干旱区生态环境知识资源中心

Instantaneous relative growth rate is true measure of growth rate and can be obtained by dividing the instantaneous weight gain (dw/dt) by the time. The various factors affecting the instantaneous relative growth rate included in the study were genetic group, sex of lamb, year of birth and centre. The least-squares means of instantaneous relative growth rate for 0- 6 months age group (1), 6-12 months age group (2) and 12-24 months age group (3) were estimated as 1.10, 0.18 and 0.07 % per day, respectively. Genetic group, sex of lamb, year of birth and centre where lambs were reared had a significant effect on the growth rate of animals in field conditions. Progeny from elite rams excelled in growth at early stage of life but with advancement of age other factors also played a significant role on growth rate such as availability of pasture land at different places in different years. It is a general accepted fact that there is preferential care and management for the female youngones. The instantaneous relative growth rate of Magra breed of sheep at fanner’s flock level in Bikaner district studied in this investigation may help in early selection program.