INFLUENCE OF ROUGHAGE AND GRAIN PROCESSING IN HIGH-CONCENTRATE DIETS ON THE PERFORMANCE OF LONG-FED HOLSTEIN STEERS

The effects of roughage source and timing of inclusion in high-concent rate diets on feedlot performance were evaluated in each of 2 yr with 144 and 120 long-fed Holstein steers, respectively. Roughage, when inc luded in the diet, was delivered in a built-in-roughage (BIR) pellet s upplying 15 and 6% roughage (percentage of DM) or hay crop silage (HCS ) supplying 7 and 10% roughage (percentage of DM) for the growing and finishing periods, respectively. The six dietary treatments (two pens each) investigated were continuous whole corn and pelleted supplement (no added roughage; WSC-PEL); BIR with cracked corn either in the grow ing (BIR-G) or finishing (BIR-F) period with whole corn being fed with pelleted supplement when BIR was not part of the diet; BIR and cracke d corn fed continuously (BIR-CONT); and two HCS treatments in which th e corn was fed either whole (HCS-WSC) or cracked (HCS-CSC) for the ent ire feeding period. Replicates were slaughtered 4 and 3 wk apart for y r 1 and 2, respectively. Pooled daily gains (yr 1 and 2) for the entir e trial(1.39 to 1.45 kg/d) were not different(P > .05). Daily DM and c oncentrate intakes were lower(P < .001) and gain efficiency was higher (P < .001) for the WSC-PEL than for the other treatments. Carcass cha racteristics were similar among treatments except for an improved yiel d grade (P < .02) for the HCS treatments over the BIR treatments. The WSC-PEL treatment was the most profitable ($/steer) and the BIR-CONT d iet was the least profitable. The HCS treatments were the most profita ble of the roughage treatments. A newly proposed intake prediction equ ation for feedlot cattle performed similarly to the 1984 NRC equation with long-fed Holstein steer calves.