A comparison of sheep breeds for lamb production on the south western slopes of New South Wales

Abstract

A comparison of the lamb producing ability of a number of breed crosses has been made over a four year period at Cowra, New South Wales. The breeds examined were Corriedale, Border Leicester x Merino, and Romney Marsh x Merino ewes mated to Dorset Horn and Southdown rams. Total live weight of finished lamb produced per 100 ewes mated was taken as the index of lamb producing ability. Dorset Horn rams produced approximately 24 per cent more finished lamb than did Southdown rams. The fertility of the two breeds was similar but Dorset Horn cross lambs were heavier at birth, grew faster and finished at a much greater weight in a given time. Border Leicester x Merino ewes produced 30 and 34 per cent more lamb than did Romney x Merino and Corriedale ewes respectively. There was no significant difference in total weight of lamb produced between the two latter types. Corriedale ewes were as fertile as the Border Leicester x Merino ewes but a greater proportion of their lambs failed to reach the finished weight. Lambs from Border Leicester x Merino ewes were heavier at birth and grew faster than lambs from the other two groups. There were no significant differences in wool production between any of the three ewe breeds. It is concluded that, of the breeds studied, a combination of Dorset Horn rams and Border Leicester x Merino ewes would give the greatest returns to lamb producers on the central-western slopes of New South Wales.