Estimation of variance components and genetic parameters for type traits and milk yield in Holstein cattle

Abstract

This research was conducted to estimate variance components and genetic parameters for type traits and milk yield in Holstein-Friesian cattle. In this study, 597 daughters of 158 sires in 128 herds were classified. In the data analysis, type scores for 354 daughters bred within 70 herds sired by 46 sires that had at least 3 daughters, and 304 lactation records for 206 daughters within 56 herds sired by 37 sires, were considered. For estimation of variance components and correlations among the traits, the MTDFREML package program was used. The mean stature was 145.56 cm. Means for linear traits varied from 4.47 for fore teat placement to 6.42 for body depth. Heritability for fore udder attachment and front teat placement were both 0.00. Heritability for linear traits estimated for lowest and highest dairy character values and for body capacity were 0.06 and 0.62, respectively. Values for heritability and repeatability of milk yield were 0.20 and 0.20, respectively.