Genetic resources to increase the profitability of crossbred lamb production

The gross margin returns of first cross ewes by different sires have been evaluated on an equivalent carrying capacity basis by taking account of the feed requirements for the ewes and lambs and their varying performance and requirements throughout the annual production cycle. The study involved 2846 crossbred ewe progeny generated by 91 maternal sires from several breeds at 3 sites over 3 years including genetic links. The ewes were joined to terminal sire rams for 3 years and 8878 of their second cross lamb carcasses were included in the evaluation. The annual gross margin (A$GM) for individual ewes included income from lamb carcasses (with fat and weight discounts), lamb skins and ewe wool production, and costs for management and marketing. Individual feed requirements were calculated for ewe maintenance, gestation, lactation and lamb growth (pre- and post-weaning) and $GM was expressed on a dry sheep equivalent (dse) basis. Sire breed was not significant with a range of $5.28 GM/dse between sire breed means. There was a considerably greater range of up to $15GM/dse among most of the sire ewe progeny groups within breeds and overlap among all sire breeds. Lamb turnoff rate was the major profit driver with lamb growth rate and carcass fat levels also contributing. The opportunities for genetic improvement in profitability of lamb enterprises are discussed.