By Connor Biehler, Beef Systems Extension Educator
Weaning and shipping can be a stressful time in a calf’s life and can cause acute illness. These conditions can include taking in high-risk cattle to co-mingle, weaning your own calves to finish or purchasing ranch source cattle. Importantly, it is our duty as stewards and caretakers of these animals to reduce these stress factors and mitigate illness. Preconditioning against disease can improve calf performance through the growing and finishing phase.
Bovine respiratory disease (BRD) is the most prevalent cause of sickness and death of weaned calves. This emphasizes the need for producers to prepare a calf’s immune system to prevent BRD. This step begins long before weaning or shipping and starts with preparing the mother’s immune system. Ideally, all replacement heifers are immunized for IBR, PI3, BVD and BRSV using a modified live virus (MLV) vaccine prior to entering the breeding herd. For the greatest effectiveness, two doses should be given no less than 21 days apart. Additionally, a booster should be administered one to two months before breeding season and pregnant cows/heifers should never receive an MLV vaccine.
An annual booster for all cows will improve BRD colostrum antibodies and decreases likelihood of BRD virus infections contaminating the herd. A vaccination program for calves should begin when they are 2–3 months old to combat BRD and clostridial (blackleg) diseases. This will provide them with proper immune responses to BRD MLV vaccines. Importantly, since bulls will not be turned out, pregnancy loss can be disregarded.
Preweaning vaccinations should be administered 4–8 weeks prior to weaning. These should include a four-way viral (IBR, PI3, BVD and BRSV), BRD bacterial (including Mannheimia hemolytica) and clostridial inoculation. Many BRD MLV vaccines include a labeled warning against administering to calves nursing pregnant cows. It is important to work with your herd veterinarian to determine the proper BRD vaccine for preweaning of calves.