EFFECT OF CORN HYBRID AND GRAIN PROCESSING METHOD ON RATE OF STARCH DISAPPEARANCE AND PERFORMANCE OF FINISHING CATTLE

Two trials evaluated the effects of different corn hybrids on in vitro rate of starch disappearance and finishing cattle performance. Hybrid s were selected, based on in vitro rate of starch disappearance (A = f astest, B = intermediate, C = slowest). In Trial 1, hybrids A and B we re fed as dry-rolled and early-harvested, high-moisture (28%) corn and hybrid C was fed as dry-rolled corn. Cattle fed dry-rolled hybrid A g ained faster (P < .10) and more efficiently(P < .10) than cattle fed d ry-rolled hybrids B and C. No differences were observed in DMI, qualit y grade, or fat thickness among hybrids fed dry-rolled. Dry matter int ake was lower (P < .10) and feed efficiency was improved (P < .10) for cattle fed corn hybrids A and B as high-moisture corn compared with t hose same hybrids fed dry-rolled. In Trial 2, hybrids A, B, and C were fed as dry-rolled and early-harvested, high-moisture (29, 28, and 29% moisture, respectively) corn. Performance and carcass measurements we re not affected by hybrid fed. Cattle fed high-moisture corn gained fa ster (P < .10), consumed less DM (P < .01), and were more efficient (P < .01) than cattle fed the same hybrids dry-rolled. Across trials, hy brids, and processing methods, in vitro rate of starch disappearance w as correlated with feed efficiency (r(2) = .58, P < .001). These data suggest that method of grain processing had a greater influence on eff iciency of gain than corn hybrid selection, and the relative ranking o f corn hybrids based on in vitro rate of starch disappearance does cha nge whether processed as dry-rolled or as early-harvested high-moistur e corn.