Estimation of Genetic and Crossbreeding Parameters for Birth Weight in Baladi Cattle and their Crosses with Abondance and Tarentaise Breeds in Egypt

Abstract

Genetic and crossbreeding parameters for birth weight (BWT) were estimated in pure Baladi (BB), Abondance (AB) with BB crossbred and Tarentaise (TR) with BB crossbred calves. Data were collected from breeders in two governorates and from Sids Experimental Farm belonging to Animal Production Research Institute. Data included 9334 records of calves born for 174 sires and 5182 dams. Data consisted of seven genotypes; BB, ½ AB/TR ½ BB, ¾ AB/TR ¼ BB and ⅞ AB/TR ⅛ BB. Group differences were highly significant, (P<0.0001). Least squares means of BWT were 22.3, 32.4, 32.4 and 32.6 kg for BB, ½ AB, ¾ AB and ⅞ AB, respectively and were 32.0, 32.0 and 31.9 kg for ½ TR, ¾TR and ⅞ TR, respectively. Individual and maternal additive and maternal heterosis effects were studied, variance components and heritability estimates were estimated. The individual additive effects of AB and TR for BWT were significant being-9.98 kg and-9.43 kg, respectively. Maternal additive effects were significant and positive being 4.86 kg and 4.81 kg for AB and TR, respectively. Maternal heterosis estimates were non-significant with small magnitude and was negative for AB crossbreds (-0.06 kg) and was positive for TR crossbreds (0.12 kg). Heritability estimates for BWT were 0.16, 0.51 and 0.55 for BB, AB crossbreds and TR crossbreds, respectively. In general, Crossbred calves of AB or TR were higher in BWT than pure BB calves. Individual additive effects show an advantage for AB and TR crossbreds, while maternal additive effects expressed the superiority of the BB dams over the crossbred dams. Results reveal that genetic improvement of BWT in BB could be achieved by crossing with AB or TR breeds for higher BWT.