Breeding Soundness for Live Cover Bulls
Improving profitability and cutting losses for cow-calf producers largely hinges on each cow’s ability to provide a viable calf year over year. While a lot of pressure is put on the cows, it is worth arguing that the virility of the herd sire (or clean up bull) is just as essential, if not more important.
To do this, bulls should be evaluated regularly not only to manage their health and nutritional needs, but to ensure they stay viable for your herd. This includes annual breeding soundness exams and also knowing when to rest and retire bulls.
Bull Health
According to Reinaldo Cooke’s Oregon State University bulletin, Basics of reproductive function in bulls, the average 12 months to reach puberty for bulls can vary quite a bit. Factors like genetics, nutrition, environment and health can all affect maturity.
“As an example, under adequate nutritional and management scenarios, Holstein bulls can reach puberty as early as 8 months of age, whereas Brahman bulls typically reach puberty after 15 months of age,” he explains. “…Bull fertility and serving ability will determine the reproductive performance of the cows that the bull is expected to breed. Consequently, the reproductive ability of bulls should be evaluated annually prior to breeding.”
Keeping track of your bull’s health is important to ensure you catch any issues as they arise so you save yourself time and money. It’s important that cows conceive and if there is an issue with a bull it can cause a domino effect.
Breeding Soundness Exams
Breeding soundness exams (BSEs) are important to ensure bulls meet the proper and standard criteria as the most beneficial and impactful for the herd.
These exams don’t guarantee everything, but they give a solid foundation and background support for a bull. A full exam should include everything from semen quality to physical characteristics impacting mobility and function.
It should especially look at overall reproductive traits in young bulls and measure testicular size via scrotal circumference. In addition to increasing the likelihood a bull will impregnate more cows, it can also help pinpoint undesirable traits and culling candidates.
“Body condition should be scored, and a general physical examination conducted with special attention paid to the feet, legs, eyes, and sheath,” says the Merck Veterinary Manual. “The inguinal rings and internal genitalia should be palpated per rectum to detect any abnormalities, eg, seminal vesiculitis. Palpate the scrotum to evaluate the testes, epididymides, spermatic cords, and scrotal skin.”
For sperm tests, there should be an evaluation of two things in a complete BSE – motility and morphology. To consider being passable, a bull should have at least 30% sperm motility and 70% of sperm being classified as physiologically “normal.”
However, this doesn’t mean that BSEs are necessarily the end all be all. Dr. Lew Strickland of the University of Tennessee Institute of Agriculture notes in his article Bull Breeding Soundness Evaluation that:
“A BSE does not evaluate a bull’s libido, nor does it ensure that a bull will remain a satisfactory potential breeder the entire breeding season. An injury to a bull’s hooves, legs or reproductive tract may render a bull incapable of breeding your cows. Therefore, it is still extremely important to observe your bulls regularly to ensure they are doing their job.”
That’s why regular observation during the breeding season is so critical. Ideal mobility means a bull moves freely without stiffness or limping whether walking or mounting. He should be able to travel the pasture with ease, keeping up with cows in heat without signs of fatigue.
While libido can’t be fully “measured” in a lab, you can still get a pretty good sense of it through pasture observation. A bull actively checking cows, exhibiting flehmen response, and making repeated, successful breeding attempts shows signs of strong breeding drive. Conversely, a bull that shows little interest in cycling cows, or fails to complete mounts, should have an evaluation immediately to prevent lost breeding opportunities.
Your bull genetics will influence not only the current calf crop but also future breeding stock if you retain bull calves. Selecting a bull with traits that complement your cow herd ensures that desirable characteristics integrate into your herd, while poor decisions can set a program back for years.
Does it really matter?
Whether a bull is physically present on the farm or accessed through an A.I. or stud service, he’s an essential part of any cow-calf operation. A thorough understanding of a bull’s physical health, reproductive soundness and nutritional needs to cover cows in a timely manner
With frozen semen, they perform much of the initial reproductive evaluation is already complete. Testing semen quality for motility, morphology and concentration before going to market to ensure the product meets fertility standards. However, it’s still up to the producer to match that semen’s genetic profile to their cow herd’s needs and goals. Likewise, proper semen storage and handling are all essential to improving its integrity.
BSEs are an invaluable tool, whether you’re purchasing a new bull or leasing one for a season. They offer a tangible, measurable way to evaluate a bull’s fertility before investing time and resources into breeding.
His genetics will influence not only the current calf crop but also future breeding stock if you retain bull calves. Selecting a bull with traits that complement your cow herd will lock in those desirable characteristics and pass them down. Conversely, poor decisions can set a program back for years.
By Jaclyn Krymowski for American Cattlemen
October 2025
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