THE INFLUENCE OF STAGE OF MATURITY OF AN ENSILED LEGUME–GRASS MTXTURE ON GROWTH AND PERFORMANCE OF WINTERED HEREFORD STEER CALVES
Yield of total digestible nutrients (T.D.N.) per acre from an alfalfa – red clover – timothy mixture stored as silage was higher when harvested early (bud) than at medium (2% bloom) or late (full bloom) maturity. Protein declined and crude fiber increased with advancing maturity. When fed to beef steer calves, digestive coefficients as a per cent in early, medium, and late-cutting silage, for protein, 50.2, 56.0, 35.7; crude fiber, 64.9, 68.2, 54.9; energy, 57.3, 65.2, 48.3; total digestible nutrient content, 58.1, 62.0, 48.5; average daily nitrogen retention in grams, 22.1, 29.7, 0.86. Differences between treatments for the above measurements were significant (P < 0.05) only for early vs. late or medium vs. late silage, but not for early vs. medium silage. Concentration of total rumen volatile fatty acids was significantly higher for early over medium and late silage.Results from the winter feeding trial for steers fed early, medium, or late silage were: average daily gain in pounds, 0.81, 0.46, 0.28; pounds of T.D.N. per pound of gain, 6.5, 13.1, 16.4. Steer calves wintered on early legume–grass silage gained more (P < 0.05) and required less T.D.N. per pound of gain than those wintered on medium or late silage, while calves fed medium silage out-gained and required less feed per pound of gain than those fed late silage (P < 0.05).Differences in daily gain between groups were reflected in carcasses of three animals slaughtered from each group. Animals were slaughtered after being fed a standard silage for 100 days following the experimental period. Eye of lean, fat cover, dressing percentage, and carcass grades were superior for steers fed early silage.