| 摘要: |
| 测定了西北农林科技大学畜牧试验站奶牛场健康、泌乳正常的 35头奶牛的衡量泌乳均衡性指标：泌乳初期日数（X1）、泌乳盛期日数（X2）、泌乳后期日数（X3）、最高日产奶量（X4）、最低日产奶量（X5）、最高日产奶量与最低日产奶量之差（X6），并测定了305 d产奶量（Y）。经过相关系数分析和统计检验后，剔除了与305 d产奶量相关不显著的指标，保留作用大的自变量（最低日产奶量，最高日产奶量与最低日产奶量之差），以305 d产奶量为依变量（Y），采用通径系数法计算了各自变量对依变量的通径系数和决定系数。结果表明，最高、最低日产奶量及其差值是影响305 d产奶量的最主要因素（通径九分别为1.208 3,－0.419 1），是衡量泌乳均衡性的重要指标。 |
| 关键词: 奶牛 泌乳均衡性 产奶量 相关分析 |
| DOI： |
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| 基金项目:西北农林科技大学青年基金资助项目(005-Y08183) |
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| Correlation analysis between 305-day yield and characters of milk proportionality in dairy cattle |
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| Abstract: |
| Data for this study were collected from 35 dairy cattle in Dairy Cattle Trial Farm of Northwest Sci-Tech University of Agriculture and Forestry.Mile days in initial stage(X1),milk days of pesk perild(X2), milk days in later period(X3),maximum daily yield(X4),minimum daily yield(X5),difference between max. and min.(X6)and 305-day yield(Y)were measured.The correlation coefficients were calculated.The former four characters of milk proportionality were omitted because of no signficance of every correlation coefficient between each of them and 305-day yield.The later two were used as independent varriables ,and 305-day yield was wsed as a dependent variable for path analysis.Path coefficient(pi),determination coeffients(di) and correlation index(R2) were calculated. The results showed that 2 correlation coefficients between chara cters of milk proportionality and the 305-day yield were with very significant difference(P<0.01).X5 gave predominant direct effects (p5=1.2083)and determination on 305-day yield,it is the key effective factor. X6 gave a large direct(p6=-0.4191)and middle indirect effect through X5 on 305-day yield,and this two characters are the good factors of milk proportionality. It is clear that the path coefficient analysis could reveal the exact relationship between the independent variables and the dependent variable. |
| Key words: dairy cattle milk proportionality milk yield correlation analysis |
