Effect of Forage Maturity on Ration Digestibility and Production by Dairy Cows

Mixed grass-legume silages harvested at early and late maturities from the same field were evaluated in three trials to determine maturity effects on ration digestibility when forages were fed alone or in complete rations. In situ dry matter disappearance was examined using a rumen-fistulated steer. Rate of disappearance of potentially digestible dry matter was reduced for forage of greater maturity (-.0504 h -1 for early versus -.0316 -1 for late cut silage). Nonlactating cows were used to determine forage digestibility. Apparent dry matter (69.2 versus 54.2%), acid detergent fiber (70.8 versus 52.7%), neutral detergent fiber (74.1 versus 55.9%), and crude protein (66.2 versus 45.6%) digestibilities were higher for early cut forage.