Increasing the crude protein (CP) concentrations of dairy concentrates in mixed diets has been found to increase milk yield and forage intake in a curvilinear manner in lactating dairy cows. In an experiment with lactating goats, linear increases in milk yield were observed as the CP in the concentrates was increased from 117 to 185 gAg DM. The purpose of the present experiment was to see if increases in hay intake and milk yield could be established to still higher levels of CP in the concentrates and to measure various associated aspects of digestion.