Estimation of Genetic Parameters for Test Day Records of Somatic Cell Score
作者： R. Reents , J. Jamrozik , L.R. Schaeffer , J.C.M. Dekkers
DOI: 10.3168/JDS.S0022-0302(95)76915-6
关键词: Dairy cattle 、 Lactation 、 Herd 、 Test day 、 Biology 、 Genetics 、 Somatic cell count 、 Somatic cell 、 Heritability 、 Trait 、 Animal science 、 Food science 、 Animal Science and Zoology
摘要: Abstract The present study estimated variance components for test day records of somatic cell score and production traits. Data consisted 235,100 observations recorded between 1986 1994 on lactations 1 to 3 15,922 Holstein cows from 143 herds. Records were considered as repeated within a lactation different traits across lactations. multiple-trait animal model analysis included random additive genetic permanent environment effects by lactation. Fixed herd date set four covariables days in lactation, parity, age, season, which accounted the shape curve. Gibbs sampling chains carried out separately milk fat protein yields. Heritabilities l .09, .11, respectively. Genetic correlations high (.88, .79, .95 2, 3, 2 respectively). Correlations smaller (.29, .19, .46 higher than score. similar those Variances differed significantly, indicating that should not be same trait.
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