Abstract
Two feedlot trials involving 65 steers and in vivo metabolism studies were conducted to evaluate micronized wheat (MW) vs dry rolled wheat (DRW) in 85% wheat rations for finishing cattle. Evaluation was based on feedlot performance, carcass merit, digestibility and ruminal lactate and volatile fatty acid (VFA) concentrations. Feedlot parameters measured in trial 1 were not significally different between DRW and MW. In trial 2, average daily dry matter intake (7.16 vs 7.81 kg) and gain (1.45 vs 1.59 kg) were greater (P<.01) on MW. The same trend existed in trial 1. No significant differences (P>.05) existed in feed efficiency (kg feed/kg gain) between DRW and MW in either trial, although there was a slight trend in favor of MW. Ruminal pH in feedlot animals was higher (P<.05) for MW in both feedlot trials. Total VFA concentrations in feedlot animals was similar for both treatments, although significantly less (P<.05) acetate was present for MW in both feedlot trials. Moreover, more butyrate (P<.05) was present for MW trial 1 and more propionate (P<.05) in trial 2. In vivo digestion coefficients for DRW and MW rations were very similar for dry matter, protein (79.3 vs 79.8%) and starch (99.2 vs 99.3%). Ruminal lactic acid levels in rumen fistulated steers were not significalty different (P>.05) between DRW and MW treatments at either 0, 1, 2, 4 or 8 hr postfeeding and, in general, were low at all time periods. VFA concentrations in fistulated steers were similar for DRW and MW at the above sampling times, although favoring less acetate and more propionate for MW 1 and 2 hr postfeeding. These results agree with those noted in feedlot animals. Copyright © 1977. American Society of Animal Science . Copyright 1977 by American Society of Animal Science.