Decreasing finishing age of early-maturing suckler heifers at a common carcass weight: growth, carcass and muscle characteristics and predicted methane emissions

Younger beef cattle can have superior meat quality than older animals, but this depends on the difference in finishing age. Finishing beef cattle at a younger age is one strategy suggested to decrease methane emissions. This study examined the effect of decreasing the finishing age of early-maturing breed suckler heifers on carcass fatness, feed conversion efficiency, meat quality and predicted methane emissions when slaughtered at the same carcass weight from a similar ration. Heifers were offered concentrates ad libitum (dry matter [DM] intake 7.7 kg per head daily) and 1.2 kg grass silage DM per head daily for a 174-d finishing period and slaughtered at 17.7 mo of age or a restricted amount of the same ration (5.2 and 1.0 kg of concentrates and grass silage DM per head daily, respectively) for 230 d such that they were 19.7 mo of age at slaughter. Younger slaughter-age animals grew faster (0.97 vs. 0.79 kg/day), had a similar carcass weight (259 kg), greater fatness (10.8 vs. 9.4 on a 1 [very lean] –15 [very fat] scale), poorer feed efficiency (9.1 vs. 7.9 kg DM/kg live weight gain) and greater predicted methane per day (184 vs. 130 g) and in total (32 vs. 30 kg) during the finishing period compared to the older animals. Trained assessors detected no difference in meat tenderness, texture and overall liking between the two slaughter age groups. It is concluded that for early-maturing suckler heifers with a similar carcass weight on a common diet, decreasing finishing age by 2 mo does not enhance beef eating quality but increases carcass fat classification and methane emissions.