Lamb growth performance and factors affecting body weight of Iranian fat-tailed Mehraban breed of sheep

Abstract

A study of the factors affecting weight in Mehraban sheep in Iran was undertaken during 1984-89. Birth weight, weaning weight (90 days of age) and daily gain from birth to weaning of 973 lambs were studied. The data have been analysed with a linear fixed model including year, sex, type of birth and age of dam. Lambs born of 4-5 year-old ewe were the heaviest and those born of one year-old ewes were the lightest at birth. The lambs reared by one year-old ewes had significantly lower rate of growth and were the lightest at weaning. Sex had highly significant effect on the pre-weaning traits in favour of the male lambs. Single births were heavier than those of twin births. Lambing year had a significant effect on all traits pre-weaning. Month of birth did not affect any trait. Weaning weight and daily gain from birth to weaning showed positive and significant associations with birth weight.