Effect of concentrate level on forage intake, milk production and energy and nitrogen utilization in organic milk production

This paper compares data on feed intake, milk production and utilization efficiency of energy and nitrogen for milk during the indoor feeding periods of three sequential years of an organic milk production unit using different levels of concentrates in a forage based diet. The production and utilization responses to increased concentrate supply was not consistent between years. In general forage dry matter intake was high (9.7-13.7 kg d-1) and total milk yield moderate (4234-5954 kg cow-1). The fraction of energy and nitrogen ingested by the animals and transferred to milk was initially high early in lactation but declined in late lactation. The most important limiting factor for milk production and energy and nitrogen utilization for milk appears to be the low levels of crude protein in harvested forages.