Influence of Hay or Silage and Ratio of Flaked Corn or Beet Pulp to Forage on Cellulose Disappearance

Diets of corn silage and hay fed with flaked corn or beet pulp supplements in grain to forage ratios of 20:80, 40:60, 60:40 and 80:20 were fed to steers with rumen fistulas. Rumen fluid from these steers was used to ferment similar diets in artificial rumina to measure diet influences on cellulose disappearance. The results indicate that coastal bermuda hay was superior to corn silage in maintaining high levels of cellulose disappearance with high levels of grain feeding. With both silage and hay, beet pulp was superior to flaked corn although each grain and each forage appeared to have an optimum grain to forage ratio. The higher ratios of grain in the corn silage rations fed the steers resulted in rumen fluid with lower pH than similar grain rations with hay. The rumen fluid with lower pH resulted in smaller losses of cellulose in vitro. This result is interpreted to indicate that rations which produce a low pH in the rumen result in a decreased population of cellulytic microorganisms.