The evaluation of genetic parameters of the type of calving in the population of Holstein Friesian cows

Genetic parameters (heritability coefficients and genetic correlations) of the type of calving, number of stillbirths and birth weight have been evaluated in the population of Holstein Friesian cattle breed. Data sets have been analysed by means of the Mixed Least Square Model (LSMLMW). Besides a random effect of bull-sires, the model has also included the fixed effects of farm, season, sex, the evaluation of viability of calves and types of birth. Estimated heritability values and heritability errors for the type of calving (TC), number of stillbirths (SB) and birth weight (BWT) were low: 0.190 ? 0.062; 0.018 ? 0.006 and 0.149 ? 0.051, respectively. Heritabilities of the analysed traits were evaluated on the grounds of the calves` bull-sires additive value (direct heritability). The values of the genetic correlation coefficients between examined traits ranged from - 0.251 (correlation between the type of calving and number of stillbirths) to 0.340 (correlation between the number of stillbirths and birth weight).