Genetic improvement in the Australasian Merino: management of a diverse gene pool for changing markets

Abstract

The Australasian Merino population has declined significantly over the last 15 years in response to a decline in the price of apparel wool, both in absolute terms and relative to the price of sheep meat. Over the same period, a national genetic evaluation system based on BLUP methods has been introduced, that is achieving steady growth in adoption by breeders. Genetic parameter estimates for the population provide evidence for considerable genetic diversity for all recorded traits, providing ample opportunity for genetic improvement. More recently, there is considerable evidence for increasingly rapid progress, both in fleece traits and a range of meat production and adaptation traits. The Merino population is evolving towards two broad types – one focused on high quality apparel wools finer than 19 μm and used in enterprises with a wool/meat income ratio of about 3:1, and the other a more dual-purpose animal producing 19–21 μm wool and an enterprise wool/meat income ratio between 1.5:1 and 1:1. Underlying these trends is a growing focus on adaptation traits including worm resistance; reduced need for veterinary interventions; and increased early growth, fertility and mothering ability. Together these trends point to increasingly ‘easy-care’ sheep and exploitation of the available genetic diversity to rapidly increase profitability.