United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Veterinary Services 

Centers for Epidemiology and Animal Health June 2009 

_________________________________________________________________________________________________________________________ 

Persistent Infection of Calves 

with Bovine Viral Diarrhea 

Virus on U.S. Beef Cow-calf 

Operations 

The U.S. Department of Agriculture’s National Animal 

Health Monitoring System conducted the Beef 2007–08 

study, which focused on beef cow-calf health and 

management practices in 24 States divided into three 

regions.*

 These major beef cow-calf producing States 

represented 79.6 percent of U.S. operations with beef 

cows and 87.8 percent of U.S. beef cows. 

One of the goals of the Beef 2007–08 study was to 

estimate the prevalence of calves persistently infected 

with bovine viral diarrhea virus (BVDV) on U.S. beef 

cow-calf operations. 

Infection with BVDV can affect an animal’s 

reproductive efficiency and cause a variety of conditions, 

including respiratory and digestive disease. 

Ultimately, bovine fetuses are the source of 

persistent infection with BVDV in cattle. Fetuses 

exposed to the virus between 40 and 120 days of 

gestation can become immunotolerant to BVDV and 

shed the virus their entire lives. These persistently 

infected animals can pass the virus to noninfected cattle, 

which develop clinical disease. If these newly-infected 

animals are pregnant, they can pass the infection to their 

calves (if the exposure occurs at the right stage of 

gestation) thereby creating the next generation of 

persistently infected calves. Infection with BVDV results 

in other effects at other stages of gestation. Vaccination 

can increase resistance to BVDV infection and thus 

lower the frequency of persistently infected calves. 

However, vaccination is not always effective in 

eliminating the risk of persistently infected calves. Herd 

BVDV control plans use surveillance, biosecurity, and 

biocontainment strategies to prevent, reduce, and 

eliminate BVDV. Appropriate testing, targeted 

vaccination, and management are integral parts of these 

plans. 

 

 

*

States/Regions 

West: California, Colorado, Idaho, Montana, New Mexico, 

Oregon, Wyoming 

Central: Iowa, Kansas, Missouri, Nebraska, North Dakota, 

South Dakota 

Southeast: Oklahoma, Texas, Alabama, Arkansas, Florida, Georgia, 

Kentucky, Louisiana, Mississippi, Tennessee, Virginia

 

Testing calf crop for BVDV 

During the Beef 2007–08 study, beef producers who 

expected to calve at least 70 percent of their cows and 

heifers from November 1, 2007, through June 30, 2008, 

were encouraged to collect ear notches from their entire 

2008 calf crop. Ear notches were subsequently frozen 

dry until tested for indications of persistent infection with 

BVDV. 

At the laboratory, notches were tested using an 

IDEXX antigen capture enzyme-linked immunosorbent 

assay test according to the manufacturer’s instructions. 

 Overall, 205 operations collected ear notches from 

calves born between November 2007 and June 2008. 

The number of notches collected per operation ranged 

from 3 to more than 500. A total of 44,150 notches were 

collected and tested. 

 The prevalence of BVDV among the tested notches 

was 0.12 percent (53/44,150). Within herds, the 

prevalence ranged from 0 to 16.0 percent. 

 Of the 205 operations that submitted ear notches, 18 

had 1 or more positive samples, for a herd-level 

prevalence of 8.8 percent. Ten operations had only one 

positive sample (1 operation with 1 to 49 cows and 9 

operations with 200 or more cows), and 1 operation with 

200 or more cows had 10 positive samples. The 

percentages of positive operations were similar across 

herd sizes (table 1) and regions (table 2) due to the large 

variability in the estimates. 

Table 1. Operations with Samples Positive for BVDV, 

by Herd Size: 

Herd Size (Number of Beef Cows) 

1-49 50-99 100-199

200 

or More

All 

Operations 

Operations 

submitting 

samples 27 37 56 85 205 

Operations 

with 

positive 

samples 1 0 6 11 18 

Percent 

operations 

with 

positive 

samples 3.7 0.0 10.7 12.9 8.8 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Table 2. Operations with Samples Positive for BVDV, 

by Region: 

Region 

West Central Southeast 

Operations 

submitting 

samples 73 88 44 

Operations with 

positive 

samples 11.0 4.5 13.6 

Percent 

operations with 

positive 

samples 8 4 6 

 BVDV prevalence was similar across calf-age 

categories (table 3). 

Table 3. Percentage of Calves Positive for BVDV, by 

Age of Calves: 

Percent Calves 

Age 

Less Than 

3 Weeks 

3 Weeks to 

3 Months 

Over 

3 Months 

Age 

Unknown 

0.14 

(8/5,635) 

0.13 

(37/29,228) 

0.14 

(6/4,424) 

.04 

(2/4,863) 

Summary 

 The low prevalence of persistent infection with 

BVDV in beef calves found in the Beef 2007–08 study is 

consistent with findings from other studies. Despite the 

low prevalence at the animal level, approximately 1 of 12 

operations had at least 1 persistently infected calf, 

suggesting that a number of operations likely have 

BVDV circulating in their herds. Producers should work 

with their veterinarian to determine the likelihood that 

their herd has an animal persistently infected with BVDV 

and, if warranted, develop a surveillance strategy to 

determine the BVDV status of their cattle. If persistently 

infected animals are discovered, a control or elimination 

plan would be advisable, based on the operation’s 

specific situation. 

For more information on BVDV, visit the following Web 

sites: 

www.bvdinfo.org

www.avc-beef.org

www.aabp.org

_______________________________ 

For more information, contact: 

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.aphis.usda.gov

#551.0609 

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