Spring SW Missouri Bull Breeding Soundness Exam Day Results

“Bull breeding soundness exams (BSEs) are important to make sure bulls are ready for the upcoming breeding season,” says Patrick Davis, University of Missouri Extension livestock field specialist.

The exam evaluates bull physical and reproductive soundness. Using bulls that fail this exam can lead to poor conception, pregnancy, calving and weaning rates, which results in poor operation productivity and profitability, Davis says.

“The BSE is a good time to deworm and vaccinate bulls to promote optimum herd health and performance,” he says. Therefore, veterinarians collaborate with pharmaceutical companies to provide vaccinations and parasite control at a reduced rate during these BSE days. Also, this is a good opportunity for MU Extension to provide education to cattle producers and collect data to use for educational purposes. Therefore, Davis with MU Extension was able to partner with six southwestern Missouri veterinary clinics to educate 52 farms and collect data on 203 bulls during March and April bull BSE days. Below, Davis will discuss the data collected and how it is used to make management decisions for optimum operation reproductive efficiency and productivity.

Soundness is evaluated by palpation of the reproductive tract and semen quality evaluation. Seven of the 203 bulls evaluated failed or were deferred due to not being sexually mature, poor semen quality or reproductive tract injury. The three bulls that failed should be replaced. There were four yearling bulls that were deferred due to either not reaching sexual maturity or poor semen morphology, so they will be retested in 60 days. However, if these bulls fail the retest, they should be culled.

“The BSE also evaluates if bull physical structure is sound to breed cows,” says Davis. Foot scoring was evaluated on the bulls through claw set (CS), which evaluates the hoof, and foot angle (FA), which evaluates the pastern and heel. These are evaluated on a 1 to 9 scale, with the ideal range being 3 to 7. Evaluation showed that two bulls had a CS score greater than 7. The veterinarian passed these bulls; however, it was suggested they may need foot trimming in the future or be replaced. Three other bulls passed the BSE but had issues such as corns, swollen hocks or pastern swelling. The veterinarian passed these five bulls as sound enough to breed cows, but Davis suggests cattle producers need to closely watch bulls with poor foot scores, corns and leg issues for lameness. If lameness appears, bulls should be evaluated by the veterinarian, treated to an acceptable outcome or replaced. Lameness issues can impair the bull’s ability to breed cows, resulting in reduced operation productivity and profitability.

“Body condition score (BCS) is a measure of the animal's energy status,” says Davis. Optimum energy status is important as bulls enter the breeding season. As they enter the breeding season, bulls should be in a BCS of 6, which is a smooth appearance of condition throughout the body. Twenty-one bulls were evaluated at a BCS of 4 or less, which is considered thin. Davis suggests cattle producers evaluate bull body condition score at BSE time and adjust nutrition so bulls reach that optimum BCS prior to the breeding season.

Seven of 203 bulls failed the BSE and were not acceptable for the upcoming breeding season. This is 3.4%, which is below the typical range of 10% to 20%. Since the beginning of this program in 2005, about 5,794 bulls have been evaluated, and the extremes for fail/deferral rate have been from 17% to 3.2%. The important part of this program is that the owners of three bulls that failed know their bulls need to be replaced. Also, the owners of the four bulls that were deferred know that if their bulls fail the retest they need to be replaced. Furthermore, these events educate cattle producers to make decisions that promote operation productivity and profitability.