Bereskin B, Steele N C
U.S. Department of Agriculture, Beltsville, MD 20705.
J Anim Sci. 1988 Oct;66(10):2498-507. doi: 10.2527/jas1988.66102498x.
Records for pigs included in an experiment on reciprocal recurrent selection conducted from 1956 through 1971 at the USDA Beltsville Agriculture Research Center were analyzed to obtain estimates of heritabilities and genetic correlations and to derive prediction equations for estimating weight of lean cuts (WTLC) and percentage of lean cuts of shrunk slaughter weight (LCPC). Lean cuts growth rate (LCGR) was then estimated as WTLC/age of pig at slaughter. The base population consisted of two unrelated crossbred strains. A total of 1,294 records of F1 and F2 crossbred pigs were analyzed with one barrow and one gilt from each litter. Estimates of heritabilities and genetic correlations were computed with sire components of variance and covariance from a nested analysis of variance with an assumed model of years, strain-lines within years, sire within strain-lines, dams within sires and residual. Degrees of freedom were 307 for sires in strain-lines, 270 for dams in sires and 646 for residual. Heritability (h2) estimates were .42 +/- .13, .41 +/- .13 and .27 +/- .18 for WTLC, LCPC and LCGR, respectively, and .71 +/- .16, .38 +/- .13, .31 +/- .13 and .25 +/- .15 for carcass length, average backfat thickness, longissimus muscle area and ADG in BW, respectively. These estimates were apparently the first published genetic estimates involving LCGR based on carcass data. It was recommended that prediction equations to estimate WTLC, LCPC and LCGR for use in swine testing programs be derived from current meat-type pigs.
对1956年至1971年在美国农业部贝尔茨维尔农业研究中心进行的一项互作轮回选择实验中所涉及的猪的记录进行了分析，以获得遗传力和遗传相关性的估计值，并推导用于估计瘦肉切块重量（WTLC）和收缩屠宰体重的瘦肉切块百分比（LCPC）的预测方程。然后将瘦肉切块生长率（LCGR）估计为WTLC除以猪的屠宰年龄。基础群体由两个不相关的杂交品系组成。对1294条F1和F2杂交猪的记录进行了分析，每个窝选一头公猪和一头母猪。遗传力和遗传相关性的估计值是根据方差和协方差的父系成分，通过对年份、年内品系、品系内父系、父系内母系和残差的假定模型进行嵌套方差分析计算得出的。品系内父系的自由度为307，父系内母系的自由度为270，残差的自由度为646。WTLC、LCPC和LCGR的遗传力（h2）估计值分别为0.42±0.13、0.41±0.13和0.27±0.18，胴体长度、平均背膘厚度、背最长肌面积和体重平均日增重（ADG）的遗传力估计值分别为0.71±0.16、0.38±0.13、0.31±0.13和0.25±0.15。这些估计值显然是基于胴体数据首次发表的涉及LCGR的遗传估计值。建议从当前的肉用型猪中推导用于猪测试计划的WTLC、LCPC和LCGR的预测方程。
