Maize gluten and rapeseed meal as protein supplements to barley or wheat for intensively finished Charolais-cross bulls

Abstract

AbstractFour diets, barley/proprietary protein concentrate (B/PC), barley/maize gluten (B/MG), barley/rapeseed meal (B/RSM) and wheat/'rapeseed meal (W/RSM) were formulated to contain 165 g crude protein and 13·0 MJ metabolizable energy per kg dry matter. In experiment 1, all four diets were offered ad libitum to Charolais × Friesian bulls from 187 kg live weight to slaughter at about 488 kg live weight. In experiment 2, the B/PC and B/RSM were offered ad libitum to Charolais × (Hereford × Friesian) bulls from 222 kg live weight to slaughter at about 491 kg live weight. There were no significant differences between treatments in daily live-weight gain, percentage fat and lean in the live animal, slaughter weight or days on experiment in either experiment. In experiment 1, the carcasses from bulls given B/PC were 14 kg heavier than carcasses from bulls given W/RSM (P<0·05), but only 10 and 7 kg heavier than from bulls given B/MG and B/RSM respectively (P<0·05). The killing-out proportion of bulls given B/PC was significantly greater (P<0·05) than bulls given B/RSM. In experiment 2, carcass weights were similar but the killing-out proportion of bulls given B/PC were again greater (P < 0·001). It is concluded that B/MG and B/RSM were as effective as B/PC as finishing diets and that wheat can be successfully substituted for barley, when offered with rapeseed meal.