Ask the Vet

By Dr. Ken McMillan
DTN Contributing Editor

QUESTION: When purchasing a new bull, what should I do to protect my herd from any possible diseases the bull might bring in?

ANSWER: Years ago the first two things on that list would have probably been brucellosis and tuberculosis, but today many states are free of those diseases. The bigger threats now are from diseases that many producers haven't even heard of.

1. Let's start with trichomoniasis. This is a venereal disease. Bulls are infected by breeding an infected cow, but show no signs. Infected cows may experience early embryonic death, abortion or pyometra (pus in the uterus). A virgin bull cannot be infected, but non-virgin bulls should be cultured for trich by a veterinarian before adding them to your breeding herd.

2. Also check for Johne's disease. This is a chronic disease causing diarrhea and severe weight loss. Test before the bull comes onto your property when possible, but realize a negative test does not mean the bull isn't incubating Johne's. Infected animals typically do not show signs until they are at least 2 years of age. Johne's status of the herd of origin and the reputation of the breeder may be as important as testing.

3. Next, consider Anaplasmosis. This is caused by a blood parasite and it can lead to severe anemia, loss of body condition, decreased milk production, abortion, infertility and death. It is transmitted by biting insects, ticks and contaminated needles or equipment.

4. Another big problem now is bovine viral diarrhea, which is very common in all parts of the country. BVD can cause fever, diarrhea, respiratory disease and reproductive problems. The biggest problem comes with the rarest form of the disease: the persistently infected animal (BVD-PI). These animals are infected in the uterus. They never clear themselves of the disease and continually shed high levels of the virus. A simple ear notch test can identify these animals.

5. In addition to these tests, bulls should be vaccinated against IBR, BVD, PI3, BRSV, Leptospirosis 5-way, and Vibriosis and quarantined for four to six weeks. The quarantine gives bulls time to recover from any illness associated with the stress of the sale or shipping, and allows time for completion of diagnostic tests and a breeding soundness evaluation.

(SK)

Copyright 2017 DTN/The Progressive Farmer. All rights reserved.