Digestibility, Rate of Digestion and Ruminoreticulum Parameters of Beef Steers Fed Low-Quality Roughages

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Abstract
Research was conducted to examine rate of digestion and ruminoreticulum parameters of beef steers fed the following ground (2.5 cm screen) roughages: (1) orchardgrass hay, (2) barley straw, (3) corn stover or (4) cottonseed hulls (not ground), plus 1 kg daily of a protein-mineral supplement per steer. In the first trial, a Latin square design was used with four Angus steers (avg wt, 242 kg) fed each roughage at 2% of body weight daily. Orchardgrass hay had the highest digestibilities of dry matter (60.1%), crude protein (54.1%) and cell wall (64.2%), whereas corn stover and cottonseed hulls had the lowest digestibilities of dry matter (48.9, 46.0%) and cell wall (52.3, 45.6%). In a second trial, four rumen cannulated Angus steers (avg wt, 238 kg) were fed the same roughages ad libitum in a Latin square design. Steers consumed 26, 49 and 71% more cottonseed hulls than orchardgrass hay, barley straw or corn stover, respectively. Steers fed cottonseed hulls had a greater amount of digesta dry matter per 100 kg empty body weight and a higher digesta density which contributed to allowing them to consume more cottonseed hulls than the other roughages. An in situ dacron bag technique was used to evaluate potential digestibility and rate of digestion for the roughages. Orchardgrass hay had the highest potential (percentage loss after 72 hr) dry matter (68.5%) and cell wall (70.3%) digestibilities while cottonseed hulls had the lowest potential dry matter (31.0%) and cell wall (33.1%) digestibilities. Copyright © 1979. American Society of Animal Science . Copyright 1979 by American Society of Animal Science.