By Frank Wardynski
Progressive beef breed associations publish sire summaries and Expected Progeny Differences (EPD’s) percentile tables and have EPD search engines to sort through bulls within the breed. Producers can use these technologies to select bulls for multiple traits specific to the needs and resources of any given farming operation.
Expected Progeny Differences (EPD’s) are the best selection tool available to beef cow-calf producers for bull selection. The data are derived from performance information collected on the given individual, its ancestors, collateral relatives, progeny, and DNA information. Values given to animals in the form of EPD’s predict the difference between individuals based on statistical analysis utilizing all information that is extremely expansive and inclusive.
Specialists and educators at Michigan State University recommend that producers select bulls based on multiple balanced traits rather than attempting to maximize one or two traits. Genetic progress can be more rapidly achieved while selecting for a single trait. However, single trait selection frequently has detrimental results regarding other traits. For example, continued selection pressure to increase yearling weights without concern for other traits may coincide with increased birth weight, mature weight, and mature height.
Selection for a balance of multiple traits is achievable with today’s technologies. Cow-calf producers can select bulls that are easy calving with low to moderate birth weights and are near the top percentile of the breed for growth traits. A progressive strategy in bull selection is to identify a few key traits for genetic improvement while selecting other traits important to maintain performance levels. With this strategy, a producer can use the EPD percentile table for a given breed and set desired performance levels, say in the top 25 percent for birth weight, calving ease and yearling weight, while setting performance criteria at breed average for maternal and/or carcass traits.
One of the best aspects of using EPD’s and their associated technologies is that each producer can select bulls based on their own specific needs on their cattle operation. They can select for growth performance traits, maternal traits, carcass traits, and/or profitability indexes. Beef producers can identify their resources and set performance parameters accordingly to uniquely match cattle performance with the environment and marketing opportunities. Cattlemen that use these tools can evaluate their selection results and adjust EPD selection criteria over time. For example, a producer may have emphasized selecting for high maternal and fertility traits, while keeping growth rate more moderate. Over time the producer may realize that cows are heavy milk producers and frequently become thin after parturition. This producer can then select for lower milk production and then decide if higher levels of growth or carcass traits are desired.
These selection tools work well in purchasing breeding bulls for the herd. Ideally, producers will develop a range of acceptable EPD values for a list of traits most important to an individual operation. In selecting bulls to be used to breed in an artificial insemination program the selection ranges can be narrowed to be very specific and ultimately used to find the very best bull to meet the genetic needs of any given operation. Producers utilizing these technologies can claim they are using the best bull in the country.
Source:msu.edu