Mello Raquel Rodrigues Costa, Sinedino Letícia Del-Penho, Ferreira Joaquim Esquerdo, de Sousa Sabrina Luzia Gregio, de Mello Marco Roberto Bourg
Department of Animal Evaluation and Reproduction, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 07, Seropedica, Rio de Janeiro, Brazil.
Department of Animal Sciences, University of Florida (UF), 2250 Shealy Drive, Gainesville, FL, 32911, USA.
Trop Anim Health Prod. 2020 Jan;52(1):273-281. doi: 10.1007/s11250-019-02009-7. Epub 2019 Aug 1.
The objective of this study was to investigate the relationship among functional traits (age at first calving (AFC), calving interval (CI), reproductive efficiency (RE), total milk yield (TMY), and lactation period (LP)) in Red Sindhi breed through multivariate techniques. For this goal, performance data provided by the Brazilian Association of Zebu Breeders related to 560 Red Sindhi dairy cattle from 28 different herds in Brazil, born in the period from 1987 to 2011, were used. Principal component analysis with correlation matrix was used to find the relationship among AFC, CI, RE, TMY, and LP. It was found that for all functional traits, first 3 principal components explained more than 90% of the total variation. Clustering analysis was performed based on Tocher method, and results showed physiological relationships among functional traits. By cluster analysis, twelve different groups were generated from the pool of Sindhi herds analyzed, with a great homogeneity among females for the traits evaluated and only few females generating separate groups. Four hundred and twenty-nine females were clustered in one group, representing 76.60% of the genotypes. Total milk yield (TMY) showed 71.92% of the total variation, and age at first calving (AFC) contributed with 23.06% of the variation, being the two most important traits for the variability of the data set. In conclusion, the multivariate procedures were effective in generating the correlations among the functional traits, showing that CI is correlated with RE and all these functional traits are related with total milk yield.
本研究的目的是通过多变量技术研究红信德牛品种功能性状（初产年龄（AFC）、产犊间隔（CI）、繁殖效率（RE）、总产奶量（TMY）和泌乳期（LP））之间的关系。为此，使用了巴西瘤牛养殖者协会提供的与巴西28个不同牛群中560头红信德奶牛相关的性能数据，这些奶牛出生于1987年至2011年期间。使用带有相关矩阵的主成分分析来寻找AFC、CI、RE、TMY和LP之间的关系。结果发现，对于所有功能性状，前3个主成分解释了总变异的90%以上。基于托赫尔方法进行聚类分析，结果显示了功能性状之间的生理关系。通过聚类分析，从所分析的信德牛群中产生了12个不同的组，在所评估的性状方面，雌性之间具有很大的同质性，只有少数雌性形成单独的组。429头雌性被聚类在一组，占基因型的76.60%。总产奶量（TMY）占总变异的71.92%，初产年龄（AFC）占变异的23.06%，是数据集中变异性最重要的两个性状。总之，多变量程序有效地生成了功能性状之间的相关性，表明CI与RE相关，并且所有这些功能性状都与总产奶量相关。
