Young bulls can begin contributing genetics to the herd at 13 to 18 months of age and on the average, continue siring calves for five to seven years or longer, if they are developed properly. Breeding longevity of bulls varies among different breeds, but it is always dependent upon how they are managed. A yearling bull is a large investment, regardless of whether he is raised or purchased, and the investment needs to be protected by bringing the animal into service gradually.
One reason cattlemen utilize young bulls is that they introduce new genetics into the herd more rapidly than older sires. Most seed stock producers strive to improve herd genetics with each new generation which means a yearling bull will have better genetics than his parents.
Giving young bulls the needed experience without setting them back involves not only starting their breeding activity gradually, but also keeping them fit with adequate nutrition, a good health program, and low stress management. Dr. James Neel, Animal Science Professor at The University of Tennessee recommends dividing the yearling bull management program into three basic periods – pre-breeding or conditioning (2 months), breeding season (2-3 months), and post-breeding (7-8 months). The periods can vary in length, but the basic management demands during each period will remain the same.
Pre-Breeding or Conditioning
“Yearling bulls should be purchased well in advance of the breeding season,” says Neel. “Get the yearling bull on the ranch at least 60 days prior to the start of the breeding season. This will provide time for bulls to adjust to their new environment, and overcome the stresses of the sale and being moved to a new location. During this adjustment time, yearling bulls should receive a complete health program as well as a breeding soundness examination (BSE). Check with your local veterinarian in regard to developing a health program to ensure a profitable level of performance.”
If the bull is purchased, it is important to learn how he was handled prior to the sale. A bull on a gain test might have gained more than 3.5 pounds per day, and may be carrying excess body condition. To do a good job of breeding, most yearling bulls should weigh no less than 1,100 pounds at 13 to 16 months of age.
“Over-weight bulls should tone up before breeding season, which means that energy intake may need to be set at a level lower than normally recommended during the conditioning period,” says Dr. Twig Marston, Extension Beef Specialist with Kansas State University. “Fat bulls should not be let down too quickly because rapid weight loss may affect libido or fertility. Conversely, thin bulls may need to be fed more than normally recommended.”
“Yearling bulls should gain about 2.0 pounds per day during the conditioning period, due to growth,” says Neel. “Provide a ration with approximately 11 to 12 percent crude protein on a dry matter basis. Meet energy needs with a 70 percent TDN (total digestible nutrients) ration, which is the equivalent of 6 to 10 pounds of grain and all the medium quality hay or excellent quality pasture forage that the bulls can eat.”
“Exercise is a critical factor during the pre-breeding period,” Neel continues. “Bulls need to have lots of stamina, be very athletic and able to travel many miles each day during the breeding season. As with any athlete, physical fitness does not occur overnight. It is up to the manager to help prepare and condition bulls by providing a good exercise lot of approximately one acre in size. If bulls have the opportunity, they will exercise themselves. Mother Nature has provided them with that instinct. Bulls that are physically fit will have a higher degree of sexual drive and will remain sound. A companion animal, such as a steer, aids in exercise.”
Dr. Glenn Selk, Emeritus Extension Animal Scientist from Oklahoma State University recommends, “Run yearling bulls only with other yearling bulls on a set of females. Yearlings that run with older bulls may be physically abused to the point that they will settle very few cows. Reduce the cow-to-bull ratio to about one female per each month of the age of the bull. For example, the true yearling may be mated only with 12 to 14 females. The fall-born bull would be placed with a maximum of 18 females if he is not used until the spring breeding season. Yearlings should be left with the cow herd for 60 days or less. Beyond that time their condition may decline and may have long-range effects upon their growth.”
“Try to observe the yearling bull closely to make certain he is detecting heat and breeding cows,” says Marston. “Also, keep an eye on his condition. If he is getting too thin and rundown, he needs a rest. Thin bulls are more apt to hurt themselves, become less fertile, and have increased nutritional needs after the breeding season. Yearling bulls should not be pasture mated to cows that are extremely large. Physically, this height mismatch may cause injury and failure to mate properly.”
“Because young bulls are still growing, they need extra feed during the breeding season,” states Neel. “Continue to feed six to eight pounds of the ration fed during the pre-breeding period. The amount of feed fed during the breeding season can be increased as needed to help maintain the bull’s condition. A feeding stall is of value to insure bulls get their ration.”
After the yearling bull has completed his first breeding season, it is time to recondition him for the next season. Neel states that care provided to yearling bulls after the breeding season is critical if they are going to continue to have a long and productive breeding life. Unfortunately, bulls do not receive proper care on most commercial beef operations.
“Yearling bulls will probably lose from 100 to 300 pounds during their first breeding season,” explains Martson. “In addition to gaining back this weight during their first rest, they must also gain enough body mass as to achieve 75 percent of their mature weight by their second birthday. For example, if a bull’s potential mature weight is 2,000 pounds, he should weigh at least 1,500 pounds at two years. If he weighed 1,250 pounds as a yearling at turnout time and lost 200 pounds during the breeding season, he would need to gain about 2.0 pounds per day during the nine months until his second birthday. In order to gain 2.0 pounds per day, coming two-year-old bulls may need to be fed 13 pounds of a grain-protein supplement, and a full feeding of hay. High quality forages can be utilized to reduce the grain and supplement portions of the diet. Do not try to bring a bull back into condition too fast with too much grain because of foundering risk.”
Neel says, “All bulls, especially yearlings, should have free access to a high quality mineral mix that is appropriate for your area. Provide a health and parasite control program as outlined by a local veterinarian. Internal and external parasites should be controlled to provide yearling bulls every opportunity to recover from the rigors of the breeding season.”
If yearling bulls are pre-conditioned properly, not over-worked during their first breeding season and reconditioned between seasons, they will give you a return on your investment.