Will selecting for liveweight lead to a population of tiny cows in Australia?
No. Selection on an APR is estimated to lead to a small reduction, just a fraction of a centimeter difference in 25 years, while Jerseys will continue to increase in size slightly. Australia’s dairy cow population is now almost entirely North American based and there is no issue of Holsteins being unacceptably small. How will the inclusion of liveweight affect other traits? Protein is the most important trait in Australia and APR and hence we will continue to select strongly for protein. Including liveweight will not affect the genetic gain for protein. Protein production is correlated positively with liveweight. Without liveweight in APR we breed for increased production without consideration of maintenance costs. The problem of heavier cows that produce no more, will be accounted for with Liveweight’s inclusion. Because ADHIS has ABV’s for all other important traits, soon to include SCC and fertility, and because these are also in the APR, the most profitable bulls are likely to be r
