of BVDV problem. If you are 

still suspicious, testing the next calf crop is recommended.

• Use IHC (immunohistochemistry), pooled PCR, ELISA of skin samples, or Virus isolation (VI) 

• Implement complete vaccination program prior to breeding in replacement animals and 

appropriate boosters in adults

• Prevent direct contact with cattle of unknown BVDV control status

* NPV = negative predictive value, i.e. likelihood that a test negative animal is truly PI negative

Eliminating Animals Persistently Infected with BVD

Source: Larsen et al., 2004a.
USDA APHIS VS / 11

Section I: Bovine Viral Diarrhea Virus—B. Control of BVDV

B. Control of BVDV

As with the design of surveillance strategies,

control strategies should be tailored to the

individual herd situation and should make use of

the most current vaccines, tests, and biosecurity

protocols. For herds affected with BVDV,

1. Identifying and

eliminating

persistently

infected animals

control revolves around identifying and

eliminating persistently infected animals,

preventing entry of new persistently infected

animals, and vaccinating to minimize the effects

of disease. (Larson et al., 2004a).

Because persistently infected animals are central

to the continuation of BVDV in a herd,

identifying and eliminating these animals is the

first and most important step in controlling

BVDV. Removal of any persistently infected

animals before the breeding season, coupled

with biosecurity practices, can effectively

prevent production of new persistently infected

animals. Numerous tests are available for

detecting animals persistently infected with

BVDV (Larson et al., 2005a). Test selection

should be based on test performance, samples

required, and the BVDV control goals of the

operation. Persistently infected animals are most

likely to be the youngest animals in the herd, so

testing programs should focus first on calves. If

BVDV is suspected in the herd because of

diagnostic test results on ill or dead cattle,

lowered reproductive efficiency, the birth of

calves with congenital anomalies, or excess

morbidity, it is important to test all calves before

the start of the breeding season to interrupt

transmission. Since animals persistently infected

with BVDV will always produce persistently

infected calves, the dams of any positive calves

should be tested to determine if they are also

persistently infected. However, few adult

animals are persistently infected; more than 90

percent of persistently infected calves are born

to dams that were transiently infected during

gestation (Wittum et al., 2001).

2. Preventing entry

of persistently

infected animals to

the herd

Preventing the entry of persistently infected

cattle is accomplished by recognizing the risks

associated with importing different classes of

cattle and by applying appropriate quarantine

and testing procedures to identify and exclude

persistently infected animals. A common factor

in herds with persistently infected cattle is the

recent importation of pregnant females or cowcalf pairs. Although it is possible that any cattle

introduced to the herd are persistently infected,

young cattle are the most likely candidates for

persistent infection with BVDV. Prevention is

achieved by not importing calves or pregnant

females into the herd, or by testing calves in the

herd to identify persistently infected animals and

removing them before the next breeding season
12 / Beef 2007–08

Section I: Bovine Viral Diarrhea Virus—B. Control of BVDV

begins. Fenceline contact with neighboring

herds that have persistently infected animals

may also expose pregnant females to BVDV.

Preventing contact with neighboring herds from

breeding to weaning is crucial, since this is the

time that most pregnancies will pass through the

high risk period (40 to 125 days of gestation) for

producing persistently infected calves.

a. Possible testing strategies for controlling BVDV infection in cow-calf herds 

Testing Strategy Test Rationale 

Testing sick suckling 

calves (scours, 

pneumonia, 

septicemia, etc.) for 

possible BVDV 

involvement 

♦ IHC or AC-ELISA from skin 

sample will identify 

persistently infected calves 

and sometimes transiently 

infected calves 

♦ PCR of blood or serum to 

identify both persistently and 

transiently infected calves 

(Use of PCR will increase 

testing cost) 

Maternal antibody may interfere with 

microtiter VI and AC-ELISA using serum 

or plasma, therefore these tests are not 

recommended for young calves. 

If a live calf is IHC or AC-ELISA 

negative from a skin sample but BVDV 

positive from a blood or serum sample, 

transient infection is likely. Retest to 

confirm. 

False positive indication of persistent 

infection with IHC or AC-ELISA of skin 

samples from transiently infected cattle 

can occur in situations with high viral 

exposure due to the presence of 

multiple persistently infected cattle. 

Testing dead 

suckling calves 

(scours, pneumonia, 

septicemia, etc.) for 

possible BVDV 

involvement 

♦ IHC or AC-ELISA from skin 

sample will identify 

persistently infected calves 

and sometimes transiently 

infected calves – IHC will work 

if skin is not desiccated 

♦ IHC, FA, or VI from tissues 

(thymus, Peyer’s patches, 

mesenteric lymph nodes,) to 

identify infected calves (will 

not differentiate between 

persistent and transient 

infection) 

Maternal antibody may interfere with 

microtiter VI and AC-ELISA using serum 

or plasma, therefore these tests are not 

recommended for young calves. 

If a dead calf is IHC or AC-ELISA 

negative from a skin sample but positive 

from a tissue sample, transient infection 

is likely. 
USDA APHIS VS / 13

Section I: Bovine Viral Diarrhea Virus—B. Control of BVDV

a. Possible testing strategies for controlling BVDV infection in cow-calf herds 

(continued) 

Testing Strategy Test Rationale 

Screening a herd 

(suckling calves, 

cows that lost 

calves, replacement 

animals) because of 

laboratory evidence 

of BVDV in the herd. 

♦ IHC or AC-ELISA from skin 

sample will identify 

persistently infected cattle and 

sometimes transiently infected 

cattle. 

Maternal antibody may interfere with 

microtiter VI and AC-ELISA using serum 

or plasma, therefore these tests are not 

recommended for young calves. 

Any animal positive by IHC and ACELISA test is usually considered 

persistently infected. However, false 

positive IHC or AC-ELISA of skin 

samples from transiently infected cattle 

can occur in situations with high viral 

exposure due to the presence of 

multiple persistently infected cattle. 

Retest valuable animals to confirm 

status. 

Screening open 

replacement heifers 

(raised or 

purchased), 

purchased open 

cows, or bulls 

(raised or 

purchased) 

♦ IHC or AC-ELISA from skin 

sample will identify 

persistently infected cattle and 

sometimes transiently infected 

cattle. 

♦ PCR – pool serum or whole 

blood into groups of 30-40 or 

less.* Test individual blood or 

skin samples of animals in 

positive pools to identify PIs. 

Animals in negative pools are 

not considered persistently 

infected. 

Any positive test in valuable animals 

could be confirmed by segregating the 

animals and using IHC, AC-ELISA, VI, 

or PCR of serum or blood samples 

taken not less than 21 days later, which 

will eliminate the possibility that 

transiently infected animals and falsepositive animals are incorrectly 

identified as persistently infected. 

Screening 

purchased pregnant 

replacement heifers 

or cows prior to 

entry into the herd 

♦ IHC or AC-ELISA from skin 

sample will identify 

persistently infected cattle and 

sometimes transiently infected 

cattle. 

♦ PCR – pool serum or whole 

blood into groups of 30-40 or 

less.* Test individual blood or 

skin samples of animals in 

positive pools to identify 

persistent infection. Animals 

in negative pools are not 

considered persistently 

infected. 

♦ Isolate pregnant cattle away 

from resident herd until calves 

are born and tested for 

persistent infection status via 

IHC or AC-ELISA from a skin 

sample. 

Any positive test in valuable animals 

could be confirmed by segregating the 

animal and using IHC, AC-ELISA, VI, or 

PCR of serum or blood samples taken 

not less than 21 days later, which will 

eliminate the possibility that transiently 

infected animals and false-positive 

animals are incorrectly identified as 

persistently infected. 

A test-negative pregnant dam can have 

a persistently infected fetus. Cattle that 

conceived off the premises should be 

isolated from the resident herd until the 

calf is born and determined to be testnegative for persistent infection. 
14 / Beef 2007–08

Section I: Bovine Viral Diarrhea Virus—B. Control of BVDV

a. Possible testing strategies for controlling BVDV infection in cow-calf herds 

(continued) 

Testing Strategy Test Rationale 

Screening raised 

replacement heifers 

and bulls prior to 

sale by a seedstock 

supplier 

♦ IHC or AC-ELISA from skin 

sample will identify 

persistently infected cattle and 

sometimes transiently infected 

cattle. 

♦ PCR – pool serum or whole 

blood into groups of 30-40 or 

less.* Test individual blood or 

skin samples of animals in 

positive pools to identify 

persistent infection. Animals in 

negative pools are considered 

persistently infected. 

Any positive test in valuable animals 

could be confirmed by segregating the 

animal and using IHC, AC-ELISA, VI, or 

PCR of serum or blood samples taken 

not less than 21 days later, which will 

eliminate the possibility that transiently 

infected animals and false-positive 

animals are incorrectly identified as 

persistently infected. 

Testing ill or dead 

stocker or feedlot 

animals for possible 

BVDV involvement 

♦ IHC or AC-ELISA from skin 

sample will identify 

persistently infected cattle and 

sometimes transiently infected 

cattle – IHC will work if skin is 

not desiccated. 

Any animal positive by IHC and ACELISA test is usually considered 

persistently infected. 

To rule-out possible transient BVDV 

infection interfering with identification of 

persistently infected animals, confirm 

any positive test on live cattle in three 

weeks. 

Modified from: Larson et al., 2005a. 

*Further information about using pooled samples is available at Munoz-Zanzi et al., 2000 and Larson et al., 

2005.
USDA APHIS VS / 15

Section I: Bovine Viral Diarrhea Virus—B. Control of BVDV

b. Tests currently available for identifying persistent BVDV infection 

Test Cost Advantages Disadvantages Specimens / Shipping 

Virus Isolation 

♦ 1-3 week 

turnaround 

Moderate to 

high 

♦ Gold Standard for 

BVDV diagnosis 

♦ High specificity 

♦ Virus available for 

study at a later date 

♦ Specimens shipped on 

ice to keep virus viable 

♦ Potential false negative 

due to interference by 

maternal antibodies in 

serum. Microplate VI may 

be less sensitive than full 

plate isolation 

♦ To distinguish between 

persistent and transient 

infections, retest positive 

cattle in 3-4 weeks 

♦ Whole blood (10 mL) 

or serum (2-3 mL) 

♦ Send in insulated 

container with cold 

packs 

♦ Do not freeze samples 

Immunohistochemistry (IHC) 

of skin 

♦ 2-5 day 

turnaround 

Low ♦ High sensitivity 

♦ Usually identifies 

persistent 

infections only – 

transiently infected 

animals usually 

test negative 

♦ Formalin usage 

♦ Will generally not 

identify transiently 

infected animals 

♦ Determine laboratory 

preferred sample 

and shipping 

♦ Skin samples, 

usually ear notch 

♦ Send fresh on wet 

ice or stored in 1:10 

volume of 10 percent 

neutral buffered 

formalin 

Antigen-capture 

ELISA of serum 

♦ 1-5 day 

turnaround 

Low ♦ High sensitivity ♦ Potential false negative 

due to interference by 

maternal antibodies 

♦ To distinguish between 

persistent and transient 

infection, must retest 

animal in 3 weeks 

♦ Serum (2 mL) 

♦ Send in insulated 

container with cold 

packs 

Antigen-capture 

ELISA of skin 

♦ 1-3 day 

turnaround 

Low ♦ High sensitivity 

♦ Usually identifies 

persistent 

infections (PI) only 

– transiently 

infected animals 

usually test 

negative 

♦ Will generally not 

identify transiently 

infected animals 

♦ Skin samples 

♦ Send in insulated 

container with cold 

packs – can hold 

samples by freezing 

♦ Determine 

laboratory’s 

preferred method of 

packaging and 

shipping 

Polymerase 

chain reaction 

(PCR) 

♦ 1-3 day 

turnaround 

Moderate to 

high (can be 

reduced by 

pooling 30 or 

more 

samples). 

♦ High sensitivity ♦ Potential for laboratory 

contamination (false 

positive) 

♦ To distinguish between 

persistent and transient 

infection, must retest 

positive cattle in 3 

weeks 

♦ Whole blood (10 mL) 

or serum (2-3 mL) 

♦ Send in insulted 

container with cold 

packs 

Modified from: Larson et al. 2005a. 
16 / Beef 2007–08

Section I: Bovine Viral Diarrhea Virus—B. Control of BVDV

3. Vaccination Vaccinating calves against BVDV may help to

protect them from respiratory disease, as BVDV

is a common etiologic agent of the bovine

respiratory disease complex. Vaccinating

replacement heifers and cows may help protect

them from reproductive disease and may

provide some degree of fetal protection from

persistent infection with BVDV if the cow is

exposed during pregnancy.

Vaccination is a useful adjunct to other

strategies for BVDV control. Vaccination can

help mitigate the effects of BVDV in a herd

should animals in the herd be exposed through

introduction of new animals or contact with

neighboring herds. Vaccination can reduce the

severity of disease (reproductive, respiratory,

digestive) and the number of animals affected.

In addition, vaccination can provide some

additional protection for the herd if the testing

program fails. While vaccinating will not

prevent all transient or persistent infections, it

will decrease the cost of an outbreak.

Available evidence suggests that modified live

virus vaccines may provide more protection

from production of persistently infected calves

than vaccination with killed virus products

(Kelling, 2004). Modified live virus vaccines

may provide sufficient immunity with a single

dose, although a multiple-dose primary series is

generally recommended for replacement heifers.

Killed virus vaccines require at least a two-dose

primary series. Modified live virus vaccines

have limitations in the timing of administration

and generally must be avoided during pregnancy

and for 3 to 4 weeks before breeding. Killed

vaccines are safe for administration at any time.

Vaccinating dams provides some protection

against fetal infection during pregnancy, thereby

decreasing the risks of persistent infection in the

calf, abortion, and congenital defects.

Vaccinating dams also increases passive

immunity to calves and may provide protection

against respiratory and digestive infections in

calves. Vaccinating calves with modified live

virus vaccines may also increase respiratory and

digestive disease protection. Cross protection

for BVDV type 2 infections when using

vaccines that contain only BVDV type 1 may be

incomplete and depends on the specific strains

of BVDV involved (Ficken et al., 2006b). Some

evidence suggests that vaccinating dams with a

vaccine containing both type 1 and type 2

genotypes may provide the most protection from

fetal infection and subsequent persistent

infections (Kovacs et al., 2003; Fairbanks et al.,

2004; Ficken et al., 2006a , 2006b). In all cases,

BVDV vaccine administration should be timed

to provide maximal immunity during the first

120 days of pregnancy.
USDA APHIS VS / 17

Section I: Bovine Viral Diarrhea Virus—B. Control of BVDV

4. Industry

concern

The cattle industry has clearly established

BVDV control as a priority concern. The

National Cattlemen’s Beef Association has

established a BVDV working group within the

Animal Health and Well-being Committee to

address research, education, technical issues,

and to liaison with other industry and allied

groups. The Academy of Veterinary Consultants

has issued a position statement on BVDV,

recognizing the “enormous losses due to the

effects of BVDV infection” and calling for “the

beef and dairy industries to adopt measures to

control and target eventual eradication of

BVDV from North America” (http://

www.bvdinfo.org/index.php?option=com_

content&view=article&id=60&Itemid=106).

This position statement has been endorsed by

the American Association of Bovine

Practitioners Board of Directors and by the

National Cattlemen’s Beef Association Animal

Health and Well-being Committee. Numerous

articles have targeted both producers and cattle

veterinarians to increase knowledge and

effective management of BVDV.
18 / Beef 2007–08

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations

Section II: P Section II: Population opulation

Estimates

A. BVDV on U.S. Cow-calf Operations

1. Producer

familiarity with

BVDV

For any BVDV control program to be

successful, producers must be knowledgeable

about the effects of BVDV and the production

and economic value of eradicating the disease.

In addition, producers must have access to the

appropriate tools/guidelines for achieving

control or elimination of BVDV.

The majority of producers surveyed in the Beef

2007–08 study had at least some knowledge of

BVDV. Approximately two of three operations

(64.0 percent) knew some basics or were fairly

knowledgeable about BVDV. A higher

percentage of operations with 200 or more beef

cows were fairly knowledgeable about BVDV

compared with operations with fewer than

100 cows.

Producers on large operations may have greater

general knowledge about issues affecting cowcalf operations than producers on smaller

operations, since large operations are more

likely to be primary or secondary sources of

income than small operations. The cow-calf

operation was the primary source of income for

only 5.3 percent of operations with 1 to 49 beef

cows but was the primary source of income for

65.0 percent of operations with 200 or more

beef cows (USDA, 2008a). Producers on almost

9 of 10 operations with 200 or more beef cows

(89.3 percent) knew some basics or were fairly

knowledgeable about BVDV. Despite numerous

articles in industry publications about BVDV,

over 4 of 10 producers (42.2 percent) with fewer

than 50 cows recognized the name only or had

not heard of BVDV.

An effective program as outlined by the

Academy of Veterinary Consultants to “adopt

measures to control and target eventual

eradication of BVDV from North America” will

likely require additional efforts to educate

producers on BVDV disease and the options for

control. These efforts may need to focus on the

large number of smaller operations. According

to the 2007 Census of Agriculture

(USDA:NASS, 2009), 79.0 percent of cow-calf

operations in the United States have fewer than

50 cows.
USDA APHIS VS / 19

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations

a. Percentage of operations by familiarity with BVDV and by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 

200 or 

More 

All 

Operations 

Level of 

Familiarity Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Fairly 

knowledgeable 26.6 (1.6) 38.2 (2.8) 47.4 (2.9) 57.4 (2.7) 31.6 (1.3) 

Knew some 

basics 31.2 (1.7) 37.6 (2.9) 33.7 (2.7) 31.9 (2.6) 32.4 (1.3) 

Recognized 

the name, not 

much else 

26.7 (1.7) 19.0 (2.3) 15.7 (2.3) 8.1 (1.5) 23.7 (1.3) 

Had not heard 

of before 15.5 (1.4) 5.2 (1.3) 3.2 (1.0) 2.6 (0.7) 12.3 (1.0) 

Total 100.0 100.0 100.0 100.0 100.0 
20 / Beef 2007–08

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations

The percentage of producers that had not heard

of BVDV was higher in the Southeast region

(15.1 percent) than in the Central and West

regions (6.5 and 7.2 percent, respectively),

perhaps because of the smaller average herd size

in the Southeast region and less knowledge of

BVDV among small operators. Average herd

size in the Southeast region was 37 cows,

compared with 60 cows in the Central region

and 84 cows in the West region (see

Appendix II, p 83).

2. Producer testing

practices

Diagnostic testing of cattle for persistent

infection with BVDV is a central part of any

control or eradication program. Numerous tests

are available for detecting BVDV in cattle.

Overall, only 4.2 percent of operations had

tested any beef calves for persistent infection

with BVDV in the past 3 years. A higher

percentage of operations with 200 or more beef

cows had tested at least some beef calves for

persistent infection (15.6 percent) compared

with operations with 1 to 49 beef cows

(1.8 percent). The percentages of operations that

had tested any calves were not different across

the West, Central, and Southeast regions (data

not shown).

There may be several reasons for the relatively

low level of BVDV testing in beef cow-calf

operations. One reason could be that producers

do not test because they do not believe the

disease is present in their herds. Available data

suggest that most operations do not have a

persistently infected animal in their herds;

however, herds with a previous history of signs

compatible with BVDV infection are more

likely to have a persistently infected animal in

the herd (Wittum et al., 2001). Producers may

b. Percentage of operations by familiarity with BVDV and by region 

Percent Operations 

Region 

West Central Southeast 

Level of Familiarity Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Fairly knowledgeable 36.4 (3.5) 35.8 (2.4) 29.4 (1.6) 

Knew some basics 34.9 (3.7) 34.1 (2.4) 31.5 (1.7) 

Recognized the name, 

not much else 21.5 (3.7) 23.6 (2.3) 24.0 (1.6) 

Had not heard 

of before 7.2 (2.5) 6.5 (1.4) 15.1 (1.4) 

Total 100.0 100.0 100.0 
USDA APHIS VS / 21

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations

be correct in not implementing testing protocols

in all herds, and further research may be

necessary to more clearly define what herd

criteria justify a testing program. Alternatively,

some producers may not test calves because

they do not believe BVDV causes important

health, performance, or value issues. Other

producers may not have sufficient knowledge of

BVDV and its possible impacts. The latter two

reasons for not testing may be best addressed

with research focused on the production,

performance, and value impacts of BVDV in

cow-calf operations and the dissemination of

those results to producers.

a. Percentage of operations that tested any beef calves for persistent infection 

with BVDV during the previous 3 years, by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More All Operations 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

1.8 (1.2) 8.4 (3.1) 7.2 (2.2) 15.6 (4.0) 4.2 (1.0) 
22 / Beef 2007–08

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations

Of operations that tested any beef calves for

persistent infection during the previous 3 years,

73.5 percent used ear-notches for testing and

35.1 percent submitted serum samples.

Producers test animals for BVDV persistent

infection for a number of reasons. In some

cases, animals are tested to diagnose disease in a

specific animal, document the status of an

individual animal to meet the requirements of a

show or sale, or to increase the perceived value

of animals prior to marketing. In other cases,

animals are tested as part of an outbreak

investigation or to determine the exposure status

of the herd. Finally, animals are tested as part of

a control program to eliminate animals

persistently infected with BVDV from the herd.

Depending on the goals of testing, different

groups of animals may be targeted for the

testing. Of operations that tested any beef calves

for persistent infection with BVDV during the

previous 3 years, about one of three

(33.8 percent) tested all calves born to heifers or

cows bred on the operation during 2007. More

than 1 of 5 operations (22.6 percent) tested all

calves born to heifers or cows purchased when

pregnant, but fewer than 1 of 10 operations

(9.0 percent) tested all calves acquired as part of

a cow-calf pair.

Of operations that tested any beef calves for

persistent infection with BVDV during the

previous 3 years, more than one of four

(28.5 percent) tested clinical suspects. Available

evidence suggests a higher morbidity and

mortality rate among persistently infected cattle.

Testing sick and dead cattle as well as poor

performers might be a reasonable method of

targeted surveillance. Operations that specified

an “other” category noted testing bulls,

replacement heifers, show and sale animals, and

randomly selected animals.

b. For operations that tested any beef 

calves for persistent infection with 

BVDV during the previous 3 years, 

percentage of operations by sample 

type collected 

Sample Type 

Percent 

Operations

Std. 

Error 

Ear notch 73.5 (15.9) 

Serum 35.1 (15.5) 
USDA APHIS VS / 23

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations

c. For operations that tested any beef calves for persistent infection with BVDV 

during the previous 3 years and had the specified class of cattle, percentage of 

operations by testing practice used in 2007 

Testing Practice 

Percent 

Operations

Standard 

Error 

All calves born to heifers/cows 

bred on the operation 33.8 (14.1) 

All calves born to heifers/cows 

purchased when pregnant 22.6 (10.6) 

All calves acquired as part 

of a cow-calf pair 9.0 (4.7) 

All heifers/cows 

purchased when open 20.3 (10.1) 

Clinical suspects 28.5 (9.6) 

Other 40.5 (11.1) 
24 / Beef 2007–08

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations
USDA APHIS VS / 25

Section II: Population Estimates—A. BVDV on U.S. Cow-calf Operations

A similar percentage of females exposed to a

bull on operations that tested for BVDV in the

past 3 years and on operations that did not test

for BVDV produced a live calf. In another

study, herds had lower pregnancy rates at fall

pregnancy exam if a BVDV persistently infected

calf was born in the herd the subsequent calving

season compared with herds without a

persistently infected calf born in the herd

(Wittum et al., 2001).

d. Of heifers and cows exposed to a bull and/or semen, percentage that produced 

a live calf, by whether the operation tested any beef calves for persistent 

infection with BVDV in the past 3 years 

Percent Exposed Heifers and Cows 

BVDV Testing 

Yes No All Operations 

Percent Std. Error Percent Std. Error Percent Std. Error 

95.0 (0.6) 92.7 (0.7) 92.9 (0.6) 

Photo courtesy of Geni Wren “Bovine Veterinarian” magazine
26 / Beef 2007–08

Section II: Population Estimates—B. Producer Expectations of Testing

B. Producer Expectations of the Economic Returns and

Health Effects Provided by Testing for BVDV Persistent

Infection

1. Effect on calf

value of testing for

persistent infection

with BVDV

The value of testing and removing persistently

infected cattle from the herd is of central

importance in the consideration of any control

program. Testing and removal must ultimately

have a positive economic return for any private

and voluntary control or eradication program to

be feasible. The positive economic return of

testing and removal may be the result of either

increased sale value of the test-negative cattle or

improved health or growth performance of the

cattle remaining in the herd.

In general, producer familiarity with BVDV did

not impact producer beliefs about the value of

calves remaining in the herd after the removal of

any persistently infected calves (P=0.24). Of

operations that were fairly knowledgeable about

BVDV, 41.8 percent believed that removing

calves that test positive for persistent infection

with BVDV affects the value of the calves

remaining in the herd.

a. Percentage of operations by whether, according to producers, removing calves 

that test positive for persistent infection with BVDV affects the value of the 

remaining calves in the herd, and by level of familiarity with BVDV 

Percent Operations 

Level of Familiarity 

Fairly 

Knowledgeable Knew Some 

Basics 

Recognized 

the Name, 

not Much 

Else 

Had not 

Heard of 

Before 

All 

Operations 

Affects 

value of 

remaining 

calves? Pct 

Std. 

Error Pct 

Std. 

Error Pct 

Std. 

Error Pct 

Std. 

Error Pct 

Std. 

Error 

Yes 41.8 (5.2) 30.3 (4.9) 31.3 (7.3) 30.3 (12.8) 34.3 (3.2) 

Do not know 39.2 (5.1) 48.8 (5.7) 46.6 (7.4) 63.7 (12.9) 46.6 (3.4) 

No 19.0 (4.2) 20.9 (4.6) 22.1 (6.6) 6.0 (4.5) 19.1 (2.7) 

Total 100.0 100.0 100.0 100.0 100.0 

Overall chi-square test P=0.24. 
USDA APHIS VS / 27

Section II: Population Estimates—B. Producer Expectations of Testing

The percentage of producers that believed

removing calves persistently infected with

BVDV increased the value of the remaining

calves (15.3 percent) was higher than the

percentage of operations that had tested any

calves for BVDV during the previous 3 years

(4.2 percent) [see table a., p 21]. Many of these

producers may have believed that testing is

valuable but did not believe BVDV was present

in their herds. This result could also represent a

lag in testing implementation, as knowledge of

BVDV and its effects has increased. Producer

belief regarding the value of testing should

precede the implementation of a testing

program.

Producers may have also believed that the value

of animals that tested negative of persistent

infection with BVDV increased, but by an

amount insufficient to offset the costs of testing.

Considerable uncertainty exists among

producers regarding the effect that testing and

removing calves persistently infected with

BVDV has on the value of remaining calves in

the herd. Almost one-half of operations

(46.6 percent) did not know if removing calves

that tested positive for persistent infection with

BVDV would change the value of the remaining

calves. A similar percentage of operations

believed that removing persistently infected

calves increased the value of remaining calves

(15.3 percent), had no effect (19.1 percent), or

affected the value but by an unknown amount

(16.4 percent). A low percentage of operations

(2.6 percent) believed that removing persistently

infected calves decreased the value of remaining

calves, but it is unclear why they believed this.

The percentages of operations in each belief

category did not differ substantially across herd

sizes.
28 / Beef 2007–08

Section II: Population Estimates—B. Producer Expectations of Testing

Between 40 and 50 percent of producers in all

three regions did not know the effect that

removing calves persistently infected with

BVDV had on the value of the remaining calves.

However, some regional differences were

apparent regarding beliefs about how removing

calves persistently infected with BVDV affects

the value of the remaining calves. A higher

percentage of operations in the West region

believed that removing BVDV persistently

infected calves from the herd increased the

value of the remaining calves compared with

operations in the Southeast region. A lower

percentage of operations in the West region

believed that removing BVDV persistently

infected calves from the herd had no effect on

the value of the remaining calves compared with

operations in the Central region.

If any voluntary control or eradication plan is to

be successful, research and production data must

be supportive of the economic value of the

program. Further research may be needed

regarding the economic impacts of BVDV, the

market rewards associated with having animals

that test negative for persistent infection with

BVDV, and the benefits of educating producers

about economic effects of BVDV.

b. Percentage of operations by how, according to producers, removing calves that 

test positive for persistent infection with BVDV affects the value of the 

remaining calves in the herd, and by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 

200 or 

More 

All 

Operations 

Effect on 

Value of 

Remaining 

Calves Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Increases value 14.2 (3.1) 16.0 (4.1) 15.7 (3.4) 27.6 (4.7) 15.3 (2.3) 

Decreases 

value 3.3 (2.0) 1.8 (1.8) 0.0 (- -) 0.8 (0.7) 2.6 (1.4) 

Has no effect 18.7 (3.6) 20.1 (4.9) 23.6 (6.4) 13.8 (3.3) 19.1 (2.7) 

Do not know 48.8 (4.5) 46.6 (6.3) 37.3 (5.4) 32.6 (5.0) 46.6 (3.3) 

Affects value, 

but amount 

unknown 

15.0 (3.3) 15.5 (4.2) 23.4 (4.5) 25.2 (4.6) 16.4 (2.4) 

Total 100.0 100.0 100.0 100.0 100.0 
USDA APHIS VS / 29

Section II: Population Estimates—B. Producer Expectations of Testing

c. Percentage of operations by how, according to producers, removing calves that 

test positive for persistent infection with BVDV affects the value of the 

remaining calves in the herd, and by region 

Percent Operations 

Region 

West Central Southeast 

Effect on Value of 

Remaining Calves Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Increases value 29.3 (5.6) 18.9 (3.8) 12.0 (3.0) 

Decreases value 0.4 (0.4) 0.0 (0.0) 3.9 (2.2) 

Has no effect 8.1 (2.4) 26.0 (4.8) 18.1 (3.6) 

Do not know 47.1 (5.6) 39.8 (5.3) 49.0 (4.6) 

Affects value, but 

amount unknown 15.1 (3.7) 15.3 (3.1) 17.0 (3.4) 

Total 100.0 100.0 100.0 

d. For operations that believed removing calves that test positive for persistent 

infection with BVDV affects the value of the remaining calves in the herd, 

operation average (dollars per head) change in value 

Change in Value 

Operation Average 

(Dollars per Head)

Standard 

Error 

Increase 32 (4.2) 

Decrease 39 (7.6) 
30 / Beef 2007–08

Section II: Population Estimates—B. Producer Expectations of Testing

2. Effect on cattle

health of testing

for persistent

infection with

BVDV

Improved health or performance in calves

following the detection and removal of calves

persistently infected with BVDV may also

justify a voluntary control or eradication

program. Overall, the majority of operations

(57.2 percent) believed that removing calves

persistently infected with BVDV would affect

the health of the remaining cattle. A higher

percentage of operations with 200 or more beef

cows believed that removing calves persistently

infected with BVDV would affect the health of

remaining cattle compared with operations with

1 to 49 beef cows. A lower percentage of

operations with 200 or more beef cows did not

know if removing calves persistently infected

with BVDV would affect the health of the

remaining cattle compared with operations with

1 to 49 beef cows. This difference may be

related to general knowledge about BVDV. A

higher percentage of operations with 200 or

more beef cows also reported that they

considered themselves to be fairly

knowledgeable about BVDV compared with

operations with fewer than 100 cows (Section II

A.1.a).

a. Percentage of operations by whether, according to producers, removing calves 

that test positive for persistent infection with BVDV affects the health of the 

remaining cattle in the herd, and by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More 

All 

Operations 

Affects 

Health Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Yes 53.4 (4.6) 67.9 (6.0) 57.7 (5.9) 74.1 (4.3) 57.2 (3.4) 

No 7.6 (2.6) 9.6 (3.8) 7.1 (2.5) 4.2 (1.6) 7.7 (1.9) 

Do not know 39.0 (4.4) 22.5 (5.2) 35.2 (6.0) 21.7 (4.1) 35.1 (3.2) 

Total 100.0 100.0 100.0 100.0 100.0 
USDA APHIS VS / 31

Section II: Population Estimates—B. Producer Expectations of Testing

The percentage of operations that believed

removing calves that test positive for persistent

infection with BVDV affects the health of the

remaining cattle was higher in the West region

than the Southeast region.

b. Percentage of operations by whether, according to producers, removing calves 

that test positive for persistent infection with BVDV affects the health of the 

remaining cattle in the herd, and by region 

Percent Operations 

Region 

West Central Southeast 

Affects Health Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Yes 76.5 (6.5) 59.6 (5.1) 53.8 (4.6) 

No 3.4 (1.5) 10.2 (3.4) 7.3 (2.5) 

Do not know 20.1 (6.4) 30.2 (5.0) 38.9 (4.4) 

Total 100.0 100.0 100.0 
32 / Beef 2007–08

Section II: Population Estimates—B. Producer Expectations of Testing

For the 57.2 percent of operations that believed

removing calves persistently infected with

BVDV affects the health of the remaining cattle

in the herd, most expected multiple health

benefits. Overall, 89.7 percent of these

operations expected improved reproductive

efficiency; 96.9 percent expected reduced

sickness and treatment costs; and 95.7 percent

expected reduced death loss. Percentages were

similar across herd sizes. All producers who

indicated “other” health effects expected

performance effects.

These expected health and performance benefits

would further justify the efforts and expense of

controlling or eradicating BVDV. Despite this

high expectation of health benefits resulting

from testing and removal, few operations had

tested any calves for BVDV during the previous

3 years. Similar to producer expectations of

increased value in tested calves, the difference

in expectation of health benefits and the

implementation of actual testing may represent a

lag, as knowledge of BVDV and its effects have

increased. Producer belief regarding the value of

testing in improving health would be expected

to precede implementation of a testing program.

c. For operations that believed removing calves that tested positive for persistent 

infection with BVDV affected the health of the remaining cattle in the herd, 

percentage of operations by expected health effect and by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 

200 or 

More 

All 

Operations 

Expected 

Health Effect Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Improved 

reproductive 

efficiency 

(fewer 

abortions, 

stillbirths) 

88.1 (3.6) 95.5 (2.3) 87.1 (3.9) 91.9 (3.0) 89.7 (2.4) 

Reduced 

sickness 

and/or 

treatment 

costs 

95.9 (2.5) 98.5 (1.5) 99.3 (0.7) 98.9 (0.9) 96.9 (1.6) 

Reduced 

death loss 95.3 (2.5) 98.6 (1.4) 94.5 (2.2) 93.2 (2.6) 95.7 (1.6) 

Other 1.3 (0.9) 4.1 (1.9) 9.2 (4.5) 13.1 (4.7) 3.4 (0.9) 
USDA APHIS VS / 33

Section II: Population Estimates—B. Producer Expectations of Testing

For the 57.2 percent of operations that believed

removing calves persistently infected with

BVDV affects the health of the remaining cattle

in the herd, the percentages of operations by

expected health benefits were similar across

regions.

Photo courtesy of Geni Wren “Bovine Veterinarian” magazine

d. For operations that believed removing calves that tested positive for persistent 

infection with BVDV affected the health of the remaining cattle in the herd, 

percentage of operations by expected health effect and by region 

Percent Operations 

Region 

West Central Southeast 

Expected Health Effect Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Improved reproductive 

efficiency (fewer 

abortions, stillbirths) 

96.2 (1.8) 84.2 (5.0) 90.9 (3.2) 

Reduced sickness and/or 

treatment costs 99.3 (0.6) 97.3 (1.9) 96.3 (2.5) 

Reduced death loss 98.9 (0.7) 98.0 (1.2) 94.1 (2.6) 

Other 2.1 (1.1) 5.0 (2.3) 3.0 (1.1) 
34 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

C. BVDV Vaccination

1. General

practices

A complete BVDV control program includes

controlling exposure and enhancing animals’

resistance to infection. Methods for enhancing

resistance can be nonspecific, such as ensuring

good nutrition and minimizing stress, or

specific, such as using vaccines directed against

pathogens. The purpose of BVDV vaccination

in cows is to increase their level of immunity

and decrease the likelihood of BVDV

transmission to the fetus, should exposure occur.

While no vaccine is 100-percent effective,

vaccination can increase immunity, decrease the

probability of transmission to the fetus, and

decrease the number of BVDV persistently

infected calves produced. Vaccination might

mitigate the impact of BVDV introduction and

is the only defense against potential exposures

not fully controlled by management, such as

fenceline contacts.

The NAHMS program has collected data on

vaccination practices on beef cow-calf

operations in three studies. The three studies had

somewhat different methodologies. Further

information on the methods for each of the

studies is available (USDA, 1994, 1997,

2008b). Briefly, the NAHMS 1992/93 CHAPA

study collected data in 18 States from a sample

of operations with 5 or more beef cows. For the

Beef ’97 study, data were collected in 23 States

from a sample of operations with 1 or more beef

cows, and for the Beef 2007–08 study, data were

collected in 24 States from a sample of

operations with 1 or more beef cows. The

percentage of operations that used BVDV

vaccines has increased since 1992 for most

classes of animals. The percentage of operations

that vaccinated cows or bulls for BVDV was

higher during the Beef 2007–08 study compared

with each of the previous studies.
USDA APHIS VS / 35

Section II: Population Estimates—C. BVDV Vaccination

a. Percentage of operations that vaccinated for BVDV, by cattle class vaccinated 

Percent Operations

1992/93 CHAPA1,2 Beef ‘973 Beef 2007–084

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Calves 1 to 

21 days 0.9 (0.8) 1.5 (0.6) 3.0 (0.9) 

Calves 22 days 

through weaning 14.5 (1.8) 25.3 (2.3) 33.1 (2.8) 

Weaned 

replacement 

heifers through 

breeding 

13.0 (2.1) 16.3 (1.9) 25.1 (2.4) 

Bred replacement 

heifers through 

calving 

6.4 (1.6) 9.2 (1.5) 13.7 (1.7) 

Cows 12.9 (2.3) 17.4 (2.0) 28.1 (2.6) 

Bulls 7.8 (1.8) 13.2 (1.9) 24.3 (2.5) 

1

Cow/calf Health and Productivity Audit. 

2

Population: spring calving operations with 5 or more cows in 18 States. 

3

Population: all cow-calf operations in 23 States. 

4

Population: all cow-calf operations in 24 States.
36 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

BVDV is one of several etiologic agents

associated with respiratory disease in beef

calves. In the Beef ’97 and Beef 2007–08

studies, data were collected on the percentage of

operations that vaccinated calves for respiratory

diseases 0, 1, 2, or 3 or more times. Similar

regional trends were evident in the frequency of

vaccination of calves prior to sale in both of the

studies.

b. Percentage of operations by number of times calves were typically vaccinated 

against respiratory disease from birth to sale, and by region 

Percent Operations

Number of Times Vaccinated 

0 1 2 3 or More

Region Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

 Beef ‘971

West 49.5 (6.5) 28.0 (5.1) 20.0 (3.7) 2.5 (0.8) 

North Central 40.1 (4.1) 37.2 (4.5) 20.2 (3.5) 2.5 (0.8) 

South Central 73.0 (6.0) 22.1 (5.9) 4.4 (2.2) 0.5 (0.2) 

Central 54.6 (5.7) 27.7 (4.7) 17.7 (4.8) 0.0 (0.0) 

Southeast 78.2 (4.8) 11.8 (3.1) 9.8 (4.0) 0.2 (0.1) 

All 64.3 (2.6) 22.8 (2.3) 12.2 (1.8) 0.7 (0.1) 

Beef 2007–082

West 42.5 (7.8) 26.1 (7.0) 28.9 (6.0) 2.5 (0.9) 

Central 33.1 (5.1) 30.1 (4.6) 30.7 (4.3) 6.1 (1.8) 

Southeast 73.3 (3.6) 10.3 (2.4) 14.8 (2.8) 1.6 (0.7) 

All 60.6 (3.0) 16.6 (2.2) 20.0 (2.2) 2.8 (0.7) 

1

Population: all cow-calf operations in 23 States. 

2

Population: all cow-calf operations in 24 States.
USDA APHIS VS / 37

Section II: Population Estimates—C. BVDV Vaccination

About 4 of 10 operations (41.0 percent)

vaccinated at least some cattle against BVDV in

2007. This percentage is roughly equivalent to

the 39.4 percent of operations that did not

typically vaccinate calves for respiratory disease

(see previous table). A higher percentage of

operations with 50 or more beef cows

vaccinated at least some cattle against BVDV

compared with operations with fewer than

50 cows.

c. Percentage of operations that vaccinated any cattle or calves against BVDV in 

2007, by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More 

All 

Operations 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

28.6 (3.8) 62.2 (6.3) 73.8 (5.3) 80.5 (4.5) 41.0 (3.1) 
38 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

A higher percentage of operations in the West

and Central regions (56.4 and 67.9 percent,

respectively) vaccinated at least some cattle

against BVDV in 2007 compared with

operations in the Southeast region

(28.9 percent).

d. Percentage of operations that vaccinated any cattle or calves against BVDV in 

2007, by region 

Percent Operations 

Region 

West Central Southeast 

Percent Std. Error Percent Std. Error Percent Std. Error 

56.4 (7.6) 67.9 (5.2) 28.9 (3.8) 
USDA APHIS VS / 39

Section II: Population Estimates—C. BVDV Vaccination

2. Vaccination by

cattle group

Vaccinating the breeding herd reduces the risk

of producing calves persistently infected with

BVDV. Cows with high levels of immunity to

BVDV are less likely to transmit the BVDV

infection to their fetuses. Vaccinating calves

may have some effect in priming immunity for

replacement heifers and in decreasing transient

infections within calves.

Of the 41.0 percent of operations that

vaccinated at least some cattle against BVDV in

2007, the highest percentage (80.7 percent)

vaccinated calves between 22 days of age and

weaning, followed by weaned replacement

heifers before breeding (61.2 percent) and bulls

(59.4 percent). Less than one-half of operations

that vaccinated at least some cattle vaccinated

cows prebreeding or precalving (44.5 and

41.5 percent, respectively). A higher percentage

of operations with 200 or more beef cows

vaccinated weaned replacement heifers before

breeding (76.5 percent) compared with

operations with 1 to 49 beef cows

(50.5 percent). For all other specific cattle

groups, the percentages that were vaccinated did

not differ substantially across herd sizes.

a. For operations that vaccinated any cattle or calves against BVDV in 2007, 

percentage of operations by cattle class vaccinated and by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More 

All 

Operations 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Calves 1 to 

21 days 8.6 (3.9) 2.4 (2.1) 9.7 (3.6) 8.2 (2.7) 7.2 (2.1) 

Calves 22 

days through 

weaning 

84.5 (5.5) 78.1 (6.0) 71.3 (7.7) 84.6 (4.4) 80.7 (3.4) 

Weaned 

replacement 

heifers 

before 

breeding 

50.5 (7.6) 69.9 (6.7) 70.2 (5.5) 76.5 (4.5) 61.2 (4.4) 

Bred 

replacement 

heifers 

precalving 

31.8 (6.6) 37.1 (6.7) 34.4 (6.0) 37.3 (5.2) 34.1 (3.8) 

Cows 

prebreeding 46.8 (7.5) 42.6 (7.0) 39.1 (6.4) 47.2 (5.5) 44.5 (4.2) 

Cows 

precalving 43.2 (7.4) 39.7 (6.8) 37.0 (6.2) 44.7 (5.3) 41.5 (4.1) 

Bulls 66.7 (7.1) 58.0 (7.2) 50.9 (6.8) 42.5 (5.5) 59.4 (4.1) 
40 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

In the West region, the highest percentage of

operations that vaccinated any cattle

(90.8 percent) vaccinated calves between

22 days of age and weaning, followed by

weaned replacement heifers before breeding

(61.1 percent), and cows precalving

(53.3 percent). The percentages of operations

that vaccinated calves between 22 days of age

and weaning, weaned replacement heifers before

breeding, and bulls were similar in the Southeast

and Central regions. In all regions, very few

operations (11 percent or less) vaccinated calves

1 to 21 days of age.

b. For operations that vaccinated any cattle or calves against BVDV in 2007, 

percentage of operations by cattle class vaccinated and by region 

Percent Operations 

Region 

West Central Southeast 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Calves 1 to 21 days 4.7 (2.5) 10.7 (4.0) 4.8 (2.5) 

Calves 22 days 

through weaning 90.8 (3.8) 82.4 (4.5) 76.5 (6.0) 

Weaned replacement 

heifers before breeding 61.1 (9.5) 61.8 (5.5) 60.8 (7.5) 

Bred replacement 

heifers precalving 47.2 (8.8) 30.4 (5.1) 33.9 (6.3) 

Cows prebreeding 38.3 (8.3) 43.3 (5.5) 47.2 (7.3) 

Cows precalving 53.3 (8.7) 35.0 (5.3) 44.0 (7.1) 

Bulls 48.7 (8.8) 52.4 (5.6) 68.4 (6.8) 
USDA APHIS VS / 41

Section II: Population Estimates—C. BVDV Vaccination

3. Timing of

vaccination for

replacement

Of the 41.0 percent of operations that

vaccinated at least some cattle against BVDV in

2007, a higher percentage of operations with

200 or more beef cows (83.7 percent)

vaccinated replacement heifers at precalving

and/or prebreeding compared with operations

with 1 to 49 beef cows (55.9 percent). Two of

three operations (66.6 percent) gave at least one

BVDV vaccination to replacement heifers,

either prebreeding or precalving.

a. For operations that vaccinated any cattle or calves against BVDV in 2007*, 

percentage of operations by timing of vaccination for replacement heifers and 

by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More 

All 

Operations 

Vaccination 

Timing Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Prebreeding 

only 24.1 (6.3) 37.8 (7.0) 39.6 (7.2) 46.4 (5.6) 32.5 (3.8) 

Precalving 

only 3.5 (2.5) 5.0 (2.8) 3.8 (1.9) 7.2 (2.7) 4.3 (1.4) 

Prebreeding 

and 

precalving 

28.3 (6.4) 32.1 (6.5) 30.6 (5.8) 30.1 (4.7) 29.8 (3.6) 

Precalving 

and/or 

prebreeding 

55.9 (7.7) 74.9 (6.2) 74.0 (5.2) 83.7 (3.9) 66.6 (4.3) 

*Operations with incomplete vaccination data were excluded. 
42 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination
USDA APHIS VS / 43

Section II: Population Estimates—C. BVDV Vaccination

The percentages of operations by timing of

replacement heifer vaccination were similar

across regions.

b. For operations that vaccinated any cattle or calves against BVDV in 2007*, 

percentage of operations by timing of vaccination for replacement heifers and by 

region 

Percent Operations 

Region 

West Central Southeast 

Vaccination Timing Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Prebreeding only 22.7 (5.7) 34.2 (5.2) 33.6 (6.6) 

Precalving only 8.8 (5.4) 2.9 (1.4) 4.4 (2.4) 

Prebreeding and 

Precalving 38.4 (8.4) 27.5 (5.0) 29.5 (6.1) 

Precalving and/ or 

Prebreeding 69.9 (9.5) 64.7 (5.5) 67.5 (7.5) 

*Operations with incomplete vaccination data were excluded.
44 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

4. Vaccination

frequency

Of the 33.1 percent of operations that

vaccinated calves against BVDV at 22 days of

age through weaning in 2007, more than 6 of 10

vaccinated calves only once. The number of

times operations vaccinated calves from 22 days

of age through weaning was similar across herd

sizes.

5. BVDV booster

injections

About one of five operations gave cows and

bulls an annual BVDV booster vaccination in

2007 (23.8 and 20.3 percent of operations,

respectively). A higher percentage of operations

with 50 or more beef cows gave booster

vaccinations to cows compared with operations

with 1 to 49 beef cows. Booster vaccinations are

particularly important when killed virus

vaccines are used.

For operations that vaccinated any calves against BVDV at 22 days of age through 

weaning in 2007, percentage of operations by number of times calves were 

vaccinated and by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More 

All 

Operations 

Number 

of Times 

Vaccinated Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

1 66.7 (8.5) 63.6 (8.9) 63.9 (6.4) 45.7 (6.0) 63.1 (4.7) 

2 33.3 (8.5) 30.6 (7.7) 30.2 (5.8) 49.8 (6.1) 34.1 (4.7) 

3 or more 0.0 (0.0) 5.8 (5.6) 5.9 (3.0) 4.5 (2.0) 2.8 (1.4) 

Total 100.0 100.0 100.0 100.0 100.0 

 a. Percentage of operations that gave an annual BVDV booster injection to cows 

or bulls in 2007, by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More 

All 

Operations 

Cattle 

Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Cows 15.9 (3.0) 37.7 (5.8) 41.9 (5.6) 54.0 (5.1) 23.8 (2.4) 

Bulls 15.1 (3.0) 31.0 (5.4) 34.3 (5.4) 31.4 (4.8) 20.3 (2.3) 
USDA APHIS VS / 45

Section II: Population Estimates—C. BVDV Vaccination

The percentages of operations that gave an

annual BVDV booster vaccination to cows or

bulls did not differ substantially across regions.

b. Percentage of operations that gave an annual BVDV booster injection to cows or 

bulls in 2007, by region 

Percent Operations 

Region 

West Central Southeast 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Cows 35.5 (6.4) 33.4 (4.5) 18.7 (3.1) 

Bulls 22.6 (5.4) 26.9 (4.2) 17.6 (3.0) 
46 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

6. BVDV vaccine

type and genotype

Of the 41.0 percent of operations that

vaccinated at least some cattle against BVDV in

2007, more than 8 of 10 used a vaccine that

included both type 1 and type 2 BVDV on all

cattle groups vaccinated. A higher percentage of

operations used a killed virus vaccine than a

modified live virus vaccine on bred replacement

heifers precalving, on cows precalving, and on

bulls. Some commercially available modified

live virus vaccines have label claims for use in

pregnant animals when label directions

regarding previous vaccination are closely

followed. In situations in which the label

directions cannot be followed, killed vaccines

are safer than modified live vaccines for

pregnant animals.

a. For operations that vaccinated any cattle or calves within each cattle class against 

BVDV in 2007, percentage of operations by BVDV vaccine type and virus genotype 

Percent Operations 

 BVDV Vaccine Type Virus Genotype 

Killed Modified 

Live Type 1 Only Types 1 & 2 

Cattle Class Pct. 

Std. 

Err. Pct. 

Std. 

Err. Total Pct. 

Std. 

Err. Pct. 

Std. 

Err. Total 

Calves 1 to 

21 days 59.2 (14.2) 40.8 (14.2) 100.0 15.5 (8.7) 84.5 (8.7) 100.0 

Calves 22 

days through 

weaning 

54.5 (4.6) 45.5 (4.6) 100.0 16.4 (3.4) 83.6 (3.4) 100.0 

Weaned 

replacement 

heifers before 

breeding 

51.5 (5.1) 48.5 (5.1) 100.0 10.7 (3.0) 89.3 (3.0) 100.0 

Bred 

replacement 

heifers 

precalving 

70.5 (5.1) 29.5 (5.1) 100.0 13.6 (4.0) 86.4 (4.0) 100.0 

Cows 

prebreeding 58.2 (6.0) 41.8 (6.0) 100.0 10.3 (3.6) 89.7 (3.6) 100.0 

Cows 

precalving 71.3 (6.3) 28.7 (6.3) 100.0 13.0 (4.0) 87.0 (4.0) 100.0 

Bulls 67.8 (5.4) 32.2 (5.4) 100.0 10.6 (3.0) 89.4 (3.0) 100.0 
USDA APHIS VS / 47

Section II: Population Estimates—C. BVDV Vaccination

For operations that gave a BVDV booster

vaccine to cows or bulls in 2007 (23.8 and

20.3 percent, respectively), a higher percentage

of operations gave killed virus vaccine boosters

to cows (64.4 percent) and bulls (69.0 percent)

than gave modified live virus boosters. A higher

percentage of operations gave booster vaccines

containing both type 1 and type 2 BVDV to

cows and bulls (88.3 and 86.4 percent,

respectively) than gave type 1 only BVDV

vaccine.

b. For operations that gave an annual BVDV booster injection to any cows or bulls in 

2007, percentage of operations by BVDV vaccine type and virus genotype 

Percent Operations 

BVDV Vaccine Type Virus Genotype 

Killed Modified Live Type 1 Only Types 1 & 2 

Cattle 

Class Pct. 

Std. 

Error Pct. 

Std. 

Error Total Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

Cows 64.4 (4.8) 35.6 (4.8) 100.0 11.7 (3.3) 88.3 (3.3) 100.0 

Bulls 69.0 (5.3) 31.0 (5.3) 100.0 13.6 (3.9) 86.4 (3.9) 100.0 
48 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

Of the 25.1 percent of operations that

vaccinated weaned replacement heifers before

breeding (see table p 50), almost one-half (47.5

percent) used a modified live virus vaccine

containing both type 1 and type 2 BVDV. Of

operations that vaccinated pregnant replacement

heifers or cows against BVDV in 2007,

approximately 6 of 10 (59.9 and

59.7 percent, respectively) used killed virus

vaccines containing both type 1 and type 2

BVDV.

c. For operations that vaccinated the specified class of cattle against BVDV in 

2007, percentage of operations by vaccine type 

Percent Operations1

Killed Modified Live 

Type 1 Types 1 & 2 Type 1 Types 1 & 2 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

Calves 1 to 

21 days2 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 

Calves 22 

days through 

weaning 

12.7 3.0 41.9 4.8 3.7 1.9 41.7 4.5 100.0 

Weaned 

replacement 

heifers before 

breeding 

9.7 3.0 41.8 5.2 1.0 0.5 47.5 5.1 100.0 

Bred 

replacement 

heifers 

precalving 

10.6 3.6 59.9 5.9 3.0 1.9 26.5 4.8 100.0 

Cows 

prebreeding 8.7 3.3 49.5 6.3 1.6 1.3 40.2 6.0 100.0 

Cows 

precalving 11.6 3.8 59.7 6.4 1.4 1.4 27.3 6.2 100.0 

Bulls 10.3 3.0 57.4 5.6 0.3 0.3 32.0 5.4 100.0 

1

Numbers in this table may differ slightly from the two preceding tables because of rounding. 

2

Too few to report. 
USDA APHIS VS / 49

Section II: Population Estimates—C. BVDV Vaccination

Among operations that used some BVDV

vaccines in calves through weaning, most used

either killed virus vaccines or modified live

virus vaccines rather than a combination of the

two.

d. Percentage of operations by type of BVDV vaccine used for calves through 

weaning 

Percent Operations

Beef ‘971 Beef 2007–082,3

BVDV Vaccine Type Pct. Std. Error Pct. Std. Error 

Killed only 12.0 (1.4) 15.8 (2.1) 

Modified live only 7.2 (1.0) 13.0 (1.6) 

Killed and modified live 3.7 (1.6) 0.0 (--) 

Unknown 2.5 (0.7) 4.4 (1.5) 

Not vaccinated for BVDV 74.6 (2.3) 66.8 (2.8) 

Total 100.0 100.0 

1

Population: all cow-calf operations in 23 States. 

2

Population: all cow-calf operations in 24 States. 

3

Question variation: In 1997, producers were asked what type of vaccine was used for calves through weaning 

(killed, modified live, both killed and modified live, do not know, and do not vaccinate). In 2007–08, producers 

were asked to identify the specific vaccine product used most commonly for calves 1 to 21 days old and calves 

22 days through weaning. Producers were not given the option to select “do not know” or to indicate “both killed 

and modified live.” If a producer indicated that he/she did vaccinate but left the vaccine product blank, “do not 

know” was inferred. If a producer gave killed virus vaccine to one age group of calves and modified live virus 

vaccine to the other age group, the operation would have been placed in the “killed and modified live” category. 

Because of the question variation, any operation that most commonly used killed virus vaccines for calves in 

2007–08 would appear in the” killed only” category, regardless of whether or not it sometimes used a modified 

live virus vaccine. Likewise, any operation that most commonly used modified live virus vaccines for calves in 

2007–08 would appear in the” modified live only” category, regardless of whether or not it sometimes used a 

killed virus vaccine. 
50 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

7. Vaccination and

familiarity with

BVDV

Operations that reported a higher degree of

familiarity with BVDV were more likely to

vaccinate any cattle for BVDV. Nearly two of

three operations (61.3 percent) that reported

being fairly knowledgeable about BVDV

vaccinated some cattle for BVDV, whereas only

15.3 percent of operations that had never heard

of BVDV vaccinated cattle for BVDV. While it

seems paradoxical that producers would

vaccinate for a disease that they had never heard

of, it is possible that they did not recognize the

specific pathogens covered by some of the

vaccine products they were using. It is also

possible that they only knew that the vaccine

they were using was to prevent certain disease

syndromes, such as respiratory disease in calves

or reproductive disease in replacement heifers or

cows.

Percentage of operations that vaccinated any cattle or calves for BVDV in 2007, by cattle 

class vaccinated and by level of familiarity with BVDV 

Percent Operations 

Level of Familiarity 

Fairly 

Knowledgeable Knew Some 

Basics 

Recognized 

the Name, not 

Much Else 

Had not Heard 

of Before 

All 

Operations 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Calves 1 to 

21 days 4.2 (1.8) 4.0 (1.7) 0.6 (0.6) 0.0 (--) 3.0 (0.9) 

Calves 

22 days 

through 

weaning 

50.4 (5.2) 27.1 (4.1) 24.8 (6.6) 15.3 (9.3) 33.1 (2.8) 

Weaned 

replacement 

heifers 

before 

breeding 

42.8 (4.9) 23.4 (3.8) 12.4 (4.5) 0.0 (0.0) 25.1 (2.4) 

Bred 

replacement 

heifers 

precalving 

27.2 (4.0) 11.9 (2.8) 2.5 (1.8) 0.0 (0.0) 13.7 (1.7) 

Cows 49.6 (5.2) 23.1 (3.8) 13.3 (5.0) 7.3 (7.0) 28.1 (2.6) 

Bulls 45.8 (5.1) 16.9 (3.4) 12.0 (5.0) 7.2 (7.0) 24.3 (2.5) 

Any 61.3 (5.5) 34.5 (4.6) 32.6 (7.1) 15.3 (9.3) 41.0 (3.1) 
USDA APHIS VS / 51

Section II: Population Estimates—C. BVDV Vaccination

8. Vaccination and

reproductive

outcome

On operations that vaccinated any cattle or

calves against BVDV in 2007, the percentage of

heifers and cows exposed to a bull and/or semen

that failed to produce a live calf was similar on

operations that vaccinated heifers against

BVDV and on operations that did not.

For operations that vaccinated any cattle or calves against BVDV in 2007, 

percentage of heifers and cows exposed to a bull and/or semen that failed to 

produce a live calf*, by whether or not the operation vaccinated replacement 

heifers against BVDV in 2007

Percent Exposed Heifers and Cows that Failed to Produce a Live Calf 

Heifers Vaccinated (Prebreeding and/or Precalving) 

Yes No All Operations 

Percent Std. Error Percent Std. Error Percent Std. Error 

8.1 (0.9) 5.2 (0.7) 7.5 (0.8) 

*Includes calf born dead, known abortions, and failure to conceive.
52 / Beef 2007–08

Section II: Population Estimates—C. BVDV Vaccination

b. [v265, v293] Percentage of operations that tested any beef calves for persistent 

infection with BVDV during the previous 3 years by level of familiarity with 

BVDV 

Level of Familiarity Percent Operations Std. Error 

Fairly knowledgeable or 

knew some basics 4.7 (1.1) 

Recognized the name, not much 

else or had not heard of before 3.0 (2.4) 

9. Use of

vaccination and

testing

Of operations that vaccinated any cattle or

calves against BVDV in 2007, 9.0 percent tested

calves for persistent infection with BVDV

during the previous 3 years, while only

0.7 percent of operations that did not vaccinate

tested calves for persistent infection. These

results may indicate a lack of familiarity with

BVDV, a lack of concern about BVDV, or a

lower level of concern for animal health in

general. Table b. suggests that the difference is

not due to a lack of familiarity with the disease,

as the percentages of operations that tested were

not substantially different for operations that

were fairly knowledgeable with or knew some

basics about BVDV (4.7 percent had tested

during the previous 3 years) compared with

operations with less familiarity (3.0 percent

tested).

a. [v265, v293] Percentage of operations that tested any beef calves for persistent 

infection with BVDV during the previous 3 years by whether or not the 

operation vaccinated any cattle or calves against BVDV in 2007 

BVDV Vaccinations Given Percent Operations Std. Error 

Yes 9.0 (2.3) 

No 0.7 (0.4) 

All Operations 4.2 (1.0) 
USDA APHIS VS / 53

Section II: Population Estimates—D. Types and Management of Herd Additions

D. Types and Management of Herd Additions

1. Cattle brought

onto the operation

Young calves and developing fetuses are the

most likely types of animals to be persistently

infected with BVDV and as such represent the

greatest risk to operations that import animals.

The percentages of operations that brought

specific classes of calves or pregnant females

onto the operation during the previous

12 months varied by herd size for some cattle

classes. Larger herds can be expected to have

more annual turnover of animals than smaller

herds. In any given year, a large herd is more

likely than a smaller operation to cull and

replace at least one animal of a particular class.

A higher percentage of operations with 100 or

more beef cows brought bred heifers and

pregnant cows onto the operation during the

previous 12 months compared with operations

with fewer than 50 cows. A higher percentage of

operations with 200 or more beef cows imported

at least one of the specific classes of cattle

compared with operations with fewer than

50 cows (26.8 and 11.2 percent, respectively).

a. Percentage of operations that brought the following classes of cattle onto the 

operation during the previous 12 months, by cattle class and by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 

200 or 

More 

All 

Operations 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Preweaned 

beef calves 

with dam 

2.9 (0.6) 3.2 (1.0) 7.7 (1.7) 4.2 (1.0) 3.4 (0.5) 

Bred beef 

heifers 2.4 (0.6) 4.8 (1.3) 8.1 (1.5) 7.9 (1.5) 3.5 (0.5) 

Beef cows 

(pregnant) 7.4 (1.0) 12.6 (2.0) 13.9 (2.1) 17.5 (2.4) 9.2 (0.8) 

Preweaned 

dairy calves 0.2 (0.1) 2.2 (1.2) 0.0 (--) 0.2 (0.2) 0.5 (0.2) 

Any of the 

above 11.2 (1.2) 20.0 (2.4) 24.8 (2.5) 26.8 (2.6) 14.5 (0.9) 
54 / Beef 2007–08

Section II: Population Estimates—D. Types and Management of Herd Additions

A higher percentage of operations in the Central

region brought on bred beef heifers compared

with operations in the West and Southeast

regions. A lower percentage of operations in the

Southeast region brought on cattle of any class

compared with operations in the Central region.

Photo courtesy of Anson Eaglin, USDA

b. Percentage of operations that brought the following classes of cattle onto the 

operation during the previous 12 months, by cattle class and by region 

Percent Operations 

Region 

West Central Southeast 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Preweaned beef 

calves with dam 5.1 (1.7) 5.2 (1.1) 2.4 (0.5) 

Bred beef heifers 2.4 (0.9) 7.4 (1.3) 2.2 (0.5) 

Beef cows (pregnant) 11.6 (2.4) 11.6 (1.6) 8.0 (1.0) 

Preweaned 

dairy calves 2.4 (1.7) 0.4 (0.3) 0.2 (0.2) 

Any of the above 19.0 (3.1) 20.6 (2.0) 11.5 (1.1) 
USDA APHIS VS / 55

Section II: Population Estimates—D. Types and Management of Herd Additions

Introducing weaned stock to the herd also poses

a risk for introducing cattle persistently infected

with BVDV. As expected, larger herds were

more likely to bring on animals in several of the

postweaning animal classes. A higher percentage

of operations with 200 or more beef cows

brought on weaned unbred beef heifers

(10.9 percent) compared with operations with

1 to 49 beef cows (5.6 percent). A higher

percentage of operations with 200 or more beef

cows brought weaned beef bulls onto the

operation compared with operations with fewer

than 100 cows, and a lower percentage of

operations with fewer than 50 cows brought on

beef bulls than all other operation sizes.

c. Percentage of operations that brought the following classes of cattle onto the 

operation during the previous 12 months, by herd size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More 

All 

Operations 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Beef heifers 

weaned, but 

not bred 

5.6 (0.9) 6.8 (1.4) 8.3 (1.6) 10.9 (1.5) 6.2 (0.7) 

Weaned 

beef bulls 14.9 (1.3) 25.7 (2.5) 33.6 (2.7) 43.1 (2.6) 19.5 (1.0) 

Weaned 

steers (all 

types) 

2.9 (0.6) 2.8 (1.0) 4.3 (1.1) 4.9 (1.0) 3.1 (0.5) 

Weaned dairy 

heifers and 

cows 

0.2 (0.1) 1.6 (0.9) 0.4 (0.3) 0.3 (0.2) 0.4 (0.2) 

Weaned 

dairy bulls 0.6 (0.3) 0.0 (--) 0.0 (--) 0.5 (0.2) 0.4 (0.2) 

Any of the 

above 20.5 (1.5) 31.5 (2.7) 40.9 (2.8) 51.6 (2.6) 25.4 (1.2) 
56 / Beef 2007–08

Section II: Population Estimates—D. Types and Management of Herd Additions

A higher percentage of operations in the West

and Central regions (32.8 and 29.8 percent,

respectively) brought weaned beef bulls onto the

operation compared with operations in the

Southeast region (13.6 percent).

d. Percentage of operations that brought the following classes of cattle onto the 

operation during the previous 12 months, by region 

Percent Operations 

Region 

West Central Southeast 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Beef heifers weaned, 

but not bred 8.5 (2.4) 7.6 (1.2) 5.4 (0.8) 

Weaned beef bulls 32.8 (3.7) 29.8 (2.1) 13.6 (1.2) 

Weaned steers 

(all types) 7.6 (2.4) 3.4 (0.8) 2.4 (0.6) 

Weaned dairy 

heifers and cows 1.2 (1.0) 0.7 (0.4) 0.2 (0.2) 

Weaned dairy bulls 0.9 (0.7) 1.0 (0.6) 0.1 (0.1) 

Any of the above 43.0 (4.0) 36.7 (2.3) 18.6 (1.4) 
USDA APHIS VS / 57

Section II: Population Estimates—D. Types and Management of Herd Additions

2. Quarantine of

cattle brought onto

the operation

Isolation alone can prevent introduction of

BVDV by transiently infected cattle if the

isolation period is of sufficient length. Cattle

persistently infected with BVDV may not

express clinical signs during a quarantine

period. Isolation as a biosecurity method for

preventing entry of cattle persistently infected

with BVDV is effective only if combined with a

testing program. For testing to be effective,

imported cattle must be isolated from the

breeding herd until test results are returned.

Isolation is particularly important during the

breeding season and early gestation when cows

are at risk for transmitting BVDV to their

developing fetuses.

Of operations that brought specific classes of

cattle onto the operation during the previous

12 months, the majority quarantined none of the

imported cattle. Over all classes of cattle, two of

three operations (66.3 percent) quarantined none

of the cattle they brought on.

a. For operations that brought any of the following classes of cattle or calves onto 

the operation during the previous 12 months, percentage of operations that 

quarantined or separated all, some, or none of the new cattle 

Percent Operations 

Level of Quarantine 

All Some None 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

Preweaned beef 

calves with dam 33.6 (6.8) 6.3 (3.8) 60.1 (7.1) 100.0 

Beef heifers weaned, 

but not bred 35.0 (5.1) 2.5 (1.6) 62.5 (5.2) 100.0 

Bred beef heifers 46.5 (6.7) 2.7 (2.0) 50.8 (6.7) 100.0 

Beef cows (pregnant) 30.0 (3.9) 2.0 (1.1) 68.0 (4.0) 100.0 

Beef cows 

(not pregnant) 23.4 (6.3) 1.6 (1.0) 75.0 (6.4) 100.0 

Weaned beef bulls 30.0 (2.6) 0.8 (0.4) 69.2 (2.6) 100.0 

Weaned steers 

(all types) 33.5 (7.6) 0.0 (--) 66.5 (7.6) 100.0 

Preweaned dairy calves 25.9 (18.0) 0.0 (--) 74.1 (18.0) 100.0 

Weaned dairy 

heifers and cows 2.6 (2.4) 0.0 (--) 97.4 (2.4) 100.0 

Weaned dairy bulls 2.3 (1.9) 0.0 (--) 97.7 (1.9) 100.0 

All cattle and calves 28.0 (1.9) 5.7 (1.0) 66.3 (2.0) 100.0 
58 / Beef 2007–08

Section II: Population Estimates—D. Types and Management of Herd Additions

Ideally, a quarantine period should be long

enough to exceed the longest expected

incubation period for the disease of concern,

which would allow an animal recently infected

with a disease agent to manifest signs of disease.

In the case of animals transiently infected with

BVDV, an incubation period of up to 14 days

could be expected. In the case of persistently

infected animals—which continuously shed

large quantities of BVDV and might only show

nonspecific or no clinical signs of disease—

quarantine alone would probably not be an

effective means of avoiding herd exposure, no

matter how long the quarantine period.

Of operations that brought cattle onto the

operation and quarantined them, approximately

one of four (24.6 percent) quarantined cattle for

1 to 13 days. For cattle transiently infected with

BVDV, 13 days would not always be sufficient

based on the possible duration of virus shedding

following transient infection. About one-half of

operations that quarantined cattle did so for

21 days or more (52.6 percent), which is

adequate for transiently infected cattle but not

for persistently infected cattle or females

carrying a persistently infected calf.
USDA APHIS VS / 59

Section II: Population Estimates—D. Types and Management of Herd Additions

b. For operations that brought any of the following classes of cattle onto the 

operation and quarantined them, percentage of operations by cattle class 

brought on and by days quarantined or separated 

Percent Operations 

Days Quarantined 

1-13 14-20 21-40 41-49 150 or More 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Preweaned 

beef calves 

with dam 

34.3 (11.2) 39.0 (11.5) 13.7 (6.8) 10.5 (6.8) 2.5 (2.2) 

Beef heifers 

weaned, but 

not bred 

15.5 (5.5) 23.1 (7.5) 36.9 (8.1) 18.7 (6.3) 5.8 (4.7) 

Bred beef 

heifers 20.5 (8.5) 16.1 (7.8) 30.7 (8.4) 29.0 (8.7) 3.7 (1.8) 

Beef cows 

(pregnant) 33.5 (7.1) 17.9 (5.4) 27.9 (6.7) 18.3 (5.7) 2.4 (1.4) 

Beef cows (not 

pregnant) 45.3 (14.1) 28.2 (12.7) 20.6 (10.9) 5.9 (3.5) 0.0 (--) 

Weaned beef 

bulls 26.4 (4.7) 17.8 (3.9) 37.0 (4.6) 18.0 (3.6) 0.8 (0.4) 

Weaned steers 

(all types) 22.3 (11.1) 35.9 (13.9) 17.0 (9.6) 13.6 (6.4) 11.2 (10.0) 

Preweaned* 

dairy calves 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 

Weaned dairy 

heifers and 

cows* 

0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 

Weaned dairy 

bulls* 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 

All classes 24.6 (3.2) 22.8 (3.2) 28.9 (3.1) 21.0 (2.8) 2.7 (1.1) 

*Too few to report. 
60 / Beef 2007–08

Section II: Population Estimates—D. Types and Management of Herd Additions

3. Testing of herd

additions

A higher percentage of operations that had not

tested beef calves for persistent infection with

BVDV during the previous 3 years brought on

pregnant beef cows (11.9 percent) compared

with operations that had tested (2.6 percent). In

addition, a higher percentage of operations that

had not tested beef calves brought on preweaned

beef calves with their dam compared with

operations that had tested beef calves. This

difference may indicate that operations that were

aware of the risks of BVDV and tested for it are

also implementing other practices to control

exposure risk, such as limiting some high risk

imports. Alternatively, operations that tested

during the previous 3 years may have done so in

response to a diagnosis of BVDV in the herd

and may also have adjusted animal addition

practices.

a. Percentage of operations that brought the following classes of cattle onto the 

operation by whether or not the operation tested any beef calves for persistent 

infection with BVDV during the previous 3 years 

Percent Operations 

BVDV Testing 

Yes No All Operations* 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Preweaned beef 

calves with dam 0.1 (0.1) 3.6 (1.0) 3.5 (1.0) 

Bred beef heifers 9.8 (5.1) 5.4 (1.4) 5.6 (1.3) 

Beef cows (pregnant) 2.6 (1.7) 11.9 (2.2) 11.5 (2.1) 

Preweaned dairy calves 0.0 (--) 0.8 (0.5) 0.8 (0.5) 

Any of the above 12.5 (5.5) 18.7 (2.5) 18.4 (2.4) 

*The population estimates for the percentage of all operations bringing various classes of cattle or calves onto 

the operation here differ from those shown on table a., p 53 because these estimates are derived from only 

those operations participating in Phase II of the study. 
USDA APHIS VS / 61

Section II: Population Estimates—D. Types and Management of Herd Additions

Testing beef calves for persistent infection with

BVDV was uncommon on operations that

brought on the following classes of cattle.

b. For operations that brought the following classes of cattle onto the operation, 

percentage of operations that tested any beef calves for persistent infection 

with BVDV during the previous 3 years 

Percent Operations 

BVDV Testing 

Yes No 

Cattle Class Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

Preweaned beef 

calves with dam 0.1 (0.1) 99.9 (0.1) 100.0 

Bred beef heifers 7.3 (3.9) 92.7 (3.9) 100.0 

Beef cows (pregnant) 0.9 (0.6) 99.1 (0.6) 100.0 

Preweaned dairy calves 0.0 (0.0) 100.0 (0.0) 100.0 

Any of the above 2.8 (1.2) 97.2 (1.2) 100.0 
62 / Beef 2007–08

Section III: BVDV Persistent Infection Testing

Section III: B Section III: BVDV Persistent

Infection T ection Testing

1. Study methods

for biological

sampling for

persistent infection

with BVDV

Producers with predominantly spring calving

herds (at least 70 percent of their calves were

expected to be born between November 2007

and June 2008) were invited to collect ear-notch

samples from their entire calf crop (or as much

of the calf crop as was available) by July 15,

2008.

Producers that ordered sample collection kits

were shipped materials to notch one ear of each

calf, record information about the animal (age

and identification), and instructions for

processing and shipping the samples to the

laboratory. Producers could collect samples

from calves throughout the calving season as the

calves were born, or at a single event such as

when the calves were vaccinated or branded. A

total of 44,150 ear-notch samples were collected

on the 205 operations. Samples were frozen dry

and shipped overnight to the laboratory for

processing. At the laboratory, samples were

logged in and processed using a commercially

available ELISA kit for detection of BVDV

antigen (IDEXX Laboratories Inc., Westbrooke,

ME) according to the manufacturer’s

instructions.

Results of the sample testing were returned to

the producers. Producers with one or more testpositive animals were encouraged to submit

whole-blood samples from the animals for virus

isolation. Producers were offered kits with all

materials needed to collect samples and to ship

them overnight to the laboratory.

Whole-blood samples were processed for virus

isolation using standard methods (Ridpath et al.,

2008). BVDV isolates were further

characterized by phylogenetic analysis

comparing the 5’ untranslated region sequences

generated by cycle sequencing of polymerase

chain reaction amplicons as described

previously (Ridpath et al., 2005). Segregation

into subgenotypes was based on comparison of

subgenotype sequences previously reported by

Vilcek et al. (Vilcek et al., 2001, 2004 [ BVDV1

subgenotype]; Flores et al., 2001 [BVDV2

subgenotype]).
USDA APHIS VS / 63

Section III: BVDV Persistent Infection Testing

2. Operations that

submitted earnotch samples for

testing

A higher percentage of operations with 200 or

more beef cows submitted samples than

operations with 1 to 49 beef cows. Regional

differences in participation were also present, as

a higher percentage of operations in the West

region submitted samples than operations in the

Southeast region.

b. Percentage of operations that submitted ear-notch samples for BVDV testing, by 

region 

Percent Operations 

Region 

West Central Southeast 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Submitted 

samples 43.8 (8.0) 29.2 (4.0) 16.7 (3.6) 

Eligible but did 

not submit 

samples 

44.3 (8.2) 54.7 (5.0) 60.7 (4.3) 

Ineligible* 11.9 (3.2) 16.1 (4.0) 22.6 (3.7) 

Total 100.0 100.0 100.0 

*Ineligible operations were those that did not have at least 70 percent of their calves born between November 

2007 and June 2008.

a. Percentage of operations that submitted ear-notch samples for BVDV testing, by herd 

size 

Percent Operations 

Herd Size (Number of Beef Cows)

1-49 50-99 100-199 200 or More All Operations 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Submitted 

samples 16.5 (3.6) 32.9 (5.7) 35.8 (5.5) 41.2 (4.8) 22.2 (2.7) 

Eligible but did 

not submit 

samples 

61.1 (4.3) 51.4 (5.9) 50.6 (5.9) 45.1 (5.1) 57.7 (3.2) 

Ineligible* 22.4 (3.7) 15.7 (3.7) 13.6 (5.7) 13.7 (3.5) 20.1 (2.7) 

Total 100.0 100.0 100.0 100.0 100.0 

*Ineligible operations were those that did not have at least 70 percent of their calves born between November 2007 

and June 2008. 
64 / Beef 2007–08

Section III: BVDV Persistent Infection Testing

Eligible operations that vaccinated at least some

cattle for BVDV in 2007 had 3.1 times higher

odds of submitting BVDV samples, and eligible

operations that tested at least some beef calves

for BVDV persistent infection in the past 3

years had 2.9 times higher odds of submitting

BVDV samples. Among operations that

submitted BVDV samples, 88.8 percent had

vaccinated at least some cattle for BVDV in

2007, and 16.8 percent had tested at least some

beef calves for BVDV persistent infection in the

past 3 years. Additionally, 89.8 percent of

operations that submitted BVDV samples were

fairly knowledgeable or knew some basics about

BVDV, compared with 64.0 percent of

operations in the general population.

c. For eligible operations, association between BVDV management practices and 

whether or not the operation submitted samples for BVDV testing 

Submitted BVDV Samples 

Yes No 

Management Practice Odds Ratio 

95-percent 

Confidence Interval Odds Ratio 

Vaccinated cattle for 

BVDV in 2007 3.1 1.6–6.1 referent 

Tested beef calves for BVDV 

persistent infection in past 

3 years 

2.9 1.1–7.6 referent 
USDA APHIS VS / 65

Section III: BVDV Persistent Infection Testing

A higher percentage of eligible operations that

submitted BVDV samples used a variety of

reproduction technologies compared with

eligible operations that did not submit samples.

d. For eligible operations, percentage of operations by reproduction technologies 

used and by whether or not operations submitted samples for BVDV testing 

Percent Operations 

Submitted BVDV Samples 

Yes No 

Reproduction Technology Pct. Std. Error Pct. Std. Error 

Estrus synchronization 15.9 (3.6) 5.8 (1.3) 

Artificial insemination 19.3 (4.0) 7.8 (1.9) 

Palpation for pregnancy 40.5 (6.2) 17.5 (2.4) 

Ultrasound for pregnancy 4.7 (1.2) 1.8 (0.7) 

Pelvic measurement 10.8 (2.9) 2.8 (1.0) 

Body condition scoring 28.6 (4.8) 16.3 (3.2) 

Semen evaluation 37.9 (5.7) 25.4 (3.7) 
66 / Beef 2007–08

Section III: BVDV Persistent Infection Testing
USDA APHIS VS / 67

Section III: BVDV Persistent Infection Testing

3. Sample testing

results

The following sample test results and

characteristics of positive operations represent a

subset of operations from which the population

estimates (presented in Section II) were

generated. Specfically, the subset is comprised

of 205 operations that participated in the

voluntary BVDV sampling study (see Appendix

I for sample profile). Data presented in items 3

and 4 are not adjusted to represent the U.S. beef

population. Rather, they describe the attributes

of the 205 operations in terms of production and

management practices. As such, a demographic

comparison of participating operations to

nonparticipating operations was included in item

2, p 63.

Of 44,150 ear-notch samples collected from the

205 cattle operations, 53 individual samples

were positive for BVDV antigen, resulting in an

individual calf persistent infection prevalence of

0.12 percent. The prevalence of calves testpositive for persistent infection with BVDV was

similar across calf ages (P=0.40). Eighteen

operations had at least one positive animal,

resulting in an estimated herd-level prevalence

of 8.8 percent. Within-herd test-positive

prevalence in positive operations ranged from

0.24 to 16 percent. Prevalence was 1.00 percent

or higher on 10 of 18 positive operations and

3.0 percent or higher on 4 of 18 positive

operations.

a. BVDV persistent infection results by age of calf 

Calf Age 

Number Samples 

Tested 

Number 

Positive 

Percent 

Positive 

Less than 3 weeks 5,635 8 0.14 

3 weeks to 3 months 29,228 37 0.13 

More than 3 months 4,424 6 0.14 

Unknown 4,863 2 0.04 

Total 44,150 53 0.12 
68 / Beef 2007–08

Section III: BVDV Persistent Infection Testing

Of the 53 animals that tested positive via

ELISA, whole-blood samples were submitted

for 5 animals from 3 operations. Virus isolation

confirmed that four of the five animals were

positive. The animal that was negative on the

confirmatory testing may have been transiently

infected with BVDV at the time the ear notch

was collected. Typing of the four BVDV isolates

showed that three were type 1b and one was

type 2a. (Because of the small number of

animals positive on the ELISA that were retested

to confirm that they were persistently infected

with BVDV, further references to BVDV

persistently infected animals will be for all

53 animals that were positive on the ELISA.)

b. Within-herd prevalence of BVDV

persistent infection 

Within Herd 

Prevalence 

(Percent) 

Number of 

Operations 

Percent 

Operations 

0 187 91.2 

0.01 to 0.49 5 2.4 

0.50 to 0.99 3 1.5 

1.00 to 1.99 4 1.9 

2.00 to 3.00 2 1.0 

Higher 

than 3.00 4 2.0 

Total 205 100.0 
USDA APHIS VS / 69

Section III: BVDV Persistent Infection Testing

4. Characteristics

of positive

operations

The small number of positive operations

identified in the survey (18) makes it difficult to

identify differences in demographics and

management practices between positive and

negative operations. For operations that

submitted samples for BVDV testing, the

percentage of operations positive for BVDV

persistent infection was lower in the Central

region than in the West and Southeast regions.

Operations with 100 or more beef cows were

more likely to have at least 1 calf positive for

BVDV persistent infection compared with

operations with fewer than 100 cows.

About 1 of 10 operations (10.7 percent) that had

not tested any beef calves for persistent

infection with BVDV during the previous

3 years had at least 1 calf positive for BVDV

persistent infection, whereas no operations that

had done some testing during the previous

3 years had a BVDV persistently infected calf

identified. Animal prevalence among operations

that had not tested any cattle for BVDV

persistent infection during the previous 3 years

was 0.16 percent. Operations that had tested

during the previous 3 years may have identified

and removed positive animals previously.

Alternatively, operations may have been more

diligent regarding general biosecurity practices

that decrease the likelihood of the presence of

BVDV persistent infection.
70 / Beef 2007–08

Section III: BVDV Persistent Infection Testing

a. For operations that submitted samples for BVDV testing, percentage of 

operations that had animals test positive for persistent infection with BVDV, by 

operation characteristics 

Operation Characteristics 

Number 

Operations 

Tested 

Number 

Operations 

Positive 

Percent 

Operations 

Positive 

Herd size 

(number of beef cows) 

 

 1 to 99 64 1 1.6 

 100 or More 141 17 12.1 

Region 

 West 73 8 11.0 

 Central 88 4 4.5 

 Southeast 44 6 13.6 

Level of Familiarity 

with BVDV 

Fairly knowledgeable or 

knew some basics 184 18 9.8 

Heard name only 

or never heard of 21 0 0.0 

Vaccinated any cattle 

against BVDV in 2007 

 Yes 182 15 8.2 

 No 23 3 13.0 

Tested beef calves for 

persistent infection with 

BVDV in the past 3 years 

 Yes 34 0 0.0 

 No 168 18 10.7 
USDA APHIS VS / 71

Section III: BVDV Persistent Infection Testing

Only 49 operations that submitted samples for

BVDV testing had brought any cattle onto the

operation during the previous 12 months. The

percentage of operations positive for BVDV

was similar, overall, between operations that

brought on any of the cattle classes and those

that did not (10.2 and 8.3 percent, respectively).

The percentage of calves born dead or that died

before weaning was similar between operations

that tested positive for BVDV persistent

infection and those that tested negative.

b. For operations that submitted samples for BVDV testing, percentage of 

operations that had animals test positive for persistent infection with BVDV, by 

whether or not the following classes of cattle were brought on during the 

previous 12 months

Brought on Cattle or Calves 

Yes No 

Cattle Class 

Number 

Ops. 

Tested 

Number 

Ops. 

Positive 

Percent 

Ops. 

Positive 

Number 

Ops. 

Tested 

Number 

Ops. 

Positive 

Percent 

Ops. 

Positive 

Preweaned 

beef calves 

with dam 

12 0 0.0 193 18 9.3 

Bred beef 

heifers 22 4 18.2 183 14 7.7 

Beef cows 

(pregnant) 29 3 10.3 176 15 8.5 

Preweaned 

dairy calves 1 0 0.0 204 18 8.8 

Any of the 

above 49 5 10.2 156 13 8.3 

c. For operations that submitted 

samples for BVDV testing, 

percentage of calves born dead or 

that died prior to weaning, by BVDV 

persistent infection status of 

operation 

Percent Calves 

BVDV Results 

Positive Negative 

All 

Operations 

Percent Percent Percent 

6.0 6.2 6.2 
72 / Beef 2007–08

Section IV: Conclusions

Section IV Section IV: Conclusions : Conclusions

In this study, the prevalence of BVDV persistent

infection in U.S. calves was low (0.12 percent of

calves) and the herd prevalence (those with at

least one BVDV persistently infected animal

identified) was modest (8.8 percent). The singlesample testing for most of the positive animals

in this study did not allow confirmation of

persistent infection with BVDV, so some

transient infections may be included.

Previous studies on weaned calves entering

feedlot or stocker operations have detected a

BVDV persistent infection prevalence of

0.3 percent (6/2,000, 95-percent confidence

interval 0.14–0.65 percent) [Loneragan et al.,

2005], 0.32 percent (3/938, 95-percent

confidence interval 0.1–0.94 percent) [Larson et

al., 2005b], and 0.4 percent (86/21,743,

95-percent confidence interval 0.32–0.49

percent) [Fulton et al., 2006]. In each study,

sampling and testing designed to identify

persistently infected animals may have also

allowed inclusion of transiently infected

animals. The reasons for the difference in

prevalence estimates between this survey and

previous studies are not clear. This study

sampled younger calves, which would be

expected to have a higher prevalence of

persistent infection than older animals, as

persistently infected calves have an increased

mortality rate (Houe, 1995). In this study, no

BVDV persistently infected calves were found

on operations that had tested for BVDV during

the previous 3 years. History of previous testing

in herds was not reported in the previous

studies. The proportion of operations that had

tested for BVDV persistent infection during the

previous 3 years may have been higher in this

study than in previous studies and might account

for some of the difference in prevalence.

Estimates in table a., p 21 show that only

4.2 percent of all cow-calf operations tested

calves for persistent infection with BVDV

during the previous 3 years, but among

operations that participated in BVDV sampling

for this study, 16.8 percent had tested calves

during the previous 3 years. The operations that

submitted ear-notch samples in this survey were

larger and more likely to implement testing,

vaccination, and reproductive technologies than

the nonsubmitters and may represent a

population less likely to have BVDV

persistently infected animals compared with

populations in previous studies. Animal

prevalence in this study for operations that had

not tested any cattle for BVDV during the

previous 3 years was 0.16 percent.

Previous studies have detected a herd

prevalence of persistent BVDV infection of

9 percent (6/66 herds, 95-percent confidence

interval 3.4–18.7 percent) [Bolin et al., 1985],

and 10.2 percent (13/128 herds, 95-percent

confidence interval 5.5–16.7 percent) [Wittum

et al., 2001], which is similar to the prevalence

found in this study (8.8 percent). Wittum et al.

(2001) found a 19-percent BVDV persistently

infected herd prevalence in herds in which the

attending veterinarian suspected BVDV

persistent infection (10/52 herds, 95-percent

confidence interval 10–33 percent) and a

2.7-percent herd prevalence in randomly

selected herds (2/75, 95-percent confidence

interval 0.5–10 percent). In this study, herd

prevalence on operations that had not tested for

BVDV persistent infection during the previous
USDA APHIS VS / 73

Section IV: Conclusions

3 years was 10.7 percent (18/168 herds). No

BVDV persistently infected positive operations

were found among operations that had tested for

BVDV persistent infection during the previous

3 years.

The prevalence of BVDV persistent infection

was similar across all calf age groups in this

study. As stated previously, persistently infected

calves are expected to have increased mortality

rates, which would produce a decreased

prevalence with age. This, however, was not

observed, and the percentages of calves that

were born dead or died prior to weaning were

similar between BVDV persistently infected

positive and negative operations. The morbidity

and mortality associated with different strains of

BVDV persistent infection is variable and, along

with the low prevalence of herd infection

detected in this study, may account for the lack

of observed effect.

The low prevalence of BVDV persistent

infection detected in this study limits the ability

to detect associations between management

practices and BVDV persistent infection risk.

One general biosecurity practice was found to

be associated with BVDV persistent infection:

no positive animals were found on operations

that reported testing during the previous 3 years.

Although this does not suggest testing performs

perfectly in eliminating BVDV persistent

infection, it is supportive of the effectiveness of

BVDV testing. Effects of BVDV infection on

positive operations were not clear, as no

differences could be detected in the proportion

of calves that were born dead or died prior to

weaning.

Generally, producers knew at least the basics

about BVDV persistent infection but were

uncertain about the value of testing. Vaccination

is the most commonly practiced intervention

against BVDV persistent infection. While

breeding females are the most important group

to vaccinate to prevent the production of

additional persistently infected calves, calves

aged 22 days to weaning were just as likely to

be vaccinated as other classes of cattle. Fewer

than one of four operations (23.8 percent) gave

a BVDV booster to cows. Most operations do

not vaccinate breeding females for BVDV,

potentially leaving them more vulnerable to

BVDV exposure. Management practices such as

quarantine and testing of cattle brought onto the

operation are necessary to prevent disease from

BVDV. Most operations quarantined none of the

new cattle brought onto the operation during the

previous 12 months, and very few tested any

calves for BVDV persistent infection during the

previous 3 years. Vaccination can clearly

provide protection against introducing BVDV

infection into the herd; however, with low levels

of testing, no quarantine of incoming cattle, and

modest vaccination levels it appears many

operations have no biosecurity and

biocontainment plan for BVDV.

Additional efforts are needed to increase

producer education, to quantify the economic

cost of BVDV infection and the value of testing

programs, and to better understand the

indications for herd testing and targeted

surveillance, quarantine, and vaccination in

cow-calf herds. There are likely several reasons

for the low level of testing and quarantine. For

some producers, lack of knowledge of effective

BVDV control methods is likely important.
74 / Beef 2007–08

Section IV: Conclusions

Other producers may not believe the value of

quarantine and testing is sufficient to warrant the

effort and expense. Some producers may

understand the importance of BVDV in cow-calf

herds but do not believe that it is present in their

herd or that they are at risk for bringing it onto

the operation and, thus, do not test.
USDA APHIS VS / 75

Section V: Methodology

Section V Section V: Methodology hodology

A. Needs Assessment

The National Animal Health Monitoring System

(NAHMS) develops study objectives by

exploring existing literature and contacting

stakeholders about their informational needs and

priorities during a needs assessment phase.

Stakeholders for NAHMS studies include

industry members, allied industry

representatives, other government agencies,

animal health officials, and many others. The

objective of the needs assessment for the

NAHMS Beef 2007–08 study was to collect

information about the most important health and

productivity issues of cow-calf production. A

driving force for the needs assessment was the

desire of NAHMS to receive as much input as

possible from a variety of producers, as well as

from industry experts and representatives,

veterinarians, extension specialists, universities,

and beef organizations. Information was

collected via interviews with key industry

figures and through a Needs Assessment Survey.

The Needs Assessment Survey was designed to

identify the most critical information gaps

regarding animal health, and health and

production management from producers,

veterinarians, extension personnel, university

researchers, and allied industry groups. The

survey, created in SurveyMonkey, was available

online from September 9, 2006, through

February 15, 2007. The survey was promoted

via electronic newsletters, magazines, and Web

sites. Organizations/magazines promoting the

study included “Beef Magazine,” “Drovers,”

“Feedstuffs,” “Bovine Veterinarian,” and “The

National Cattleman.”

Email messages identifying the online site and

asking for input were also sent to State

extension personnel as well as State and Federal

animal health officials. A total of 94 people

completed the survey. Universities/extensions

accounted for 41.5 percent of respondents, and

veterinarians/consultants accounted for

31.9 percent.

Objectives for the Beef 2007–08 study, using

input from interviews, literature searches, and

the online survey, were drafted and circulated to

stakeholder groups. Following this review, six

final study objectives were identified:

1. Describe trends in beef cow-calf health and

management practices.

2. Evaluate management factors related to beef

quality assurance.

3. Describe record-keeping practices on cowcalf operations.

4. Determine producer awareness of bovine viral

diarrhea (BVD) and management practices

used for BVD control.

5. Describe current biosecurity practices.

6. Determine the prevalence and antimicrobial

resistance patterns of potential food safety

pathogens.
76 / Beef 2007–08

Section V: Methodology

B. Sampling and Estimation

1. State selection The preliminary selection of States to be

included in the study was done in October 2006

using the National Agricultural Statistics Service

(NASS) Cattle Report. A goal for NAHMS

national studies is to include States that account

for at least 70 percent of the animals and

producer population in the United States. The

initial review identified 24 States representing

87.8 percent of the Nation’s beef cow inventory

and 79.6 percent of operations with beef cows

(cow-calf herds). The States were: Alabama,

Arkansas, California, Colorado, Florida,

Georgia, Idaho, Iowa, Kansas, Kentucky,

Louisiana, Mississippi, Missouri, Montana,

Nebraska, New Mexico, North Dakota,

Oklahoma, Oregon, South Dakota, Tennessee,

Texas, Virginia, and Wyoming.

A memo identifying the States was provided in

November 2006 to the USDA-APHIS-VS

CEAH Director and, in turn, the VS Regional

Directors. Each Regional Director sought input

from the respective States about being included

or excluded from the study.

2. Operation

selection

The list sampling frame was provided by NASS.

Within each State a stratified random sample

was selected. The size indicator was the number

of beef cows for each operation. NASS selected

a sample of beef producers in each State for

making the January 1 cattle estimates. The list

sample from the January 2007 survey was used

as the screening sample. Those producers in the

24 States reporting 1 or more beef cows on

January 1, 2007, were included in the sample for

contact in October 2007.

3. Population

inferences

a. Phase I: General Beef Management

Report; and Phase II: VS Initial and Second

Visits

Inferences cover the population of beef

producers with at least 1 beef cow in the

24 participating States. As of January 1, 2008,

these States accounted for 87.8 percent

(28.6 million) of beef cows and 79.6 percent

(603,000) of operations with beef cows in the

United States. (See Appendix II for respective

data on individual States.) All respondent data

were statistically weighted to reflect the

population from which they were selected. The

inverse of the probability of selection for each

operation was the initial selection weight. This

selection weight was adjusted for nonresponse

within each State and size group to allow for

inferences back to the original population from

which the sample was selected.
USDA APHIS VS / 77

Section V: Methodology

C. Data and Sample Collection

1. Data collectors

and data collection

periods

a. Phase I: General Beef Management Report

From October 22 through November 30, 2007,

NASS enumerators administered the General

Beef Management Report. The interview took

slightly over 1 hour.

b. Phase II: VS Initial Visit Questionnaire

From January 14 through March 31, 2008, State

and Federal animal health personnel

administered the Beef 2007–08 VS Initial Visit

Questionnaire.

c. Phase II: VS Second Visit Questionnaire

From July 1 through August 15, 2008, State and

Federal animal health personnel administered

the Beef 2007–08 Second VS Visit

Questionnaire.

d. Phase III: Biological Sample Collection

From March 25 through August 20, 2008,

producers collected ear notches from calves for

submission to the laboratory.

2. Biological

sample collection

and testing for

BVDV

During the Phase II visit, producers were trained

in how to collect samples, record data, and ship

samples. Producers were provided sampling kits

with ear notchers and encouraged to take ear

notches from all calves in the calf crop. Samples

could be taken at one time or over the course of

the calving season. Producers were asked to

place each sample in an individual submission

bag labeled with the calf’s ID and age group.

Calf age groups at the time of sampling were

defined as: less than 3 weeks, 3 weeks to

3 months, and greater than 3 months. Samples

were frozen dry and shipped overnight to the

laboratory.

Submitted samples were tested with the IDEXX

antigen capture ELISA according to the

manufacturer’s directions. Samples with an

ELISA S/P ratio of less than 0.2 were

categorized as negative. Samples with an ELISA

S/P ratio of 0.2 to 0.39 were categorized as

suspect, and samples with an ELISA S/P ratio

greater than 0.39 were categorized as positive.

All suspect and positive samples were retested

using the IDEXX modified detector to confirm

sample status as positive or negative. All

samples were tested individually; no pooling

was done. Results were mailed to producers

within 3 weeks, and producers with positive

results were offered the opportunity for

followup confirmatory testing by virus isolation

from a whole-blood sample.
78 / Beef 2007–08

Section V: Methodology

D. Data Analysis

1. Phase I:

Validation—

General Beef

Management

Report

Initial data entry and validation for the General

Beef Management Report were performed in

individual NASS State offices. Data were

entered into a SAS® data set. NAHMS national

staff performed additional data validation on the

entire data set after data from all States were

combined.

2. Phase II:

Validation—VS

Initial and Second

Visit

Questionnaires

After completing both VS questionnaires, data

collectors sent them to their respective State

NAHMS Coordinators who reviewed the

questionnaire responses for accuracy. Data entry

and validation were completed by CEAH staff

using SAS.

E. Sample Evaluation

The purpose of this section is to provide various

performance measurement parameters.

Historically, the term “response rate” was used

as a catchall parameter, but there are many ways

to define and calculate response rates.

Therefore, the following table presents an

evaluation based on a number of measurement

parameters, which are defined with an “x” in

categories that contribute to the measurement.

1. Phase I: General

Beef Management

Report

A total of 4,001 operations were selected for the

survey. Of these operations, 3,648

(91.2 percent) were contacted. There were

2,872 operations that provided usable inventory

information (71.8 percent of the total selected

and 78.7 percent of those contacted). In

addition, there were 2,159 operations

(54.0 percent of total selected) that provided

“complete” information for the questionnaire.

Of operations that provided complete

information, 1,033 (47.8 percent) consented to

be contacted for consideration/discussion about

further participation in Phase II (VS collection)

of the study.
USDA APHIS VS / 79

Section V: Methodology

Responses for Phase I: General Beef Management Report 

Measurement Parameter

Response Category 

Number 

Operations 

Percent 

Operations Contacts Usable1 Complete2

Survey complete and 

VMO consent 1,033 25.8 x x x 

Survey complete, 

refused VMO consent 1,126 28.1 x x x 

No beef cows on 

October 1 and July 1, 

2007 469 11.7 x x 

Out of business 244 6.1 x x 

Out of scope (prison 

and research farms, 

etc.) 7 0.2 

Refusal of GBMR 776 19.4 x 

Office hold (NASS 

elected not to 

contact) 46 1.2 

Inaccessible 300 7.5 

Total 4,001 100.0 3,648 2,872 2,159 

Percent of total 

operations 91.2 71.8 54.0 

Percent of total 

operations weighted3

 92.9 77.8 52.1 1 Useable operation—respondent provided answers to inventory questions for the operation (either zero or 

positive number on hand). 

2

Survey complete operation—respondent provided answers to all or nearly all questions. 

3

Weighted response—the rate was calculated using the initial selection weights. 
80 / Beef 2007–08

Section V: Methodology

2. Phase II: VS

Initial Visit

There were 1,033 operations that consented

during Phase I to be contacted by a veterinary

medical officer (VMO) for Phase II. Of these

1,033, 567 (54.9 percent) agreed to continue in

Phase II of the study and completed the VMO

Initial Visit Questionnaire; 365 (35.3 percent)

refused to participate. Approximately 8 percent

of the 1,033 operations were not contacted, and

2.0 percent were ineligible because they had no

beef cows at the time they were contacted by the

VMO during Phase II.

Responses for Phase II: VS Initial Visit 

Measurement Parameter 

Response Category Number 

Operations 

Percent 

Operations Contacts Usable1 Complete2

Survey complete 567 54.9 x x x 

Survey refused 365 35.3 x 

Not contacted 80 7.8 

Ineligible3 21 2.0 x x 

Total 1,033 100.0 953 588 567 

Percent of total 

operations 92.2 56.9 54.9 

Percent of total 

operations weighted4

 91.1 49.1 45.9 1

Useable operation—respondent provided answers to inventory questions for the operation (either zero or 

positive number on hand). 

2

Survey complete operation—respondent provided answers to all or nearly all questions. 

3

Ineligible—no beef cows at time of interview, which occurred from January 14 through March 31, 2008. 

4

Weighted response—the rate was calculated using the turnover weights. 
USDA APHIS VS / 81

Section V: Methodology

3. Phase II: VS

Second Visit

There were 567 operations that completed the

VS initial visit. Of these 567, 470 (82.9 percent)

agreed to continue in Phase II of the study and

completed the VMO Second Visit

Questionnaire; 60 (10.6 percent) refused to

participate further. A total of 5.1 percent of the

567 operations were not contacted, and

1.2 percent were ineligible because they had no

beef cows at the time they were contacted by the

VMO during Phase II for the second visit.

Responses for Phase II: VS Second Visit 

Measurement Parameter 

Response Category Number 

Operations 

Percent 

Operations Contacts Usable1 Complete2

Survey complete 470 82.9 x x x 

Survey refused 60 10.6 x 

Not contacted 29 5.1 

Ineligible3 8 1.4 x x 

Total 567 100.0 538 478 470 

Percent of total 

operations 94.9 84.3 82.9 

Percent of total 

operations weighted4

 93.9 77.7 75.8 1

Useable operation—respondent provided answers to inventory questions for the operation (either zero or 

positive number on hand). 

2

Survey complete operation—respondent provided answers to all or nearly all questions. 

3

Ineligible—no beef cows at time of interview, which occurred from July 1 through August 15, 2008. 

4

Weighted response—the rate was calculated using the turnover weights. 
82 / Beef 2007-08

Appendix I: Sample Profile

Responding Operations

a. Number of responding operations, by herd size 

Herd Size (Total Beef 

Cow Inventory) 

Phase I: General 

Beef 

Management 

Report 

Phase II: VS 

Initial Visit BVDV Sampling 

1 to 49 819 163 27 

50 to 99 386 96 37 

100 to 199 381 125 56 

200 or more 573 183 85 

Total 2,159 567 205 

b. Number of responding operations, by region 

Region

Phase I: General 

Beef 

Management 

Report 

Phase II: VS 

Initial Visit BVDV Sampling 

West 370 138 73 

Central 612 196 88 

South Central* 483 

233 44 

East* 694 

Total 2,159 567 205 

* Regions were combined for VS portion of study. 

Appendix I: Sam Appendix I: Sample Profile
USDA APHIS VS / 83

Appendix II: U.S. Beef Cow Population and Operations

Appendix II: U Appendix II: U.S. Beef Co .S. Beef Cow

Population and Oper opulation and Operations

Number of Beef Cows on January 1, 2008* 

Region State 

Beef Cow 

Inventory 

Jan. 1, 2008 

(Thousand Head) 

Beef Cow 

Operations 

2007 

West California 655 11,200 

Colorado 730 9,900 

 Idaho 460 7,100 

Montana 1,523 11,000 

 New Mexico 460 5,900 

Oregon 605 11,500 

 Wyoming 733 4,800 

Total 5,166 61,400 

Central Iowa 1,015 25,000 

Kansas 1,511 26,000 

 Missouri 2,080 54,000 

Nebraska 1,883 20,000 

 North Dakota 922 10,500 

South Dakota 1,644 14,500 

 Total 9,055 150,000 

Southeast Alabama 677 23,000 

Arkansas 943 26,000 

Florida 936 15,500 

Georgia 553 17,500 

Kentucky 1,159 38,000 

Louisiana 513 12,100 

Mississippi 519 18,500 

Oklahoma 2,053 48,000 

Tennessee 1,079 42,000 

Texas 5,240 130,000 

Virginia 692 21,000 

Total 14,364 391,600 

Total (24 States) 28,585 603,000 

Percentage of U.S. 87.8 79.6 

Total U.S. (50 States) 32,553 757,900 

*Source: NASS Cattle report, February 1, 2008, and NASS Farms, Land in Farms, and Livestock Operations 

2007 Summary report, February 2008. An operation is any place having one or more head of beef cows, 

excluding cows used to nurse calves, on hand at any time during the year. 
84 / Beef 2007–08

Appendix III: References

Appendix III: R Appendix III: References

Baker JC. 1995. The clinical manifestations of

bovine viral diarrhea infection. Vet Clin of North

Am Food An Prac 11:425–446.

Bolin SR, McClurkin AW, Coria MF. 1985.

Frequency of persistent bovine viral diarrhea

virus infection in selected cattle herds. Am J Vet

Res 46:2385–2387.

Donis RO. 1995. Molecular biology of bovine

viral diarrhea virus and its interactions with the

host. Vet Clin of North Am Food An Prac

11:393–424.

Fairbanks KK, Rinehart CL, Ohnesorge WC,

Laughin MM, Chase CC. 2004. Evaluation of

fetal protection against experimental infection

with type 1 and type 2 bovine viral diarrhea

virus after vaccination of the dam with a

bivalent modified live virus vaccine. J Am Vet

Med Assoc 225:1898–1904.

Ficken MD, Ellsworth MA, Tucker CM. 2006a.

Evaluation of the efficacy of a modified live

combination vaccine against bovine viral

diarrhea virus types 1 and 2 challenge exposures

in a one-year duration-of-immunity fetal

protection study. Vet Ther 7:283–294.

Ficken MD, Ellsworth MA, Tucker CM, Cortese

VS. 2006b. Effects of modified live bovine viral

diarrhea virus vaccines containing either type 1

or types 1 and 2 BVDV on heifers and their

offspring after challenge with noncytopathic

type 2 BVDV during gestation. J Am Vet Med

Assoc 228:1559–1564.

Flores EF, Ridpath JF, Weiblen R, Vogel FS, Gil

LH. 2002. Phylogenetic analysis of Brazilian

bovine viral diarrhea virus type 2 (BVDV-2)

isolates: evidence for a subgenotype within

BVDV-2. Virus Res 87:51–60.

Fulton RW, Hessman B, Johnson BJ, Ridpath JF,

Saliki JT, Burge LJ, Sjeklocha D, Confer AW,

Funk RA, Payton ME. 2006. Evaluation of

diagnostic tests used for detection of bovine

viral diarrhea virus and prevalence of subtypes

1a, 1b, and 2a in persistently infected cattle

entering a feedlot. J Am Vet Med Assoc

228:578–584.

Grooms DL. 2004. Reproductive consequences

of infection with bovine viral diarrhea virus. Vet

Clin of North Am Food An Prac 20:5–19.

Houe H. 1995. Epidemiology of bovine viral

diarrhea virus. Vet Clin of North Am Food An

Prac 11:521–548.

Kelling CL. 2004. Evolution of bovine viral

diarrhea virus vaccines. Vet Clin of North Am

Food An Prac 20:115–130.

Kovacs F, Magyar T, Rinehart C, Elbers K,

Schlesinger K, Ohnesorge WC. 2003. The live

attenuated bovine viral diarrhea virus

components of a multi-valent vaccine confer

protection against fetal infection. Vet Micro

96:117–131.
USDA APHIS VS / 85

Appendix III: References

Larson RL, Grotelueschen DM, Brock KV,

Dargatz DA, Ellis JA, Hunsaker BD, Lewis SD,

MacGregor DS, Smith RA, Sprowls RW, Traffas

V. 2004a. BVD decision/management guidelines

for beef veterinarians. Bov Prac 38:103-112.

Larson RL, Grotelueschen DM, Brock KV,

Hunsaker BD, Smith RA, Sprowls RW,

MacGregor DS, Loneragan GH, Dargatz DA.

Bovine viral diarrhea (BVD): Review for beef

cattle veterinarians. 2004b. Bov Prac 93–102.

Larson RL, Brodersen BW, Grotelueschen DM,

Hunsaker BD, Burdett W, Brock KV, Fulton

RW. Goehl DR, Sprowls RW, Kennedy JA,

Loneragan GH, Dargatz DA. 2005a.

Considerations for bovine viral diarrhea (BVD)

Testing. Bov Prac 39:96–100

Larson RL, Miller RB, Kleiboeker SB, Miller

MA, White BJ, 2005b. Economic costs

associated with two testing strategies for

screening feeder calves for persistent infection

with bovine viral diarrhea virus. J Am Vet Med

Assoc 226:249–254.

Loneragan GH, Thomson DU, Montgomery DL,

Mason GL, Larson RL. 2005. Prevalence,

outcome, and health consequences associated

with persistent infection with bovine viral

diarrhea virus in feedlot cattle. J Am Vet Med

Assoc 226: 595–601.

Ridpath JF. 2005. Practical significance of

heterogeneity among BVDV strains: impact of

biotype and genotype on UY.S. control

programs. Prev Vet Med 72:17–30, discussion

215–219.

Ridpath JF, Neill JD, Vilcek S, Dubovi EJ,

Carman S. 2006. Multiple outbreaks of severe

acute BVDV in North America occurring

between 1993 and 1995 linked to the same

BVDV2 strain. Vet Microbiol 114:196–204.

USDA. 1994, Cow/Calf Health and Productivity

Audit, Part III: Beef Cow/Calf Health

Management. USDA:APHIS:VS, CEAH. Fort

Collins, CO.

Available at http://nahms.aphis.usda.gov/

beefcowcalf/chapa/ChapaPt3.pdf

USDA. 1997. Part III: Reference of 1997 Beef

Cow-Calf Production Management and Disease

Control. USDA:APHIS:VS, CEAH. Fort

Collins, CO, # N247.198.

Available at http://nahms.aphis.usda.gov/

beefcowcalf/beef97/bf97pt3.pdf

USDA. 2008a. Beef 2007–08, Part I: Reference

of Beef Cow-calf Management Practices in the

United States, 2007–08, USDA–APHIS–VS,

CEAH. Fort Collins, CO, #N512-1008.

USDA. 2008b. Beef 2007-08, Part IV:

Reference of Beef Cow-calf Management

Practices in the United States, 2007–08, USDA–

APHIS–VS, CEAH. Fort Collins, CO,

#N523.0809.
86 / Beef 2007–08

Appendix III: References

USDA:NASS. 2009. 2007 Census of

Agriculture United States: Summary and State

Data v 1, pt 51.

Vilcek S, Durkovic B, Kolesarova M, GreiserWilke I, Paton D. 2004. Genetic diversity of

international bovine viral diarrhea virus

(BVDV) isolates identification of a new BVDV1 genetic group. Vet Res 35:609–615.

Vilcek S, Paton DJ, Durkovic B, Strojny L,

Ibata G, Moussa A, Loitsch A, Rossmanith W,

Vega S, Scicluna MT, Paifi V. 2001. Bovine

viral diarrhea virus genotype 1 can be separated

into at least eleven genetic groups. Arch Virol

146:99–115.

Wittum TE. 2001. Grotelueschen DM, Brock

KV, Kvasnicka WG, Floyd JG, Kelling CL,

Odde KG. Persistent bovine viral diarrhea virus

infection in U.S. beef herds. Prev Vet Med

49:83–94.
USDA APHIS VS / 87

Appendix IV: Study Objectives and Related Outputs

Appendix IV Appendix IV: Study

Objectiv Objectives and R es and Related

Outputs Outputs

1. Describe trends in beef cow-calf health and

management practices

• Part I: Reference of Beef Cow-calf

Management Practices, October 2008

• Part II: Reference of Beef Cow-calf

Management Practices, February 2009

• Part III: Changes in the U.S. Beef Cattle

Industry, 1993–2008, May 2009

• Part IV: Reference of Beef Cow-calf Health

and Health Management, February 2010

• Part V: Reference of Beef Cow-calf

Management Practices, April 2010

• Bull Management Practices on U.S. Beef Cowcalf Operations, info sheet, February 2009

• Calving Management Practices on U.S. Beef

Cow-calf Operations, info sheet, February

2009

• Mortality of Calves and Cattle on U.S. Beef

Cow-calf Operations, info sheet, May 2010

• Parasite Control Practices on U.S. Cow-calf

Operations, 2007–08, info sheet, December

2009

• Parasites on U.S. Beef Cow-calf Operations,

2007–08, info sheet, December 2009

• Use of Nutritional Supplements on U.S. Beef

Cow-calf Operations, info sheet, May 2010

• Vaccination of Cattle and Calves on U.S. Beef

Cow-calf Operations, info sheet, December

2009

• Vaccination of Calves for Respiratory Disease

on U.S. Beef Cow-calf Operations, info sheet,

December 2009

2. Evaluate management factors related to beef

quality assurance

• Part I: Reference of Beef Cow-calf

Management Practices, October 2008

• Injection Practices on U.S. Beef Cow-calf

Operations, 2007–08, info sheet, December

2009

3. Describe record-keeping practices on cowcalf operations

• Part I: Reference of Beef Cow-calf

Management Practices, October 2008

• Part III: Changes in the U.S. Beef Cattle

Industry, 1993–2008, May 2009

• Cattle Identification Practices on U.S. Beef

Cow-calf Operations, info sheet, February

2009

• Record Keeping, info sheet, expected summer

2010

4. Determine producer awareness of bovine viral

diarrhea (BVD) and management practices used

for BVD control

• Part IV: Reference of Beef Cow-calf Health

and Health Management, February 2010

• BVD Control on U.S. Beef Cow-calf

Operations, Interpretive Report, July 2010

• Beef Producers’ Perceptions About the Value

of Testing for Persistent Infection with Bovine

Viral Diarrhea Virus in Calves, info sheet,

June 2009

• Persistent Infection of Calves with Bovine

Viral Diarrhea Virus on U.S. Beef Cow-calf

Operations, info sheet, June 2009
88 / Beef 2007–08

Appendix IV: Study Objectives and Related Outputs

5. Describe current biosecurity practices on

cow-calf operations

• Part IV: Reference of Beef Cow-calf Health

and Health Management, February 2010

• Biosecurity on U.S. Beef Cow-calf Operations,

info sheet, December 2009

• Producer Disease Awareness, info sheet,

expected summer 2010

6. Determine the prevalence and antimicrobial

resistance patterns of potential food-safety

pathogens

• Antimicrobial Drug Use and Antimicrobial

Resistance on U.S. Cow-calf Operations,

2007–08, Interpretive Report, expected

summer 2010

• Campylobacter on U.S. Beef Cow-calf

Operations, 2007–08, info sheet, June 2009

• Enterococcus on U.S. Beef Cow-calf

Operations, 2007–08, info sheet, June 2009

• Salmonella on U.S. Beef Cow-calf Operations,

2007–08, info sheet, June 2009