Ask the Vet

Dr. Ken McMillan, Contributing Columnist

DTN is rerunning this column from our archives because it's still relevant and useful advice.

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READER QUESTION:

Do I need to semen-check my bull every year, even though he is in good shape and seems healthy?

DR. MCMILLAN'S ANSWER:

I firmly believe every bull should have a Breeding Soundness Exam (BSE) done before every breeding season. A BSE is much more than a "semen check." It is done by a veterinarian and includes a physical assessment of the bull. That assessment includes a measurement and examination of the testicles, and an evaluation of the penis and all accessory sex organs, as well as an evaluation of semen motility and morphology (normal versus abnormal shape).

I have addressed this in past columns and noted that in my career, I've identified several completely sterile bulls. Unfortunately, in one case, we identified the infertile bull after we found more than 30 open cows at the end of the breeding season. He had passed a "semen check" but was unable to extend his penis.

The more common scenario is the subfertile bull. These bulls will get some cows pregnant, but not as many as a bull that has passed a BSE. How much are just two or three more calves worth at weaning? The other silent thief is that many of these calves will be born later in the calving season. This can impact weaning weights from just a few pounds to over 100 pounds in a 60-day calving season.

I also tell my clients that when I "pass" a bull, it's not the end of the BSE. A bull can "go bad" at any time from disease or injury.

The second phase of the BSE falls to the producer. Watch the bull closely to make sure he can and will breed cows. Libido is not assessed in a BSE, and penile deviations are also not always noted. Lots of cows returning to heat 18 to 24 days after a heat is also a red flag that must be addressed immediately.

Putting a bull in without a BSE is like playing Russian roulette. Please don't take that chance.

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Editor's Note: Please contact your veterinarian with questions about the health of your herd or other animals. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes. Email Dr. Ken McMillan at vet@dtn.com.

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