Estimation of genetic parameters for body weight in Charolais calves in Slovenia

The aim of the present study was to estimate genetic parameters for growth traits of Charolais calves in Slovenia. Analysed traits included birth weight (BW), weight at the beginning (WB) and at the end of grazing season (WE), as well as yearling weight (WY). Data were collected on 340 Charolais calves. The total number of records, including pedigree data (parents and grandparents) was 401 animals. (Co)variance components were estimated by REML method for the animal model that included fixed effects of sex, parity and year of birth in the models for all traits. Age of calves at the beginning of grazing season was included as linear regression in models for all traits except for birth weight. The age of calves at the end of grazing season, and age at approximately one year were included as linear regression in the models for corresponding weights. Random effects included direct and maternal additive genetic effects. Direct heritabilities (h(a)(2)) were decreased from 0.74 at birth to 0.19 at yearling weight. Inversely, maternal heritabilities (h(m)(2)) were increased from 0.04 at birth to 0.12 at all other included weights. Direct-maternal genetic correlation (ram) was negative for all weights except for yearling weight (0.10).