The single most important component of a successful breeding program is using fertile bulls that have passed a bull breeding soundness evaluation (BSE). Each bull is expected to contribute to 20 to 50 pregnancies each year. Having a BSE conducted on breeding bulls is crucial to a successful breeding program. The BSE is an exam conducted by veterinarians that includes a physical exam, semen evaluation, and an internal and external exam of the reproductive tract. The BSE should be conducted 30 to 60 days prior to breeding to allow sufficient time to retest or replace bulls that fail the BSE. It is important to note that the bull’s sperm production cycle is approximately 60 days. If illness, injury or other issues occur, this could negatively impact the BSE and breeding capability of the bull.
The physical examination evaluates the bull’s physical ability to breed cows. The physical exam identifies problems such as poor vision, bad teeth, and poor feet and leg structure. Body condition, or flesh cover, varies by breed, age, physical demands of winter, the previous breeding season, and feed availability. Body condition should be adequate at the beginning of the breeding season. A good “rule of thumb” is that bulls should have enough fat cover at the beginning of the breeding season that their ribs are not visible but are felt. A thin bull may not have enough stamina to breed many cows in the timeframe allotted. However, a fat bull may not be able to travel extensive distances to breed. Sperm quality can also be negatively impacted in fat or thin bulls. Bulls should have sound physical structure which will improve mobility. Good feet and legs are needed to travel to the cows, breed, and travel to water and feed sources. Sore feet or stress on tendons and joints due to sickle hocks or post legs can reduce mobility and result in fewer cows being bred. Checking joints for swelling or injury can aid in identifying bulls that are not physically sound to breed. If hooves need to be trimmed, trim four to six weeks prior to turnout to ensure recovery prior to the breeding season. Vision is an integral component of the BSE because bulls use sight to identify cows in estrus. Eyes should be clear and free of injury and disease such as cancer eye and pinkeye.
For further information on reproductive tract information, scrotal circumference requirements, semen evaluation and classification, please see the Montguide. Information for this article was taken from the Montguide MT201901AG. Authors include Megan Van Emon (MSU Extension Beef Cattle Specialist), Colleen Buck (Hill County Extension and Molly Hammond (Big Horn County Extension). The electronic version of the Montguide is available at MSU Extension Publications. If you would like a paper copy, we have the Montguide available at the Chouteau County Extension office. We are located in the green building behind the courthouse.
Montana State University, U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.
