Study of the growth traits relationship of lambs in the postnatal development

Abstract

Data from the Pirot improved sheep were use to estimate postnatal development and growth traits relationship of lambs from birth to weaning. The experiment included 360 lambs, divided into three groups (I, II, III). Lamb traits included BW at birth and approximately 30d, 60d and 90d (weaning). Lambs managed under conditions typical of the area. Male lambs in-group I had a total gain of 22.97 kg (0.255 kg/d), in group II 25.97 kg (0.286 kg/d) (P (lt) 0.01). Lambs in-group III the total gain was 24.64 kg (0.274 kg/d), which was lower than lambs of group II (P>0.05). On the other side, III group of lambs had a higher gain than the I group (P (lt) 0.01). Development of female lambs in the postnatal period was slightly weaker. Lambs of I group, from birth to weaning had a total gain of 21.27 kg, (0.236 kg/d), II group was 23.32 kg (0.259 kg/d). The difference was statistically very significant (P (lt) 0.01). Lambs of group III had a total gain of 23.54 kg (0.261kg/d) and higher growth rate then lambs of group II, but not significant (P>0.05). From the other side, the difference in comparison with the groups III and I was very significant (P (lt) 0.01). Correlations between BWB and BW30, 60, 90 are ranged from low to moderate among the respective traits and ranged between positive from 0.001 to 0.365 and negative from -0.005 to -0.279. Can conclude that the selection should direct towards producing lambs with intermediate birth weight.