PRESERVATION AND FEEDING VALUE FOR YEARLING STEERS OF WHOLE PLANT CORN ENSILED AT 28 AND 42% DRY MATTER WITH AND WITHOUT COLD FLOW AMMONIA TREATMENT

Abstract

Corn was ensiled at both 28 and 40% dry matter (DM) with and without prior treatment of anhydrous ammonia using the cold-flow technique. Crude protein of treated silage was from 3.37 to 3.82% units higher than untreated silage. Lactic and acetic acid levels and pH were greater in treated than in untreated silage. As true protein-N was greater in ammonia-treated than untreated silage by between 0.09 and 0.23 percentage units, DM basis, and amine-N was correspondingly decreased, a significant inhibitory effect of ammonia on degradation of corn protein was observed. In a 112-day feeding trial utilizing 96 yearling Charolais × steers (mean weight, 300 kg), ammonia treatment of corn silage improved intake by 5% and gain by 6% over untreated corn silage supplemented with urea at feeding time. Intake of high dry matter corn was 5% greater than that of the lower dry matter corn, but gain was unaffected by corn dry matter. Ammonia treatment significantly improved aerobic stability of both corn silages. Effluent losses caused a 10% unit reduction in recovery of dry matter from 28% DM compared to 40% DM corn and ammonia treatment had no pronounced effect upon nutrient losses during ensiling. Significance of these results for effective preservation of corn silage and the relevance of protein degradation to the nutritive value of corn silage are discussed. Key words: Corn silage, yearling steers, dry matter level, analytical effects, amonia treatmeet