Pre-weaning performance of Hereford, Angus, Salers and Nellore crossbred calves: Individual and maternal additive and non-additive effects

Abstract

Individual and maternal additive and non-additive effects for gestation length (GL), birth (BW) and weaning weights (WW) were estimated in Hereford (H/H), Aberdeen Angus (A/A), Salers (S/S) and Nellore (N/N) breeds. Data were recorded on 4474 calves of 39 genotypes (pure- and cross-bred) which were sired by 141 bulls and born in two connected crossbreeding experiments carried out between 1993 and 2004. Five crossbreeding parameter models were compared. The best fit, assessed by the Akaike Information Criterion, was obtained by the additive model for GL and by the Dickerson full model for BW and WW. The individual additive effect of N/N increased GL by 12.0days compared to H/H, whilst the maternal additive effect reduced it by 3.1days. The individual additive effects of A/A and N/N for BW were +1.8kg and −2.3kg, respectively. Maternal effects had opposite sign to the individual effects (A/A, +3.6kg; N/N, −8.3kg). Additive effects of S/S were not significant (P>0.10). Maternal heterosis increased BW in all crosses with H/H (from +1.8 to +5.1kg) but the individual heterosis was only significant in the crosses with N/N (2.3kg). In the case of WW, maternal additive effects as well as individual and maternal heterosis improved WW by 18.5, 5.3 and 11.9kg, respectively. Additive effects of N/N decreased WW (individual, −12.1kg; maternal, −34.6kg) whilst the individual and maternal heterosis had a favourable effect (+20.2kg; +63.1kg). In both N/N and S/S breeds, maternal recombination losses increased WW (30.7 and 48.2kg) and individual recombination losses have the opposite effect (from −12.1 to −27.0kg). In general terms, additive and non-additive effect of European breeds did not increase GL or have any effect on BW. However, increasing proportions of Nellore were associated with longer GL compared to H/H. The use of Nellore as paternal breed may be related to heavier BW which may increase the incidence of dystocia. Positive effects of crossbreeding on WW were mainly due to the use of crossbred dams given the significant magnitude of maternal heterosis. The best combination of individual additive effects came from the utilisation of European breeds, whilst the greater magnitudes of both heterosis and recombination losses were observed in the Nellore crosses.