Short-term grain feeding and its effect on carcass and meat quality

Abstract

Forty-five crossbred steers weighing 540-580 kg were assigned to three treatment groups. Group 1 received pasture only for 58 days; Group 2 grazed at a similar herbage mass to Group 1 and were supplemented with 4 kg/hd/day of a concentrate ration; Group 3 were on a feedlot and fed 8 kg/hd/day of concentrate together with 2.0 kg/hd/day of straw. Groups 2 and 3 each had a 28 day preconditioning period followed by a 30 day concentrate feeding period. Final fasted liveweight, liveweight gains, and carcass weights for concentrate, concentrate plus pasture and pasture alone grou ps were 546 ± 9, 548 ± 9, 547 ± 8 kg; 0.33 ± 0.09, 0.42 ± 0.09, -0.05 ± 0.09 kg/hd/day and 293 ± 7, 315 ± 4 and 313 ± 4 kg, respec tively. The concentrate plus pasture and pasture only fed groups had greater fat depths. Ultimate pH was slightly lower in concentrate fed than pasture fed cattle but there were no differences in fat colour or tenderness as measured in the laboratory. Plasma ca rotene levels were significantly lowered by a factor of 10 in the concentrate fed group compared to the grass fed group, but this did not aff ect fat colour when measured subjectively at the meat processing plant or objectively in the laboratory. Apparently feeding concentrates for 30 days is insufficient to affect fat colour characteristics.