Replacement rate and its components in Malpura sheep at an organised farm in Rajasthan

Disposal and replacement indexes are two important indicators of flock management. A study was carried out to assess the replacement rate (RR) of Malpura sheep flock and the factors affecting it. Data on 2341 lambs born to 609 Malpura sheep spread over a period of 14 years from 1996 to 2010 at ICAR-Central Sheep and Wool Research Institute, Avikanagar, Rajasthan were used for the study. Replacement rate was 34.39% on total lambs born and 69.10% on female lambs born basis. The overall mortality of female lambs from birth to age at first lambing (AFL) was 17.17%, it was 6.95% in 0–3 months, 5.99% in 3–12 months and 5.29% in 12 months-age at first lambing age groups. The overall culling in female lambs till they attained AFL was 13.73%, it was higher for 6–12 months group (7.15%). The annual replacement index (ARI) ranged from 0.25 to 2.03 in different years with overall mean of 1.18, showing positive trend of flock strength with significant variation across years. Sire had significant effect on RR (female lamb basis) and nonsignificant effect on RR (total lamb basis). The study concluded that proper management and breeding decisions can favourably account for population structure of breeding females for harvesting more lambs from the breeding flock.