Cattle Chat: What to do when a bull fails a breeding soundness exam

Cattle Chat: What to do when a bull fails a breeding soundness exam
May 1st, 2024 | K-State Research and Extension

Depending on the job, some people may have to complete a fitness test to prove that they can complete what will be required of them to be successful.

For bulls whose job it is to breed cows, the fitness test often comes in the form of a breeding soundness exam completed by a veterinarian in the weeks ahead of pasture turnout, say the experts at the Kansas State University Beef Cattle Institute.

Speaking on a recent Cattle Chat podcast, K-State veterinarian Bob Larson said there are several components to a breeding soundness exam.

“With that exam, we make sure the bull is in good body condition and that his feet and legs are sound. We also palpate the scrotum and observe his penis to be sure it moves freely. And then we test a semen sample to assess the quality of the sperm he is producing,” Larson said.

Relating to the semen sample, K-State veterinarian Brian Lubbers explained what the base criteria are for the semen to pass.

“We want 70% of the bull’s sperm cells to be normal morphology and 30% of those cells to have a normal, forward-progressive motility,” Lubbers said.

These tests are typically done in the spring before the bulls are turned out into breeding pastures with the females.

Unfortunately, not all bulls pass their breeding soundness exam. That can happen for a variety of reasons, said the veterinarians.

So that begs the question: What should producers do with a bull who fails the exam?

“It really depends on the age of the bull and why he failed,” Lubbers said.

If the bull is around 12 months of age and he fails on semen quality, Larson recommends producers retest the bull in a few weeks.

“Because of the cattle breeds that we have in the U.S., I don’t expect all bulls will be fertile at 12 months of age, but by the time they are 15 months old, their age should not be a limiting factor,” Larson said.

Lubbers said there are some health challenges relating to a bull’s movement that can cause him to fail on exam day, but as he recovers that should not be a barrier to him passing a future evaluation.

“If he has a foot abscess, he will fail the exam but that is easy to treat and his prognosis of being able to return to breeding is good,” Lubbers said. “However, if he only has 20% normal sperm under the microscope, he may never pass. And that is why some fails are different than others.”

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