When implementing a fall vaccination program for the cow herd it is important to keep in mind long-term goals, short term needs, and herd reproductive status. Implementing a health program that can achieve its goals is more important than using products because of convenience.
There are many vaccines available that can be given to pregnant cows under certain conditions but there is always some risk to the fetus. Therefore, a good health program starts pre-breeding when there is not a fetal risk. Fall vaccines can offer short term protection until a pre-breeding program is fully established.
There is always debate about using modified-live (MLV) versus killed vaccines during pregnancy. MLV vaccines tend to give a more complete immune response but can also cause abortions. There are some MLV vaccines approved for pregnant cows as long as cows have been vaccinated within the previous 12 months with the same vaccine. Killed vaccines are safer but may not provide the same degree of protection. Discuss the benefits and risks with your veterinarian to determine the best program for your herd.
Fall is an ideal time to vaccinate cows against lepto. Most pre-breeding vaccines include a 5 way lepto but duration of immunity is limited. Lepto can cause mid to late term abortions in cows so fall is the perfect time to provide additional immunity. Operations that incorporate some degree of confinement in winter should seriously consider a lepto booster.
Scours vaccines can be given in the fall but may need to be boosted in the spring. For optimum efficacy, scours vaccines should be given several weeks prior to calving. The best timing to achieve colostral protection is to vaccinate 2-12 weeks before calving. Scours vaccines administered more than 16 weeks prior to calving probably have minimal impact on colostral antibody levels.