The use of double-muscled cattle breeds in terminal crosses: Animal performance and blood metabolites

Eighty-nine calves born of dams from British (50% Hereford and 50% Red Angu s) and Continental (50% Simmental and 50% Maine Anjou) breeds crossed with Charolais (CH), Belgian Blue (BB) and Piedmontese (PM) sires were used to e valuate the productivity of using double-muscled cattle in terminal crosses . Breed of sire did not exert a significant effect on any parameter measure d before weaning. Calving difficulty was related to breed of dam, being hig her in British than in Continental dams (P < 0.05) and tended to be higher for male than for female calves (P < 0.10). Average daily gains to weaning and weight corrected at 200 d were higher for male than for female calves ( P < 0.05), and for calves from Continental dams than for those from British dams (P < 0.05). Average daily gain during backgrounding was higher for CH than for PM-sired calves (P < 0.05). Also, ADG in feedlot (backgrounding fattening) was higher for male than for female calves (P < 0.05). Slaughte r weight and dressing percentage were higher in calves from Continental dam s than in those from British dams (P < 0.05). At similar backfat thickness, slaughter weight was higher in male than in female calves (P < 0.05). Tota l plasma cholesterol, HDL cholesterol and triglycerides were higher in PM s ired cattle than in those sired by CH (P < 0.01 to 0.10). Similarly, cattle from British dams presented higher values of plasma cholesterol, HDL chole sterol and LDL cholesterol than cattle from Continental darns (P < 0.01 to 0.05). Insulin and IGF-I values increased with age (P < 0.01). Plasma insul in concentrations during fattening were higher for PM than for BE or CH sir ed cattle (P < 0.05), for cattle from Continental than from British dams (P < 0.01) and for males than for females (P < 0.01). During fattening, IGF-T values were higher in male than in female cattle (P < 0.01). The use of do uble-muscled sires in terminal crosses resulted in little effect on perform ance of the progeny.