| Xinjiang Brown cattle are dual-purpose breed of milk and meat,body size and body weight are the important indicators for growth and development.Therefore,this paper takes Xinjiang Brown cattle as the research object,the growth curve of Xinjiang Brown cattle was fitted and the correlation and principal component analysis of body size and body weight of adult cattle were carried out by analyzing the factors affecting its birth weight.The main research contents and results are as follows:1.In this study,1388 calving records of Xinjiang Brown cows from 2012 to 2017 in Urumqi cattle farm,Xinjiang,conducted the descriptive statistical analysis on the birth weight of Xinjiang Brown calf.The GLM program of SAS 8.1 software was used to analyze the effects of 6 factors including bull,parity,length of pregnancy,birth season,birth year and calf sex,respectively,on the birth weight of Xinjiang Brown calves.The results showed that bull,gestation period,season,sex,and birth year had a significant effect on calf birth weight(P<0.01),while parity had no significant effect on calf birth weight(P>0.05).2.Records of body weight and body size traits at different months of age of 341 cows and 325 bulls were obtained from the Xinhe cattle farm in Yili.The growth curve of body weight and body size traits of bulls and cows of Xinjiang Brown cattle was fitted by NLIN process of SAS 9.2 software.The differences of traits between different months of age and the effects of birth season on body weight of Xinjiang Brown cattle were compared.The results showed that both growth model and exponential model could be used as the best fitting models(R2>0.90)for body weight,cannon circumference,body height,body length,and chest measurement of both bulls and cows.3.The body size of 569 adult Xinjiang brown cows from 3 cattle farms as Xinyuan County,Nileke County and Zhaosu County in Yili area was measured,and 13 body size traits were selected for correlation and principal component analysis.The results showed that the body weight of Xinjiang Brown cattle was significantly related to body height,body oblique length,rump length,chest circumference,abdominal circumference,half circumference of hind leg,rump width,hind leg width and hind leg thickness(P<0.01).The contribution rate of the first principal component was the best,which could reflect the whole structure of Xinjiang Brown cattle,while the second and third principal components reflected the characteristics of hindquarters and twists. |
