Veterinarians and cattle producers have long embraced pre-weaning vaccinations as effective ways to reduce the impact of respiratory disease in calves following the stress of weaning. Vaccination against viral pathogens such as BRSV, IBR, PI3, and BVD roughly a month prior to weaning, with appropriate boosters at or near the time of weaning, has been the hallmark of many cow-calf producers’ preconditioning programs.
Typically pre-weaning vaccinations have been a task completed in early fall—September, for example. Enter this year’s drought, and with it the specter of early weaning in light of decreasing pasture quality. These circumstances create a different schedule for the cattle producer. If calves are weaned at 100 days of age in August this year, for example, pre-weaning shots would best be done in July, a month prior to weaning.
The specific timing of respiratory vaccines (along with the typical Clostridium combinations) is something best discussed with your veterinarian. Recommendations for timing may vary according to the products being used (whether the vaccines are killed or modified live, for example) and the particular management and risk factors present on a particular operation. Some general statements can be made, however:
- If calves are seeing respiratory vaccines for the first time now, ideally they should get that vaccine no less than two weeks prior to weaning. Any vaccine, especially the first dose, needs time to stimulate the immune system prior to exposure (in this case, exposure to the stress of weaning)—often the longer the better.
- Paying attention to booster doses of vaccine and their timing is important. The best immunological “bang for the buck” is when the booster dose is given in the time frame mentioned on the product label (typically 3-4 weeks after the initial dose). Try to give boosters at that time regardless of how close to weaning the first dose was given.
- Calves that have had respiratory vaccines at branding time are blessed with a bit more flexibility. The response to a booster dose of vaccine is quicker than the response to the initial dose. Boostering the vaccine at weaning time is an acceptable practice; however doing this even a few days prior to weaning would ensure a good immune response on board when the calf is weaned.
Producers should not be discouraged from vaccinating calves at this early stage of life. In the past, researchers worried about antibodies from colostrum interfering with the response to vaccines. Newer work shows that, killed vaccines, modified live intranasal vaccines, or adjuvanted modified live vaccines, used in calves as young as a couple months of age can be protected against active infection with viruses such as BVDV. Changing the timing of vaccination programs to respond to challenges such as drought always brings a bit of uncertainty. As always, a cattle producer’s best resource for preventive health issues is the local veterinarian.
Source: Russ Daly DVM, DACVPM, SDSU Extension Veterinarian