Influence of live weight, sex and type of birth on growth and slaughter characteristics in early weaned lambs

The aim of the present study was to analyze live weight and growth data from birth to a live weight of 24-26 kg in early weaned lambs. The growth in the different age periods was determined on the basis of live weight changes for 152 lambs from the Blackhead Pleven breed. The results showed that the single lambs with a higher live weight at birth grew faster, but for twins there were no differences (P > 0.05). The difference in live weight was largely related to sex and type of birth. During the first 14 days of the suckling period the growth of lambs depended mainly on the amount of suckled milk. The male lambs grew faster than females after weaning. The lambs born as twins or singles placed under the same conditions of feeding and management did not differ in daily growth after weaning. Differences in live weight of lambs at birth and at weaning time were apparent until lambs reached 25 kg live weight. Correspondingly, this led to an increase of 5-10 days to reach 25 kg live weight of the lambs weaned at less than 9-11 kg and under 19-21 days, compared with the older lambs or born or lambs weaned at heavier live weights. The live weight from 7 to 11 kg and age from 17 to 28 days of weaning did not affect daily gain after weaning. However, all lambs have relatively low daily gain during the first week after weaning (about 50-60% of expected) and during the second week (about 60-70% of expected gain).