Abstract: In this study,the growth and development of body size and body weight of Xinjiang Yemule white sheep lambs from 0 to 120 days old were analyzed in order to provide a theoretical basis for the breeding of the Muller Aries variety.222 Yemule White newborn lambs were chosen and the body weight,body size indexes were measured every 30 d,until 120 days of age.The results showed that there was an extremely significant difference in the cumulative growth of body weight and body size at the early age (P<0.01),The male lamb grows faster than female lamb with a fastest grow at 30 to 60 days of age.The ADG of male lamb at 30 to 60 das old was 6.8 g/d more than that of female lambs.The results of the body size indexes analysis showed that,body length,body height,tube circumference,fat hip width and fat hip thickness were the fastest growing at 0 to 30 days of age;The chest circumference and fat hip length grow fastest at 30 to 60 days of age;The fat hip length indicator of male and female lambs were significantly different at 90 to 120 days old.The correlation analysis between body size indexes and body weight phenotype of 120-day-old weaned lambs showed that,the correlation coefficient between body weight and chest circumference was the largest of male and female lambs,while that between fat hip length and body weight was the smallest.Path analysis results showed that the direct effect of chest circumference on body weight of male and female lambs was largest,while body height,body length,fat hip length and fat hip width mainly affect body weight through indirect effects.The direct effect of tube circumference on body weight of male lamb was greater than that of indirect effect,while that of female lambs showed the opposite tendency.

Key words: Yemulle White sheep; body weight; body size indexes; growth and development