Spring and early summer before breeding is breeding soundness exams (BSE) time for young and mature bulls. Especially with the last two years of drought, every calf on the ground will be critical this year for beef herds, and bull management is an important part of the equation.
Now more than ever it’s important to do a thorough exam when it’s time to bring in bulls for BSEs. When doing BSEs, Bob Larson, DVM, PhD, Dipl. ACVPM, Dipl. ACT, Kansas State University, has different priorities and concerns when evaluating yearling bulls compared to evaluating mature bulls. “Yearling bulls have not established their fertility by successfully getting cows pregnant and they have only recently reached puberty and may or may not be sufficiently sexually mature to be successful breeders,” Larson explains. “They are at risk for young bull problems such as persistent frenulum and penile warts.”
On the other hand, young bulls have had less opportunity to become injured or to develop structural or degenerative problems compared to mature bulls. “Mature bulls have proven their ability to achieve pregnancy in exposed cows in the past, but because of time and age, they may have musculoskeletal injury or degeneration, the penis or prepuce may have become injured, the testicles or epididymis may have experienced infectious, toxic, or degenerative insults, and disease of any major body system can reduce the ability or desire to successfully mate cows,” Larson notes.
We look for different things in different ages of bulls, agrees Dave Rethorst, DVM, Kansas State University. “But the fact remains that we must do a complete exam on each and every bull,” Rethorst says. “This includes measuring and palpating testicles, palpate epididymis, rectal exam, extend penis and then semen evaluation. This is done after looking at condition, feet, legs and eyes. Usually condition, feet/ legs, movement are done before the bull actually gets to the chute.”
Preparing the young bull
Before their first BSE, young bulls need to be in good shape. Larson says young bulls should be in a body condition score of about 6 (on a 9-point scale) prior to the start of their first breeding-season. “I expect bulls to lose weight as the breeding season progresses and they need to have some energy reserve stored as body fat.”
The drought and subsequent forage shortage may lead to some under-conditioned young bulls this year. Poor body condition can affect young bulls in a number of ways. “First, the onset of puberty is influenced by both age and weight,” Larson says. “Bulls that should be old enough to be producing viable sperm will be delayed if they have not received adequate nutrition.”