Abstract
Animal metabolism and performance were used to evaluate ryegrass straw ensiled with selected additives following laboratory silo and in vitro digestion trials. Lambs consumed more dry matter and nitrogen from silage having 4.5% NaOH:KOH, 20% molasses, 1% urea and .5% limestone as compared to ensilage having these additives except hydroxide. Ensilage with hydroxide gave higher digestibility of organic matter components and retained nitrogen, while urine volume and density were greater. Rumen fluid of these lambs had more volatile fatty acids while ratios were not altered. Body weight gains were similar in heifers fed ryegrass silage, or straw ensiled with molasses, urea and limestone, with or without hydroxide, when each animal received .9 kg barley-cottonseed supplement daily. An equal amount of fat-molasses-urea supplement reduced silage intakes and gains. These results suggest that straw silage as the sole roughage source, with judicious supplementation, will support moderate body growth and that the benefit of added hydroxide is relatively lower in long term ensiling periods. Copyright © 1974. American Society of Animal Science . Copyright 1974 by American Society of Animal Science.