The Cow-Calf Manager

Livestock Update, March 2006

John B. Hall and W. Dee Whittier Extension Beef Cattle Specialist and Extension Veterinarian VA Tech

Pre-breeding Excellent Time to Vaccinate Cows

Cow vaccination programs are often overlooked by producers. However, these vaccinations are important to reproductive success. Diseases that are part of the bovine respiratory disease (BRD) complex can also cause abortions in cattle. Two viruses from the BRD complex implicated in abortions are Infectious Bovine Rhinotracheitis (IBR) and Bovine Viral Diarrhea (BVD). In addition, leptospirosis (Lepto) is common in Virginia and causes abortion in cattle. Vaccinating lactating or open cows before breeding with a high quality vaccine will reduce chances that these diseases will cause a decrease in reproductive efficiency.

Another recent benefit of vaccinating cows prebreeding is that certain vaccines now allow for the use of modified-live virus vaccines against BRD to be used in calves nursing pregnant cows IF cows were vaccinated with the same vaccine prebreeding. The use of modified-live virus vaccines in calves allows for nursing calves to be vaccinated in accordance to VQA Certified Feeder Calf requirements with only one shot for the BRD complex. Currently, Bovi-Shield and PregGaurd (Pfizer), and Pyramid (Ft. Dodge) vaccines are labeled for use in calves nursing previously vaccinated cows. Before using any of these modified-live virus products in calves nursing pregnant cows, please consult your veterinarian to ensure your herd health program and product choice is compatible with use in nursing calves and pregnant cows.

Recommended Vaccinations for Cows
Recommended prebreeding vaccinations for cows include IBR, PI3, BVD, BRSV, 5-way Leptospirosis. A new Lepto organism called Lepto hardjo-bovis is also gaining current attention and vaccines are now available for this agent. While it seems clear that the organism is present in our Virginia cattle, there is still a lack of data on whether vaccination for the disease will improve reproductive performance in our herds. Vaccinations against Vibrio, a venereal disease, should be included if recommended by your veterinarian. Either killed or modified-live virus products may be used as prebreeding vaccinations. However, producers must be careful to follow label directions. Remember all killed virus vaccines must be boostered with same product in 14 to 28 days as indicated on the label. Most modified-live virus vaccines only require one dose, but several require a booster for BRSV. In addition, not all modified-live virus vaccines are approved for use in calves nursing pregnant cows even if the cows were previously vaccinated.

For more information on a recommended herd health program for the cow-calf herd see "Beef Cow/Calf Herd Health Program and Calendar" authored by Drs. Whittier and Currin. This publication is available at http://www.ext.vt.edu/pubs/beef/400-007/400-007.pdf or through your local Extension office.

In addition to prebreeding vaccinations, all cows should receive a revaccination against Lepto at weaning or pregnancy exam. Because of the nature of the Lepto vaccine, immunity to Lepto developed by cows is relatively short lived. So revaccination every 6 months is essential to adequate protection against leptospirosis.

Barriers to Prebreeding Vaccinations
One of the biggest barriers to a quality prebreeding vaccination program is a long calving season. Calving seasons extending beyond 75 to 90 days often have cows still calving when bulls are turned in. Producers should strive for a calving season that is only 75 to 80 days long. Initially, producers with herds with extended calving seasons can vaccinate cows in groups as they calve. Some vaccines are approved for annual revaccination at pregnancy exam once initial vaccinations have been completed.

Producers should also work with their veterinarian on a vaccination program for their replacement heifers. Having these animals properly immunized with a modified-live virus product before their initial breeding season can help in establishing a routine of prebreeding vaccinations for the cow herd.

Another barrier is time management. Calving season and prebreeding season often overlap. Producers need to be careful and plan ahead for timing of vaccinations. A good herd health program can go awry if one forgets prebreeding vaccinations only one year.

Lack of time between calving and the beginning of the breeding season is often cited by producers as a barrier to prebreeding vaccinations. Traditional recommendations were to complete all vaccinations by 30 days before the breeding season especially for modified-live virus vaccines. Research indicated that exposure of previously unvaccinated cows to a modified-live vaccine within 2 weeks of the breeding season reduced pregnancy rates due to the immune response to the vaccine. Recent research by Dr. Dee Whittier at Virginia Tech indicates that vaccinations with a modified-live virus product can occur as little as 10 days before the breeding season IF the cows have been vaccinated with the same product in previous years.

Plan now to incorporate prebreeding vaccinations in your herd health program and it will make your entire herd health program easier. In addition, calf health may be improved by vaccination of the calf pre-weaning.

Disclaimer
Commercial products are named in this article for informational purposes only. Virginia Cooperative Extension, Virginia Tech, and Virginia State University do not endorse these products and do not intend discrimination against other products that also may be suitable.

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