Date of this Version
Microbial protein synthesis and efficiency were estimated in springborn nursing calves grazing native range and subirrigated meadow. Forage intake increased from 1.5 lb/ day (0.6% BW) in June to 5.9 lb/day (1.2% BW) in September while milk intake decreased over the same period. Microbial protein (MCP) synthesis increased from 67 g/day in May to 278 g/day right before weaning in September. Urinary allantoin was used as a marker. Efficiency of MCP synthesis was approximately 19% of forage digestible organic matter (OM) intake.