Performance and Nutrient Intake of High Producing Holstein Cows Consuming Pasture or a Total Mixed Ration

摘要: We compared the intakes of nutrients by high producing Holstein cows consuming pasture or a full nutrient positive control ration (total mixed ration; TMR) and identified that limited milk production quality pasture. Cows (n = 8) were adapted to an all diet incrementally reducing amount TMR fed over 4-wk period. A group remained in confinement was TMR. The performance grazing differed significantly from dry matter (DM) intake (19.0 vs. 23.4 kg/d DM), (29.6 44.1 kg/d), protein content (2.61% 2.80%), live weight (562 597 kg), body condition score (2.0 2.5). permitted consume same daily neutral detergent fiber crude (kilograms per day) as TMR, but provided 19% less DM, organic matter, net energy for lactation. Predictions using National Research Council estimates Cornell Net Carbohydrate Protein System model indicated supply metabolizable first-limiting rather than amino acids. Although 19 kg DM achieved on spring pasture, significant mobilization reserves supplemental is required achieve greater 30 intensive systems.