Maintaining a healthy and sound bull battery is of utmost importance for breeders. There are many factors that go into making sure sires are ready for the upcoming breeding season. How ranchers develop their yearling bulls can have a big impact on the success of their herd down the road.
At the recent Three-State Beef Conference, Kacie McCarthy, beef cow-calf Extension specialist at the University of Nebraska-Lincoln, discussed best practices for producers who are developing yearling bulls.
The three big topics ranchers need to keep in mind are nutrition, weaning practices and management during the breeding season. When these practices are monitored closely, there is a better chance that producers can have a successful breeding season and keep their bull battery profitable.
Proper nutrition
Nutrition management of the young bull starts at preweaning. The biggest question that McCarthy presented to ranchers when talking about preweaning nutrition was, “Are calves meeting their nutrient requirements from their mothers?”
This becomes important not only for bull development, but also for sperm quality.
“By the time they are weaned, all the sperm that they are ever going to need to use to breed and service females is all getting developed when they are on their mom,” McCarthy said. “They are going through that spermatogenesis cycle after they have hit puberty and are generating that sperm consistently for breeding purposes.”
It is important to keep in mind that preweaning nutrition cannot be reversed through proper postweaning nutrition. For ranchers to be set up for success, it is crucial to make sure that energy and protein requirements are being reached. This might mean adding a creep feed or supplement to reach those nutrition goals.
“When we think about energy or protein restriction, this is where we start to see delays in puberty, which ultimately delays growth,” McCarthy said. “When we start to think about fertility and hitting puberty in a timely fashion, if we start to restrict protein and energy, it is ultimately a detriment to that sperm production and semen characteristics.”
With high planes of nutrition, ranchers can see increased body weight and testosterone at a lower age of puberty.
Postweaning considerations
General recommendations for postweaning growth (ages 6 to 16 months) include targeting bulls to gain 2.2 to 3.5 pounds per day, McCarthy said.
While it's crucial for yearling bulls to gain weight, it's important not to overfeed them. McCarthy reported on a study that noted bulls gaining more than 4 pounds per day experienced complications due to scrotal fat accumulation. This excess fat led to higher scrotal temperatures, which ultimately resulted in detriments to semen quality.
Effective management of yearling diets requires a balanced approach, with careful consideration of their previous nutritional intake before integration into your operation. Typically, yearlings may have been on diets with higher concentrate levels. McCarthy noted, "If we start to encounter acidosis issues by pushing those high concentrates, it all comes back to reevaluating your nutrition."
In addition to making sure that body condition is in a proper place postweaning, it is also important to perform breeding soundness exams on yearling bulls.
McCarthy emphasized the importance of conducting breeding soundness exams, noting that morphological and motility issues can still arise at this stage. Ensuring that these bulls are pubertal and free from fertility issues as they approach the breeding season is crucial when considering their integration into your operation.
According to a study mentioned by McCarthy, 57% of operations that purchase bulls had a breeding soundness exam conducted on newly introduced bulls. But only 17% of cow-calf operations had a breeding soundness exam done on bulls that were already on their operation.
While not a lot of producers are conducting these exams, it is important to ensure a successful breeding season.
Breeding season
Now that young bulls have made it to the breeding season, it is crucial to keep these four considerations in mind:
- length of breeding
- pasture size
- female-to-bull ratio
- weight loss management post-breeding
Producers might be able to push more mature bulls to cover more cows. However, this is not the same for yearling bulls, which can be a little bit less (i.e. 1: 18-to-20 bull-to-cow ratio).
“Workload will be important to think about and giving time to rest,” McCarthy said.
Keep in mind that young bulls are still growing, so paying attention to the number of cows you want the young bull to cover, the length of the season and the nutrient demands for growth can help keep your yearling bulls sound and ensure longevity on the operation. During the breeding season, bulls are putting in a lot of work, so it is expected that they will lose some weight.
“What we can see from some older literature, is that bulls can really lose anywhere from 100 to 400 pounds,” McCarthy said.
At the end of the day, proper management of yearling bulls starts preweaning and still requires proper management for a successful breeding season and those that follow.
Bull outlook this spring
Veterinarian Brady Dierks works with his wife, Ashley, also a veterinarian, at Bloomfield Veterinary Clinic in Bloomfield, Neb. Over the past few months, Dierks has seen better pregnancy rates than the previous year in his part of northeast Nebraska when he has been out pregnancy-checking local herds.
“I attribute this to the milder breeding season last year,” he says.
As for bull breeding soundness exams, it has been hit and miss. “Mostly at or above average exams,” says Dierks. “However, bulls that did not have adequate bedding and protection this past February seem to be below average due to frostbite injuries.”
The most common issue Dierks has seen with yearling bulls has been erection abnormalities.
“However, the most frequent issue seems to be immaturity,” Dierks adds. “Samples are either not concentrated or lacking a sperm rich sample all together. More time and female exposure are the best fix for this issue.”
Dierks recommends remembering the bull herd in your mineral program this summer and making sure to properly bed and shelter bulls through the cold of winter to keep them healthy and ready for breeding season.