ABSTRACT
Rates of genetic gain in dairy cows are impressive, especially for milk production traits that drive profitability (VanRaden 2004). However, narrow breeding goals focused on milk production traits are detrimental to reproductive performance and health of cows (Rauw et al. 1998), and consequently there has been pressure to develop breeding values to enable selection that balances both production and non-production traits. Although, the rationale to extend breeding goals initially focused entirely on the impact of the new breeding value to farmer profitability, breeding goals are now becoming more complex in order to meet challenges set by consumers and society (Boichard and Brochard 2012; Martin-Collado et al. 2015). For example, the growing human population places more pressure on the available limited resources; global changes may mean hotter drier conditions to manage livestock and there is also increased consumer awareness about animal welfare and farming conditions. To accommodate this requirement, over recent decades there has been a rapid expansion of the number of breeding values that are available for farmers to select on. Almost without exception these breeding values rely on large amounts of field data that are freely available through current recording systems, such as milk production, calving records, insemination dates, pregnancy test outcomes, health records and culling dates.
