Effect of ewe born type, growth rate and weight at conception on the ewe subsequent productivity of Rahmani sheep

Abstract

Background and Objective: Generally, the major factors that affect profitability in sheep production are the total number and the total weight of lambs produced per ewe. Therefore, the aim of this study was to determine the effect of born type, growth rate, growth trend of Rahmani ewes as a lamb and the weight at conception on their subsequent productivity. Materials and Methods: The data used in the present study were collected from 1728 Rahmani ewes during the period from 1991-2001.These animals were maintained at El-Serw Experimental Station belonging to Animal Production Research Institute, Ministry of Agriculture, Egypt. The studied traits were number of lambs born per ewe lambing (NLB), number of lambs weaned per ewe lambing (NLW), weight of lambs at birth (WLB) and weight of lambs at weaned (WLW). Results: The ewe from single born affected significantly (p<0.05) the lambs weights of birth and weaning but not the total number of lambs born. The increase of ewes growth rate as a lamb (>100 g day−1) during their rearing period from birth and from weaning to a year of age resulted a significant increase in the total number and weight of lambs born and weaned. Ewes that gained from 80 g day−1 growth rate before their weaning and continued with >100 g day−1 from weaning upto a year of age had the profitable values of all tested parameters for produced lambs. The lambs number, weights of birth and weaning were increased significantly (p<0.05) with advancing weight of their ewes at conception (>50 kg). Conclusion: In summary, the ewes born type, growth rate as a lamb and their weight at conception has detrimental effect on total number and weights of lambs produced.