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Submitted to: Beef Cattle Short Course Proceedings
Publication Type: Proceedings Publication Acceptance Date: 7/1/2005 Publication Date: 9/1/2005 Citation: Thallman, R.M. 2005. Incorporating marker assisted selection and expected progeny differences (EPD) as an aid to selection. Proceedings of the 51st Annual TexasA&M University Beef Cattle Short Course, p. J-21/J-29. Interpretive Summary: The benefits of DNA testing are briefly discussed. The number of DNA tests for quantitative traits in beef cattle has increased rapidly over the past five years. With the rapid growth of DNA testing in beef cattle, breeders have many decisions to make and little information with which to make them. Independent validation of DNA tests is a process designed to provide some of that information and is described briefly. Most current tests are for genes primarily related to carcass traits. Research aimed to develop tests for feed efficiency, reproduction, and disease resistance are underway. DNA tests should not be used as all-or-none selection criteria, but rather should be used as one of several sources of information upon which selection is based. The proper allocation of selection pressure to these various sources of information will be easier when DNA test results are incorporated into the national cattle evaluation system. An hypothetical example of DNA-adjusted expected progeny differences is included to illustrate that DNA tests provide the most information when applied to animals that would otherwise have genetic evaluations with low accuracy. Young bulls that are candidates to be used as sires of seedstock are excellent candidates for DNA testing. In the future, DNA tests may be used to enhance mating strategies in seedstock cattle or to enhance management of commercial cattle. There are many challenges ahead in the adoption of DNA testing by the beef industry, but it is expected to result in greater genetic progress, especially for traits for which data are limited. Technical Abstract: The benefits of DNA testing are briefly discussed. The number of DNA tests for quantitative traits in beef cattle has increased rapidly over the past five years. With the rapid growth of DNA testing in beef cattle, breeders have many decisions to make and little information with which to make them. Independent validation of DNA tests is a process designed to provide some of that information and is described briefly. Most current tests are for genes primarily related to carcass traits. Research aimed to develop tests for feed efficiency, reproduction, and disease resistance are underway. DNA tests should not be used as all-or-none selection criteria, but rather should be used as one of several sources of information upon which selection is based. The proper allocation of selection pressure to these various sources of information will be easier when DNA test results are incorporated into the national cattle evaluation system. An hypothetical example of DNA-adjusted expected progeny differences is included to illustrate that DNA tests provide the most information when applied to animals that would otherwise have genetic evaluations with low accuracy. Young bulls that are candidates to be used as sires of seedstock are excellent candidates for DNA testing. In the future, DNA tests may be used to enhance mating strategies in seedstock cattle or to enhance management of commercial cattle. There are many challenges ahead in the adoption of DNA testing by the beef industry, but it is expected to result in greater genetic progress, especially for traits for which data are limited. |
