Protein requirements of lactating Chios ewes.

The digestible protein requirements of lactating ewes were studied with Chios 3 ewes during the declining state of lactation in two nitrogen balance and three feeding trials. A 60 kg ewe producing 1.0 or 2.0 kg milk of 6% protein and maintaining weight equilibrium, required 134 and 230 g digestible protein daily, respectively. These requirements were obtained with ewes receiving 110 Kcal metabolizable energy (ME)/kg .73 and 1,800 kcal ME/kg milk. At the levels of digestible protein intake used, which ranged from 4.5 to 12.2 g/kg -73 there was a linear response to protein level in milk nitrogen plus retained nitrogen. Straw intake and crude fiber digestibility increased in response to higher protein intake; within a protein level, straw intake increased as the amount of concentrates fed declined. The intake of concentrates and milk yield, declined when the crude protein content of the diet was below 10%. (