A new tool to select Angus bulls to breed to dairy cows

Abstract

<p>Widespread use of sexed semen among other factors has resulted in a dramatic increase in dairy cows being mated to beef bulls. Economic selection indexes were developed to identify the best Angus bulls, a predominant breed in this market, to use on Holstein and Jersey cows. Through interviews and site visits with key participants in the dairy beef supply chain, production and economic parameters were sourced to inform the modification of the standard American Angus terminal sire index $Beef. $Angus-on-Holstein Value ($AxH) and $Angus-on-Jersey Value ($AxJ) were developed and although highly correlated to each other (0.96), were considered to rank bulls different enough, especially at the top end, that both were needed. Generally, the dairy indexes identify bulls with the best $Beef but avoid three particular traits that are problematic in the dairy industry, with non-linear emphasis. Calving ease had relatively lower emphasis with a similar penalty in both the $AxH and $AxJ indexes , where muscling was heavily weighted with greatest emphasis in $AxJ and a penalty for excessive yearling height EPD was implemented in $AxH in an effort to reduce excessively long carcasses in that cross. These new indexes provide dairy farmers and players in the supply chain through to slaughter a tool to select Angus bulls to produce calves that are better suited to the requirements of this unique sector.</p>