United States

Department of

Agriculture

Animal and

Plant Health

Inspection

Service

Veterinary

Services

National

Animal Health

Monitoring

System

December 2007

Swine 2006

Part II: Reference of Swine Health and

Health Management Practices in the United

States, 2006
Mention of companies or commercial products does

not imply recommendation or endorsement by the

USDA over others not mentioned. USDA neither

guarantees nor warrants the standard of any product

mentioned. Product names are mentioned solely to

report factually on available data and to provide

specific information.

USDA:APHIS:VS:CEAH

NRRC Building B, M.S. 2E7

2150 Centre Avenue

Fort Collins, CO 80526-8117

970.494.7000

E-mail: NAHMS@aphis.usda.gov

http://nahms.usda.aphis.gov

#N479.1007

The U.S. Department of Agriculture (USDA) prohibits

discrimination in all its programs and activities on the

basis of race, color, national origin, age, disability, and

where applicable, sex, marital status, familial status,

parental status, religion, sexual orientation, genetic

information, political beliefs, reprisal, or because all or

part of an individual’s income is derived from any

public assistance program. (Not all prohibited bases

apply to all programs.) Persons with disabilities who

require alternative means for communication of

program information (Braille, large print, audiotape,

etc.) should contact USDA’s TARGET Center at (202)

720–2600 (voice and TDD). To file a complaint of

discrimination, write to USDA, Director, Office of Civil

Rights, 1400 Independence Avenue, S.W.,

Washington, D.C. 20250–9410, or call (800) 795–

3272 (voice) or (202) 720–6382 (TDD). USDA is an

equal opportunity provider and employer.

Cover photo courtesy of National Pork Board
USDA APHIS VS / i

Acknowledgments

This report was prepared from material received and analyzed by the U.S.

Department of Agriculture (USDA), Animal Plant Health Inspection Service

(APHIS), Veterinary Services (VS) during a study of animal health and health

management on swine operations.

The Swine 2006 study was a cooperative effort between State and Federal

agricultural statisticians, animal health officials, university researchers, extension

personnel, owners, and operators. We want to thank the industry members who

helped determine the direction and objectives of this study.

Thanks to the State and Federal veterinary medical officers (VMOs), and animal

health technicians (AHTs) who visited the operations and collected the data.

Their hard work and dedication to the National Animal Health Monitoring System

(NAHMS) are invaluable. The roles of the producer, area veterinarian in charge

(AVIC), NAHMS coordinator, VMOs, AHTs, and National Agricultural Statistics

Service enumerators were critical in providing quality data for Swine 2006

reports. Thanks also to the personnel at the Centers for Epidemiology and

Animal Health (CEAH) for their efforts in generating and distributing valuable

reports from Swine 2006 data.

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

efforts made this report possible.

Larry M. Granger

Director

Centers for Epidemiology and Animal Health
ii / Swine 2006

Suggested bibliographic citation for this report:

USDA. 2007. Swine 2006, Part II: Reference of Swine Health and Health

Management Practices in the United States, 2006

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

#N479.1207

Contacts for further information:

Questions or comments on data analysis: Dr. Charles Haley (970)-494-7000

Information on reprints or other reports: Ms. Kathy Snover (970) 494-7000

E-mail: NAHMS@aphis.usda.gov
USDA APHIS VS / iii

Table of Contents

Introduction 1

Terms Used in This Report 3

Section I: Population Estimates 5

A. Site Classification by Pig Type 5

1. Pig types present 5

B. Breeding Female and Preweaned Pig Morbidity 6

1. Breeding females 6

2. Preweaned pigs 9

C. Vaccinations in Breeding Females 12

1. Vaccination practices 12

2. Mycoplasma pneumonia 13

3. PRRS 14

4. Swine influenza 17

D. Use of Antimicrobials in Breeding Females 21

1. To treat disease conditions 21

2. Primary decision-maker 22

E. Weaned Pig Morbidity 23

1. Nursery-age pigs 23

2. Grower/finisher pigs 26

3. Porcine circovirus associated diseases (PCVAD) 30

4. Disease signs 34

F. Vaccinations in Weaned Pigs 37

1. Mycoplasma pneumonia 37

2. PRRS 38

3. Swine influenza 39

G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in

Weaned Pigs 43

1. Nursery-age pigs 43

2. Grower/finisher pigs 55

H. Other management practices 67

1. Split-sex feeding 67

2. Re-sorting pigs 69

3. Feed supplements 70

Section II: Methodology 71

A. Needs Assessment 71

1. Number of respondents, by respondent type 71
iv / Swine 2006

B. Sampling and Estimation 72

1. State selection 72

2. Operation selection 72

3. Population inferences 73

C. Data Collection 73

1. General Swine Farm Report, July 17 – September 15, 2006 73

2. Initial VS Visit, September 5, 2006 - March 15, 2007 73

D. Data Analysis 73

1. Validation and estimation 73

E. Sample Evaluation 74

1. General Swine Farm Report 74

Appendix I: Sample Profile 76

A. Responding Sites 76

1a. Total inventory 76

1b. Sow inventory 76

2. Type of site 76

3. Regions 77

4. Production phase 77

Appendix II: U.S. Swine Population and Operations 78

Appendix III: Study Objectives and Related Outputs 79
Introduction

USDA APHIS VS / 1

Introduction

In 1983, promoters of the concept that would become the USDA’s National Animal

Health Monitoring System (NAHMS) envisioned a program that would monitor

changes and trends in national animal health and management, thereby providing

periodic snapshots of the U.S. food-animal industries. With these industry

overviews, members could identify opportunities for improvement, provide changing

foundations for research and special studies, and detect emerging problems.

NAHMS first national study of the swine industry, the 1990 National Swine Survey,

provided a snapshot of animal health and management that would serve as a

baseline from which to measure industry changes in animal health and

management. NAHMS conducted the 1990 National Swine Survey in 18 States,

with a target population of operations with at least one sow. The sample

represented 95 percent of the U.S. swine population. National estimates

generated from this study are reported in Morbidity/Mortality and Health

Management of Swine in the United States (November 1991).

NAHMS second national swine study was Swine ’95 and was conducted in the

top 16 swine States, which represented 91 percent of the U.S. swine population.

The target population for the first phase of Swine ‘95 was producers with at least

one pig. National estimates generated from this study are reported in Swine ’95

Part I: Reference of 1995 Swine Management Practices (October 1995). The

second phase of Swine ’95 was conducted on sites with at least 300 market pigs.

National estimates generated from this study are reported in Part II: Reference of

1995 Grower/Finisher Health and Management (May 1996).

Swine 2000 was designed to provide both participants and the industry with

information on the U.S. swine herd on operations with 100 or more pigs. The

National Agricultural Statistics Service (NASS) collaborated with Veterinary

Services to select a producer sample statistically designed to provide inferences

to the Nation’s swine populations on operations with 100 or more pigs. Included in

the study were 17 of the major pork-producing States that accounted for 94

percent of the U.S. pig inventory and 92 percent of U.S. pork producers with 100

or more pigs. Results from this study are reported in Part I: Reference of Swine

Health and Management, 2000 (August 2001); Part II: Reference of Swine Health

and Management, 2000 (March 2002); Part III: Reference of Swine Health and

Environmental Management, 2000 (September 2002); and Part IV: Changes in the

U.S. Pork Industry, 1990-2000 (August 2005).
Introduction

2 / Swine 2006

The Swine 2006 study is NAHMS’ fourth national study of the U.S. swine industry.

Seventeen States participated in the Swine 2006 study (see map below). These

States accounted for 94 percent of swine operations and inventory on operations

with 100 or more pigs. A random sample of 5,000 swine producers was selected to

be visited by representatives from NASS between July 17 and September 15,

2006. An onsite questionnaire was administered by NASS enumerators during this

visit. Results from the first data collection period of this study were presented in

Swine 2006 Part I: Baseline reference of Swine Health and Management, 2006.

Producers that chose to continue in the study were visited twice by veterinary

medical officers (VMOs), who administered questionnaires and took biological/

environmental samples.

Part II: Reference of Swine Health and Health Management in the United

States, 2006 is the second of a series of reports from the NAHMS Swine 2006

study. Data for Part II were collected from 514 swine production sites between

September 5, 2006 and March 15, 2007.

Methodology and number of respondents can be found at the end of this report.

All NAHMS swine study reports are accessible online at http://

nahms.aphis.usda.gov.

Swine 2006 Participating States

Regions

North

West Central

East Central

South
Introduction

USDA APHIS VS / 3

Terms Used in

This Report

Average: For site average—a single value for each operation summed over all

sites reporting divided by the number of operations reporting (see average age that

nursery-age pigs are first vaccinated against Mycoplasma p 28). For a pig-level

average —a single operation value multiplied by the number of animals on that

operation; then values are summed across sites and divided by total number of

animals on all operations (see average age of ileitis onset on p 25).

Operation: The overall business and top-level management unit for a swinerearing facility, which might consist of one or more sites. An operation can

encompass all production phases of swine rearing (e.g., gestation, farrowing,

nursery, and grower/finisher) on one or more sites (geographic locations), each

devoted to a different production phase or combination of phases (see also “Site”).

Percent sites: The number of sites with a certain attribute divided by the total

number of sites. Percentages will sum to 100 where the attributes are mutually

exclusive (i.e., percentage of sites located within each region). Percentages will

not sum to 100 where the attributes are not mutually exclusive (i.e., the

percentage of sites using treatment methods where sites may have used more

than one method). The “percent sites” estimates primarily reflect the smaller

producers, since they make up the majority of sites.

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 left, 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, the

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 (—).

Standard Errors

(1.0)

10

9

8

7

6

5

4

3

2

1

0 (0.3)

Examples of a 95% Confidence Interval

95% Confidence

Intervals
Introduction

4 / Swine 2006

Regions:

North: Michigan, Minnesota, Pennsylvania, Wisconsin

West Central: Colorado, Kansas, Missouri, Nebraska, South Dakota

East Central: Illinois, Indiana, Iowa, Ohio

South: Arkansas, North Carolina, Oklahoma, Texas

Sample profile: Information that describes characteristics of the operations and

sites from which Swine 2006 data were collected.

Separate site: This term can mean that a facility is at a completely separate

geographical location or in the same location but physically separated (no

livestock runways or paths joining to other production facilities). It also might be

managed as its own site, with separate procedures, biosecurity measures, and

workers, for example.

Size of site: Size groupings were based on total number of swine present on June

1, 2006. Size of site was categorized as small (fewer than 2,000), medium (2,000-

4,999), and large (5,000 or more). For tables relating to sow and gilt management,

size of site was based on the number of sows and gilts on-site: small (fewer than

250), medium (250 to 499), and large (500 or more).

Site: One geographic location or address that functions as a unit to produce one

or more production phases in swine rearing. An example would be a gestation/

farrowing site or a nursery site. A site can encompass more than one production

phase, such as a “farrow to finish” site, which has gestation, farrowing, nursery,

and grower/finisher hogs all at the one location. A site can be a part of an

operation or it can be the whole operation, if the operation has only one site. (See

also “Operation.”)

Total Inventory: All swine present on the site on June 1, 2006.
Section I: Population Estimates—A. Site Classification by Pig Type

USDA APHIS VS / 5

Section I: Population Estimates

A. Site Classification

by Pig Type

1. Pig types present

Four of five sites (82.2 percent) had grower/finisher pigs during the previous 12

months, and 40.2 percent had breeding females. Nine of 10 sites (90.4 percent)

had weaned pigs, either nursery or grower/finisher.

Percentage of sites that had the following types of swine during the previous 12

months, by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 

or More) All Sites

Swine Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Breeding females 47.8 (3.9) 19.1 (3.6) 33.9 (5.7) 40.2 (2.7) 

Nursery-age pigs 61.4 (3.8) 39.2 (4.6) 49.4 (5.7) 55.4 (2.7) 

Grower/finisher pigs 84.1 (2.8) 78.2 (3.7) 78.6 (5.3) 82.2 (2.1) 

Weaned market 

pigs (nursery or 

grower/finisher 90.4 (2.4) 90.3 (3.1) 90.6 (3.2) 90.4 (1.7) 
Section I: Population Estimates—B. Breeding Female and Preweaned Pig Morbidity

6 / Swine 2006

B. Breeding Female and

Preweaned Pig Morbidity

Note: All tables and graphs in sections B, C, and D represent sites that had

any breeding females during the 12 months before the interview.

1. Breeding females

Over 20 percent of sites reported sickness or mortality in breeding females due to

porcine reproductive and respiratory syndrome (PRRS), swine influenza, and

roundworms (27.3, 22.3, and 26.8 percent of sites, respectively) during the

previous 12 months. A higher percentage of large sites reported problems with

swine influenza, gastric ulcers, and ileitis compared to small sites. Only 0.2

percent of producers believed they had a problem related to pseudorabies,

although there were no veterinary or laboratory confirmations.

a. Percentage of sites where the following disease problems were known or

suspected to have caused sickness or mortality in one or more breeding females

during the previous 12 months, by size of site:

Percent Sites* 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites

Disease Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

APP (Actinobacillus 

pleuropneumoniae) 5.3 (2.8) 2.0 (1.9) 2.3 (2.1) 4.2 (1.9) 

PRRS (porcine 

reproductive and 

respiratory 

syndrome) 22.5 (5.8) 29.8 (11.6) 38.7 (7.0) 27.3 (4.3) 

Mycoplasma

pneumonia 14.2 (4.1) 24.0 (10.3) 21.5 (6.0) 17.0 (3.2) 

Swine influenza 14.6 (4.6) 27.6 (11.9) 40.6 (7.7) 22.3 (3.9) 

Salmonella 8.8 (3.7) 0.0 (--) 1.5 (1.5) 6.1 (2.5) 

Swine dysentery 2.2 (2.1) 2.4 (2.3) 0.3 (0.3) 1.7 (1.4) 

TGE (transmissible 

gastroenteritis) 2.2 (2.1) 0.0 (--) 2.3 (1.9) 2.0 (1.5) 

Gastric ulcers 8.3 (2.8) 18.4 (7.8) 42.3 (7.4) 17.8 (3.1) 

Pseudorabies 0.3 (0.3) 0.0 (--) 0.1 (0.1) 0.2 (0.2) 

Ileitis (Lawsonia 

intracellularis) 11.0 (3.8) 14.9 (7.5) 30.6 (7.3) 16.2 (3.3) 

Leptospirosis 4.6 (2.4) 6.2 (4.5) 7.3 (3.2) 5.5 (1.8) 

Parvovirus 5.1 (2.6) 0.0 (--) 6.8 (3.0) 5.0 (1.9) 

Erysipelas 8.5 (4.0) 2.0 (1.9) 5.4 (4.6) 7.1 (2.9) 

Glasser’s disease 

(Haemophilus 

parasuis) 1.5 (1.5) 7.0 (4.6) 13.5 (3.8) 5.0 (1.4) 

Roundworms 26.7 (5.2) 33.2 (12.1) 24.6 (7.6) 26.8 (4.1) 

Other 8.2 (3.4) 3.0 (1.8) 3.0 (2.2) 6.4 (2.3) 

*This table reflects producer opinion, which may or may not have been confirmed by a veterinarian or 

laboratory diagnosis. 
USDA APHIS VS / 7

 Section I: Population Estimates—B. Breeding Female and Preweaned Pig Morbidity
Section I: Population Estimates—B. Breeding Female and Preweaned Pig Morbidity

8 / Swine 2006

Nearly half of sites that reported problems with swine influenza in breeding

females did not know whether the problems were due to swine influenza H3N2 or

H1N1.

b. For sites where swine influenza was a problem in breeding females during the

previous 12 months, percentage of sites where swine influenza H3N2 and H1N1

were problems:

Percent Sites 

Yes No Don’t Know 

Influenza Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

H3N2 29.8 (9.0) 23.8 (8.4) 46.4 (10.2) 100.0 

H1N1 36.3 (9.2) 18.0 (8.2) 45.7 (10.2) 100.0 

A veterinary or laboratory diagnosis was obtained by approximately half the sites

that reported problems with Mycoplasma pneumonia, swine influenza, gastric

ulcers, and ileitis in breeding females, and by over two-thirds of sites that reported

problems with PRRS.

c. For sites that reported the following disease problems in breeding females

during the previous 12 months, percentage of sites where the disease was

diagnosed by a veterinarian or laboratory:

Disease* 

Percent 

Sites 

Standard 

Error 

PRRS (porcine reproductive 

and respiratory syndrome) 69.2 (10.5) 

Mycoplasma pneumonia 51.8 (10.2) 

Swine influenza 47.9 (10.0) 

Gastric ulcers 52.8 (8.9) 

Ileitis (Lawsonia intracellularis) 48.3 (11.1) 

Roundworms 9.7 (5.3) 

*Estimates not reported for other diseases due to small sample size. 
USDA APHIS VS / 9

 Section I: Population Estimates—B. Breeding Female and Preweaned Pig Morbidity

2. Preweaned pigs

The most common problems reported in preweaned pigs were colibacillosis, navel

infections, and Streptococcus suis (47.4, 43.1, and 38.5 percent of sites,

respectively). One in four small sites (25.0 percent) reported problems with

Streptococcus suis meningitis, compared to approximately two-thirds of medium

and large sites (63.4 and 66.2 percent, respectively).

a. Percentage of sites where the following disease problems were known or

suspected to have caused sickness or mortality in one or more preweaned pigs

during the previous 12 months, by size of site:

Percent Sites* 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites

Disease Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

PRRS (porcine 

reproductive and 

respiratory 

syndrome) 7.2 (3.1) 18.9 (9.9) 28.1 (7.2) 13.3 (2.9) 

Undifferentiated 

pneumonia 26.4 (5.2) 22.3 (9.7) 22.2 (5.6) 25.0 (3.8) 

TGE (transmissible 

gastroenteritis) 2.3 (2.1) 0.0 (--) 2.5 (2.1) 2.1 (1.5) 

Rotavirus 1.4 (1.0) 3.2 (1.4) 24.0 (6.1) 6.9 (1.7) 

E. coli (colibacillosis) 43.8 (6.1) 30.8 (10.4) 64.6 (7.1) 47.4 (4.6) 

Coccidiosis 7.3 (3.3) 9.5 (4.9) 20.2 (5.7) 10.6 (2.6) 

Clostridium 8.4 (3.0) 14.2 (6.0) 39.1 (6.7) 16.2 (2.8) 

Streptococcus suis

(meningitis, 

polyserositis, arthritis) 25.0 (5.3) 63.4 (10.2) 66.2 (7.0) 38.5 (4.4) 

Greasy pig disease 

(S. hyicus) 16.3 (4.5) 33.0 (10.4) 57.6 (7.0) 27.6 (4.0) 

Navel infections 36.7 (5.5) 52.4 (11.6) 57.0 (7.4) 43.1 (4.3) 

Other 11.8 (4.3) 0.0 (--) 6.8 (6.3) 9.5 (3.2) 

*This table reflects producer opinion, which may or may not have been confirmed by a veterinarian or 

laboratory diagnosis. 
Section I: Population Estimates—B. Breeding Female and Preweaned Pig Morbidity

10 / Swine 2006
USDA APHIS VS / 11

 Section I: Population Estimates—B. Breeding Female and Preweaned Pig Morbidity

Over one-half of sites with problems in preweaned pigs due to PRRS, rotavirus,

coccidiosis, and clostridium had the disease diagnosed by a veterinarian or

laboratory.

b. For sites that reported the following disease problems in preweaned pigs during

the previous 12 months, percentage of sites where the disease was diagnosed by

a veterinarian or laboratory:

Disease* 

Percent 

Sites 

Standard 

Error 

PRRS (porcine reproductive 

and respiratory syndrome) 57.7 (12.9) 

Undifferentiated pneumonia 13.8 (5.5) 

Rotavirus 79.0 (9.8) 

E. coli (colibacillosis) 44.0 (6.4) 

Coccidiosis 75.6 (11.3) 

Clostridium 57.8 (8.8) 

Streptococcus suis (meningitis, 

polyserositis, arthritis) 34.4 (6.5) 

Greasy pig disease (S. hyicus) 37.8 (8.2) 

Navel infections 21.5 (5.3) 

*Estimates not reported for other diseases due to small sample size. 
Section I: Population Estimates—C. Vaccination in Breeding Females

12 / Swine 2006

1. Vaccination practices

Over 80 percent of sites vaccinated breeding females against Leptospirosis,

parvovirus, and erysipelas. In general, vaccination practices were similar across

size categories for all diseases shown.

Percentage of sites that usually vaccinated breeding females against the following

diseases, by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites

Disease Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

APP (Actinobacillus 

pleuropneumoniae) 5.4 (2.3) 6.2 (4.5) 1.1 (0.7) 4.4 (1.6) 

Salmonella 2.7 (1.8) 2.0 (1.9) 1.5 (1.5) 2.3 (1.2) 

Swine dysentery 0.7 (0.4) 0.0 (--) 0.0 (--) 0.4 (0.3) 

TGE (transmissible 

gastroenteritis) 9.3 (3.7) 7.5 (5.4) 6.1 (3.5) 8.4 (2.6) 

Pseudorabies 5.4 (3.1) 0.0 (--) 0.8 (0.8) 3.8 (2.0) 

Leptospirosis 82.9 (4.8) 98.1 (1.8) 88.4 (6.2) 85.7 (3.5) 

Parvovirus 81.8 (5.0) 98.1 (1.8) 93.5 (2.9) 86.4 (3.4) 

Erysipelas 81.3 (4.9) 83.6 (10.7) 94.1 (2.6) 84.7 (3.5) 

Glasser’s disease 

(Haemophilus 

parasuis) 8.3 (3.4) 6.2 (4.5) 17.1 (4.2) 10.3 (2.5) 

Other (not including 

Mycoplasma, PRRS, 

or influenza) 28.8 (5.6) 40.0 (11.0) 38.5 (7.0) 32.3 (4.2) 

C. Vaccinations in

Breeding Females
Section I: Population Estimates—C. Vaccination in Breeding Females

USDA APHIS VS / 13

2. Mycoplasma pneumonia

The percentage of sites that usually vaccinated breeding females against

Mycoplasma pneumonia ranged from 23.7 percent of small sites to 62.5 percent of

large sites. Overall, about one in three sites (34.9 percent) vaccinated breeding

females against Mycoplasma pneumonia.

a. Percentage of sites that usually vaccinated breeding females against

Mycoplasma pneumonia:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer than 250) 

Medium 

(250-499) 

Large 

(500 or more) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

23.7 (5.2) 39.7 (10.9) 62.5 (6.8) 34.9 (4.2) 

The most common reproductive time period that sites vaccinated breeding females

against Mycoplasma pneumonia were prior to entering the breeding herd and as

gilts entering the breeding herd (84.4 and 57.3 percent of sites that vaccinated,

respectively).

b. For sites that vaccinated breeding females against Mycoplasma pneumonia,

percentage of sites that usually vaccinated during the following time periods:

Time Period Percent Sites Standard Error 

Prior to entering the breeding herd 84.4 (5.4) 

As gilts at time of entering 

the breeding herd 57.3 (7.2) 

During gestation up to 

4 weeks before farrowing 10.7 (4.0) 

During the last 

4 weeks of gestation 21.5 (5.1) 

From farrowing to weaning 3.9 (2.2) 

After weaning through 

breeding/mating 11.8 (4.9) 

At regular intervals, regardless 

of reproductive stage 5.3 (2.5) 
Section I: Population Estimates—C. Vaccination in Breeding Females

14 / Swine 2006

Percent Sites 

Size of Site (Total Sow and Gilt Inventory) 

Small 

(Fewer than 250) 

Medium 

(229-499) 

Large 

(500 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

24.4 (5.0) 28.6 (10.8) 34.0 (7.2) 27.3 (3.9) 

About two-thirds of sites that vaccinated breeding females against PRRS (69.2

percent) did so as gilts entering the breeding herd, and nearly half of sites (47.0

percent) vaccinated breeding females at regular intervals, regardless of

reproductive stage.

b. For sites that vaccinated breeding females against PRRS, percentage of sites

that usually vaccinated during the following reproductive time periods:

Time Period Percent Sites Standard Error 

Prior to entering the breeding herd 38.1 (8.4) 

As gilts at time of 

entering the breeding herd 69.2 (7.9) 

During gestation up to 

4 weeks before farrowing 10.9 (4.5) 

During the last 

4 weeks of gestation 3.5 (1.9) 

From farrowing to weaning 6.8 (3.5) 

After weaning through 

breeding/mating 28.2 (8.7) 

At regular intervals, regardless 

of reproductive stage 47.0 (8.6) 

3. PRRS

About one in four sites (27.3 percent) usually vaccinated breeding females against

PRRS.

a. Percentage of sites that usually vaccinated breeding females against PRRS, by

size of site:
Section I: Population Estimates—C. Vaccination in Breeding Females

USDA APHIS VS / 15

About one in five sites that usually vaccinated breeding females against PRRS

(20.6 percent) used more than one brand or type of vaccine.

c. For sites that usually vaccinated breeding females against PRRS, percentage

of sites that used more than one brand or type of PRRS vaccine during the

previous 12 months in breeding females:

Percent Sites Standard Error 

20.6 (6.9) 

Overall, 72.5 percent of sites that vaccinated breeding females against PRRS

used a commercial vaccine, accounting for 61.7 percent of breeding females on

sites that vaccinated.

d. For sites that usually vaccinated breeding females against PRRS, percentage

of sites by type of PRRS vaccine used during the previous 12 months, and

percentage of breeding females on those sites:

PRRS Vaccine Type

Percent 

Sites 

Standard 

Error 

Percent 

Breeding 

Females 

Standard 

Error 

Commercial 

modified live or killed 72.5 (7.0) 61.7 (9.4) 

Autogenous 30.6 (7.7) 35.2 (8.9) 

On-farm serum 

exposure 9.0 (5.8) 25.8 (11.1) 
Section I: Population Estimates—C. Vaccination in Breeding Females

16 / Swine 2006

The most common measures of controlling PRRS in breeding females were using

only PRRS-negative semen or boars, closing the herd to new gilt introductions,

and obtaining replacement gilts from PRRS-negative sources (59.4, 44.5, and 33.0

percent of sites, respectively). A higher percentage of large sites obtained

replacement gilts from PRRS-negative sources and tested replacement gilts for

PRRS, compared to medium and small sites.

e. Percentage of sites by measures specifically used to control or prevent PRRS

in breeding females and by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory) 

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Control Measure Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Obtain replacement 

gilts from PRRSnegative source 19.0 (4.5) 27.8 (9.5) 71.7 (6.3) 33.0 (4.0) 

Test replacement gilts 

for PRRS 4.0 (1.7) 15.0 (5.0) 57.9 (7.4) 18.5 (2.8) 

Expose incoming gilts 

to PRRS 5.6 (2.6) 13.2 (8.9) 20.9 (6.8) 10.2 (2.6) 

Herd closed to new 

gilt introduction 48.2 (6.4) 35.8 (10.9) 38.1 (6.8) 44.5 (4.7) 

Use only PRRSnegative semen or 

boars 50.5 (6.3) 63.7 (12.1) 81.0 (5.7) 59.4 (4.6) 

Other measures not 

including vaccination 11.0 (4.2) 14.2 (4.9) 12.5 (4.0) 11.7 (2.9) 

Any of above 69.1 (5.5) 73.9 (12.2) 92.2 (4.7) 75.3 (4.0) 
Section I: Population Estimates—C. Vaccination in Breeding Females

USDA APHIS VS / 17

4. Swine influenza

The percentage of sites that vaccinated against swine influenza increased as size

of site increased.

About one in four sites (26.4 percent) vaccinated breeding females against both

swine influenza H1N1 and H3N2. The percentage of sites that vaccinated against

both types of swine influenza was nearly the same as the percentage that

vaccinated against either type, indicating that if a site vaccinated against one it

vaccinated against both.

a. Percentage of sites that usually vaccinated breeding females against swine

influenza H1N1 and/or H3N2, by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory) 

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Vaccinated 

Against . . . Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Swine influenza 

H1N1 11.5 (3.8) 33.2 (10.3) 69.3 (6.4) 27.9 (3.8) 

Swine influenza 

H3N2 12.8 (3.9) 33.6 (10.4) 65.2 (6.7) 27.8 (3.8) 

Both H1N1 and H3N2 11.5 (3.8) 29.7 (10.0) 64.5 (6.8) 26.4 (3.7) 

Either H1N1 or H3N2 12.8 (3.9) 37.1 (10.6) 70.0 (6.4) 29.3 (3.9) 
Section I: Population Estimates—C. Vaccination in Breeding Females

18 / Swine 2006

The most common reproductive time periods that sites vaccinated breeding

females against swine influenza H1N1 were prior to entering the breeding herd and

as gilts at time of entering the breeding herd.

b. For sites that vaccinated breeding females against swine influenza H1N1,

percentage of sites that usually vaccinated during the following time periods:

Time Period 

Percent 

Sites 

Standard 

 Error 

Prior to entering the breeding herd 64.7 (7.4) 

As gilts at time of entering the 

breeding herd 67.9 (6.9) 

During gestation up to 

4 weeks before farrowing 27.4 (7.0) 

During the last 

4 weeks of gestation 25.0 (6.3) 

From farrowing to weaning 3.5 (2.2) 

After weaning through 

breeding/mating 8.7 (4.4) 

At regular intervals, regardless 

of reproductive stage 21.6 (6.1) 

A commercial killed vaccine was used by 81.3 percent of sites that vaccinated

breeding females against swine influenza H1N1, accounting for 80.2 percent of

breeding females on sites that vaccinated.

c. For sites that usually vaccinated breeding females against swine influenza

H1N1, percentage of sites and percentage of breeding females on those sites by

type of vaccine used during the previous 12 months:

Swine Influenza 

H1N1 Vaccine Type

Percent 

Sites 

Standard 

Error 

Percent 

Breeding 

Females 

Standard 

Error 

Commercial killed 81.3 (5.9) 80.2 (6.4) 

Autogenous 22.2 (6.1) 28.1 (7.2) 
Section I: Population Estimates—C. Vaccination in Breeding Females

USDA APHIS VS / 19

As with swine influenza H1N1, the most common reproductive times that sites

vaccinated breeding females against swine influenza H3N2 were prior to entering

the breeding herd and as gilts at time of entering the breeding herd.

d. For sites that vaccinated breeding females against swine influenza H3N2,

percentage of sites that usually vaccinated during the following time periods:

Time Period 

Percent 

Sites 

Standard 

Error 

Prior to entering the breeding herd 63.0 (7.4) 

As gilts at time of entering the 

breeding herd 68.8 (6.8) 

During gestation up to 

4 weeks before farrowing 33.0 (7.7) 

During the last 

4 weeks of gestation 25.9 (6.4) 

From farrowing to weaning 4.3 (2.3) 

After weaning through 

breeding/mating 8.7 (4.4) 

At regular intervals, regardless 

of reproductive stage 21.7 (6.1) 

A commercial killed vaccine was used by 79.7 percent of sites that vaccinated

breeding females against swine influenza H3N2.

e. For sites that usually vaccinated breeding females against swine influenza

H3N2, percentage of sites and percentage of breeding females on those sites, by

type of vaccine used:

Swine Influenza 

H3N2 Vaccine Type

Percent 

Sites 

Standard 

Error 

Percent 

Breeding 

Females 

Standard 

Error 

Commercial killed 79.7 (6.1) 79.0 (6.6) 

Autogenous 22.3 (6.1) 29.1 (7.4) 
Section I: Population Estimates—C. Vaccination in Breeding Females

20 / Swine 2006
Section I: Population Estimates—D. Use of Antimicrobials in Breeding Females

USDA APHIS VS / 21

D. Use of Antimicrobials

in Breeding Females

1. To treat disease conditions

The percentage of sites that used an antimicrobial to treat a disease condition in

breeding females increased from small to large sites (67.1 and 93.6 percent,

respectively).

Percentage of sites that gave at least one breeding female an antimicrobial during

the previous 12 months to a treat disease condition, by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory) 

Small 

(Fewer than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

67.1 (5.4) 71.0 (12.1) 93.6 (2.1) 74.1 (3.9) 
Section I: Population Estimates—D. Use of Antimicrobials in Breeding Females

22 / Swine 2006

2. Primary decision-maker

On nearly all small sites (95.3 percent), the owner of the operation decided which

antimicrobials to use when treating sick breeding females, compared to 76.8

percent of medium sites and 29.5 percent of large sites. Large sites were more

likely than small sites to use a farm manager or company nutritionist/veterinarian

to make antimicrobial decisions.

Percentage of sites by person primarily responsible for deciding which

antimicrobials were used to treat sick breeding females, by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory) 

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Primary 

Decision-Maker* Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Owner of operation 95.3 (2.1) 76.8 (7.6) 29.5 (6.8) 76.9 (3.2) 

Farm manager, 

not the owner 0.9 (0.5) 6.0 (4.5) 22.9 (7.1) 7.0 (2.2) 

Local veterinary 

practitioner 1.4 (1.3) 6.8 (4.9) 11.8 (4.0) 4.5 (1.4) 

Consulting or secondopinion veterinarian 1.3 (1.3) 0.0 (--) 8.2 (4.9) 2.9 (1.5) 

Company veterinarian 

or company 

nutritionist 0.8 (0.8) 5.7 (2.0) 22.6 (4.7) 6.8 (1.3) 

Service manager who 

oversees more than 

one site 0.0 (--) 4.7 (2.1) 4.6 (1.4) 1.6 (0.4) 

Other 0.0 (--) 0.0 (--) 0.4 (0.4) 0.1 (0.1) 

Did not use 

antimicrobials for 

sickness in breeding 

females 0.3 (0.3) 0.0 (--) 0.0 (--) 0.2 (0.2) 

Total 100.0 100.0 100.0 100.0 

*The owner and farm manager categories do not reflect whether or not antimicrobial decision protocols were 

developed with veterinary input. 
Section I: Population Estimates—E. Weaned Pig Morbidity

USDA APHIS VS / 23

E. Weaned Pig

Morbidity

1. Nursery-age pigs

Nearly half of sites with nursery-age pigs (49.9 percent) reported sickness in these

pigs due to Streptococcus suis meningitis during the previous 12 months. The

percentage of sites reporting sickness due to PRRS ranged from 18.6 percent of

small sites to 61.6 percent of large sites. Small sites were more likely to have

problems due to roundworms compared to medium and large sites. A higher

percentage of large sites (39.6 percent) reported porcine circovirus associated

diseases (PCVAD)—formerly known as postweaning multisystemic wasting

syndrome (PMWS)—than medium sites (12.5 percent).

a. For sites with nursery-age pigs during the previous 12 months, percentage of

sites where the following disease problems were known or suspected to have

caused sickness or mortality in one or more nursery-age pigs during the previous

12 months, by size of site:

Percent Sites 1

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Disease 2

 Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

APP (Actinobacillus 

pleuropneumoniae) 1.2 (0.5) 6.2 (3.0) 9.6 (4.9) 2.9 (0.8) 

Glasser’s disease 

(Haemophilus parasuis) 12.5 (3.6) 23.2 (5.0) 42.0 (8.9) 17.4 (3.0) 

Mycoplasma pneumonia 30.8 (4.9) 29.1 (6.3) 20.6 (6.5) 29.4 (3.8) 

Influenza 22.2 (4.9) 21.7 (5.7) 43.9 (9.1) 24.6 (3.9) 

PRRS (porcine 

reproductive and 

respiratory syndrome) 18.6 (3.9) 40.6 (7.7) 61.6 (8.1) 26.6 (3.5) 

Salmonella 8.6 (3.0) 12.9 (5.1) 6.1 (4.1) 8.9 (2.4) 

Swine dysentery 4.9 (2.6) 2.2 (1.5) 6.9 (4.6) 4.8 (2.0) 

TGE (transmissible 

gastroenteritis) 2.0 (1.6) 0.0 (--) 2.9 (2.8) 1.8 (1.2) 

E. coli diarrhea 27.8 (5.1) 45.5 (6.9) 41.0 (8.9) 31.8 (4.0) 

Other diarrhea 21.4 (4.0) 15.1 (4.4) 23.5 (7.2) 20.7 (3.2) 

Edema disease 8.8 (3.3) 13.8 (4.9) 4.7 (3.0) 9.0 (2.6) 

PCVAD (porcine circovirus 

associated diseases) 3 21.5 (4.0) 12.5 (4.3) 39.6 (8.6) 22.3 (3.2) 

PDNS (porcine dermatitis 

and nephropathy 

syndrome)4 3.3 (1.7) 0.0 (--) 3.4 (3.2) 2.9 (1.3) 

Greasy pig disease (S. 

hyicus) 17.9 (4.0) 55.4 (7.3) 54.7 (8.7) 27.5 (3.5) 

Streptococcus suis (S.

meningitis) 42.3 (5.2) 72.0 (7.3) 71.5 (7.9) 49.9 (4.2) 

Roundworms 20.7 (4.1) 2.8 (2.0) 0.0 (--) 15.8 (3.1) 

Lice 14.6 (3.6) 0.0 (--) 0.0 (--) 10.8 (2.7) 

Other 12.4 (3.6) 4.3 (2.2) 5.8 (3.4) 10.5 (2.7) 

1

This table reflects producer opinion, which may or may not have been confirmed by a veterinarian or 

laboratory diagnosis.

2

Approximately 4 to 5 percent of sites reported “Don’t Know.” 

3

Formerly known as PMWS. Survey question read “. . . postweaning multisystemic wasting syndrome 

(PMWS aka PCVAD).” 

4

PDNS is currently believed to be a component of PCVAD. 
Section I: Population Estimates—E. Weaned Pig Morbidity

24 / Swine 2006

Over half of sites with sickness or mortality in nursery-age pigs due to influenza

(54.6 percent) reported that the problem was due to H1N1, while about 4 in 10 (

39.6 percent) did not know which type of influenza caused the illness.
Section I: Population Estimates—E. Weaned Pig Morbidity

USDA APHIS VS / 25

Over 7 of 10 sites that reported sickness in nursery age pigs due to Glasser’s

disease (73.4 percent) and 8 of 10 sites that reported sickness due to PRRS (80.7

percent) obtained a veterinary or laboratory diagnosis.

c. For sites that reported the following disease problems in nursery-age pigs

during the previous 12 months, percentage of sites where the disease was

diagnosed by a veterinarian or laboratory:

Disease* 

Percent 

Sites 

Standard 

Error 

Glasser’s disease 

(Haemophilus parasuis) 73.4 (7.1) 

Mycoplasma pneumonia 42.7 (7.6) 

Influenza 46.1 (9.3) 

PRRS (porcine reproductive 

and respiratory syndrome) 80.7 (5.8) 

E. coli diarrhea 53.7 (8.0) 

Other diarrhea 8.8 (3.2) 

PCVAD (porcine circovirus 

associated diseases)** 58.1 (8.5) 

Greasy pig disease (S. hyicus) 32.2 (6.4) 

Streptococcus suis (S. meningitis) 43.4 (5.5) 

Roundworms 13.4 (7.8) 

Lice 8.2 (7.7) 

*Estimates not reported for other diseases due to small sample size. 

**Formerly known as PMWS. Survey question read “. . . postweaning multisystemic wasting 

syndrome (PMWS aka PCVAD).” 

b. For sites where swine influenza was a problem in nursery-age pigs during the

previous 12 months, percentage of sites where swine influenza H3N2 and H1N1

were problems:

Percent Sites 

Yes No Don’t Know

Influenza Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

H3N2 22.4 (6.7) 38.0 (9.8) 39.6 (9.1) 100.0 

H1N1 54.6 (9.3) 5.8 (3.8) 39.6 (9.1) 100.0 
Section I: Population Estimates—E. Weaned Pig Morbidity

26 / Swine 2006

Photo courtesy of National Pork Board

2. Grower/finisher pigs

Over 60 percent of large sites with grower/finisher pigs reported sickness or

mortality in these pigs due to Mycoplasma pneumonia, influenza, PRRS, or ileitis

during the previous 12 months. No sites reported sickness in grower/finisher pigs

due to pseudorabies. The prevalence of two emerging diseases, PCVAD and

PDNS, varied by size of site. The percentages of sites that reported sickness in

grower/finisher pigs due to PCVAD increased steadily from small to large sites

(ranging from 25.0 percent of small sites to 59.9 percent of large sites). The

percentages of sites with sickness due to PDNS also differed by size—particularly

between small and medium sites (1.6 and 10.4 percent, respectively).
Section I: Population Estimates—E. Weaned Pig Morbidity

USDA APHIS VS / 27

a. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites where the following disease problems were known or suspected to have

caused sickness or mortality in one or more grower/finisher pigs during the

previous 12 months, by size of site:

Percent Sites* 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or more) All Sites 

Disease Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

APP (Actinobacillus 

pleuropneumoniae) 7.4 (2.3) 10.0 (3.1) 12.9 (4.8) 8.5 (1.8) 

Glasser’s disease 

(Haemophilus parasuis) 11.7 (3.6) 33.9 (5.1) 34.1 (7.1) 18.7 (2.9) 

Mycoplasma pneumonia 32.6 (4.6) 47.2 (5.4) 66.1 (6.9) 39.5 (3.5) 

Influenza 27.4 (4.7) 53.3 (5.2) 60.6 (6.7) 36.4 (3.6) 

Porcine reproductive 

and respiratory 

syndrome (PRRS) 19.2 (4.0) 46.3 (5.2) 66.9 (6.3) 30.2 (3.2) 

Salmonella 7.1 (3.3) 17.6 (3.9) 31.1 (6.8) 12.0 (2.5) 

Pseudorabies 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Atrophic rhinitis 6.1 (1.8) 5.0 (2.4) 4.1 (2.7) 5.7 (1.3) 

Hemorrhagic bowel 

syndrome 29.5 (4.7) 54.9 (5.4) 47.0 (6.9) 36.5 (3.5) 

Ileitis (Lawsonia 

intracellularis) 33.1 (4.7) 58.7 (5.3) 63.7 (6.6) 41.7 (3.6) 

Swine dysentery 

(bloody scours) 2.0 (1.1) 6.4 (2.8) 2.3 (2.1) 2.8 (0.9) 

Gastric ulcers 18.5 (3.5) 49.7 (5.6) 49.6 (7.2) 28.3 (3.0) 

Erysipelas 3.1 (1.6) 4.9 (1.9) 7.0 (2.8) 4.0 (1.2) 

PCVAD (porcine 

circovirus associated 

diseases)** 25.0 (4.3) 35.4 (4.9) 59.9 (6.9) 31.3 (3.3) 

PDNS (porcine 

dermatitis and 

nephropathy 

syndrome)*** 1.6 (1.2) 10.4 (3.1) 23.9 (5.9) 6.0 (1.3) 

Roundworms 19.4 (4.0) 7.5 (2.7) 6.6 (3.1) 15.5 (2.8) 

Mange 12.0 (3.7) 0.0 (--) 0.0 (--) 8.2 (2.6) 

Other disease problems 

in grower/finisher pigs 11.0 (2.7) 26.7 (4.9) 10.5 (4.5) 14.0 (2.2) 

*This table reflects producer opinion, which may or may not have been confirmed by a veterinarian or 

laboratory. 

**Formerly known as PMWS. Survey question read “. . . postweaning multisystemic wasting syndrome (PMWS 

aka PCVAD).” 

***PDNS is currently believed to be a component of PCVAD. 
Section I: Population Estimates—E. Weaned Pig Morbidity

28 / Swine 2006

Swine influenza H1N1 was a problem for about half the sites (48.0 percent) that

reported sickness in grower/finisher pigs due to swine influenza, while a similar

percentage of sites did not know which type of influenza was the problem.

b. For sites where swine influenza was a problem in grower/finisher pigs during the

previous 12 months, percentage of sites where swine influenza H1N1 and H3N2

were problems:

Percent Sites 

Yes No Don’t Know

Influenza Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

H3N2 26.8 (5.0) 26.2 (6.0) 47.0 (6.6) 100.0 

H1N1 48.0 (6.5) 5.5 (2.2) 46.5 (6.6) 100.0 
Section I: Population Estimates—E. Weaned Pig Morbidity

USDA APHIS VS / 29

In general, the majority of sites obtained a veterinary or laboratory diagnosis for

grower/finisher pigs that had the problems listed in the table below.

c. For sites that reported the following disease problems in grower/finisher pigs

during the previous 12 months, percentage of sites where the disease was

diagnosed by a veterinarian or laboratory:

Disease* 

Percent 

Sites 

Standard 

Error 

APP (Actinobacillus 

pleuropneumoniae) 59.6 (10.9) 

Glasser’s disease 

(Haemophilus parasuis) 60.2 (9.2) 

Mycoplasma pneumonia 57.9 (5.3) 

Influenza 54.7 (6.6) 

Swine influenza H3N2 79.1 (9.1) 

Swine influenza H1N1 70.9 (9.7) 

Porcine reproductive and 

respiratory syndrome 

(PRRS) 79.2 (4.8) 

Salmonella 60.9 (13.1) 

Atrophic rhinitis 23.6 (10.6) 

Hemorrhagic bowel 

syndrome 53.3 (6.1) 

Ileitis (Lawsonia 

intracellularis) 60.4 (5.7) 

Gastric ulcers 51.9 (5.5) 

PCVAD (porcine circovirus 

associated diseases)** 69.7 (6.6) 

PDNS (porcine dermatitis 

and nephropathy 

syndrome)*** 79.5 (8.6) 

Roundworms 23.1 (11.7) 

*Estimates not reported for other diseases due to small sample size. 

**Formerly known as PMWS. Survey question read “. . . postweaning multisystemic wasting 

syndrome (PMWS aka PCVAD).” 

***PDNS is currently believed to be a component of PCVAD. 
Section I: Population Estimates—E. Weaned Pig Morbidity

30 / Swine 2006

For sites that had grower/finisher pigs with ileitis, the average earliest age of onset

was 13.1 weeks, and average latest age of onset was 21.9 weeks.

d. For sites that had grower/finisher pigs with ileitis during the previous 12 months,

earliest and latest average age (in weeks) that pigs first showed symptoms:

Time of Onset Average Age (Weeks) Standard Error 

Earliest 13.1 (0.5) 

Latest 21.9 (0.6) 

3. Porcine circovirus associated diseases (PCVAD)*

Approximately one in three sites with weaned market pigs (either nursery or

grower/finisher pigs) reported PCVAD in these pigs during the previous 12 months,

ranging from 29.7 percent of small sites to 59.9 percent of large sites.

a. For sites with weaned market pigs, percentage of sites that reported one or

more weaned pigs with PCVAD during the previous 12 months, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

29.7 (4.3) 32.4 (4.5) 59.9 (7.5) 34.2 (3.2) 

*Formerly known as PMWS. Survey question read “. . . postweaning multisystemic wasting

syndrome (PMWS aka PCVAD).”
Section I: Population Estimates—E. Weaned Pig Morbidity

USDA APHIS VS / 31
Section I: Population Estimates—E. Weaned Pig Morbidity

32 / Swine 2006

On sites that reported PCVAD in weaned market pigs, 15.4 percent of these pigs

were affected.

b. For sites that reported one or more weaned market pigs with PCVAD during the

previous 12 months, percentage of weaned pigs affected by PCVAD, by size of

site:

Percent Pigs* 

Size of Site (Total Inventory) 

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

7.7 (1.5) 13.7 (5.2) 19.8 (6.0) 15.4 (3.4) 

*As a percentage of weaned pig inventory on day of interview. 

For sites that reported PCVAD in weaned market pigs, the average earliest age of

onset was 8.9 weeks and average latest age of onset was 16.3 weeks.

c. For sites that reported one or more weaned market pigs with PCVAD during the

previous 12 months, average earliest and average latest age that pigs first showed

symptoms:

Time of Onset Average Age (Weeks) Standard Error 

Earliest 8.9 (0.6) 

Latest 16.3 (0.6) 
Section I: Population Estimates—E. Weaned Pig Morbidity

USDA APHIS VS / 33

Over 90 percent of sites that reported weaned market pigs with PCVAD observed

clinical signs of rapid weight loss, pigs off feed, and death. Nearly half the sites

(44.8 percent) had pigs with enlarged lymph nodes in affected pigs, although

another 23.3 percent did not know if lymph nodes were enlarged.

d. For sites that reported one or more weaned market pigs with PCVAD,

percentage of sites where pigs showed any of the following clinical signs:

Clinical Sign Percent Sites 

Standard 

Error 

Difficulty breathing 75.1 (4.8) 

Rapid weight loss (wasting) 98.1 (1.0) 

Enlargement of mandibular 

or inguinal lymph nodes 44.8* (5.9) 

Diarrhea 77.2 (5.1) 

CNS signs 

(including behavior changes) 39.6 (6.4) 

Yellowing of skin 37.1 (5.4) 

Off feed 90.4 (3.1) 

Death 96.8 (1.7) 

*Note: One in four respondents (23.3 percent) did not know if lymph nodes were enlarged. 
Section I: Population Estimates—E. Weaned Pig Morbidity

34 / Swine 2006

4. Disease signs

Note: This section discusses symptoms that might be consistent with

foreign animal and domestic diseases. However, at this time no foreign

animal disease is present in U.S. pigs.

No sites observed blisters on the snouts of weaned pigs, and very few sites

observed lame pigs with reddened areas above the hooves. About one in five sites

with weaned market pigs (20.8 percent) reported unusually high numbers of pigs

that died during the previous 12 months.

a. For sites with weaned market pigs, percentage of sites where these pigs

showed any of the following signs during the previous 12 months, by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 

or More) All Sites

Sign Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Combination of skin 

blotches, matted 

eyes, and diarrhea 13.3 (3.7) 17.5 (3.8) 18.1 (5.5) 14.7 (2.8) 

Unusually high 

number of pigs 

unwilling to eat or 

stand up* 3.5 (1.2) 17.5 (4.2) 12.8 (4.4) 7.3 (1.4) 

Unusually high 

number of pigs 

that had died* 17.3 (3.9) 29.2 (4.9) 27.4 (6.3) 20.8 (2.9) 

Difficulty breathing 27.1 (4.3) 31.1 (5.1) 40.6 (7.3) 29.5 (3.3) 

Lame pigs with 

reddened areas 

above the hooves 1.7 (0.9) 5.5 (2.4) 1.6 (1.2) 2.4 (0.8) 

Blisters on snouts 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Any of the above 34.2 (4.5) 47.3 (5.3) 49.0 (7.9) 38.5 (3.5) 

*In excess of what was considered normal for each individual herd. 
Section I: Population Estimates—E. Weaned Pig Morbidity

USDA APHIS VS / 35

On sites with unusually high mortality, 11.8 percent of weaned pigs were affected.

b. For sites where weaned market pigs showed any of the following signs,

percentage of pigs affected:

Sign* Percent Pigs Standard Error 

Combination of skin blotches, 

matted eyes, and diarrhea 9.0 (2.9) 

Unusually high number of pigs unwilling 

to eat or stand up** 20.9 (4.1) 

Unusually high number of pigs that 

have died** 11.8 (1.3) 

Difficulty breathing 11.2 (1.9) 

*Estimates for other signs not reported due to small sample size. 

**In excess of what was considered normal for each individual herd. 

Over three-fourths of sites with unusually high mortality in weaned market pigs

(76.1 percent) sought veterinary or diagnostic lab assistance, and 62.1 percent of

sites with unusually high numbers of pigs unwilling to eat or stand up did so as

well.

c. For sites where weaned market pigs showed any of the following signs,

percentage of sites by highest level of response taken:

Percent Sites 

Level of Response

 Did Nothing 

Self-treated 

on Site 

Sought 

Nonveterinarian 

Assistance 

Off Site* 

Sought 

Veterinarian or 

Diagnostic Lab 

Assistance 

Sign** Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

Combination of 

skin blotches, 

matted eyes, and 

diarrhea 23.3 (7.6) 44.4 (10.3) 4.9 (2.5) 27.4 (7.9) 100.0 

Unusually high 

number of pigs 

unwilling to eat or 

stand up*** 0.0 (--) 33.0 (8.5) 4.9 (3.5) 62.1 (8.8) 100.0 

Unusually high 

number of pigs that 

have died*** 2.0 (1.3) 8.7 (3.6) 13.2 (4.6) 76.1 (5.8) 100.0 

Difficulty breathing 1.5 (1.0) 52.2 (6.6) 5.9 (2.8) 40.4 (6.8) 100.0 

*e.g., field manager. 

**Estimates for other signs not reported due to small sample size. 

***In excess of what was considered normal for each individual herd. 
Section I: Population Estimates—E. Weaned Pig Morbidity

36 / Swine 2006

Symptoms responded to antimicrobial treatment on over half (53.5 percent) of

sites where weaned market pigs showed the signs in table c. Antimicrobials were

not given on 3.6 percent of sites with signs.

d. For sites where weaned market pigs showed any of the signs in table c,

outcome of antimicrobial treatment:

Outcome Percent Sites Standard Error 

Symptoms responded 

positively with antimicrobials 53.5 (5.6) 

Symptoms unresponsive 

to antimicrobials 42.1 (5.7) 

Antimicrobials not given 3.6 (1.5) 

Don’t know if treated 

with antimicrobials 0.8 (0.8) 

Total 100.0 
Section I: Population Estimates—F. Vaccinations in Weaned Pigs

USDA APHIS VS / 37

F. Vaccinations in

Weaned Pigs

1. Mycoplasma pneumonia

Over half the sites with nursery-age pigs vaccinated nursery pigs against

Mycoplasma pneumonia, ranging from 46.3 percent of small sites to 81.2 percent

of large sites.

a. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that usually vaccinated pigs against Mycoplasma pneumonia while in the

nursery phase, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

46.3 (5.3) 62.2 (7.7) 81.2 (7.0) 52.6 (4.2) 

On average, sites first vaccinated nursery-age pigs against Mycoplasma

pneumonia at 4.4 weeks of age.

b. For sites that usually vaccinated pigs against Mycoplasma pneumonia while in

the nursery phase, site average age that nursery-age pigs are first vaccinated

against Mycoplasma pneumonia:

Site Average (Weeks) Standard Error 

4.4 (0.3) 
Section I: Population Estimates—F. Vaccinations in Weaned Pigs

38 / Swine 2006

Vaccinating pigs against Mycoplasma pneumonia was less common during the

grower/finisher phase than the nursery phase, with only 4.1 percent of sites with

grower/finisher pigs vaccinating against Mycoplasma pneumonia.

c. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that usually vaccinated pigs against Mycoplasma pneumonia while in the

grower/finisher phase, by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

2.9 (1.4) 6.3 (2.5) 7.8 (3.9) 4.1 (1.2) 

2. PRRS

Less than 10 percent of sites with nursery-age pigs vaccinated them against

PRRS.

a. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that usually vaccinated pigs against PRRS while in the nursery phase, by

size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

7.9 (3.1) 9.8 (4.3) 13.6 (7.9) 8.8 (2.6) 
Section I: Population Estimates—F. Vaccinations in Weaned Pigs

USDA APHIS VS / 39

No sites vaccinated grower/finisher pigs against PRRS.

b. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that usually vaccinated pigs against PRRS while in the grower/finisher

phase, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

3. Swine influenza

One in 10 sites with nursery-age pigs (10.8 percent) vaccinated nursery-age pigs

against either H1N1 or H3N2 swine influenza.

a. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that usually vaccinated pigs against swine influenza H1N1 and/or H3N2 while

in the nursery phase, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Vaccinated 

Against . . . Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Swine influenza 

H1N1 6.7 (2.9) 22.1 (5.5) 20.0 (6.6) 10.4 (2.4) 

Swine influenza 

H3N2 6.0 (2.8) 19.7 (5.0) 20.0 (6.6) 9.6 (2.3) 

Both H1N1 and H3N2 6.0 (2.8) 17.5 (4.6) 20.0 (6.6) 9.2 (2.3) 

Either H1N1 or H3N2 6.7 (2.9) 24.4 (5.8) 20.0 (6.6) 10.8 (2.4) 
Section I: Population Estimates—F. Vaccinations in Weaned Pigs

40 / Swine 2006

Only 4.3 percent of sites with grower/finisher pigs vaccinated grower/finisher pigs

against either H1N1 or H3N2 swine influenza.

b. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that usually vaccinated pigs against swine influenza H1N1 and/or H3N2 while

in the grower/finisher phase, by size of site:

The majority of sites that vaccinated nursery-age pigs against swine influenza

H1N1 (86.2 percent) used a commercial killed vaccine.

c. For sites that usually vaccinated pigs against swine influenza while in the

nursery phase, percentage of sites (and percentage of nursery-age pigs on those

sites) by type of vaccine used during the previous12 months:

Swine Influenza 

H1N1 Vaccine Type

Percent 

Sites 

Standard 

Error 

Percent 

NurseryAge Pigs Standard 

Error 

Commercial killed 86.2 (6.7) 89.2 (7.8) 

Autogenous 9.1 (5.1) 9.1 (7.3) 

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 

2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Vaccinated 

Against . . . Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Swine influenza 

H1N1 1.7 (0.9) 6.1 (2.7) 15.1 (4.8) 4.2 (1.0) 

Swine influenza 

H3N2 1.9 (0.9) 4.2 (2.0) 15.1 (4.8) 3.9 (0.9) 

Both H1N1 and H3N2 1.7 (0.9) 4.2 (2.0) 15.1 (4.8) 3.8 (0.9) 

Either H1N1 or H3N2 1.9 (0.9) 6.1 (2.7) 15.1 (4.8) 4.3 (1.0) 
Section I: Population Estimates—F. Vaccinations in Weaned Pigs

USDA APHIS VS / 41

On average, sites first vaccinated nursery-age pigs against swine influenza H1N1

at 6.0 weeks of age.

d. For sites that usually vaccinated pigs against swine influenza H1N1 while in the

nursery phase, average age that nursery-age pigs were first vaccinated against

H1N1:

Average Age (Weeks) Standard Error 

6.0 (0.4) 

Nine of 10 sites that vaccinated nursery-age pigs against swine influenza H3N2

used a commercial killed vaccine.

e. For sites that usually vaccinated pigs against swine influenza H3N2 while in the

nursery phase, percentage of sites (and percentage of nursery-age pigs on those

sites) by type of vaccine used during the previous 12 months:

Swine Influenza 

H3N2 Vaccine Type

Percent 

Sites 

Standard 

Error 

Percent 

Nursery-age 

Pigs 

Standard 

Error 

Commercial killed 90.0 (5.6) 90.2 (8.0) 

Autogenous 10.0 (5.6) 9.8 (8.0) 

On average, sites first vaccinated nursery-age pigs against swine influenza H3N2

at 6.1 weeks of age.

f. For sites that usually vaccinated nursery-age pigs against swine influenza

H3N2, average age that nursery-age pigs were first vaccinated against H3N2:

Average Age (Weeks) Standard Error 

6.1 (0.4) 
Section I: Population Estimates—F. Vaccinations in Weaned Pigs

42 / Swine 2006
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 43

G. Use of Antimicrobials,

Parasite Treatments, or

Feed Additives in

Weaned Pigs

1. Nursery-age pigs

One in three sites with nursery-age pigs (32.9 percent) reported no clinical

respiratory disease in these pigs during the previous 12 months. The percentage

of sites that did not observe clinical respiratory disease in nursery pigs varied by

size of site, ranging from 6.3 percent of large sites to 39.9 percent of small sites.

The most common actions taken for pigs with clinical respiratory disease were to

administer antimicrobials to all pigs in the entire room with clinically ill pigs (39.6

percent of sites) or to treat only clinically ill pigs (23.4 percent of sites).

a. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that used the following courses of action for their most recent occurrence of

respiratory disease in nursery-age pigs, by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 

or More) All Sites

Action Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Did not treat any 

pigs with 

antimicrobials 3.4 (1.5) 2.7 (2.6) 0.0 (--) 2.9 (1.2) 

Treated only 

clinically ill pigs with 

antimicrobials 24.0 (4.5) 29.8 (7.4) 11.0 (4.8) 23.4 (3.6) 

Treated all pigs in 

same pen with 

clinically ill pigs with 

antimicrobials 1.4 (1.2) 0.0 (--) 0.0 (--) 1.0 (0.9) 

Treated all pigs in 

same pen and 

adjacent pens with 

antimicrobials 0.2 (0.2) 0.0 (--) 0.0 (--) 0.2 (0.1) 

Treated all pigs in 

entire room with 

clinically ill pigs with 

antimicrobials 31.1 (4.9) 49.9 (7.4) 82.7 (5.8) 39.6 (4.0) 

Have not had 

clinical respiratory 

disease 39.9 (5.4) 17.6 (4.8) 6.3 (3.4) 32.9 (4.2) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

44 / Swine 2006

The percentage of sites where the owner of the operation was the primary decision

maker regarding antimicrobial use in sick nursery-age pigs decreased as size of

site increased. A higher percentage of large and medium sites relied on a

company nutritionist or company veterinarian compared to small sites.

b. For sites with nursery-age pigs during the previous 12 months, percentage of

sites by person primarily responsible for deciding which antimicrobials were used

to treat sick nursery-age pigs, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Primary 

Decision-Maker* Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Owner of operation 75.8 (4.5) 46.3 (7.6) 35.0 (8.2) 67.0 (3.8) 

Farm manager, 

not the owner 8.2 (3.1) 9.1 (3.7) 16.1 (8.2) 9.2 (2.5) 

Local veterinary 

practitioner 6.1 (2.2) 9.8 (4.1) 14.2 (5.7) 7.6 (1.8) 

Consulting or secondopinion veterinarian 0.3 (0.3) 3.5 (3.4) 5.2 (2.8) 1.3 (0.6) 

Company 

veterinarian or 

company nutritionist 4.4 (2.4) 22.4 (5.9) 20.0 (6.1) 8.7 (2.1) 

Service manager who 

oversees more than 

one site 2.5 (1.8) 4.9 (2.0) 9.5 (5.0) 3.7 (1.5) 

Other 1.6 (1.6) 1.3 (0.9) 0.0 (--) 1.4 (1.2) 

Did not use 

antimicrobials for 

sickness in 

nursery-age pigs 1.1 (0.7) 2.7 (2.6) 0.0 (--) 1.1 (0.6) 

Total 100.0 100.0 100.0 100.0 

*The owner and farm manager categories do not reflect whether or not antimicrobial decision protocols were 

developed with veterinary input. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 45

As was the case for treating sick pigs (table b), the owner of the operation was the

primary decision-maker on the majority of sites regarding which antimicrobials to

use for growth promotion in nursery-age pigs. Overall, 8.2 percent of sites did not

use antimicrobials for growth promotion in nursery age pigs.

c. For sites with nursery-age pigs during the previous 12 months, percentage of

sites by person primarily responsible for deciding which antimicrobials were used

in nursery-age pigs for growth promotion, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 

2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Primary 

Decision-Maker* Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Owner of operation 75.7 (4.5) 43.0 (7.6) 37.4 (8.2) 66.7 (3.8) 

Farm manager, 

not the owner 3.3 (1.7) 5.7 (3.2) 0.0 (--) 3.3 (1.4) 

Local veterinary 

practitioner 3.2 (1.5) 5.3 (3.0) 17.9 (6.5) 5.1 (1.4) 

Consulting or secondopinion veterinarian 0.0 (--) 3.5 (3.4) 3.3 (2.4) 0.9 (0.6) 

Company 

veterinarian or 

company nutritionist 6.7 (3.2) 28.6 (6.4) 34.7 (8.7) 13.0 (2.8) 

Service manager who 

oversees more than 

one site 1.9 (1.1) 4.4 (2.0) 5.8 (3.8) 2.7 (1.0) 

Other 0.0 (--) 0.6 (0.5) 0.0 (--) 0.1 (0.1) 

Did not use 

antimicrobials for 

growth promotion in 

nursery-age pigs 9.2 (2.7) 8.9 (3.5) 0.9 (0.9) 8.2 (2.1) 

Total 100.0 100.0 100.0 100.0 

*The owner and farm manager categories do not reflect whether or not antimicrobial decision protocols were 

developed with veterinary input. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

46 / Swine 2006

The most common antimicrobials given by injection to nursery-age pigs for any

reason were ceftiofur and procaine penicillin G (43.0 and 43.9 percent of sites with

nursery-age pigs, respectively). About half of sites with nursery-age pigs (48.6

percent) used an injectable antimicrobial to treat respiratory disease during the

previous 6 months.

d. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that gave any nursery-age pigs the following antimicrobials or parasite

treatments by injection during the previous 6 months, by primary reason given:

Percent Sites

 Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Any 

Reason 

Active 

Ingredient Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. 

Antimicrobial 

Ampicillin 0.0 (--) 1.7 (1.0) 2.0 (0.9) 0.3 (0.2) 3.0 (0.9) 0.0 (--) 2.2 (1.0) 9.2 (1.9) 

Amoxicillin 0.3 (0.3) 1.3 (1.1) 0.7 (0.5) 0.3 (0.3) 2.0 (0.9) 0.0 (--) 0.0 (--) 4.6 (1.6) 

Ceftiofur 0.2 (0.2) 3.6 (1.4) 30.2 (3.8) 2.5 (1.3) 4.0 (1.0) 0.0 (--) 2.5 (1.3) 43.0 (4.1) 

Erythromycin 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Florfenicol 0.0 (--) 0.3 (0.2) 5.9 (2.0) 0.5 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 6.7 (2.0) 

Gentamycin 0.0 (--) 0.7 (0.6) 0.5 (0.3) 6.4 (2.0) 0.1 (0.1) 0.0 (--) 0.0 (0.0) 7.7 (2.1) 

Lincomycin 0.0 (--) 2.1 (0.9) 4.5 (1.8) 1.3 (0.9) 1.7 (0.8) 0.0 (--) 1.4 (1.0) 11.0 (2.5) 

Oxytetracycline 0.0 (--) 6.5 (3.1) 11.7 (2.7) 0.0 (--) 0.4 (0.3) 0.0 (--) 1.4 (1.0) 19.9* (3.9) 

Procaine 

penicillin G 0.2 (0.2) 7.5 (2.2) 18.0 (3.3) 0.8 (0.4) 14.1 (3.6) 0.0 (--) 3.2 (1.2) 43.9* (4.2) 

Penicillin 

benzathine 0.0 (--) 2.9 (1.2) 5.1 (2.0) 0.2 (0.2) 3.7 (1.5) 0.0 (--) 4.7 (1.7) 16.5* (3.0) 

Spectinomycin 0.0 (--) 0.5 (0.5) 1.0 (0.8) 2.3 (1.0) 0.3 (0.3) 0.0 (--) 0.0 (--) 4.0* (1.4) 

Tulathromycin 0.2 (0.2) 1.6 (0.7) 9.0 (2.3) 0.0 (--) 0.3 (0.3) 0.0 (--) 1.6 (1.0) 12.7 (2.6) 

Tylosin 0.8 (0.8) 1.2 (0.7) 6.3 (2.1) 9.2 (2.4) 1.1 (0.8) 0.0 (--) 1.1 (0.9) 19.6* (3.4) 

Any of the 

above 

antimicrobials 1.4 (0.8) 20.9 (3.8) 48.6 (4.2) 19.1 (3.1) 25.1 (3.8) 0.0 (--) 10.4 (2.2) 83.1 (3.0) 

Parasite 

treatment 

Doramectin 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.8 (0.4) 0.0 (--) 0.8 (0.4) 

Ivermectin 0.0 (--) 0.8 (0.7) 0.0 (--) 0.0 (--) 0.0 (--) 16.5 (3.0) 0.0 (--) 17.3 (3.0) 

Levamisole 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Any of the 

above parasite 

treatments 0.0 (--) 0.8 (0.7) 0.0 (--) 0.0 (--) 0.0 (--) 17.3 (3.0) 0.0 (--) 18.1 (3.0) 

Other 

antimicrobial or 

parasite 

treatment 0.0 (--) 0.0 (--) 0.0 (--) 1.4 (0.9) 0.1 (0.1) 0.5 (0.3) 0.0 (--) 1.9* (1.0) 

*Total may not sum to “Any Reason” estimate due to rounding of specific antimicrobials by reason. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 47
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

48 / Swine 2006

For sites with nursery-age pigs, 43.2 percent of sites administered

chlortetracycline via feed during the previous 6 months. In addition, 31.1 percent of

sites administered carbadox and 25.9 percent administered tiamulin via feed

during the previous 6 months. The most common reason for giving antimicrobials

in feed was disease prevention (50.9 percent of sites).

e. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that gave the following antimicrobials or feed additives to any nursery-age

pigs via feed during the previous 6 months, by primary reason given:

Percent Sites

Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Any 

Reason 

Antimicrobial or 

Feed Additive Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. 

Amoxicillin 0.0 (--) 0.0 (--) 0.0 (--) 0.4 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 0.4 (0.4) 

Arsanilic acid 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Bacitracin 4.8 (2.8) 0.8 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 0.1 (0.1) 0.0 (--) 5.7 (2.8) 

Bacitracin zinc 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Bambermycin 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Carbadox 3.5 (1.5) 19.3 (3.3) 1.1 (0.6) 7.1 (1.7) 0.0 (--) 0.0 (--) 0.1 (0.1) 31.1 (3.7) 

Chlortetracycline 10.0 (2.8) 21.4 (3.7) 11.3 (2.5) 0.5 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 43.2 (4.2) 

Chlortetracycline/ 

sulfathiazole/ 

penicillin 0.6 (0.3) 4.3 (1.5) 2.2 (1.4) 1.5 (1.0) 0.0 (--) 0.0 (--) 0.0 (--) 8.5* (2.3) 

Chlortetracycline/ 

sulfamethazine/ 

penicillin 0.9 (0.7) 3.7 (1.4) 2.8 (1.6) 0.0 (--) 0.3 (0.3) 0.0 (--) 0.0 (--) 7.8* (2.2) 

Florfenicol 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Lincomycin 1.1 (0.8) 5.2 (1.8) 2.1 (0.8) 0.4 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 8.9* (2.1) 

Neomycin and 

Terramycin® 5.2 (2.9) 1.8 (1.0) 0.2 (0.2) 0.8 (0.5) 0.0 (--) 0.0 (--) 0.0 (--) 8.0 (3.1) 

Oxytetracycline 0.8 (0.5) 1.0 (0.7) 2.4 (1.5) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 4.2 (1.7) 

Ractopamine 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Roxarsone 0.3 (0.3) 0.2 (0.2) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.5 (0.3) 

Tiamulin 1.8 (1.0) 18.0 (3.6) 0.7 (0.5) 5.1 (2.0) 0.3 (0.3) 0.0 (--) 0.0 (--) 25.9 (3.9) 

Tilmicosin 0.5 (0.5) 5.1 (1.6) 3.4 (1.6) 1.2 (1.1) 0.1 (0.1) 0.0 (--) 0.0 (--) 10.3 (2.5) 

Tylosin 1.9 (1.0) 7.6 (2.2) 0.5 (0.5) 3.4 (1.5) 0.0 (--) 0.0 (--) 0.0 (--) 13.4 (2.8) 

Tylosin and 

sulfamethazine 1.4 (0.8) 4.0 (1.9) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 5.4 (2.1) 

Virginiamycin 0.3 (0.3) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 1.0 (1.0) 0.0 (--) 1.3 (1.0) 

Other 1.0 (1.0) 2.8 (1.3) 0.1 (0.1) 0.1 (0.0) 0.0 (--) 5.7 (1.9) 0.0 (--) 9.7 (2.5) 

Any antimicrobial 

or feed additive 24.5 (4.0) 50.9 (4.2) 17.0 (2.9) 14.8 (2.8) 0.7 (0.4) 6.8 (2.2) 0.1 (0.1) 82.3 (3.2) 

*Sum of specific antimicrobials by reason may not sum to “Any Reason” estimate due to rounding. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 49
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

50 / Swine 2006

Antimicrobials were administered via feed to nursery-age pigs for growth promotion

for an average of 32.4 days, while respiratory disease was treated for an average of

20.2 days.

f. For sites that gave any nursery-age pigs an antimicrobial or feed additive via

feed during the previous 6 months, site average number of days given, by primary

reason given:

Site Average (Days) 

Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Avg. 

Std. 

Err. Avg. 

Std. 

Err. Avg. 

Std. 

Err. Avg. 

Std. 

Err. Avg. 

Std. 

Err. Avg. 

Std. 

Err. Avg. 

Std. 

Error 

32.4 (3.2) 28.6 (1.6) 20.2 (2.0) 26.1 (3.8) * * * 

*Estimate not reported due to small sample size. 

The average number of days antimicrobials were administered to nursery-age pigs

via feed ranged from 18.5 days for lincomycin to 32.8 days for tilmicosin.

g. For sites that gave the following antimicrobials to nursery-age pigs via feed

during the previous 6 months, site average number of days given:

Antimicrobial* 

Site Average 

(Days) 

Standard 

Error 

Carbadox 28.4 (2.2) 

Chlortetracycline 29.4 (2.2) 

Chlortetracycline/ 

sulfathiazole/ 

penicillin 

23.7 (3.9) 

Chlortetracycline/ 

sulfamethazine/ 

penicillin 

21.5 (4.0) 

Lincomycin 18.5 (2.7) 

Tiamulin 27.8 (2.6) 

Tilmicosin 32.8 (4.0) 

Tylosin 25.7 (3.8) 

*Estimates not reported for other antimicrobials due to small sample size. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 51

Overall, 40.3 percent of sites with nursery-age pigs administered an antimicrobial

via water during the previous 6 months. Amoxicillin was the most common

antimicrobial administered via water (19.1 percent of sites). Amoxicillin was given

primarily for disease prevention (8.1 percent of sites), respiratory disease

treatment (5.8 percent of sites), and polyserositis/meningitis treatment (4.4

percent of sites).

h. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that gave any nursery-age pigs the following antimicrobials via water during

the previous 6 months, by primary reason given:

Percent Sites

Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Any 

Reason 

Antimicrobial Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. 

Amoxicillin 0.2 (0.2) 8.1 (2.2) 5.8 (2.1) 0.4 (0.2) 4.4 (1.4) 0.0 (--) 0.2 (0.2) 19.1 (3.1) 

Bacitracin 0.2 (0.2) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.2 (0.2) 

Chlortetracycline 0.0 (--) 0.3 (0.3) 5.0 (1.8) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 5.4* (1.8) 

Chlortetracycline/ 

sulfathiazole/ 

penicillin 0.0 (--) 0.0 (--) 0.3 (0.3) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.3 (0.3) 

Chlortetracycline/ 

sulfamethazine/ 

penicillin 0.0 (--) 0.5 (0.4) 0.0 (--) 0.6 (0.6) 0.0 (--) 0.0 (--) 0.0 (--) 1.1 (0.7) 

Florfenicol 0.0 (--) 0.3 (0.3) 0.4 (0.3) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.7 (0.4) 

Lincomycin 0.0 (--) 1.3 (0.6) 0.4 (0.4) 0.7 (0.7) 0.0 (--) 0.0 (--) 0.2 (0.1) 2.5* (1.0) 

Neomycin and 

terramycin 0.0 (--) 2.4 (1.3) 1.3 (0.7) 2.9 (1.4) 0.0 (--) 0.0 (--) 0.0 (--) 6.5* (2.0) 

Oxytetracycline 0.0 (--) 0.5 (0.3) 3.7 (1.5) 0.9 (0.9) 0.0 (--) 0.0 (--) 0.0 (--) 5.1 (1.7) 

Tiamulin 0.0 (--) 0.2 (0.2) 1.0 (0.6) 1.9 (1.4) 0.0 (--) 0.0 (--) 0.0 (--) 3.2* (1.5) 

Tylosin 0.0 (--) 0.0 (--) 0.3 (0.3) 0.6 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 0.9 (0.5) 

Tylosin and 

sulfamethazine 0.0 (--) 0.1 (0.1) 1.7 (1.6) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 1.8 (1.6) 

Other 0.1 (0.1) 4.1 (1.5) 3.2 (1.3) 3.3 (1.3) 1.3 (0.9) 0.4 (0.4) 0.4 (0.4) 12.9* (2.5) 

Any antimicrobial* 0.5 (0.3) 14.6 (2.8) 17.7 (3.2) 9.9 (2.3) 4.8 (1.5) 0.4 (0.4) 0.7 (0.4) 40.3 (4.0) 

*Sum of specific antimicrobials-by-reason may not sum to “Any Reason” estimate due to rounding. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

52 / Swine 2006
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 53

Antimicrobials were administered to nursery-age pigs via water to prevent disease

for an average of 13.6 days, to treat respiratory disease for an average of 12.5

days, and to treat enteric disease for an average of 8.3 days.

i. For sites that gave any antimicrobials or feed additives to any nursery-age pigs

via water during the previous 6 months, site average number of days given, by

primary reason given:

Site Average (Days) 

Primary Reason 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

* 13.6 (2.4) 12.5 (2.2) 8.3 (1.0) * * * 

*Estimate not reported due to small sample size. 

When amoxicillin was administered to nursery-age pigs via water, it was given an

average of 16.6 days.

j. For sites that gave the following antimicrobials to any nursery-age pigs via water

during the previous 6 months, site average number of days given:

Antimicrobial* 

Site Average 

(Days) Standard Error 

Amoxicillin 16.6 (2.2) 

Chlortetracycline 9.8 (3.2) 

*Estimates not reported for other antimicrobials due to small sample size. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

54 / Swine 2006

Photo courtesy of National Pork Board
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 55

2. Grower/finisher pigs

Overall, 20.1 percent of sites with grower/finisher pigs did not have clinical

respiratory disease in these pigs during the previous 12 months. For grower/

finisher pigs affected by respiratory disease, the most common course of action

was to give all pigs in the entire room antimicrobials.

a. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that used the following courses of action for their most recent occurrence of

respiratory disease in grower/finisher pigs during the previous 12 months, by size

of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer than 

2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or 

More) All Sites

Action Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Did not treat any 

pigs with 

antimicrobials 5.4 (2.2) 3.3 (2.0) 0.0 (--) 4.3 (1.5) 

Treated only 

clinically ill pigs with 

antimicrobials 27.9 (4.1) 22.8 (4.8) 30.7 (6.6) 27.3 (3.2) 

Treated all pigs in 

same pen with 

clinically ill pigs with 

antimicrobials 2.8 (1.4) 4.5 (3.2) 0.8 (0.7) 2.9 (1.2) 

Treated all pigs in 

same pen and 

adjacent pens with 

antimicrobials 3.0 (1.6) 0.3 (0.3) 0.0 (--) 2.1 (1.1) 

Treated all pigs in 

entire room with 

clinically ill pigs with 

antimicrobials 34.8 (4.9) 65.1 (5.5) 57.6 (7.0) 43.3 (3.6) 

Have not had 

clinical respiratory 

disease 26.1 (4.1) 4.0 (1.6) 10.9 (3.8) 20.1 (2.9) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

56 / Swine 2006

The owner of the operation was the primary decision-maker regarding antimicrobial

usage in sick grower/finisher pigs on 67.9 percent of small sites and 29.0 percent

of large sites. Large sites were more likely than small sites to use a company

nutritionist or company veterinarian for antimicrobial decisions.

b. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites by person primarily responsible for deciding which antimicrobials were used

to treat sick grower/finisher pigs, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 

2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Primary 

Decision-Maker* Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Owner of operation 67.9 (4.4) 40.1 (5.4) 29.0 (6.2) 57.7 (3.5) 

Farm manager, not 

the owner 7.9 (2.7) 14.4 (5.1) 8.9 (5.2) 9.3 (2.5) 

Local veterinary 

practitioner 7.5 (2.2) 8.2 (2.7) 11.0 (4.0) 8.1 (1.7) 

Consulting or secondopinion veterinarian 2.7 (1.8) 3.7 (2.2) 3.8 (1.8) 3.0 (1.3) 

Company 

veterinarian or 

company nutritionist 6.6 (2.2) 17.2 (3.7) 28.8 (6.3) 11.4 (1.9) 

Service manager who 

oversees more than 

one site 6.6 (2.3) 16.1 (3.5) 18.5 (5.4) 9.9 (1.8) 

Other 0.0 (--) 0.3 (0.3) 0.0 (--) 0.1 (0.1) 

Did not use 

antimicrobials for 

sickness in 

grower/finisher pigs 0.8 (0.5) 0.0 (--) 0.0 (--) 0.5 (0.4) 

Total 100.0 100.0 100.0 100.0 

*The owner and farm manager categories do not reflect whether or not antimicrobial decision protocols were 

developed with veterinary input. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 57

As was the case with sick pigs (table b), the owner of the operation was the

primary decision-maker on the majority of sites regarding which antimicrobials to

use for growth promotion in grower/finisher pigs.

c. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites by person primarily responsible for deciding which antimicrobials were used

in grower/finisher pigs for growth promotion, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Primary 

Decision-Maker* Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Owner of operation 67.0 (4.5) 41.8 (5.4) 33.9 (6.4) 58.1 (3.6) 

Farm manager, not 

the owner 6.1 (2.5) 9.1 (4.3) 0.6 (0.6) 6.0 (2.2) 

Local veterinary 

practitioner 3.8 (1.7) 3.6 (1.8) 7.5 (3.4) 4.2 (1.3) 

Consulting or secondopinion veterinarian 1.2 (0.9) 3.6 (2.2) 1.2 (0.8) 1.7 (0.8) 

Company 

veterinarian or 

company nutritionist 12.9 (3.2) 24.6 (4.3) 49.9 (6.8) 19.7 (2.6) 

Service manager who 

oversees more than 

one site 2.0 (1.3) 4.7 (1.8) 4.6 (2.5) 2.8 (1.0) 

Other 0.3 (0.3) 1.6 (1.3) 0.0 (--) 0.5 (0.3) 

Did not use 

antimicrobials for 

growth promotion in 

grower/finisher pigs 6.7 (1.9) 11.0 (3.7) 2.3 (1.8) 7.0 (1.5) 

Total 100.0 100.0 100.0 100.0 

*The owner and farm manager categories do not reflect whether or not antimicrobial decision protocols were 

developed with veterinary input.
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

58 / Swine 2006

The most common antimicrobials given by injection to grower/finisher pigs were

procaine penicillin G (46.6 percent of sites) and ceftiofur (42.1 percent of sites).

The most common reason for administering injectable antimicrobials to grower/

finisher pigs was to treat respiratory disease (63.7 percent of sites).

d. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that gave any grower/finisher pigs the following antimicrobials or parasite

treatments by injection during the previous 6 months, by primary reason given:

Percent Sites

Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Any 

Reason 

Product Given Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. 

Antimicrobial 

Ampicillin 0.0 (--) 0.9 (0.6) 2.5 (1.0) 0.1 (0.1) 3.0 (1.1) 0.0 (--) 0.5 (0.3) 6.9* (1.6) 

Amoxicillin 0.0 (--) 0.6 (0.5) 5.4 (1.9) 0.5 (0.5) 1.4 (0.7) 0.0 (--) 0.6 (0.4) 8.5 (2.2) 

Ceftiofur 0.0 (--) 3.4 (1.8) 36.3 (3.2) 0.4 (0.4) 1.9 (0.8) 0.0 (--) 0.1 (0.1) 42.1 (3.5) 

Erythromycin 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Florfenicol 0.0 (--) 0.1 (0.1) 5.9 (1.5) 0.0 (--) 1.3 (1.2) 0.0 (--) 0.0 (--) 7.3 (1.9) 

Gentamycin 0.0 (--) 0.0 (0.0) 1.2 (0.7) 2.0 (1.3) 0.0 (--) 0.0 (--) 0.0 (--) 3.2 (1.4) 

Lincomycin 0.0 (--) 0.9 (0.5) 7.0 (1.6) 1.1 (0.7) 2.8 (1.1) 0.0 (--) 2.4 (1.1) 14.2 (2.3) 

Oxytetracycline 0.0 (--) 1.1 (0.7) 18.8 (2.8) 0.2 (0.1) 0.2 (0.2) 0.0 (--) 0.1 (0.1) 20.4 (2.9) 

Procaine 

penicillin G 0.0 (--) 4.1 (1.4) 31.1 (3.4) 0.1 (0.1) 5.1 (1.6) 0.0 (--) 6.2 (1.5) 46.6 (3.6) 

Penicillin 

benzathine 0.0 (--) 2.1 (1.0) 8.1 (2.5) 0.3 (0.2) 1.6 (0.9) 0.0 (--) 1.9 (1.2) 13.9* (3.0) 

Spectinomycin 0.0 (--) 0.0 (--) 2.9 (1.1) 1.9 (1.1) 0.6 (0.6) 0.0 (--) 0.0 (--) 5.4 (1.8) 

Tylosin 1.0 (0.6) 1.1 (0.5) 5.6 (1.6) 12.9 (2.4) 0.6 (0.4) 0.0 (--) 2.5 (1.2) 23.7 (3.0) 

Tulathromycin 0.0 (--) 0.6 (0.3) 10.2 (2.1) 0.0 (--) 0.0 (--) 0.0 (--) 0.3 (0.3) 11.0* (2.1) 

Any of the above 

antimicrobials 1.0 (0.6) 10.8 (2.5) 63.7 (3.6) 15.9 (2.7) 14.3 (2.5) 0.0 (--) 12.1 (2.3) 75.6 (3.3) 

Parasite 

treatment 

Doramectin 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.7 (0.4) 0.0 (--) 0.7 (0.4) 

Ivermectin 0.0 (--) 0.5 (0.5) 0.3 (0.3) 0.0 (--) 0.0 (--) 6.9 (2.4) 0.0 (--) 7.7 (2.5) 

Levamisole 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 2.9 (2.1) 0.0 (--) 2.9 (2.1) 

Any of the above 

parasite 

treatments 0.0 (--) 0.5 (0.5) 0.3 (0.3) 0.0 (--) 0.0 (--) 7.5 (2.4) 0.0 (--) 8.0 (2.5) 

Other 

antimicrobial or 

parasite 

treatment 0.0 (--) 0.2 (0.2) 0.0 (--) 0.0 (--) 0.0 (--) 0.3 (0.3) 0.0 (--) 0.5 (0.3) 

*Sum of specific antimicrobials by reason may not sum to “Any Reason” estimate due to rounding. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 59
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

60 / Swine 2006

Parasite treatments were administered to grower/finisher pigs via feed on 19.9

percent of sites, the most common being fenbendazole. About half of sites with

grower/finisher pigs (55.1 percent) administered an antimicrobial or feed additive

via feed for growth promotion. The most common products administered via feed to

grower/finisher pigs were chlortetracycline (52.6 percent of sites), tylosin (44.2

percent of sites), bacitracin (29.1 percent of sites), and ractopamine (28.0 percent

of sites).

e. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that gave the following antimicrobials, parasite treatments, or feed additives

to any grower/finisher pigs via feed during the previous 6 months, by primary

reason given:
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 61

Percent Sites

Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Any 

Reason 

Product Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Antimicrobial or 

feed additive 

Amoxicillin 0.0 (--) 0.9 (0.9) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.9 (0.9) 

Arsanilic acid 0.0 (--) 0.3 (0.3) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.3 (0.3) 

Bacitracin 25.7 (3.5) 1.5 (0.9) 0.6 (0.5) 1.4 (0.7) 0.0 (--) 0.0 (--) 0.0 (--) 29.1* (3.6) 

Bacitracin zinc 0.5 (0.3) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.5 (0.3) 

Bambermycin 0.5 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.5 (0.4) 

Carbadox 4.4 (1.1) 3.6 (1.1) 0.0 (--) 3.4 (1.8) 0.0 (--) 0.0 (--) 0.0 (--) 11.4 (2.3) 

Chlortetracycline 11.5 (2.4) 18.5 (2.6) 22.3 (3.4) 0.3 (0.2) 0.0 (--) 0.0 (--) 0.0 (--) 52.6 (3.6) 

Chlortetracycline/ 

sulfathiazole/ 

penicillin 0.1 (0.1) 0.7 (0.4) 2.1 (1.1) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 2.8* (1.1) 

Chlortetracycline/ 

sulfamethazine/ 

penicillin 0.8 (0.6) 0.2 (0.2) 1.2 (0.9) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 2.2 (1.1) 

Florfenicol 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Hygromycin B 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Lincomycin 0.7 (0.5) 2.8 (0.8) 1.6 (0.6) 2.4 (1.2) 0.0 (--) 0.0 (--) 0.0 (--) 7.5 (1.6) 

Neomycin and 

Terramycin 1.6 (0.8) 2.7 (0.7) 0.8 (0.6) 1.7 (0.6) 0.0 (--) 0.0 (--) 0.7 (0.7) 7.4 (1.4) 

Oxytetracycline 0.7 (0.4) 2.2 (1.1) 2.2 (1.3) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 5.1 (1.7) 

Ractopamine 27.9 (3.5) 0.0 (--) 0.0 (--) 0.1 (0.1) 0.0 (--) 0.0 (--) 0.0 (--) 28.0 (3.5) 

Roxarsone 0.3 (0.3) 0.0 (--) 0.6 (0.5) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.8* (0.6) 

Tiamulin 2.3 (1.8) 4.9 (1.5) 2.0 (0.8) 1.0 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 10.1* (2.4) 

Tilmicosin 0.0 (--) 5.1 (1.7) 1.4 (0.6) 0.5 (0.5) 0.0 (--) 0.0 (--) 0.0 (--) 7.0 (2.0) 

Tylosin 13.3 (2.4) 13.0 (2.2) 4.9 (1.3) 11.3 (2.8) 0.0 (--) 0.0 (--) 1.6 (1.1) 44.2* (3.6) 

Tylosin and 

sulfamethazine 0.5 (0.4) 0.2 (0.1) 0.8 (0.5) 1.5 (0.8) 0.0 (--) 0.0 (--) 0.0 (--) 2.9* (1.1) 

Virginiamycin 4.4 (1.2) 2.9 (0.7) 0.0 (--) 0.1 (0.0) 0.0 (--) 0.0 (--) 0.0 (--) 7.4 (1.3) 

Any of the above 

antimicrobial or 

feed additive 55.1 (3.6) 37.5 (3.4) 29.0 (3.5) 17.1 (3.2) 0.0 (--) 0.0 (--) 1.6 (1.1) 83.6 (2.5) 

Parasite 

treatment 

Dichlorvos 0.1 (0.1) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.1 (0.1) 

Fenbendazole 0.0 (--) 0.1 (0.1) 0.0 (--) 0.1 (0.1) 0.0 (--) 12.2 (3.0) 0.0 (--) 12.3* (3.0) 

Ivermectin 0.0 (--) 1.5 (0.9) 0.0 (--) 0.1 (0.1) 0.0 (--) 2.9 (1.0) 0.0 (--) 4.5 (1.3) 

Levamisole 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Pyrantel tartrate 0.1 (0.1) 0.0 (--) 0.0 (--) 0.1 (0.1) 0.0 (--) 4.8 (2.0) 0.0 (--) 4.9* (2.0) 

Any of the above 

parasite 

treatments 0.2 (0.1) 1.6 (0.9) 0.0 (--) 0.1 (0.1) 0.0 (--) 18.0 (3.4) 0.0 (--) 19.9 (3.5) 

Other 

antimicrobial, 

feed additive, or 0.5 (0.4) 0.8 (0.6) 0.4 (0.4) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 1.6* (0.8) 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

62 / Swine 2006
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 63

Parasite treatments were administered to grower/finisher pigs via feed for an

average of 16.1 days, while medications for growth promotion were administered

for an average of 62.3 days.

f. For sites that gave an antimicrobial, parasite treatment, or feed additive to any

grower/finisher pigs via feed during the previous 6 months, site average number of

days given, by primary reason given:

Site Average (Days) 

Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

62.3 (4.0) 38.4 (3.6) 27.3 (3.7) 40.8 (6.4) NA* 16.1 (2.9) NA* 

*Estimate not reported due to small sample size. 

When bacitracin or virginiamycin were administered to grower/finisher pigs via

feed, they were given for more than 70 days on average.

g. For sites that gave the following antimicrobials, parasite treatments, or feed

additives to any grower/finisher pigs via feed during the previous 6 months, site

average number of days given:

Antimicrobial, Feed 

Additive, 

or Parasite Treatment* 

Site Average 

(Days)

Standard 

Error 

Bacitracin 76.8 (5.9) 

Carbadox 37.2 (10.3) 

Chlortetracycline 41.5 (4.3) 

Fenbendazole 14.7 (3.5) 

Lincomycin 22.7 (3.6) 

Neomycin and Terramycin 18.2 (2.5) 

Ractopamine 32.6 (2.4) 

Tiamulin 35.6 (6.5) 

Tylosin 48.8 (4.1) 

Virginiamycin 75.2 (6.8) 

*Estimates for other antimicrobials not reported due to small sample size. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

64 / Swine 2006

The most common reasons sites with grower/finisher pigs used antimicrobials in

water were to treat respiratory disease (42.4 percent of sites) followed by treating

enteric disease (15.8 percent of sites).

h. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that gave the following antimicrobials or parasite treatments to any grower/

finisher pigs via water during the previous 6 months, by the primary reason given:

Percent Sites

Primary Reason Given 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Any 

Reason 

Product Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. Pct. 

Std. 

Err. 

Antimicrobial 

Bacitracin 0.0 (--) 0.0 (--) 0.0 (--) 0.3 (0.3) 0.3 (0.3) 0.0 (--) 0.0 (--) 0.5* (0.4) 

Chlortetracycline 0.0 (--) 1.4 (0.5) 17.4 (2.4) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 18.8 (2.5) 

Florfenicol 0.0 (--) 0.2 (0.2) 0.8 (0.5) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 1.0 (0.6) 

Lincomycin and 

Spectinomycin 0.0 (--) 0.5 (0.3) 3.8 (1.6) 1.1 (0.7) 0.0 (--) 0.0 (--) 0.0 (--) 5.4 (1.7) 

Neomycin 0.0 (--) 0.9 (0.5) 2.8 (1.8) 7.0 (1.3) 0.0 (--) 0.0 (--) 0.0 (--) 10.7 (2.2) 

Oxytetracycline 0.0 (0.0) 0.8 (0.4) 12.9 (2.2) 2.0 (1.7) 0.0 (--) 0.0 (--) 0.4 (0.3) 16.2* (2.6) 

Penicillin G 

potassium 0.0 (--) 0.3 (0.3) 3.3 (1.2) 0.0 (0.0) 0.7 (0.4) 0.0 (--) 0.0 (--) 4.4* (1.5) 

Spectinomycin 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Sulfachlorpyridazine 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 

Sulfadimethoxine 0.0 (--) 0.0 (--) 3.9 (1.4) 0.2 (0.1) 0.0 (--) 0.0 (--) 0.4 (0.3) 4.5 (1.4) 

Sulfamethazine 0.0 (--) 0.0 (--) 6.4 (1.3) 0.0 (--) 0.0 (--) 0.0 (--) 0.1 (0.1) 6.5 (1.3) 

Tetracycline 0.0 (--) 0.7 (0.4) 7.3 (1.7) 0.6 (0.6) 0.0 (--) 0.0 (--) 0.0 (--) 8.6 (1.8) 

Tiamulin 0.0 (--) 0.0 (--) 1.8 (0.7) 4.9 (1.9) 0.0 (--) 0.0 (--) 0.0 (--) 6.7 (2.0) 

Tylosin 0.1 (0.1) 0.6 (0.3) 2.2 (1.5) 9.1 (1.9) 0.0 (--) 0.0 (--) 0.0 (--) 12.0 (2.4) 

Any of the above 

antimicrobials 0.2 (0.1) 3.7 (0.9) 42.4 (3.5) 15.8 (2.7) 0.9 (0.5) 0.0 (--) 0.6 (0.4) 47.9 (3.6) 

Parasite 

treatment 

Levamisole 0.0 (--) 0.0 (0.0) 0.0 (--) 0.0 (--) 0.0 (--) 0.2 (0.1) 0.0 (--) 0.2 (0.1) 

Piperazine 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 0.0 (--) 1.5 (0.7) 0.0 (--) 1.5 (0.7) 

Any of the above 

parasite 

treatments 0.0 (--) 0.0 (0.0) 0.0 (--) 0.0 (--) 0.0 (--) 1.7 (0.7) 0.0 (--) 1.8* (0.7) 

Other 0.1 (0.1) 0.7 (0.4) 5.4 (1.5) 1.4 (0.8) 1.1 (0.6) 0.0 (--) 0.0 (--) 8.7 (1.8) 

*Sum of specific antimicrobials by reason may not sum to “Any Reason” estimate due to rounding. 
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

USDA APHIS VS / 65
Section I: Population Estimates—G. Use of Antimicrobials, Parasite Treatments, or Feed Additives in Weaned Pigs

66 / Swine 2006

On average, antimicrobials were administered to grower/finisher pigs via water to

treat respiratory disease for 10.1 days, while enteric disease was treated for 6.4.

i. For sites that gave any antimicrobials or parasite treatments to grower/finisher

pigs via water during the previous 6 months, site average number of days given, by

primary reason given:

Site Average (Days) 

Primary Reason 

Growth 

Promotion 

Disease 

Prevention 

Respiratory 

Disease 

Treatment 

Enteric 

Disease 

Treatment 

Polyserositis/ 

Meningitis 

Treatment 

Parasite 

Treatment 

Other 

Reason 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

*NA 10.4 (2.3) 10.1 (0.9) 6.4 (0.7) *NA *NA *NA 

*Estimates not reported due to small sample size. 

Tylosin, which was used most frequently to treat enteric disease (table h), was

administered to grower/finisher pigs via water for a shorter average number of days

than oxytetracycline, which was used most frequently to treat respiratory disease.

j. For sites that gave the following antimicrobials to grower/finisher pigs via water

during the previous 6 months, site average number of days given:

Antimicrobial* 

Site Average 

(Days)

Standard 

Error 

Chlortetracycline 8.8 (1.0) 

Neomycin 6.9 (1.1) 

Oxytetracycline 11.5 (1.4) 

Penicillin G 4.6 (0.6) 

Sulfamethazine 7.3 (1.3) 

Tetracycline 7.4 (0.9) 

Tiamulin 6.5 (1.6) 

Tylosin 5.8 (0.6) 

*Other antimicrobials not reported due to small sample size. 
Section I: Population Estimates—H. Other Management Practices

USDA APHIS VS / 67

H. Other management

practices

1. Split-sex feeding

Split-sex feeding in the nursery occurred on 9.3 percent of sites with nursery-age

pigs. There were no differences in split sex feeding by size of site, when

considering the relatively large standard errors.

a. For sites with nursery-age pigs during the previous 12 months, percentage of

sites that practiced split-sex feeding* in the nursery phase, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

6.9 (3.0) 9.9 (3.7) 24.2 (7.1) 9.3 (2.4) 

*Most nursery-age males and females are fed different rations. 

On average, split-sex feeding in the nursery was initiated when pigs were 3.7

weeks of age.

b. For sites that practiced split-sex feeding in nursery phase, site average age (in

weeks) when split-sex feeding started:

Site Average (Weeks) Standard Error 

3.7 (0.5) 
Section I: Population Estimates—H. Other Management Practices

68 / Swine 2006

Split-sex feeding was a more common practice used for grower/finisher pigs than

for nursery-age pigs; 29.6 percent of sites with grower/finisher pigs practicing splitsex feeding compared to 9.3 percent of sites with nursery-age pigs (table a). A

higher percentage of medium sites practiced split-sex feeding compared to small

sites (45.7 and 22.9 percent, respectively). Large sites did not differ from medium

and small sites, when considering the relatively large standard error.

c. For sites with grower/finisher pigs during the previous 12 months, percentage of

sites that practiced split-sex feeding in the grower/finisher phase, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

22.9 (3.9) 45.7 (5.5) 42.0 (6.8) 29.6 (3.1) 

Split-sex feeding in the grower/finisher phase started at 9.9 weeks of age on

average.

d. For sites that practiced split-sex feeding in the grower/finisher phase, site

average age (in weeks) when split-sex feeding started:

Site Average (Weeks) Standard Error 

9.9 (0.4) 
Section I: Population Estimates—H. Other Management Practices

USDA APHIS VS / 69

2. Re-sorting pigs

Overall, 31.1 percent of sites with grower/finisher pigs re-sorted the pigs at least

once. A smaller percentage of large sites (10.1 percent) re-sorted pigs compared

to small and medium sites (34.2 and 33.3 percent, respectively).

For sites with grower/finisher pigs during the previous 12 months, percentage of

sites by the number of times pigs were usually re-sorted from 60 pounds until

market weight, by size of site:

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Number Times 

Re-sorted Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

0 65.8 (4.3) 66.7 (5.5) 89.9 (4.1) 68.9 (3.2) 

1 22.1 (3.7) 22.6 (5.3) 4.4 (3.3) 20.0 (2.9) 

2 7.3 (2.0) 6.2 (2.5) 5.7 (2.6) 6.9 (1.5) 

3 or more 4.8 (1.9) 4.5 (2.0) 0.0 (--) 4.2 (1.3) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates—H. Other Management Practices

70 / Swine 2006

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer than 

2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Supplement Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Fish meal* 9.6 (2.5) 13.9 (3.2) 16.7 (5.4) 11.3 (2.0) 

Meat or bone meal 17.7 (3.9) 23.0 (5.0) 11.6 (4.1) 18.0 (2.9) 

Soybean meal or 

other vegetable 

protein source 95.8 (1.9) 98.2 (0.6) 94.1 (2.6) 96.1 (1.4) 

Other protein 

sources** 10.1 (2.7) 16.8 (4.1) 9.5 (4.1) 11.3 (2.1) 

Bakery/food 

manufacture 

byproducts (not table 

waste)*** 7.3 (2.1) 29.9 (4.6) 20.7 (5.6) 13.2 (1.9) 

Animal and/or 

vegetable fat 41.8 (4.9) 66.9 (5.4) 66.8 (6.5) 49.7 (3.7) 

Distillers’ dried grain 30.5 (4.7) 41.7 (5.3) 39.1 (6.8) 33.7 (3.5) 

*13.6 percent “Don’t Know.” 

**9.6 percent “Don’t Know.” 

***74. percent “Don’t Know.” 

3. Feed supplements

Nearly all sites with grower/finisher pigs (96.1 percent) supplemented feed with

soybean meal or other vegetable protein sources. A higher percentage of large and

medium sites supplemented feed with animal and/or vegetable fat compared to

small sites.

Percentage of sites that included the following supplements or feed types in any of

the grower/finisher diets, by size of site:
Section II: Methodology

USDA APHIS VS / 71

Section II: Methodology

A. Needs Assessment During the needs assessment phase of the NAHMS Swine 2006 study, input was

sought from stakeholders regarding the critical swine production and health

information needs of the swine industry. These stakeholders included producers,

industry associations, researchers, and government agencies. A needs

assessment questionnaire was developed to facilitate input by a variety of groups.

The primary sources utilized in the needs assessment were the National Pork

Board (NPB) and the American Association of Swine Veterinarians (AASV).

The NPB needs assessment questionnaire for NAHMS Swine 2006 was included

in the October 20, 2005, Pork Leader Letter. This letter and a questionnaire were

distributed by conventional mail and by e-mail to 2,800 and 5,000 subscribers,

respectively.

The AASV needs assessment questionnaire for NAHMS Swine 2006 was included

in the November 2, 2005, AASV newsletter. This newsletter was also distributed

by mail and by e-mail to approximately 440 practitioners and 700 newsletter

subscribers.

In addition, between November 1 and 30, 2005, a letter of introduction and

questionnaire were e-mailed to government contacts at the Centers for Disease

Control; APHIS in Riverdale, MD; National Veterinary Services Laboratories;

Centers for Epidemiology and Animal Health; regional epidemiologists; area

veterinarians in charge; and the Food Safety Inspection Service. Overall, there

were 528 responses to the Needs Assessment questionnaire.

1. Number of respondents, by respondent type

Nearly half respondents (46.4 percent) characterized themselves as producers:

Respondent Type Frequency Percent Respondents 

Producer 245 46.4 

Practitioner 206 39.0 

Researcher 22 4.2 

Federal or State government 16 3.0 

Other allied industry 21 4.0 

Unknown 18 3.4 

Total 528 100.0 
Section II: Methodology

72 / Swine 2006

B. Sampling and

Estimation

1. State selection

A goal for NAHMS’ national studies is to include States that represent at least 70

percent of the animal and producer population in the United States. This study

focuses on operations with 100 or more hogs. Information from the National

Agricultural Statistics Service (NASS) December 28, 2004, “Hog and Pig” report

for numbers of hogs and pigs and the January 1, 2005, “Farms and Land in Farms”

report for number of operations with 100 or more hogs was used to select States.

The NASS hog and pig estimation program collects data quarterly from producers

in 17 States* and annually in all States. These 17 States accounted for 94.0

percent of the December 1, 2004, U.S. swine inventory for operations with 100 or

more hogs and 94.2 percent of U.S. operations with 100 or more hogs (See

Appendix II for data on individual States, updated to June 1, 2006, inventory and

number of operations in 2006.) An additional advantage of selecting these 17

States is that NASS’ list frame is more complete due to the more frequent contact

with producers.

2. Operation selection

In the Swine 2000 and 2006 surveys, an evaluation of the U.S. total inventory and

number of operations revealed that operations with 1 to 99 pigs accounted for 60.3

percent of pig operations in the 17 participating States but just 1.0 percent of total

pig inventory. Because this segment of the industry represented such a small

percentage of the total U.S. inventory, it was ineligible for the study. Therefore,

larger operations representing 99.0 percent of the pig inventory were selected.

NASS chose a stratified random sample of 5,006 operations selected from their

list sampling frame comprised of independent and contract producers.

Stratification was based on State and herd size. Larger operations were selected

with a higher probability of being included in the sample in order to reduce

variability. Operations with 100 or more pigs were eligible for an on-site interview.

At the first interview, if operations had multiple production sites under different dayto-day management, a maximum of three sites were randomly selected (one with

breeding animals and two with weaned pigs).

*Arkansas, Colorado, Iowa, Illinois, Indiana, Kansas, Michigan, Minnesota, Missouri, Nebraska,

North Carolina, Ohio, Oklahoma, Pennsylvania, South Dakota, Texas, and Wisconsin
Section II: Methodology

USDA APHIS VS / 73

3. Population inferences

Inferences cover the population of swine operations with 100 or more total pigs in

the 17 participating States for all phases of data collection. Appendix II shows that

these States accounted for 93.6 percent of operations with 100 or more pigs and

94.2 percent of the U.S. pig inventory on operations with 100 or more pigs (based

upon the June 1, 2006, inventory and 2006 number of operations). All respondent

data were statistically weighted to reflect the population from which they were

selected. The inverse of probability of selection for each operation was the initial

selection weight. This selection weight was adjusted for nonresponse within each

region and size group to allow for inferences back to the original population from

which the sample was selected. This weight was adjusted further for the number of

separate sites each operation had, relative to the number of sites that responded

to the survey.

C. Data Collection 1. General Swine Farm Report, July 17 – September 15, 2006

NASS enumerators administered the General Swine Farm Report questionnaire in

person with each selected producer that agreed to participate in the study. The

interview took approximately 1 hour. For producers that had 100 or more head on

June 1, 2006, NASS enumerators asked permission for veterinary medical officers

(VMOs) to contact the producer and discuss additional phases of data collection.

2. Initial VS Visit, September 5, 2006 - March 15, 2007

State and Federal VMOs contacted producers to solicit participation in this phase

of the study. A producer agreement that explained data confidentiality and

indicated producer intentions for biological sampling was signed by respondents. A

face-to-face interview was conducted to complete the Initial VS

Visit questionnaire, which took approximately 1 hour.

1. Validation and estimation

a. General Swine Farm Report

Initial data entry and validation for the General Swine Farm Report (results

reported in Swine 2006, Part I) were performed in individual NASS State offices.

Data were entered into a SAS data set, followed by the execution of the edit and

validation program. NAHMS national staff performed additional data validation on

the entire data set after data from all States were combined. The statistical

estimation was done using SUDAAN. SUDAAN uses a Taylor series expansion to

estimate appropriate variances for the stratified/clustered, weighted data.

D. Data Analysis
Section II: Methodology

74 / Swine 2006

b. Initial VS Visit Questionnaire

After completing the Initial VS Visit Questionnaire, data collectors sent them to

the State NAHMS coordinators where they were manually reviewed for errors and

accuracy, then forwarded to CEAH. Data entry and validation were performed by

NAHMS staff. Data were entered into a SAS data set, followed by the execution of

the data entry edit and validation program. NAHMS staff performed additional data

validation on the entire data set after data from all States were combined. The

statistical estimation was done using SUDAAN. SUDAAN uses a Taylor series

expansion to estimate appropriate variances for the stratified/clustered, weighted

data.

E. Sample Evaluation 1. General Swine Farm Report

The purpose of this section is to provide various performance measurement

parameters. Historically, the term “response rate” was used as a catch-all

parameter, but there are many ways to define and calculate response rates.

Therefore, the table to the right presents an evaluation based upon a number of

measurement parameters, which are defined with an “x” in those categories that

contribute to the measurement. Of the 5,006 operations selected, 3,071 (61.3

percent) provided usable inventory information. Note, the comparable weighted rate

was calculated at 65.7 percent usable operations. There were 2,079 operations

(41.5 percent) of the sample that provided “complete” information for the

questionnaire. About 9 of 10 operations (87.9 percent) were actually contacted for

the study.
Section II: Methodology

USDA APHIS VS / 75

1a. Operation level response

Evaluation 

Parameters 

Response Category Number 

Operations 

Percent 

Operations Contacts Usable 1/ 

Survey complete 2/ 2,079 41.5 x x 

No pigs on June 1, 2006 696 13.9 x x 

Out of business 296 5.9 x x 

Out of scope (prison and 

research farms, etc.) 13 0.3 

Refusal of GSFR 1,327 26.5 x 

Office hold (NASS elected 

not to contact) 315 6.3 

Inaccessible 280 5.6 

Total 5,006 100.0 4,398 3,071 

Percent of total operations 87.9 61.3 

Percent of total 

operations weighted 3/ 90.7 65.7 

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 for at least 

one site. 

3

Weighted response – the rate was calculated using the initial selection weights.

Survey complete operations were subdivided if multiple production sites existed.

A maximum of three sites were randomly selected. Overall, 2,230 site

questionnaires were completed for essentially the entire questionnaire, and 45.1

percent of the sites agreed to be contacted by APHIS for discussion about

participation in further phases of the study.

1b. Site level response

Response Category Number Sites* Percent Sites 

Survey complete and 

VMO consent 1,005 45.1 

Survey complete and 

refused VMO consent 1,225 54.9 

Total 2,230 100.0 

*There were 1,005 sites with survey complete and consent for the APHIS or VMO phase 

of the study, which originated from 912 selected operations. Similarly, there were 1,225 

sites that completed the survey but declined the VMO phase, which came from the rest 

of the original 2,079 selected operations or 1,167 selected operations. 
 Appendix I: Sample Profile

76 / Swine 2006

Appendix I: Sample Profile

A. Responding Sites 1a. Total inventory

Phase I: General Swine 

Farm Report Phase II: Initial VS Visit 

Size of Site 

(Total Inventory) 

Number 

Responding Sites 

Number 

Responding Sites 

Fewer than 2,000 1,157 260 

2,000 to 4,999 724 176 

5,000 or more 349 78 

Total 2,230 514 

Phase I: General Swine 

Farm Report Phase II: Initial VS Visit 

Size of Site 

(Total Sows 

and Gilts) 

Number 

Responding Sites 

Number 

Responding Sites 

No sows and 

gilts 1,353 278 

Fewer than 250 468 100 

250 to 499 102 37 

500 or more 307 99 

Total 2,230 514 

1b. Sow inventory

2. Type of site

Phase I: General Swine 

Farm Report Phase II: Initial VS Visit 

Type of Site Number 

Responding Sites 

Number 

Responding Sites 

Contract producer 1,027 237 

Independent—

market own pigs 1,086 246 

Independent—

market through 

cooperative 105 

30 

Other 12 1 

Total 2,230 514 
Appendix I: Sample Profile

USDA APHIS VS / 77

3. Regions

Phase I: General Swine 

Farm Report Phase II: Initial VS Visit 

Region Number Responding Sites Number Responding Sites 

North 499 96 

West Central 456 135 

East Central 888 156 

South 387 127 

Total 2,230 514 

4. Production phase

Phase I: General Swine 

Farm Report Phase II: Initial VS Visit 

Production Phase 

Combination

Number 

Responding Sites 

Number 

Responding Sites 

All four phases 502 120 

Gestation, farrowing, 

and nursery 81 14 

Nursery and 

grower/finisher 357 74 

Gestation and 

farrowing 226 83 

Nursery only 217 44 

Grower/finisher only 809 170 

Other combination 38 9 

Total 2,230 514 
Appendix II: U.S. Swine Population and Operations

78 / Swine 2006

Appendix II: U.S. Swine Population and Operations

Number of Pigs on June 1, 2006, and Number of Operations in 2006

 Number Pigs 

(Thousand Head) 

Number Operations 

in 2006 

Region State 

All 

Operations 

Operations 

with 100 

or More 

Head* 

All 

Operations 

Operations 

with 100 or 

More Head 

East 

Central Illinois 4,200 4,179 2,900 2,080 

 Indiana 3,200 3,171 2,800 1,500 

 Iowa 16,600 16,550 8,700 7,670 

 Ohio 1,620 1,539 4,000 1,300 

 Total 25,620 25,439 18,400 12,550 

North Michigan 980 965 2,100 560 

 Minnesota 6,800 6,766 4,800 3,600 

 Pennsylvania 1,100 1,067 3,100 800 

 Wisconsin 430 400 2,200 660 

 Total 9,310 9,198 12,200 5,620 

West 

Central Colorado 840 834 750 60 

 Kansas 1,840 1,827 1,400 540 

 Missouri 2,700 2,673 2,000 1,070 

 Nebraska 2,950 2,929 2,500 1,700 

South 

Dakota 1,470 1,455 1,100 730 

 Total 9,800 9,718 7,750 4,100 

South Arkansas 280 272 750 150 

North 

Carolina 9,600 9,590 2,300 1,510 

 Oklahoma 2,370 2,346 2,600 300 

 Texas 970 941 3,700 168 

 Total 13,220 13,149 9,350 2,128 

Total (17 States) 

57,950 

(93.9% of 

U.S.) 

57,504 

(94.2% of 

U.S.) 

47,700 

(72.8% of 

U.S.) 

24,398 

(93.6% of 

U.S.) 

Total U.S. (50 States) 61,687 61,070 65,540 26,058 

*Derived from NASS publication Farm, Land in Farms, and Livestock Operations, February 2007. 
Appendix III: Swine 2006 Study Objectives and Related Outputs

USDA APHIS VS / 79

1. Describe swine management practices used during the gestation, farrowing,

nursery, and grower/finisher phases of production.

• Part I: Reference of Swine Health and Management Practices in the United

States, 2006, October 2007

• Part II, Reference of Swine Health and Health Management in the United

States, 2006, December 2008

• Part III, Reference of Swine Health, Productivity and General Management,

expected winter 2007

•Info sheets, expected fall and winter 2007

2. Determine the prevalence and risk factors for a variety of pathogens found in

nursery and grower/finisher pigs.

• Part II, Reference of Swine Health and Health Management in the United

States, 2006, December 2007

• Part III, Reference of Swine Health, Productivity and General Management,

expected winter 2007

• Info sheets, expected fall and winter 2007

3. Examine vaccination and antimicrobial use practices.

• Part II, Reference of Swine Health and Health Management in the United

States, December 2007

4. Provide an overview of the changes in U.S. swine management and health from

1990 through 2006.

• Part IV: Changes in the U.S. Pork Industry, 1990-2006, expected early 2008

• Info sheets, expected early 2008

Appendix III: Study Objectives and Related Outputs