Genetic parameters for somatic cell score in the first three lactations of Czech Holstein and Fleckvieh breeds using a random regression model

ZAVADILOVÁ, L., WOLF, J., ŠTÍPKOVÁ, M., NĚMCOVÁ, E. & JAMROZIK, J. Genetic parameters for somatic cell score in the first three lactations of Czech Holstein and Fleckvieh breeds using a random regression model. Czech Journal of Animal Science, 2011, roč.
ZAVADILOVÁ, Ludmila, WOLF, Jochen, ŠTÍPKOVÁ, Miloslava, NĚMCOVÁ, Eva and JAMROZIK, J. Genetic parameters for somatic cell score in the first three lactations of Czech Holstein and Fleckvieh breeds using a random regression model. Czech Journal of Animal Science, 2011, 56, 251-260. ISSN 1212-1819.
Year2011
CathegoryScientific publication in impacted journals
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Abstract

A multiple-lactation random regression model was applied to test-day somatic cell score (SCS) records from the first three lactations of Czech Holstein (26 314 cows) and Fleckvieh breed (24 061 cows). The linear model for SCS included fixed herd-test date effect, fixed regressions on days in milk within the age-season class, random regressions for the animal genetic and random regressions for the permanent environmental effect of the cow (Legendre polynomials were used for all regressions.) The resulting daily heritability ranged from 0.08 to 0.11 in the middle part of the lactation and only slightly increased with parity. Daily permanent environmental variances were higher than the genetic variances and daily residual variances decreased with DIM. The residual variances in early lactation increased with lactation number. For both breeds, the highest genetic correlations computed for the part of lactation between DIM 45 and DIM 255 were between the second and third lactation (0.95).