With calving season and bull sales going on, many producers are evaluating their herd genetics and determining what bulls to purchase to reach their production goals, but even if you purchase the “perfect” bull, he may not perform as well as you would like because of nutrition and management.
Most frequently you will purchase yearling bulls that have been fed a high grain diet to get optimal growth and performance, but this is not ideal for a bull that will be turned out to pasture with the cows. The key with these bulls is to bring them down off of that high grain diet slowly, rather than turning them out to “rough it”. Yearling bulls are still growing, so they need to be gaining weight and maintaining condition for 120 days prior to breeding, but we don’t want them to be overly fat, as this could have a negative impact on their breeding performance. In order to transition the bulls to a 100% forage diet, determine what their diet consisted of prior to you owning the bull. Then provide that ration or a similar quality grain diet at 60-70% of their total daily intake. Decrease this portion of the diet by 10% each week, until they are on a 100% forage diet. Plan at least 7 weeks to step the diet down, if this process is rushed, semen production can be negatively impacted, which may not be detected until pregnancy check time.
Another key to handling newly purchased bulls is to put the bulls that will be working together in the same pen or pasture prior to the breeding season so they can determine their social structure. Research has determined that socially dominate bulls will breed more cows, so a good practice is to put similarly aged bulls together in breeding pastures, rather than a mix of young and mature bulls, as the young bulls may be constantly fighting the dominance of the mature bulls resulting in fewer bred cows and injury.
Exercise is another key factor to ensure longevity and performance of bulls. In many cases, yearling bulls are developed in a drylot situation, which limits the opportunity for exercise. If bulls are given a larger area for exercise, they will remain sound longer and will have increased libido during the breeding season. Periodically, we will observe a bull being “lazy” and not working as he should. In some instances, this is a result of inadequate exercise or being over-conditioned prior to breeding season.
The ideal body condition for any bull prior to breeding is 6. This is slightly more condition than cows should be in at calving, but the bulls will lose approximately 100 lbs during breeding so they need to be carrying more condition. You may be asking, how do I know if the bull is in a condition score 6? This is described as spongy fat over all ribs, hooks and pins, shoulder muscle movement is slightly visible, and fat deposits appear in the brisket.
Key points to remember especially with yearling bulls but important for all bulls is to bring them down off of a high grain diet slowly so that there is not a negative impact on semen production. Allow the bulls to develop and determine their social structure prior to turn-out. Allow for adequate room for exercise to ensure soundness and increased libido. All bulls should be in a body condition score 6 prior to breeding.
Source: Adele Harty