Is a dam-level scours vaccine worth the risk?

Calves are born with an immature immune system and they don’t develop their own antibodies until weeks after they hit the ground. Colostrum antibodies are vital to preventing diseases, such as E. coli, coronavirus and rotavirus. However, the quality of maternal colostrum can be comprised, leaving a newborn calf without adequate protection.

For decades, producers and veterinarians have used dam-level scours vaccines with the hope that the dam will impart antibodies into the colostrum to protect her calf. It’s an approach with some challenges and risks.

study shows that farmers don’t always achieve accurate vaccine implementation. It revealed that approximately 40 percent of producers using a dam-level calf scours vaccine do not vaccinate first-calf heifers. Nearly 80 percent of operations were shown noncompliant with label requirements that directly affect product efficacy.

In order for a dam scours vaccine to work, a cow has to be vaccinated in the correct window of time, she has to respond to the vaccine, and then she has to calve during a specific time frame. These steps leave a lot of room for protocol drift and error.

Most dam-level scours vaccines are contingent on the fact that you have to give two vaccinations to your heifers and then one annual booster every year after that to your cows.

Meaningful antibody generation typically takes about seven to 14 days after vaccination, and the mammary gland receptors are most efficient two to three weeks prior to calving. Because antibodies are not transferred in utero, the only way the calf can absorb them is through drinking colostrum within the first 12 hours of birth.

On top of all these potential timing issues, cows only respond to a vaccine under perfect conditions 80 percent of the time. This means that even if you vaccinate cows when the weather is ideal, and cows are nutritionally sound and not stressed, 20 percent of your calves will still be left with inadequate antibodies in the colostrum.

Not to mention the fact that some of the cows that do respond will calve early or late, and therefore, they will not be at peak antibody level when they give colostrum.

Significant variability is a constant challenge with vaccination. It’s no wonder there’s been a push for new science. Human health practitioners and researchers have been using preformed antibodies to combat a wide variety of human diseases for years. This technology is also available to the livestock industry.

Dr. Chris Chase, Department of Veterinary and Biomedical Sciences at South Dakota State University, has highlighted the use of passive polyclonal antibody products. According to Chase, these products provide the right amount of antibodies needed by the calf to protect against both bacterial and viral scours.

A 100 percent immunization response rate is biologically impossible with a vaccine. But with an antibody product, farmers know exactly what they’re getting – a known and proven level of protection against scours.

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