Geni Wren Spring is usually the time for breeding soundness exams of beef bulls, but don't forget about BSEs for dairy bulls if your clients use them.
There are still a lot of dairy bulls in use on dairies, and they need breeding soundness exams, too. However, as of a few years ago, less than 10% of dairy clients (based on two different surveys of producers) had ever had BSEs performed on their bulls, says Mike Overton, DVM, MPVM, University of Georgia. “BSEs are a vastly underutilized screening tool and unfortunately, due to the current, tough financial times, it seems unlikely that we will convince more dairy owners to begin using this tool.”
When he does perform BSEs, Overton says, “The single most common reason for failure in my hands for Holstein bulls is related to testicular or seminal vesicle issues — inadequate scrotal circumference, infections resulting in white blood cells in the semen, testicular injuries, testicular hypoplasia, etc. The second most common category of reasons was sperm morphology and the third was actually lameness or other disease issue.”
Dairy bulls aren’t kept around as long as beef bulls. Overton says they’ll start using them at about 15-months of age, and then they are usually culled no more than 12 months later.
Dairy bull health protocols
Overton offers this hypothetical vaccine schedule as an example of a dairy bull vaccination protocol:
At 12–13 months of age, IBR, BVDV, BRSV, PI3. Overton prefers modified live virus (MLV) and a cytopathic virus vaccine to reduce the risk of persisently-infected testicles that may result from use of noncytopathic vaccine. Bull are also given a leptospirosis hardjo-bovis and 5-way vaccine, a double dose of vibrio and a 7-way clostridial.
At 13–14 months, bulls are given IBR, BVDV, BRSV, PI3 (cytopathic and MLV). Bulls are also given a leptospirosis hardjo-bovis and 5-way vaccine, a double dose of vibrio and a 7-way clostridial.
At 20-months of age bulls are given another dose of vibrio and a leptospirosis hardjo-bovis plus a 5-way vaccine.
As far as internal parasites, Overton notes that in the Southeast, it’s primarily important to be aware of Ostertagia issues.
Dairy bull nutrition
Dairy bulls should be introduced at a body condition score of about 2.5 to no more than 3.0 on a 1 to 5 scale, Overton suggests. Dairy bulls will definitely gain weight while in the breeding pens since they are consuming the lactating diet.
“Fat bulls are usually lazy with a reduced libido and more susceptible to the effects of heat stress,” says Overton, and there can be issues with overfeeding protein, energy and calcium since they are eating the same ration as the cows. Because of this, Overton recommends a rotational management system for dairy bulls.
Read more on bull breeding soundness exams from Bovine Veterinarian here.