The Importance of Sire Selection
Dan W. Moser, Kansas State University
Bull selection presents an important opportunity to enhance the profitability of the beef production enterprise. For several reasons, bull selection is one of the most important producer decisions, and as such, requires advance preparation and effort to be successful. To effectively select sires, producers must not only be well versed in the use of expected progeny differences (EPD) and understand breed differences, they must accurately and objectively assess their current genetics, resources and management. Furthermore, recent advances in DNA technology and decision-support tools add complexity to selection, but will ultimately enhance selection accuracy. Producers who stay up to date on advances in beef cattle genetics should profit from enhanced revenue and reduced production costs, as they best match genetics to their production situation.
Opportunity for Genetic Change
Sire selection represents the greatest opportunity for genetic change. Genetic change in cow-calf operations can occur both through sire selection and through replacement female selection in conjunction with cow culling. Most producers raise their own replacement heifers rather than purchasing from other sources. This greatly limits contribution of female selection to genetic change because a large fraction of the heifer crop is needed for replacements. Depending on culling rate in the cowherd, usually one-half or more of the replacement heifer candidates are retained at weaning to allow for further selection at breeding time. So even if the best half of the heifers are retained, some average heifers will be in that group. Finally, the information used to select replacement heifers in commercial herds is limited. Producers may use in-herd ratios along with data on the heifers' dams, but these types of data on females do not reflect genetic differences as well as do the EPD used to select bulls. In contrast, whether selecting natural service sires for purchase or sires to be used via artificial insemination (AI), the amount of variation available can be almost overwhelming. Producers can find bulls that will increase or decrease nearly any trait of economic importance. Furthermore, since a relatively few bulls will service a large number of cows, producers can select bulls that are fairly elite even when natural mating. Use of AI allows commercial producers to use some of the most outstanding bulls in the world at a reasonable cost, allowing for enormous amounts of genetic change, if desired. Finally, selection of bulls is more accurate than female selection. Seedstock breeders provide genetic information in the form of EPD, which allow for direct comparison of potential sires across herds and environments. Unlike actual measurements, EPD consider the heritability of the trait to accurately predict genetic differences between animals. If AI is used, even greater accuracy is possible. Bulls used in AI may have highly proven EPD, calculated from thousands of progeny measured in many herds and environments.
Beef Sire Selection
Whether a seedstock breeder or a commercial cattleman...
... sire selection is the premier decision that all cattle breeders make. Understanding the concepts and the tools is the first step in increasing your chance of success.
EPD is an effective tool for producing better cattle, but EPD alone will not produce better cattle. In fact the use of EPD alone for selection can actually create negative progress in other traits, because there are a multitude of important traits for which there are no EPD values.
Across-Breed EPD Factors
In leiu of a true, nationwide multi-breed cattle evaluation, the researchers at United States Meat Animal Research Center (US-MARC) provide adjustment factors, on an annual basis, for use in comparing the genetic differences in bulls of different breeds.
National Animal Germplasm Program
The principle objectives of the NAGP are to:
--- provide secure, long term collection and storage of plant and animal genetic resources
--- provide monitoring and documentation of collections
--- an increased understanding of genetic diversity of these life forms
--- development of effective protocols for the safe storage of genetic resources
--- to provide a wide array of users with insight about the breadth and depth of the germplasm stored at NCGRP