Feeding Swine Waste. II. Nitrogen Utilization, Digestibility and Palatability of Ensiled Swine Waste and Orchardgrass Hay or Corn Grain Fed to Sheep

Abstract
Four diets were fed to 12 wethers in each of two digestion trials and to 24 wethers in a palatability trial: (1) ground orchardgrass hay alone (negative control), (2) ensiled swine waste and orchardgrass hay (40:60), (3) ensiled swine waste and orchardgrass hay (60:40) and (4) ground orchardgrass hay plus soybean meal (positive control). Organic matter digestibility tended to be higher for swine waste-orchard-grass hay silages (56.4 and 56.4 vs 53.8%) than for orchardgrass hay fed alone, and was highest (P<.05) for the orchardgrass hay plus soybean meal diet (61.2%). Crude protein digestibility was higher (P<.05) for the orchardgrass hay plus soybean meal diet than for any of the other diets. N retention was negative (P<.05) for sheep fed the swine waste-containing silages, a reflection of poor retention of absorbed N. The organic matter digestibility of the swine waste, calculated by difference, was over 60% for both silages. No significant differences in dry matter intake between diets were recorded in the sheep palatability trial. Thirty crossbred wethers were used in a digestion trial and a subsequent palatability trial. The animals were fed the following diets on a dry basis: (1) basal, (2) 80% basal and 20% of 40:60 swine waste-ground corn grain mixture, (3) 60% basal and 40% ensiled 40:60 mixture, (4) 80% basal ensiled and 20% of a 60:40 mixture and (5) 60% basal and 40% ensiled 60:40 mixture. The digestion coefficients for dry matter, crude protein, organic matter and NFE increased linearly (P<.01) as proportion of either silage in the diets increased. N retention, expressed as a percentage of absorbed N, decreased linearly (P<.05) as the level of 60:40 silage increased. The same trend was noted with the 40:60 silage, but the pattern was not significant. In the palatability trial, lambs fed the basal diet plus 20% of the 60:40 silage and the basal diet plus 40% of the 40:60 silage consumed more (P<.01) dry matter, both in grams per day and grams per kilogram weight-75 /day, than lambs fed the basal alone. Copyright © 1981. American Society of Animal Science . Copyright 1981 by American Society of Animal Science.