Factors affecting reproduction traits of Bharat Merino sheep under hot semi-arid climate

The data on 221 service records and 343 lambing records including 645 and 871 observations on lambing interval and service period of Bharat Merino strain (75% Rambouillet/Merino and and 25% of Chokla/Nali/Malpura/Jaisalmeri sheep) maintained at this institute, were subjected to least-squares analysis to assess the status of reproductive traits and the effect of non-genetic factors. The data extended over a period of nine years from 1985 to 1993. The overall least-squares means of age and weight at first service were 604.9±8.2 days and 34.8±0.34 kg, and those of age and weight at first lambing were 744.0±16.3 days and 37.9±0.75 kg respectively. The flock averages for service period and lambing interval were 165.0±2.7 and 372.4±5.4 days. All the six traits were influenced significantly by year of service/lambing. The season was also significant source of variation for most of the traits, except the weight at first lambing and lambing interval. The coefficient of variation in these traits varied from 12.02% in weight at first service to 28.79% in service period. The study tends to conclude that improvement in these reproductive traits can be effected by optimizing the management especially the plane of nutrition and effective utilization of grazing/lopping resources.