Column: purchasing and managing young bulls

By Sharla Sackman

A Cattle Producer’s Library article on purchasing and managing young bulls has some good considerations to keep in mind this time of year. Following are some highlights from that article.

Purchasing young bull calves has become an economic reality in the beef industry.

The breeding ability of bulls usually is at its highest between 1 1/2 and 2 1/2 years of age and declines after 5 or 6 years of age. Often an extra calf crop can be sired by using younger bulls as yearlings. The new owner must grow out young bulls in a satisfactory manner, however. The need for proper growth and development still exists and continues after the breeding season.

The best tool available to evaluate the breeding value of a bull is Expected Progeny Differences (EPDs).

For EPDs to be useful, buyers must first determine their production goals. For example, is the goal to increase weaning or yearling weights, increase maternal milk, or increase calving ease? The selection then should emphasize those traits most related to the breeding goals of the rancher.

Buyers choose bulls based on their expected ability to improve a particular area of production. One bull cannot have the same impact on all cows within a herd. It is therefore the buyer’s responsibility to match the bull calves they select to their cow breeding objectives.

A buyer can use EPDs to group potential sires and then select an individual(s) from the group of bulls on visual evaluation. EPDs are used to compare bulls within the breed and are not intended to compare bulls between breeds.

A calf at weaning time is mainly a reflection of the mothering ability of its dam. Milking ability of the dam is responsible for about 60 percent of the variation in weaning weight of the calf. The other 40 percent is determined by the genetics of both sire and dam for growth.

Probably the most common mistake made in purchasing young bulls is failure to provide an adequate diet to continue their growth and development. Often bulls are delivered, turned out with other bulls, and left to “rough it” until breeding time. Thus, bull development is delayed, sexual maturity is not achieved, and the resulting calf crop is less than it should have been.

Rations should include concentrates fed at about 1 percent of body weight. Bulls should continue on a similar nutritional diet for the approximate 120 days from yearling age until breeding time. All bulls should be gaining weight and some condition during this time. A young bull will use body stores of energy and lose over 100 pounds during the breeding season. This should come from energy stored as fat (condition) rather than muscle tissue since the bull is still growing. Conversely, excess condition lowers the bull’s fertility and libido and should be avoided.

Rapidly growing young bulls need about 13 to 14 percent crude protein in their diet. The ration should also be from 65 to 70 percent total digestible nutrients. As the bulls approach 10 to 12 months of age, the protein can be reduced to 10 percent.

For a yearling bull to be used successfully, he should have reached puberty 3 to 4 months before breeding time. The age of a bull at puberty depends on several interrelated factors, but size or weight is probably the controlling factor.

The production of semen by a young bull largely depends on his overall growth as well as the development of his testicles and other reproductive organs. The size of testicles and volume of semen produced are positively correlated.

When developing breeding plans that include different breeding pastures for different groups, separate the bulls based on age to ensure good breeding response. If older bulls are going to run common with younger bulls, pen them together before the season to allow time for social interaction that always occurs.

Bulls bought as weaners or yearlings have time to adjust to any environmental problems particular to the new ranch. Buying bulls at a young age gives the new owner opportunity to include the new animals in the overall herd-health program. The breeder or seller should indicate what vaccinations have already been given.

To summarize, buying bull calves can be a sound practice if they are properly selected using EPDs, performance data, and visual appraisal. After the selection is made, proper management and development are necessary, including considerations of herd health, nutrition, and environment to ensure a successful program. Proper development of young bulls after purchase can have a positive impact on herd fertility, since low fertility in the bull battery can mean fewer calves.

( Sharla Sackman is an MSU extension agent in Prairie County.)

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