EFFECT OF NON-GENETIC AND GENETIC FACTORS ON BIRTH WEIGHT OF MENGALI SHEEP OF BALOCHISTAN

Abstract

Data on birth weight of 2377 lambs obtained from 581 dams and 56 sires of Mengali sheep born during 2005 and 2009 were recorded and analyzed to identify the factors affecting birth weight of Mengali lambs. Mengali flocks were kept under semi-intensive condition in four stations at three different locations (Experimental Station Center for Advanced studies in Vaccinology and Biotechnology (CASVAB), University of Balochistan, (ESC), Quetta, Killi Hassni, Quetta; Khadkucha, Mastung and Peer Wala (Mal), Nushki). The lambing occurred spring and autumn, however majority of the Mengali sheep (85 %) lambed during spring between (February and March months). Among the total lambs born, the male to female sex ratio was 49.43: 50.57 respectively and shown no significant difference between two sexes. The overall least-squares means for birth weight of males and females pooled over parity and type of birth were 3.61±0.36 and 3.48±0.39 kg respectively. The estimate of heritability for birth weight was observed as 0.39±0.06. Study on non-genetic factors revealed that the birth weight was significantly (P<0.05) affected by period of birth, season of birth, sex of the lamb, parity and location of flock. Hence, efforts should be made for better management of pregnant ewes when the climatic conditions are not conducive to them.