Evaluation of Green Chop and Ensiled Sorghums, Corn Silage and Perennial Forages Using Digestion Trials and VFA Production in Sheep

Three digestion and rumen metabolism trials were conducted with sheep to compare sorghum and sorghum-sudan crosses to corn silage and perennial forages. In trial 1, green chopped alfalfa, sudangrass and two sorghum-sudangrass crosses were compared. Corn silage was compared to corn stover silage and grain type sorghum silages in trial II, while forage type sorghum silage was compared to alfalfa (bud stage) and orchardgrass (boot stage) hays in trial III. Dry matter digestibility was lower for alfalfa green chop than for the other green chops, but digestible dry matter intake and protein digestibility was higher. Dry matter digestibility of corn silage was higher than stover silage or either of the sorghum silages. The two sorghum silages were quite similar in nutritive value, although the grain type sorghum had a higher protein content and slightly higher intake. Digestibilities of both hays were high and equal to that of the alfalfa green chop and somewhat superior to corn silage. Rumen liquor samples were taken prior to feeding and 3, 6, 9 and 12 hr. after feeding for VFA analysis. The highest rumen TVFA values were produced by feeding alfalfa and orchardgrass hays followed by corn and stover silages. Alfalfa green chop and the sorghum silages produced somewhat lower levels in TVFA, while the sudangrass and sorghum-sudangrass crosses produced only slight or no increases. The proportion of propionic acid was increased slightly after feeding sudangrass green chop and greatly after feeding corn, corn stover or sorghum silages.