Ruminal Digestion by Dairy Cows Grazing Winter Oats Pasture Supplemented with Different Levels and Sources of Protein

摘要

Six Holstein cows fitted with ruminal cannulae were used in two simultaneous 3 ×3 Latin squares to study the effects of protein supplements on ruminal fermenta - tion and in situ crude protein degradability. Cows rota - tionally grazed a winter oats (Avena sativa L.) pasture and were supplemented with one of three concentrate supplements: 1) low protein sunflower meal (L-SM); 2) high protein sunflower meal (H-SM) or 3) high protein feather meal (H-FM). Concentrates (6.5 kg/d) were of - fered in equal portions twice daily during milking.