Moser D W, Bertrand J K, Misztal I, Kriese L A, Benyshek L L
Animal and Dairy Science Department, University of Georgia, Athens 30602-2771, USA.
J Anim Sci. 1998 Oct;76(10):2542-8. doi: 10.2527/1998.76102542x.
Carcass measurements of 12th-rib fat thickness (CARCFAT), longissimus muscle area (CARCLMA), and weight (CARCWT) on 2,028 Brangus and Brangus-sired fed steers and heifers, as well as yearling weights (YWT) and ultrasound measures of 12th-rib fat thickness (USFAT) and longissimus muscle area (USLMA) on 3,583 Brangus bulls and heifers were analyzed to estimate genetic parameters. Data were analyzed using a six-trait animal model and an average information REML algorithm. The model included fixed effects for contemporary group and breed of dam, covariates for age at slaughter or measurement, and random animal and residual effects. Heritabilities for CARCFAT, CARCLMA, CARCWT, USFAT, USLMA, and YWT were .27+/-.05, .39+/-.05, .59+/-.06, .11+/-.03, .29+/-.04, and .40+/-.04, respectively. Genetic correlations between CARCFAT and USFAT, CARCLMA and USLMA, and CARCWT and YWT were .69+/-.18, .66+/-.14, and .61+/-.11, respectively. The favorable and moderately strong genetic correlations between carcass measurements and similar yearling breeding-animal ultrasound measurements indicate that such measurements of 12th-rib fat and longissimus muscle area are useful in predicting genetic values for carcass leanness and longissimus muscle area. Selection using yearling ultrasound measurements of breeding cattle should result in predictable genetic improvement for carcass characteristics. Inclusion of yearling ultrasound measurements for fat thickness and longissimus muscle area should enhance national cattle evaluation programs.
对2028头婆罗门牛及其杂交育肥牛和小母牛的胴体进行了测量，包括第12肋处脂肪厚度（CARCFAT）、背最长肌面积（CARCLMA）和体重（CARCWT），同时对3583头婆罗门公牛和小母牛进行了周岁体重（YWT）以及第12肋处脂肪厚度（USFAT）和背最长肌面积（USLMA）的超声测量，以估计遗传参数。使用六性状动物模型和平均信息REML算法对数据进行了分析。该模型包括当代组和母本品种的固定效应、屠宰或测量时年龄的协变量，以及随机动物效应和残差效应。CARCFAT、CARCLMA、CARCWT、USFAT、USLMA和YWT的遗传力分别为0.27±0.05、0.39±0.05、0.59±0.06、0.11±0.03、0.29±0.04和0.40±0.04。CARCFAT与USFAT、CARCLMA与USLMA、CARCWT与YWT之间的遗传相关性分别为0.69±0.18、0.66±0.14和0.61±0.11。胴体测量值与类似的周岁种用动物超声测量值之间存在良好且中等强度的遗传相关性，这表明第12肋处脂肪和背最长肌面积的此类测量对于预测胴体瘦肉率和背最长肌面积的遗传值是有用的。使用周岁种牛的超声测量值进行选择应能带来胴体性状可预测的遗传改良。纳入周岁脂肪厚度和背最长肌面积的超声测量值应能加强国家牛只评估计划。
