A Nutritional Evaluation of Mixed Winter Cereals with Vetch Utilized as Silage or Hay

Abstract
Cereal-vetch silage replaced chopped alfalfa in the forage portion of diets fed to lactating cows, resulting in diets containing 100, 66, and 34% of the forage as chopped hay. Winter cereal (oat, wheat, and barley) and vetch mixture was harvested when the oats were at the bloom stage, field wilted, and ensiled. Total DM intake of cows during the first 15 wk of lactation was reduced at the highest amount of cereal silage inclusion. Gut fill may have restricted DM intake since NDF intakes were similar across diets. Yields of milk and 4% FCM were not different with cereal-vetch silage addition to the diets. Milk composition of fat and solids were not altered by diet, but protein was lowest on the high silage diet. Cereal-vetch forage was harvested as hay at four stages of maturity based on maturity of oats: bloom, milk, soft dough, and hard dough. As forage matured, content of CP, ADF, and NDF and in vitro DM digestibility decreased and lignin content increased. Hays were pelleted and fed to 16 wethers in a total collection digestion study. Digestibilities of DM energy, and fiber were similar for bloom and milk stages but decreased as maturity progressed to the hard dough stage.