Scour vaccinations for cows: convenience vs. effect back
Few cattlemen would dispute the opportunity to eliminate an extra trip through the working chute for their cowherd. Reduced trips mean reduced stress for cattle and crew with the end result being less cost.
Vaccinating cows at pregnancy testing time with an approved scour vaccine is one management practice that offers producers that cost-saving opportunity: one trip, two functions. However, the convenience in the application may not generate the desired effect: optimum calf immunity.
Vaccine labels reflect the fact that in the governmental approval process, the vaccine company has demonstrated that their vaccine produces a minimum level of antibody in the colostrum over a period of time. Whether that level is enough to protect a baby calf from scours depends on many factors—one of which is timing. Vaccines given months prior to calving, while producing higher levels of antibodies than non-vaccinated animals, usually will not produce higher antibody levels than the same vaccine given closer to calving.
Dr. Mike Stiefvater, Salem Veterinary Clinic, recommends that scour vaccines should be administered as close as possible to calving time. Research indicates that it takes a minimum of two weeks to achieve the antibody levels that will provide optimum protection for the newborn calf.
Some veterinarians also recommend that other vaccines not be given at the same time. Keeping stress to a minimum can improve response. In the case of heifers and cows that have not previously been vaccinated for scours, a booster vaccination is required two weeks after the initial dose to increase the effectiveness of the protection offered to the calf.
Timing of scour vaccinations is not the only factor that dictates the effectiveness of a scour vaccination protocol. Cow nutrition plays a huge role in the attempt to reduce or control calf scours:
The ability of a cow’s immune system to function properly is directly correlated to a balanced diet that satisfies her nutritional needs for her present stage of production.
The absence of calf scours is directly proportional to the quality and quantity of colostrum consumed by the infant calf. Both quality and quantity of colostrum are influenced by proper cow nutrition.
Calf scour prevention is an economic consideration for cow/calf producers. Optimum levels of calf immunity are the result of proper timing of vaccination programs and meeting cows’ nutritional needs, not necessarily the convenience of the cattleman. — Jim Krantz, South Dakota State University