The past winter has been one of the coldest on record and it may have affected the fertility of Tennessee herd bulls, says a University of Tennessee Extension beef cattle expert.

Jim Neel, a professor of animal science, says the cold months of December and January could have produced frost bite on the scrotum of bulls, which can lower their reproductive potential. “Bulls may look vigorous and virile, but ‘looks’ are not an indication of reproductive capabilities,” he cautions producers. “A breeding soundness examination will give a better indication, not a guarantee, of a bull’s fertility.”

Neel says statistics show that some 15 to 20 percent of the bulls currently running with cow herds are either sub-fertile or sterile. “Producers cannot afford to have a ‘reproductively challenged’ bull running with the cow herd,” he said.

Ideally, breeding soundness examinations (BSEs) should be performed annually by a veterinarian and should take less than 30 minutes to conduct. Neel says the exam should be performed 60 days prior to the beginning of breeding season. “If a bull does not meet the criteria to be capable of fulfilling the role of a ‘breeder,’ there is still time for a retest, and if needed, for the producer to purchase a replacement for next year’s late-winter, early spring calving season.”

In addition to evaluating the bull’s reproductive tract and semen, the bull’s physical condition, skeletal soundness, eyes, and body condition should also be evaluated. These items also have a large effect on reproductive performance.

Additional information may be available online at the national eXtension website. eXtension delivers knowledge from land-grant university experts across America, including the University of Tennessee. Visit