SOME MATERNAL EFFECTS ON GROWTH IN LAMBS PRODUCED BY RECIPROCAL CROSSBREEDING BETWEEN LINCOLN AND SOUTHDOWN SHEEP

Abstract

Effects due to maternal environment, sex of lamb and litter size on the growth of lambs were studied in lambs produced by reciprocal crossbreeding of Lincoln and Southdown sheep. At birth, maternal environment (Lincoln vs. Southdown) had a highly significant (P < 0.001) effect on the fetal weight. The difference at birth increased slightly at 40 days (weaning) but at 150 and 190 days the difference was small and nonsignificant. The effect of maternal environment on cannon bone length, although small compared with body weight, had a significant effect (P < 0.05) extending to at least 150 days of age. The difference in cannon bone width due to maternal environment was significant (P < 0.05) at birth. However, after 90 days the difference was small and nonsignificant. Litter size had a highly significant effect (P < 0.001) on body weight, cannon bone length and cannon bone width at birth and postnatally. Birth differences due to sex of lamb were rather small in all three traits, but increased as the lambs grew older. The effects of breed of sire on body weight and cannon bone length were relatively small at birth but increased with age. Breed of sire, however, had no effect on cannon bone width at birth or postnatally but interacted significantly with breed of dam on birth and weaning weight.