黑白花奶牛泌乳曲线参数的方差组份和遗传特性分析

AN ANALYSIS ON VARIANCE COMPONENTS AND GENTIC CHARACTERISTICS OF LACTATION CURVE PARAMETERS OF HOLSTEIN-FRIESIANS

本文根据北京黑白花奶牛８６０个有完整记录的泌乳期资料，利用Ｗｏｏｄ模型进行了泌乳曲线参数估计，并通过最小二乘法对估计结果进行了方差分析和相关性分析，估计了曲线参数的遗传力（ｈ￣２）、遗传相关（ｒ＿Ａ）、表型相关（ｒ＿ｐ）和环境相关（ｒ＿Ｅ）。方差分析表明，父畜和胎次对产奶量（ＭＹ）、估计产奶量（ＥＭＹ）、ａ、ｃ、高峰月份（ＭＰＹ）和高峰月产奶量（ＰＹ）有极显著影响（Ｐ＜０．０１）；对持久力有显著影响（Ｐ＜０．０５）；场别对ｂ和上述所有参数均有极显著影响（ｐ＜０．０１）；产犊年份对ＥＹ、ＥＭＹ、ａ、ｃ和ＰＹ有极显著影响（Ｐ＜０．０１）。ｈ￣２的估计结果为：ＭＹ、ＥＭＹ、ａ和ＰＹ的ｈ￣２幅度在０．２３１～ｏ．２７１之间；ｃ和ＭＰＹ的h￣2分别为０．１８３±０．０９３和０．１６７±０．０８９；持久力的ｈ￣２为０．１１５±０．０７６。相关分析结果表明，ＰＹ与ＭＹ有强相关（ｒ＿Ａ、ｒ＿ｐ、ｒ＿Ｅ分别为Ｏ．７２１、０．８１２和０．８４２），与ａ有强相关（ｒ＿Ａ、ｒ＿ｐ、ｒ＿Ｅ分别为０．８２４、０．７８０和０．７６６），与ｂ、ｃ均有正相关（ｒ＿Ａ、和ｒ＿Ｅ的幅度为０．３５５～０．４３７）。ＭＹ与ａ有正相关（ｒ＿Ａ、ｒ＿ｐ和?

In this paper,an estimation is made on the lactation curve parameters,after aWood model on the basis of 860 complete lactation period records of Holstein-Friesiansin Beijing.A variance analysiS and a correlate analvsis are made on the estimation resultin a method of least square for an estimation of heritabilities,genetic,phenotypic,andenvironmental correlation of the curve parameters.The variance result shows that thesires and parities have significant influence on milk yield(MY),estirnated milk yield(EMY),parameters a,b,c,month of peak yield(MPY),peak yield(PY) and persi-stency(P<0.0l).The year of parturition has sisnificant influence on MY,EMY,cand PY. The farms have significant influence on b and all parameters as mentionedabove(P<0.0l).The range of h￣2 values of MY, EMY, a and PY are 0.231～0.271.Heritability estimation values of parameter c and MPY are 0.183 and 0.167 respectively,and h￣2 values of persistency are 0.ll5. The correlate analysis shows that PY has highcorrelation with MY(r_A=0.721,r_p=0.8l2,r_E=0.842) and with parameter a(r_A=0.824,r_p=0.780,r_E=0.766),and it has positive correlation with parameter b and c(r=0.355～0.477). The MY has positive correlation with parameter a(r_A=0.335,r_p=0.531,r_E=0.600),genetic correlation with parameter b and MPY(r_A=0.348 and 0.346, respectively) and negative genetic correlation with parameter c(r_A=-0.370).The persistency has all negative correlation with parameters a,b,and PY but haspositive correlation with MPY.