Sire Selection

Livestock Update, February 2002

Scott Greiner, Extension Animal Scientist, Beef, VA Tech

Sire Selection- Job #1
Its bull buying season! From a genetic standpoint, sire selection is the most important decision a cattle producer makes. The vast majority of genetic improvement in commercial herds is the direct result of sire selection. Consider the fact that 87.5% of the genetics of an individual calf were inherited from three sires in that calf's pedigree (50% from the sire, 25% from the dam's sire, and 12.5% from the dam's maternal grandsire). This fact alone emphasizes the importance of proper sire selection, and the impact that each sire has on economically relevant traits. For herds with small numbers of cows and in single-sire herds, the importance of an individual sire is even further exaggerated- as one sire alone accounts for a large proportion of the genetics represented in each calf crop. Relative to other production and management decisions, sire selection is an infrequent occurrence for many cow-calf producers. However, these decisions have long-term impact relative to the productivity and profitability of the cow-calf enterprise.

In many ways, the process of bull selection in analogous to hiring a new employee. Initially, a job description needs to be written which defines the responsibilities and qualifications for a new herd sire. Given these responsibilities and qualifications, the task of evaluating applications and narrowing the candidate pool becomes much more efficient.

Define Job Responsibilities: Defining the responsibilities of the new herd sire needs to be the initial step in bull selection. This list of responsibilities may be quite long, or could be relatively short- depending on the specific intended contributions of the bull. Breeding system, marketing system, management level, and feed/environmental resources are important considerations for writing the job description. Specific questions that warrant consideration when defining these responsibilities include:

Will the bull be used exclusively on heifers, mature cows, or both?
Will replacement females be retained in the herd?
How will the calf crop be marketed?
At weaning as graded feeder cattle?
As backgrounded calves?
Through a retained ownership venture?
What are the labor and management resources available?
What are the feed resources and environmental conditions of the operation?
How will this sire contribute to the overall breeding system plan?

Answers to these questions and others that may be appropriate will allow for a general description of the intended purpose of the bull, and a definition of his role in moving the herd forward genetically.

Define Job Qualifications: With answers to these general questions, individual traits and their relative importance can be identified. From this, specifications/qualifications for each trait can be defined. As an example, if we have determined that replacement females will be retained out of the bull, individual traits that should be considered include milk production and frame size, coupled with structural soundness, body capacity, and potential fleshing ability. Bull selection for these traits will therefore include milk EPD, maternal weaning weight EPD, frame score (or mature height and weight EPDs), and visual appraisal. Upon determination of these EPDs, specifications can be set for an EPD value that is most desirable. In this example, setting EPD specifications for milk will be highly dependent on feed resources as well as the milk genetics contributed from the cow herd. In the case of milk EPDs, specifications will likely be determined within a range of acceptability. For other traits, minimum or maximum values may be more appropriate as specifications- minimum values in the case of growth EPDs, and a maximum value for birth weight EPD. Determination of the primary strengths and weaknesses of the herd will assist in prioritizing traits/EPDs. As the number of traits that are included in a selection scheme increases, the number of bulls that will meet the specifications for each of these traits is likely to decrease. This is amplified when specifications are set at a very high level.

Several tools can be utilized to assist in the determination of EPD specifications. EPD values for current and past sires can be used as benchmarks. With these benchmarks, EPD specifications can be set to reflect the desired increase or moderation in performance for a particular trait. Breed is an important consideration as specifications are set for individual EPDs. The genetic merit for an average bull for any trait varies considerably from breed to breed. A milk EPD of +20 has a drastically different meaning for a Simmental bull as compared to an Angus bull. The genetic merit for milk production of the daughters of these two bulls is quite different, despite the fact they have the same milk EPD. The same holds true for growth and carcass traits.

Evaluating the Applicants: Upon determination of the responsibilities and qualifications, proceed with screening potential applicants. There are many sources of bulls that warrant consideration- production sales, test stations, and private treaty sales. Of critical importance is that the bull come from a reputable breeder who will stand behind his genetics and product. It may be necessary to take applications from several sources in order to find the correct bull. The first step to doing so is to evaluate the resume' and transcripts of the bull, which can be found in the sale catalog, performance pedigree, or data sheet. By examination of the bull's performance record, determine which bulls meet the EPD and other specifications that have been (and likewise eliminate those that do not meet the specifications). Be prepared to make trade-offs, as the perfect record may not be attainable. Do not be surprised or alarmed when the bulls you have highlighted appear scattered through the sale order. Remember to stick to the selection criteria and qualifications/specifications that have been established. Doing this homework prior to arrival at the auction or farm will not only save time, but also assist in making sure the right bull for the situation is purchased. Upon narrowing the potential candidates on paper, the bulls can be evaluated for suitability of phenotypic traits and the potential candidate list shortened even further. The final step is to make an offer- which is between you and the auctioneer!

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