While breeding season for most cow herds is still months away, it’s time cattle producers begin planning breeding soundness exams for their fleet of bulls, says Robin Salverson, SDSU Extension Cow/Calf Field Specialist, during a recent iGrow Radio Network interview.
"Herd bulls influence overall herd fertility more than any other single animal, which makes the bull breeding soundness exam a high priority for every cattle producer," said Salverson, of the veterinary exam which begins with physical look at the bull’s feet and legs, eyes, teeth and body condition score of the bull.
"The exam then looks at scrotal measurement, which is an indicator of semen quality and production. The last part of the exam is a semen evaluation which includes both the motility of the semen and the morphology."
Salverson says breeding exams should be conducted every year, on every bull, about three to four weeks before pasture turnout as the quantity and quality of semen can change due to nutrition, environmental factors or possible injuries. It can also change as a bull matures.
"A young bull’s semen quality will continue to improve up to 16 months of age, however, regardless of whether it’s a young bull or an older bull, an evaluation needs to be done yearly," says Salverson, who adds that because the capabilities of a yearling bull compared to an older bull differ, a typical bull-to-cow ratio for yearling bulls should be about one yearling bull for every 25 cows.
However, she says research has shown that if an older bull has been examined and is in good health, it can handle many more cows.
To prevent social dominance issues from impacted breeding success, she advises not mixing mature bulls with yearlings in the same breeding pasture.