It’s difficult to manage nutrition of the young bull after turnout with the cows in its first breeding season, but there are some things that can be done to maximize the season. Bulls should be transitioned slowly to a roughage diet and introduced to pasture at least 10 days before being turned in with the cows.
Jeremy Martin, PhD, Great Plains Livestock Consulting Inc., Eagle, Neb., says most bulls will lose some weight during breeding simply due to the miles they cover in the breeding process. If possible, put yearling bulls in pastures with less area to cover, to limit the amount of weight lost. Make sure they have access to salt and mineral at all times during the breeding season.
“In my opinion, the most important thing is pulling young bulls out of cows in a timely fashion,” Martin suggests. “Many young bulls remain with cows long after the cows are bred, but most young bulls are not smart enough to quit chasing cows and continue to lose weight. After 45–60 days with cows, get yearling bulls out of the cowherd.”
Once young bulls are pulled out of the cowherd, don’t neglect them as they start approaching winter. Yearling bulls in particular need to keep growing after they are pulled from breeding pastures. Protein and energy supplementation is dependent on forage quality. “Ideally, yearling bulls would be fed to gain 1.5–2 pound/day through that first winter, and/or managed to a BCS of 6 prior to their second breeding season,” Martin says.
If yearling bulls don’t continue to grow and develop as they should, you can try to play catch up in their second breeding season, but Martin says it takes less feed to keep them in shape than to try and catch them up. In addition, fertility as a 2-year old can be compromised if bulls are underfed after their first breeding season, particularly if they are severely underfed. “Severe undernutrition can also stunt a bull’s growth, probably reducing their mature size and thus reducing their eventual salvage value,” he says.
Read more on young bull management in Bovine Veterinarian here.