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Producers should consider breeding soundness exams before breeding season

by Wyoming Livestock Roundup

Breeding soundness exams (BSE) are a tool producers can use to help assess the reliability and capability of their bulls and the likelihood their bulls will be effective for the breeding season. 

The exam consists of three different evaluations that analyze structural soundness, the reproductive tract and semen quality. 

Exam components

The physical condition of the bull is examined during the structural soundness portion and looks at the overall condition of the animal, particularly the fleshiness of the animal, his feet, legs, eyes and teeth. 

The analysis of the reproductive tract inspects the bull’s scrotum, testicles and penis. 

A rectal palpation is also conducted to determine any internal abnormalities to the sex glands. 

Motility, morphology and concentration of semen are assessed to find any irregularities that could affect the bull’s fertilization. Semen collection is primarily performed via electro-ejaculation. A microscope is then used to look at the semen and its quality. 

The scoring system for a BSE is satisfactory, unsatisfactory or suspect to be retested at a later date. 

Producers can usually make a decision on whether to keep a bull or not in their breeding program once the semen quality has been assessed and the structural integrity of the bull have been completed. 

Conducting exams

“Anybody trained to perform a BSE can conduct the exam, but usually a local veterinarian will perform a BSE because they are the ones who can collect a bull and test them,” explains Gary Moss, reproductive biology professor at University of Wyoming.

Producers can expect to pay $25 to $40 for a BSE per bull, plus any set-up fees or farm call charges a veterinarian may have. 

Semen quality

“Before a producer starts using a bull as a sire they should perform a BSE every year. Something could have happened to the bull during the offseason causing it to be infertile for some reason,” comments Moss.

“The exam should be performed at least once a year around 60 days before the breeding season,” adds Moss. 

The sperm in the bull’s reproductive tract is 30 to 45 days old when it is collected. 

If a bull receives an unsatisfactory rating for his semen quality, potential explanations could be from an illness, heat stress or extreme cold the bull may have previously encountered. 

“The semen quality is an indication of what the bull’s health was at that time,” states Moss. “It’s important to know the history of the bull being tested.”

The bull should be retested 30 days after the initial test to determine if any changes have occurred in the semen quality. 


“Producers should give enough time before the breeding season, so if they find something wrong with their bulls, they have a chance to retest the bull or find another bull,” says Moss. 

To improve the quality of a bull’s performance, Moss advises producers to have bulls on an appropriate nutritional plane before the breeding season.

“It takes a lot of energy to breed cows,” says Moss. “Producers should have their bull in shape and have him in good flesh before he goes into the breeding season. Often times a bull goes downhill during the breeding season.”


Yearling bulls may not test very well during a BSE, and a common reason for that is they are still immature and have not reached puberty yet. 

Another factor could be the yearling bulls are at the bottom of a pecking order when placed with a bunch of other bulls. 

“There is some pretty interesting data out there showing that when a young bull is in with a bunch of old bulls, that young bull is probably not going to breed many cows because of the social structural of the group of bulls,” explains Moss. 


“If a bull passes everything and still doesn’t breed any cows, there might be a libido reason involved,” suggests Moss. “If libido is down, he’s not going to breed very many cows.”

Libido is the desire to breed, and testing for it in bulls is very rarely done, comments Moss. 

To conduct a libido test a group of cows in heat are turned out with the bull and then watched to see how the bull reacts to them and if he shows interest in breeding them. 

“It takes a lot of time, is labor intensive and costly to do a libido test,” says Moss. “I think most ranchers intuitively do it on their own by keeping an eye on their bulls to see if they are mingling with their cows or not.”

Addressing libido issues

The reasoning for low libido can be for a number of behavioral or social issues.

Some more prominent reasons are either the bull has low to no interest or the bull is at the bottom of the pecking order with older, larger bulls not allowing them to breed any cows. 

Moss recommends if a producer is going to purchase a very expensive bull, a libido test might be worth considering.

Madeline Robinson is editor of the Wyoming Livestock Roundup and can be reached at

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