Abstract

The efficiency of conversion of feed protein to milk protein (protein use efficiency (PUE)) is important in ruminants as protein is the most valuable component of milk (Ryan et al. 2011). It is also essential to reduce nutrient and resource costs when the efficiency of nutrient use is low (Roberts, 2008). In ruminants, dietary protein has three main routes of metabolism, namely microbial fermentation in the rumen, absorption in the small intestine, and catabolism and excretion of excess digestible protein into faeces and urine nitrogen (Agricultural Research Council 1980). This makes PUE difficult to explain and predict because of the interaction of these pathways. Rumen degradable protein (RDP) and metabolisable protein (MP) are the two main protein pools for milk protein production.

NW, Wheadon, L Cheng, RJ Dewhurst, and GR Edwards

Proceedings of the New Zealand Society of Animal Production, Volume 73, Hamilton, 100-102, 2013