Bull Selection - Do Your Homework
Livestock Update, December 2005
Dr. Scott P. Greiner Extension Animal Scientist, Beef, VA Tech
Now through spring marks the traditional bull buying season in Virginia. While new tools such as additional EPDs and indexes have enhanced our ability to more accurately define the genetic merit of an individual herd sire prospect, it could be argued that the vast amount of information now available to us complicates the selection process. With over 30 individual EPDs currently in use, coupled with individual performance data and ratios (such as test ADG, ultrasound information, etc.), it can become a major task to sort through the information and arrive at a decision. The importance of these decisions have long-term consequences, particularly in single-bull units since the genetic merit of future generations is impacted by only a few bulls. Additionally, market signals are clearly sending the message that cattle with superior genetics and management have more value- further emphasizing the importance of sire selection. With some planning prior to sale season, bull selection can be simplified and chances of success enhanced by thinking through the following:
Define Job Responsibilities for the Bull -
In simple terms, how will the bull be used and how will the new herd sire contribute to the herd's overall genetic plan and goals?
Will the bull be used on heifers, mature cows, or both?
Will replacement females be retained in the herd?
How will the calf crop be marketed (at weaning?, backgrounded?, retained ownership?)
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 basic questions will outline the basics from which individual selection traits can be defined, categorized, and prioritized.
Define Traits of Interest and Tools for Selection -
From the previous considerations on how the bull will be used, individual traits and their relative importance can be identified. From this, specifications/qualifications for each trait can be defined. Let's assume the bull will be used on mature cows, steer calves will be sold through a value-added feeder calf program such as VQA, and replacement heifers will be kept. Since the bull will not be used on heifers, calving ease/birth weight EPDs become less important (and likely we will have more bulls from which to choose as a result). If our marketing strategy includes selling VQA calves, the bull must meet the minimum YW EPD qualifications for the program. For 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, 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 perhaps a maximum value for birth weight EPD (in this scenario, there are likely few bulls with too much BW EPD since the bull will be used on mature cows). 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.
Final Step- Evaluation -
With the above defined, we can now begin to look at individual bulls. There are many sources of bulls that warrant consideration- production sales, test stations, and private treaty sales. Of critical importance is that the bull be from a reputable breeder who will stand behind his genetics and product. It may be necessary to look at several sources in order to find the correct bull. The first step to doing so is to evaluate 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. Once the list has been narrowed to only bulls which meet the criteria, these bulls can be further evaluated and selection refined. 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.