STOCKTON, Mo. — “Bull breeding soundness exams (BSE) are important to make sure bulls are ready for the upcoming breeding season,” says Patrick Davis MU Extension Livestock Field Specialist. These exams determine if bulls are physically and reproductively sound to breed cows during the breeding season. Using bulls that are unsatisfactory in reproductive and physical soundness can lead to poor conception, pregnancy, calving and weaning rates which results in poor cattle operation productivity and profitability.
“The BSE is a good time to deworm and vaccinate bulls to make sure they are not bringing anything into the herd that will cause health or performance problems,” says Davis. Therefore, veterinarians work with ZOETIS to provide vaccinations and parasite control at a reduced rate during these BSE Days. Also, this is a good opportunity to provide education to cattle producers and collect data to use for educational purposes. Therefore, Davis with MU Extension was able to partner with 4 SW MO veterinary clinics to educate 40 farms and collect data on 164 bulls during October bull BSE days. Below, Davis will discuss the data collected and how it is used to make management decisions to better cattle operation reproductive efficiency and productivity.
“One reason for the BSE is to determine if the bull is reproductively sound for the upcoming breeding season,” says Davis. Soundness is determined by palpation of the reproductive tract and evaluation of semen quality. Of the 164 bull records collected, 5 bulls were failed or deferred because of the semen quality issue such as abnormal sperm morphology or not giving a semen sample. One young bull had abnormal sperm morphology and the veterinarian chose to defer the bull and have him retested in 60 days due to his age to see if his semen is acceptable. However, in this bull’s case, if he has unacceptable semen at retest, he should be culled.
“Another reason for the BSE is to determine if the physical structure of the bull is sound to breed cows during the breeding season,” says Davis. Foot scoring was evaluated on the bulls by looking at the claw set which evaluates the hoof and the foot angle which evaluates the pastern and heal. These are evaluated separately on a 1 to 9 scale with the ideal range for both measurements being 3 to 7. For the bulls evaluated during the bull BSE Days 3 bulls had a foot angle and claw set score greater than 7. The veterinarians passed two of these bulls and failed one of them. The bull that failed had a hoof injury and the veterinarian trimmed the hoof, treated the injury and blocked one of the claws on the hoof to help it heal. Even though the veterinarian felt the other two bulls were sound enough to breed cows, Davis suggests cattle producers need to watch bulls with poor foot scores closely for lameness issues. If lameness appears in these bulls they should be evaluated immediately by the veterinarian to determine if the bull can be treated to an acceptable outcome or if he needs to be replaced. Bulls with untreated lameness issues will negatively affect the bull’s ability to breed cows, as well as operation productivity, and profitability.
Body condition score (BCS) is a measure of the animal’s energy status. Davis suggests that optimum energy status is important as bulls enter the breeding season to make sure they have the energy to breed cows during the breeding season. The ideal BCS for bulls as they enter the breeding season is a 6 which is a smooth appearance of condition throughout the body. Sixteen of the 164 bulls evaluated had a body condition score of 4, which is considered thin. Of these 16 bulls 3 bulls failed the BSE due to bad semen morphology or hoof injury. Davis suggests cattle producers evaluate bull BCS at BSE time and adjust nutrition, so bulls reach that optimum BCS of 6 prior to the breeding season.
Six of 164 bulls failed the BSE and are not acceptable bulls for the upcoming breeding season. This is 3.7% which is below the typical range of 10 to 20%. Since the beginning of this program in 2005 approximately 5,591 bulls have been tested and the extremes for fail/deferral rate were from 17% to 3.2%. The important part of this program is that the owners of 5 of these bulls know that their bulls are subfertile and these bulls either need to be retested later under veterinary recommendation or culled and replaced with bulls that have passed a BSE. As for the owner of the injured bull, if the bull recovers from his injury and passes a BSE, he would be acceptable to breed cows. Furthermore, these events help cattle producers make decisions that promote operation productivity and profitability. For more information on any information discussed in this article contact Davis at (417) 276-3313 or by email at email@example.com or your local MU Extension Livestock Field Specialist.
— MU Extension