Lactation and Sample Test-Day Multi-trait animal model for genetic evaluation of somatic cell scores in Hungarian Holstein-Friesian crossbreeds

摘要

Genetic and phenotypic correlations were estimated for means of log SCC (somatic cell scores: SCS) with milkproduction traits using complete lactation and sample test-day data sets. Data of SCS and milk production traitsfor six genetic groups of Holstein-Friesian (HF), Hungarian Native Breed (NHB) and four of their crossbreedswere used. Multi trait animal model was used for the estimation of all genetic and phenotypic (co)-variances Allestimates of correlations either genetic (R) or phenotypic (R) between SCS and milk production traits weremostly negative except with protein percentage. Lactation (L) estimates of R between SCS and total milk yield(MY), fat (F), protein (P) and lactose (Lc) percentages were -.11 ±10, -.12 ± .04, .09 ± .03, and -.18 ± .09,respectively and the corresponding sample test-day estimates (STD) were -. 13 ± .07, -. 13 ± .08, -.11 ± 04, -.11 ± 08respectively. L and STD R estimates of SCS with MY and protein were higher than the corresponding R. L-R of SCS with MY and protein and L-R with fat and lactose were increased with parity. R either L or STDwith fat decreased with the parity. The highest estimates of L-R of SCS with MY were negative for HF in the2nd and the 3rd parity and were ranged from −0.13 to −0.17. R of SCS with daily milk yield (DY) across parityin different genetic groups were higher than the corresponding with MY. All correlations of SCS with proteinwere positive. L-R ranged from .17 to .22 for HF vs. .01 to .04 for NHB. While L-R ranged from 06 to 15for HF vs. .04 to .11 for NHB. It could be concluded that, trend of the relationship for SCS with milk productionmay had some change in crossbred than purebred aecording to percentage of crossing.