Tiezzi Francesco, Maisano Antonio Marco, Chessa Stefania, Luini Mario, Biffani Stefano
Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA.
Istituto Zooprofilattico Sperimentale Lombardia Emilia Romagna "Bruno Ubertini"-I.Z.S.L.E.R. Territorial Section of Lodi and Brescia Sector Diagnostic, Animal Health and Welfare, 26900 Lodi, Italy.
Animals (Basel). 2020 Dec 2;10(12):2271. doi: 10.3390/ani10122271.
In spite of the impressive advancements observed on both management and genetic factors, udder health still represents one of most demanding objectives to be attained in the dairy cattle industry. Udder morphology and especially teat condition might represent the first physical barrier to pathogens' access. The objectives of this study were to investigate the genetic component of teat condition and to elucidate its relationship with both milk yield and somatic cell scores in dairy cattle. Moreover, the effect of selection for both milk yield and somatic cell scores on teat condition was also investigated. A multivariate analysis was conducted on 10,776 teat score records and 30,160 production records from 2469 Italian Holstein cows. Three teat scoring traits were defined and included in the analysis. Heritability estimates for the teat score traits were moderate to low, ranging from 0.084 to 0.238. When teat score was based on a four-classes ordinal scoring, its genetic correlation with milk yields and somatic cell score were 0.862 and 0.439, respectively. The scale used to classify teat-end score has an impact on the magnitude of the estimates. Genetic correlations suggest that selection for milk yield could deteriorate teat health, unless more emphasis is given to somatic cell scores. Considering that both at national and international level, the current selection objectives are giving more emphasis to health traits, a further genetic deterioration in teat condition is not expected.
尽管在管理和遗传因素方面都取得了令人瞩目的进展，但乳房健康仍然是奶牛养殖业中最具挑战性的目标之一。乳房形态，尤其是乳头状况，可能是病原体进入的第一道物理屏障。本研究的目的是调查乳头状况的遗传成分，并阐明其与奶牛产奶量和体细胞评分之间的关系。此外，还研究了对产奶量和体细胞评分的选择对乳头状况的影响。对来自2469头意大利荷斯坦奶牛的10776条乳头评分记录和30160条生产记录进行了多变量分析。定义了三个乳头评分性状并纳入分析。乳头评分性状的遗传力估计值为低到中等，范围从0.084到0.238。当乳头评分基于四类序数评分时，其与产奶量和体细胞评分的遗传相关性分别为0.862和0.439。用于分类乳头末端评分的量表对估计值的大小有影响。遗传相关性表明，除非更加强调体细胞评分，否则对产奶量的选择可能会损害乳头健康。考虑到在国家和国际层面，当前的选择目标都更加重视健康性状，预计乳头状况不会进一步遗传恶化。
