Study on growth and reproductive traits of Nellore sheep in semi-arid region of Andhra Pradesh

Data on 1533 Nellore lambs maintained at Livestock Research Station, Palamaner, (Andhra Pradesh) from 2011–12 to 2015–16 were used to study the effectsofyear of birth and sexon growth and reproductive performance. Traits under study were weights at birth, 3, 6, 9 and 12 months of age, average daily gains during 0–3, 3–6, 6–9 and 9–12 months of age, tupping, lambing and replacement rate. Overall least-squares means of body weights at birth, 3, 6, 9 and 12 months were 3.10±0.01, 13.65±0.08, 18.68±0.12, 23.44±0.50 and 27.43±0.15 kg, respectively and overall least-squares means of average daily gains at 0–3, 3–6, 6–9 and 9–12 months of age were 116.82±0.85, 52.83±0.90, 40.75±3.14 and 29.20±1.23 g, respectively. Year of birth had significant (P<0.01) effect on all growth traits studied. Sex of lamb had significant effect (P<0.01/0.05) on all the body weights. The tupping and lambing rates on ewe available basis ranged between 95.21 and 97.52% and between 84.24 and 87.16%, respectively. Heritability estimates of body weights in general were moderatein magnitude, genetic and phenotypic correlations were mediumto high. The study indicatedapossible scopeofgenetic improvementin the flock through selection.