اثر ديواره سلولي علوفه فرآيندشده بر روي تركيب و توليد شير گاوهاي هلشتاين

Effects of Cell Wall of Different Forage Sources on Milk Production and Composition in Lactating Holestein Cows

Alfalfa hay, alfalfa haylage, corn silage and a 1:I combination of corn silage and alfalfa hay were evaluated as sources of forage cell wall in diets for twelve early to mid lactation Holstein cows. Diets were formulated to contain equal amounts of natural detergent fiber (31.5%), crude protein (17.1%) and NEI. (1.65 M K Call KgDM) in an incomplete change - over design. Dry matter intake was highest for cows fed alfalfa haylage diet (P<0.05), but no significant difference was found among the experimental means for actual milk yield, 4% and 3.2% fat corrected milk yield, although actual milk yield was higher for cows fed alfalfa haylage diet. Milk composition was not affected by experimental diets with exception of milk fat percentage, so that corn silage caused lowest and alfalfa hay the highest milk fat percentage (P<0.05). Dry matter, organic matter and cell wall digestibility were highest for diet containing both alfalfa hay and corn silage (P< 0.05). Alfalfa hay and haylage had highest buffering capacity and caused highest rumen pH (P<0.05), maintaining higher milk fat percentage.