Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark, Fermoy, Co., Cork, Ireland.
ICBF, Highfield House, Shinagh, Bandon, Co., Cork, Ireland.
J Anim Sci. 2019 Jul 2;97(7):2769-2779. doi: 10.1093/jas/skz152.
The ability to alter the morphology of cattle towards greater yields of higher value primal cuts has the potential to increase the value of animals at slaughter. Using weight records of 14 primal cuts from 31,827 cattle, the objective of the present study was to quantify the extent of genetic variability in these primal cuts; also of interest was the degree of genetic variability in the primal cuts adjusted to a common carcass weight. Variance components were estimated for each primal cut using animal linear mixed models. The coefficient of genetic variation in the different primal cuts ranged from 0.05 (bavette) to 0.10 (eye of round) with a mean coefficient of genetic variation of 0.07. When phenotypically adjusted to a common carcass weight, the coefficient of genetic variation of the primal cuts was lesser ranging from 0.02 to 0.07 with a mean of 0.04. The heritability of the 14 primal cuts ranged from 0.14 (bavette) to 0.75 (topside) with a mean heritability across all cuts of 0.48; the heritability estimates reduced, and ranged from 0.12 (bavette) to 0.56 (topside), when differences in carcass weight were accounted for in the statistical model. Genetic correlations between each primal cut and carcass weight were all ≥0.77; genetic correlations between each primal cut and carcass conformation score were, on average, 0.59 but when adjusted to a common carcass weight, the correlations weakened to, on average, 0.27. The genetic correlations among all 14 primal cut weights was, on average, strong (mean correlation of 0.72 with all correlations being ≥0.37); when adjusted to a common carcass weight, the mean of the genetic correlations among all primal cuts was 0.10. The ability of estimated breeding values for a selection of primal cuts to stratify animals phenotypically on the respective cut weight was demonstrated; the weight of the rump, striploin, and fillet of animals estimated to be in the top 25% genetically for the respective cut, were 10 to 24%, 12 to 24%, and 7 to 17% heavier than the weight of cuts from animals predicted to be in the worst 25% genetically for that cut. Significant exploitable genetic variability in primal carcass cuts was clearly evident even when adjusted to a common carcass weight. The high heritability of many of the primal cuts infers that large datasets are not actually required to achieve high accuracy of selection once the structure of the data and the number of progeny per sire is adequate.
改变牛的形态以获得更高价值的主要切块产量的能力有可能提高屠宰动物的价值。本研究使用 31827 头牛的 14 个主要切块的重量记录，目的是量化这些主要切块的遗传变异程度；同样感兴趣的是调整到常见胴体重量后的主要切块的遗传变异程度。使用动物线性混合模型为每个主要切块估计方差分量。不同主要切块的遗传变异系数范围为 0.05（牛里脊）至 0.10（眼肉），平均遗传变异系数为 0.07。当表型调整到常见胴体重量时，主要切块的遗传变异系数较小，范围为 0.02 至 0.07，平均值为 0.04。14 个主要切块的遗传力范围为 0.14（牛里脊）至 0.75（肋排），所有切块的平均遗传力为 0.48；当统计模型中考虑胴体重量差异时，遗传力估计值降低，范围为 0.12（牛里脊）至 0.56（肋排）。每个主要切块与胴体重量之间的遗传相关性均≥0.77；每个主要切块与胴体形态评分之间的遗传相关性平均为 0.59，但调整到常见胴体重量后，相关性减弱至平均 0.27。所有 14 个主要切块重量之间的遗传相关性平均较强（平均相关系数为 0.72，所有相关性均≥0.37）；调整到常见胴体重量后，所有主要切块之间的遗传相关性平均值为 0.10。估计的育种值选择一组主要切块对各自切块重量进行表型分层的能力得到了证明；估计为各自切块遗传排名前 25%的动物的臀部、里脊和菲力的重量分别比预测为遗传最差的 25%的动物的切块重量重 10%至 24%、12%至 24%和 7%至 17%。即使调整到常见胴体重量，主要胴体切块中仍存在明显的可利用遗传变异。许多主要切块的高遗传力表明，一旦数据结构和每个 sire 的后代数量足够，实际上不需要大量数据集即可实现高选择准确性。
