Effect of the amount and form of roughage in the diet on digestibility of whole maize grain in cows and steers

Abstract

SUMMARYFour experiments investigated some of the factors affecting the digestion of whole maize grain in non-lactating cows and yearling steers. With steers, but not cows, maize in diets containing small amounts of hay (14%) and large amounts of whole grain were better digested than those with 37 or 48% hay. The higher digestibility of maize in steers was associated with a greater time spent ruminating per kg feed and a longer retention time of maize in the gut than in cows. Replacing long roughage with ground and pelleted roughage in diets for steers improved the digestion of whole maize but not as well as reducing the hay to 14% of the diet. Finely grinding the maize produced a large increase in digestibility of the feed in cows and steers and both digested it to the same extent. It was concluded that the motility of the reticulo-rumen during eating and ruminating largely determines the extent of the digestion of whole maize grain.