不同月龄青海藏羊体尺与体重的相关性及主成分分析OA

In order to explore the relationship between body size and body weight of Qinghai-Tibetan sheep at different months of age,145 Qinghai-Tibetan sheep(70 rams and 75 ewes)were selected in the study,and the body size and body weight data were determined at newborn,3-month,6-month,8-month,and 10-month ages,and correlation,path,and principal component analysis were carried out using SPSS19.0 and SAS8.0 software.The results showed that:1)Among different age groups,the coefficient of variation of body weight was the largest for males and females at different ages,and the coefficient of variation of tube circumference was the largest among the body-size indicators.2)There was a highly significant positive correlation between body weight and body height,body length,chest circumference and tube circumference at newborn,3-month,8-month and 10-month ages.There was also a highly significant positive correlation between various body size traits.3)The indicators that had the largest direct effect on body weight of males and ewes were body height,followed by body length and chest circumference.4)In terms of the eigenvectors and contribution rates of the principal components,at the newborn stage,the first 2 principal components were selected for rams and the first 3 for ewes.At the 3-month-old stage,the first 3 principal components were selected for rams and the first 1 for ewes.At the 6-month-old stage,the first 3 principal components were selected for both males and females.At the 8-month-old stage,the first 3 principal components were selected for rams and the first 2 for ewes.At the 10-month-old stage,the first 3 principal components were selected for rams and the first 3 for ewes.And at the 10-month-old stage,the first 3 for rams and the first 1 for ewes were selected for rams.At the 8-month-old stage,the first 3 principal components were selected for rams and the first 2 principal components were selected for ewes.The first principal component of both rams and ewes was the body size factor,reflecting the overall body structure of Qinghai-ibetan sheep.In conclusion,except for the age of 6 months,there was a highly significant positive correlation between body weight and body size traits at all ages.The principal components at different stages reflected the growth and development characteristics of Qinghai-Tibetan sheep at different stages,and the first principal component was the body size factor,which played a dominant role.Thestudy could optimize and adjust the current breeding program of Qinghai-Tibetan sheep of different ages,and provide a theoretical guidance for the selection of Qinghai-Tibetan sheep in the later stage.