Breeding soundness exams provide producers peace of mind

Whether producers are preparing to turn out bulls they’ve overwintered or bulls purchased this spring, ensuring their ability to breed cows successfully is an important step to take. Montana’s Extension Beef Specialist Dr. Megan Van Emon shared breeding soundness exams (BSEs) give producers some guarantee bulls will be viable. “Producers know at the time of testing bulls – which pass on certain requirements – can be turned out, used on females and see breeding success,” Van Emon said.

Soundness examination

During BSEs, an external physical will check structural soundness of hooves and legs, as well as body condition, while an internal exam focuses on reproductive organs, Van Emon explained. In addition, a sperm sample will look at semen quality.

Van Emon noted each component of the BSE is important in ensuring bulls are ready to work. 

“In western states, bulls will often have to travel long distances to maintain themselves with cows,” she said. “Because they travel miles, we want to see good hoof and leg structure. Bulls also need to be in good body condition – not overly fat – because they need to be able to travel physically.”  

Spermatogenic cycles

Van Emon noted it is important to keep in mind when scheduling BSEs before the breeding season the spermatogenic cycle – the process of producing mature sperm cells – of cattle is 60 days. 

“The timing of spermatogenic cycles and BSEs can make it hard to determine when to turn out because sperm can sit in the scrotum for up to two weeks,” she explained, noting sperm quality can change between the time of the test and when bulls are turned out. “Typically, BSEs are conducted two to three months prior to the breeding season.” 

Van Emon continued, “The biggest issue many producers face is injury occurring between the time of BSE and turn out which could lead to reduced sperm quality. A lot of producers rely on bull power to make sure if an injury does occur, there are other bulls available to cover cows.” 

Injury is typically more of an issue in dominant bulls, Van Emon said, as they are more likely to push and fight. However, if dominant herd bulls have injuries leading to nonviable sperm, producers may see reduced pregnancy rates. 

She recommended producers avoid putting newly purchased bulls in with bulls not familiar with each other. 

“It is good to get bulls acclimated to each other early to avoid running everyone together at the beginning of the breeding season, but I recommend introducing bulls on different sides of a strong fence and acclimating them slowly,” she said. 

“Watch bulls closely. If producers notice a couple bulls getting beat up, be proactive and remove them before further injury, which could potentially lead to culling, can occur,” Van Emon said. 

Testing advancements

BSEs haven’t changed much throughout the years, Van Emon noted. The process may be subjective, depending on the veterinarian and is still a pass/fail exam. 

Scientists at Fort Keough, the Miles City, Mont. research station where Van Emon is stationed, have been looking at technology called flow cytometry. This process examines morphology and abnormalities of sperm which may not be evaluated in normal sperm quality tests. 

“This process could help us understand why bulls appearing normal during the BSE may have issues during breeding season which were unnoticed or unexplained by sperm quality testing,” she said. “Flow cytometry could identify factors, such as certain proteins on sperm heads which don’t allow attachment to the egg, which could further the BSE process.” 

Nutritional
considerations

In addition to BSEs, before turn out with cows, Van Emon asked producers to remember drought could play a factor in sperm quality based on nutrition. 

“With drought, producers need to be selective in their feed,” she said. “Don’t forget about bulls when overwintering cattle. Often, bulls “tough out” through the winter on poor pasture and aren’t worried about until it’s time to get ready for breeding season.”

It is important to make sure bulls are in good body condition before turn out, Van Emon said. Many purchased bulls are highly conditioned for sales, and when brought home for breeding season, can lose condition quickly. It is recommended producers manage bulls to ensure they don’t lose weight too quickly while working.

Averi Hales is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.