BEEF HEALTH

Advice on killed vs. live vaccines, long-range dewormer, and nutrition.

- Gene Johnston

Viral diseases in beef cow herds are pesky and serious. That's why you vaccinate at least once a year for such things as BVD (Types 1 and 2), IBR, PI3, Lepto, and a few others that your veterinarian recommends.

If that were the whole story, it would be fairly simple. But sometimes the type of vaccine becomes an issue with reproductive performance.

Vaccines come in two types: killed vaccine and modified-live vaccine (MLV).

A killed vaccine has a killed portion of the pathogen and no live material. It still triggers an immune response.

MLV, on the other hand, contains an attenuated version of the live virus that comes closer to mimicking a real infection. It gives a stronger response, experts say, but it can also on rare occasions lead to pregnancy loss.

Elanco cattle reproductive specialist Frank White says research reveals that the strong response to an MLV stresses a cow's reproductive system. It interferes with her ability to form a functional corpus luteum on her ovaries and to produce progesterone, the hormone needed to maintain pregnancy. Sometimes this results in early pregnancy loss.

Elanco, which makes cattle vaccines, has tested its killed vaccine, Vira Shield, against competitive MLVs. Vira Shield resulted in a 4.3% higher pregnancy rate 56 days after breeding. "With 100 cows, that's four more pregnancies," White says.