The 'Lustre' mutation in Merino sheep

Abstract

The Lustre mutation was reported by Short (1958) who concluded that it was inherited as a single dominant autosomal gene. In five matings, from 1960 to 1965, rams heterozygous for Lustre were mated to Normal Merino ewes. From these matings 543 Normal and 469 Lustre lambs were born, a result which deviates significantly from the 1 : 1 ratio expected (P<0.05). Significantly higher proportions of Lustre lambs were assisted at birth (20.0 per cent v 13.8 per cent) and died before weaning (34.8 per cent v 21.7 per cent) (P<0.05). The greater mortality of Lustre lambs was most marked in the periods before birth and between birth and four days of age. Lustre lambs were lighter at birth (P<0.05) but the differences in body weight between Normal and Lustre ewes at weaning and following the two-tooth shearing were small and not significant. At the two-tooth shearing the clean fleece weight of Lustre ewes was 56 per cent that of Normal Merinos (P<0.05). The components of fleece weight mainly responsible for this reduction were skin wrinkle, staple length, and follicle density (all P<0.05).