AN ESTIMATE OF NUTRIENTS UTILIZED FOR LIVE-WEIGHT GAIN BY MERINO SHEEP

1. One hundred and seven fine-wool Merino wethers and non-pregnant ewes varying in age from newly born to 110 months and in live weight from 1.7 to 55.1 kg were slaughtered and minced. 2. The nitrogen, fat, ash, calcium, phosphorus, sodium and potassium contents of the mince were determined. Energy content was estimated from the contents of fat and fat-free organic matter. 3. Weighted regression relationships were calculated between the energy, N, Ca, P, Na and K contents of the sheep, and age, live weight and (age x live weight). The relationships were differentiated with respect to age and live weight, and the rates of nutrient deposition at different rates of live-weight gain, and for sheep differing in age and live weight were calculated. 4. The rates of nutrient deposition were compared with those estimated by the Agricultural Research Council (1965) and by Mitchell (1962). and were in general lower in energy content and higher in ash constituents per unit live-weight gain. © 1969, The Nutrition Society. All rights reserved.