Abstract
In a 90-day fattening trial, 234 head of 32 kg Texas feeder lambs were fed ad libitum a complete pelleted 60% concentrate ration. Lambs were allotted by sex and weight to three replications each of three dose levels of an experimental methane inhibitor—Hemiacetal of Chloral and Starch (HCS: .3 chlorals/anhydroglucose unit) and four replications of the controls. HCS was added at concentrations of 0.5, 1.0 and 2.0 g/kg to the basal ground corn-soybean, mixed hay, and molasses ration and pelleted. Cumulative daily feed consumption and weight gains (kg) were 1.65 and 0.205 for the controls and 1.64, 0.211; 1.62, 0.215; and 1.59, 0.212 for the three dose levels, respectively, the rate of gain being significantly increased at P<.05 level when compared to controls for 1 and 2 g levels of the additive. Corresponding values for feed conversion of 8.06, 7.78, 7.55 (P<.05), and 7.49 (P<.05) demonstrated a significant dose response relationship for feed efficiency despite a trend toward a dose correlated reduction in feed intake. Although for the first 30 days the 1 g level of HCS provided the greatest gain and efficiency response, by the second 30-day period efficiency responses paralleled the dose with 3.3%, 6.0% and 8.6% increases in feed efficiency over the controls for the three HCS concentrations. At the two higher concentrations of HCS weight gains increased significantly (P<.05) for the second and third periods. The high correlation of dose and degree of ruminal methane inhibition with improvement of feed efficiency after 90 days of continuous feeding indicates that energy normally lost as methane can be retained in productive metabolites. The possible favorable effects that HCS may have on minimizing other rumen fermentation losses and thereby contributing to the observed performance response are also discussed. Copyright © 1972. American Society of Animal Science . Copyright 1972 by American Society of Animal Science.