Motivation for Genetic Improvement
Motivation for Genetic Improvement
At its most basic, genetic evaluation is accomplished through computer services processing pedigree information and performance records for one or more traits. These records are systematically recorded and submitted by breeders. The choice of traits to measure and record involves some collective judgment about what traits are economically relevant, and what traits can be routinely measured in the breeders’ operations . Genetic evaluation is simply the analysis of that data using some defined statistical model(s) to arrive at estimates of the genetic merit of animals in the population. The output from a genetic evaluation is, in the case of beef cattle, an Expected Progeny Difference, or EPD, which measures the difference in performance that is expected from future progeny of a parent. Genetic evaluation procedures that produce EPD for specific performance traits should be considered a means to an end (and not the end). The desired end is an improved economy of producing consumable and desirable livestock products for the benefit of the breeder and the consumer . Seedstock producers are in business primarily to make a profit, as are their breeding stock customers, who produce food products. Producers' profits are influenced by consumers' demand for their products. Purchase of breeding stock involves a cost but can provide a positive influence on the functioning of the system by reducing other expenses or increasing income from output, or both. The producer will be motivated to pay more for breeding stock if given assurance that profit will increase because of these increased costs. Products sold to earn income for a breeder are primarily breeding stock (or alternatively semen). Efforts to improve the value of this product (and thus the income earned) are likely to add expenses due to the extra labor of recording data, registration and computer charges, marketing of intact animals for slaughter, and so on. The breeder will be motivated if given assurance that greater income will adequately cover these increased expenses  .
To summarize, genetic evaluation makes genetic improvement possible. It provides the capability to benchmark individuals within a breed, or possibly different breeds. It is a means whereby the joint investment in recording and selection can be converted to market advantage. It is possible to maximize returns in this process by recording the right traits, and make sensible use of indexing, selection and mating. To maximize the quantity and quality of data recorded so that genetic evaluation can be used most efficiently to add value a well-defined breeding structure is of fundamental importance.
- Dewey L. Harris, Scott Newman, Breeding for profit: synergism between genetic improvement and livestock production (a review), Journal of Animal Science, Volume 72, Issue 8, August 1994, Pages 2178–2200, https://doi.org/10.2527/1994.7282178x
- D. J. Garrick, B. L. Golden, Producing and using genetic evaluations in the United States beef industry of today, Journal of Animal Science, Volume 87, Issue suppl_14, April 2009, Pages E11–E18, https://doi.org/10.2527/jas.2008-1431
- Dewey L. Harris, Breeding for Efficiency in Livestock Production: Defining the Economic Objectives, Journal of Animal Science, Volume 30, Issue 6, June 1970, Pages 860–865, https://doi.org/10.2527/jas1970.306860x