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Bull power and breeding potential provided through soundness exams

by Wyoming Livestock Roundup

Many producers overlook the importance of doing a breeding soundness exam (BSE) for their bulls, and it is simply because they are busy. When bulls need tested, producers are typically calving and cannot get away. Then comes breeding season. 

Dr. Tyler Dohlman of Iowa State University Veterinary School shares a BSE is a tool to manage bulls for a successful breeding season.  

“There are many tough decisions to make to successfully run a cow/calf operation,” he says. “The one good thing producers can do is test their bulls from a BSE standpoint.” 

BSE as insurance 

 Testing makes for a great insurance policy for a couple reasons. 

“Sub-infertility and infertility can have long-term effects,” Dohlmans says.  

He notes if a bull has no defects and is producing good quality sperm cells, then he is a return investment for the producer. Every year the producer has the guarantee their bulls have passed the soundness exam and are able to breed successfully in the upcoming season.  

 “Every 21 days a cow is left open, it leaves the producer with a loss of 55 to 60 pounds come weaning weight on their calves,” says Dohlman.  

 The return investment is simple considering every cattle producer wants a consistent set of calves. 

 “Producers want nice consistency in the group – they don’t want 400 weights and also 600 weights in the same group,” explains Dohlman. “They want a nice equal group throughout so they can put calves in their feedlot and finish them at the same time.” 

Additionally, Dohlman shares cattle producers utilize BSE as much or more than pregnancy testing, adding he has only touched about 50 to 60 percent of the bulls coming through the university.  

BSE physical examinations 

Dohlman says, “In general, bull BSE is actually a snapshot of the bull’s breeding potential for the date the exam was performed. This basically means if we bring a bull in, we examine him from a thorough breeding soundness exam and qualify him as a satisfactory potential breeder. It doesn’t mean he’ll be a satisfactory breeder for the rest of his life, or even the next day.”  

There are four main exams making up the BSE.  

“Its not just collecting the bulls and seeing what their semen looks like or what their sperm cells look like,” explains Dohlman.  

There is a general physical examination, internal reproductive examination, external genitialia examination and semen quality examination.   

“I see way too many bulls coming in this time of year with a body condition score of 4.5 to five, which has a lot to do with Mother Nature,” says Dohlman. “But, we know when we turn bulls out, they’re going to have a job to do and they’re going to lose some body mass.”  

Preferably, bull body condition scores should be in the six to seven range, Dolhman adds. The physical examination covers general health, body condition, eyes, dentition/mouth and musculoskeletal features.  

Internal evaluations 

“Our internal reproductive exam is very similar to the pregnancy check on a female,” shares Dohlman. “This is usually just a rectal palpation, sometimes an ultrasound is used just to make sure we have normal organs on the reproductive side of the male.”  

The external genitialia examination looks at the scrotum, penis and prepuce. Dohlman explains from this, veterinarians can tell if there is some abnormalities which could inhibit reproductive performance. 

He explains the scrotum should be symmetrical in shape and be free of blemishes such as frost bite, warts or scars. For the penis/prepuce examination, Dohlman studies the important anatomy structures to rule out any abnormalities such as retroprepucial lacerations, hair-rings and more.  

“During the semen quality part of the exam, we evaluate the semen motility,” shares Dohlman. “We’re looking for those sperm cells which have progressive linear motility.”  

Then, they look at semen morphology.  

Dohlman continues, “I can’t stress it enough, morphology has to be done on sperm cells to get an accurate diagnosis of a satisfactory potential breeder versus a sub-fertile or infertile bull.”  

According to Dohlman, morphology has a higher predictability of success in natural cover, artificial insemination and in vitro fertilization than motility. To rate the bull satisfactory, the morphology of sperm cells must be 70 percent or greater.  

A solid build 

“It’s kind of like the manufacturing a car – each part of the testicle and epididymis, the components or anatomy of the testicle itself has each individual part. The last thing we put on a car is the steering wheel, so if everything goes right except for the last part, we basically have a lemon of a vehicle,” says Dohlman. “This would be the same thing as a sperm –  everything has to be built right.”  

Dohlman explains, in whole, a BSE not only evaluates fertility, but rather looks at all exam components added together to rate the bull as a satisfactory potential breeder.  

Information for this article was compiled from a Focusing on the Bull Power lecture in April 2020.   

Delcy Graham is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to 

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