Getting the most out of the probe
Laurin cautions that there are differences in probes. Some provide more electrical stimulation than others, and a user has to be prepared to understand how each one can work well. She says young bulls tend to perform better with the smaller probe size and less electrical stimulation. “Once a bull is about 4-years old, a larger probe and a hotter probe can work more satisfactorily,” she says.
Technique is important to successful collection. Handling bulls as gently as possible and rectal palpation prior to collection generally leads to easier ejaculation after the probe is stimulated. First time collection on a young bull takes some patience, so introduce electrical stimulation slowly, then speed up as the bull becomes acclimated. “A mature bull can be stimulated quickly and read a hotter setting right away,” says Laurin. “There are times where if a first and second collection in the chute is unsuccessful, it is best to put the bull to the back of the lineup, let it stand for 10-15 minutes, then try collecting again. Also, a full bladder will provide difficulty in getting satisfactory stimulation, so putting the bull through the chute again can be beneficial by allowing it time to urinate.”
Dairy bull BSEs
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