BIF-Proceedings-Final-flip

38 2018 BIF Research Symposium and Convention • Proceeding Papers Focus on Traits Not Considered Dorian Garrick • D.Garrick@massey.ac.nz Chief Scientist, AL Rae Centre of Genetics and Breeding, Massey University, NZ Introduction Phenotypes are observable and typically measurable characteristics or traits, such as birth weight, coat color, stature, reproductive status, behavior etc. Improvement programs typically focus on a relatively small subset of all the possible traits, most commonly those that are associated with growth, calving ease, and ultrasound measures of carcass characteristics. It is well known that selection will be much more effective when the measured performance of the selection candidate and its relatives is adjusted for non-genetic effects, summarised in terms of the estimated breeding value (EBV) or expected progeny difference (EPD) of the animal for each trait of interest, then weighted by its economic value in an economic index. The purpose of this paper is to consider EPDs for those traits that might be important but are not currently attracting much focus in national improvement programs, and to discuss the manner in which there might be improved emphasis on those traits. There are several different approaches in which the various stakeholders in beef improvement might consider EPDs they believe should receive focus. These include the data driven approach used by cattlemen and others directly involved in the supply chain, the bio economics driven approach used by animal breeders, and the gene driven approach used by molecular geneticists. However, despite positive industry-wide value propositions for some traits not typically considered, market failure at the level of the bull breeder commonly contributes to valuable traits having inadequate focus. The data driven approach used in the supply chain Bull breeders directly control the nature and rate of genetic improvement as it is the bull breeders that choose the sires they will use to produce sons for sale, the sires they will use to produce daughters to retain as replacements, and the sires of the bulls they will market to bull buyers. Further, bull breeders choose the traits to invest in measuring, in order to generate EPDs for immediate use in selection, or for inclusion in economic indexes to use for selection. Bull buyers indirectly influence the nature and rate of genetic improvement by rewarding some bull breeders with increased demand and higher prices for sale bulls. For every bull breeder, buyers send market signals when they invest more in the purchase of the bulls they like. Bull breeders respond by attempting to produce more such bulls in the future. Bull breeders and bull buyers tend to focus more on attributes that they can easily visualize or measure, such as growth rate or calving ease, and less on attributes that are less visible in their production systems, such as feed intake during grazing, eating quality of the final product, and disease resistance. Further, they tend to focus more on traits with moderate to high rather than low heritability, and those measured early rather than late in life, as they can easily validate the effects of their selection choices within their own production systems. Sadly, the current status of most national and international beef cattle evaluation systems reflects a narrow data driven approach to choosing traits on which to focus selection. The bio economics driven approach used by animal breeders There is a logical approach to developing a breeding program that includes thorough biological and economic considerations of the traits to consider. The first step is the formulation of the goal of the breeding program. That would normally reflect some measure of increasing satisfaction – and in an agricultural context profitability is usually a major determinant of satisfaction. A goal would often be more finely tuned, for example by expressing it per unit of limiting resource – such as profit per unit of land, or profit per cow place. The second step in developing a breeding program is to define the breeding objective. This involves two components – the list of traits that influence the goal, and the relative emphasis to be placed on each of those traits. A profit- based goal should consider every trait that influences any component of whole system income, or any component of whole system cost. Given such a list of traits, determination of the relative emphasis of each trait in the list is an economics problem. It can be solved by calculating the partial derivative of the profit function of the production system if that can be specified, or it may be computed more simply by partial budgeting. Traits can vary in their number of expressions over the lifetime of the animal, and in the timing of those expressions, and these factors should be considered to determine the economic values. This approach