Vaccinations:

Cows should receive their annual booster at least two weeks prior to the onset of breeding for both BVD and lepto. For bought-in animals or maiden heifers that require both courses, the primary should be administered about six weeks prior to breeding, with the booster administered two weeks prior to the targeted breeding. It’s important that the bull receives his booster shot also, and that bought-in bulls are given an initial shot and the booster shot.