Ten lactating cows (Holtein and H*Z crossbreed) after 55d calving, with average weigth of 540 kg alloted to a switch-back design, were used in order to evaluate the intake and apparent digestibilities of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), crude protein (CP), total carbohydrates (TC) and ether extract (EE), the pH and ruminal ammonia concentration and milk yield and composition. The animals were fed ad libitum with diets containing alfalfa hay (AH), coastcross bermudagrass hay (CCH), corn silage (CS), ½ AH + ½ CS and and ½ CCH + ½ CS in 60% of the total diet (dry matter basis). The nutrients intake were not affected by the diets. The dry matter, crude protein and neutral detergent fiber apparent digestibilities were higher for diets with corn silage. The experimental diets did not affect pH and the ruminal ammonia concentration, however quadratic effect was observed for collection time. The highest milk productions were observed for the animals that received CS and ½ AH + ½ CS diets. The diets did not affect the crude protein and fat milk contents.
crude protein; dry matter; neutral detergent fiber; milk composition
