Estimation of Variance Components for Birth and Weaning Weights in Holstein-Friesian Calves by using WOMBAT software

Abstract

The aim of this study was to determine the variance components for birth and weaning weights in Holstein calves. In this purpose, a total of 675 calf birth weight and 295 weaning weight records of Holstein calves raised at Kuzucu Dairy Cattle Farm in Eregli, Konya Province were used for estimation of phenotypic and genetic parameters for calf birth weight and weaning weight. Phenotypic and genetic parameters were estimated by WOMBAT program using a Single Trait Animal Model (STAM). The model constitutes of additive direct effect, maternal genetic effect (only for Model II) and errors as random effects, birth type, sex of calf, season of birth, year of birth and age of dam as fixed effects. Least square mean of calf birth weight was determined as 34.992 ± 0.572 kg. The direct heritability (h a 2 ) of calf birth weight was calculated as 0.180±0.109 in Model I and the direct heritability (h a 2 ) and maternal heritability (h m 2 ) of calf birth weight were calculated as 0.154±0.096 and 0.141±0.106 in Model II, respectively. The effect of calving season, birth type, sex and age of dam on birth weight of calf were significant (P 0.05). As for calf weaning weight, least square mean was determined as 74.250 ± 1.775 kg. For calf weaning weight, the direct heritability (h a 2 ) in Model I was calculated as 0.104± 0.126 and the direct heritability (h a 2 ) and maternal heritability (h m 2 ) in Model II were calculated as 0.104± 0.127 and 0.00002±0.341, respectively. The effect of calving year (P 0.05) Furtermore, estimated breeding values (EBVs) estimated by BLUP (Best Linear Unbiased Prediction) for calves, sires and dams were found to be in general with the range of -3.245 to 2.577, -2.607 to 2.631 and -1.714 to 1.747 for birth weight and -2.969 to 2.274, -2.650 to 2.376 and -1.456 to 1.301 for weaning weight, respectively.