Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, Legnaro, Italy.
J Dairy Sci. 2013 Aug;96(8):5344-51. doi: 10.3168/jds.2012-6352. Epub 2013 May 30.
The objectives of this research were to estimate genetic parameters for body condition score (BCS) and locomotion (LOC), and to assess their relationships with angularity (ANG), milk yield, fat and protein content, and fat to protein content ratio (F:P) in the Italian Holstein Friesian breed. The Italian Holstein Friesian Cattle Breeders Association collects type trait data once on all registered first lactation cows. Body condition score and LOC were introduced in the conformation scoring system in 2007 and 2009, respectively. Variance (and covariance) components among traits were estimated with a Bayesian approach via a Gibbs sampling algorithm and an animal model. Heritability estimates were 0.114 and 0.049 for BCS and LOC, respectively. The genetic correlation between BCS and LOC was weak (-0.084) and not different from zero; therefore, the traits seem to be genetically independent, but further investigation on possible departures from linearity of this relationship is needed. Angularity was strongly negatively correlated with BCS (-0.612), and strongly positively correlated with LOC (0.650). The genetic relationship of milk yield with BCS was moderately negative (-0.386), and was moderately positive (0.238) with LOC. These results indicate that high-producing cows tend to be thinner and tend to have better locomotion than low-producing cows. The genetic correlation of BCS with fat content (0.094) and F:P (-0.014) was very weak and not different from zero, and with protein content (0.173) was weak but different from zero. Locomotion was weakly correlated with fat content (0.071), protein content (0.028), and F:P (0.074), and correlations were not different from zero. Phenotypic correlations were generally weaker than their genetic counterparts, ranging from -0.241 (BCS with ANG) to 0.245 (LOC with ANG). Before including BCS and LOC in the selection index of the Italian Holstein breed, the correlations with other traits currently used to improve type and functionality of animals need to be investigated.
本研究旨在估计意大利荷斯坦牛的体况评分（BCS）和运动能力（LOC）的遗传参数，并评估它们与角度（ANG）、产奶量、脂肪和蛋白质含量以及脂肪与蛋白质含量比（F：P）之间的关系。意大利荷斯坦牛饲养者协会在所有注册的初产奶牛身上收集一次类型特征数据。BCS 和 LOC 分别于 2007 年和 2009 年引入体型评分系统。通过 Gibbs 抽样算法和动物模型，采用贝叶斯方法估计了性状之间的方差（协方差）分量。BCS 和 LOC 的遗传力估计值分别为 0.114 和 0.049。BCS 和 LOC 之间的遗传相关性较弱（-0.084），与零无差异；因此，这些性状似乎在遗传上是独立的，但需要进一步研究这种关系是否存在线性偏离。角度与 BCS 呈强烈负相关（-0.612），与 LOC 呈强烈正相关（0.650）。产奶量与 BCS 的遗传关系为中度负相关（-0.386），与 LOC 为中度正相关（0.238）。这些结果表明，高产奶牛往往较瘦，运动能力也较好。BCS 与脂肪含量（0.094）和 F：P（-0.014）的遗传相关性非常弱且与零无差异，与蛋白质含量（0.173）的遗传相关性较弱但与零有差异。LOC 与脂肪含量（0.071）、蛋白质含量（0.028）和 F：P（0.074）呈弱相关，且与零无差异。表型相关性一般弱于遗传相关性，范围从-0.241（BCS 与 ANG）到 0.245（LOC 与 ANG）。在将 BCS 和 LOC 纳入意大利荷斯坦品种的选择指数之前，需要研究与其他当前用于提高动物体型和功能的性状的相关性。
