The influence of type and timing of protein supplementation on wool growthand protein synthesis in the skin of young Merino sheep

There is limited evidence that the response in wool growth resulting from f eeding protected protein supplements continues after the feeding has stoppe d. Feeding such proteins, alternated with traditional supplements, may incr ease wool growth as much as continuous feeding but at a lower cost. This ex periment aimed to determine whether the response to protected protein conti nued after the sheep were switched to a cereal supplement. Over a 2-month experimental period, 56 weaners (5 months old, weighing 26 k g) were used in a 2 x 2 factorial experiment. Half were fed a diet containi ng 25% canola meal [partially protected protein with high concentrations of sulfur amino acids (SAA)] mixed with oaten hay, urea, and minerals. The ot her half were fed the same diet but with lupin seed (highly degradable prot ein with low concentrations of SAA) replacing the canola meal. Within each of the 2 dietary treatments and in each of 2 months, half of the weaners we re fed the diet continuously, the other half were fed the diet for 2 weeks followed by 2 weeks of a barley, oats, hay, urea, and minerals diet. Anothe r group of 8 weaners was fed the oats-barley diet continuously for 2 months . All sheep were fed to lose 35 g liveweight/day. Weaners fed canola meal grew 11% more wool during the experiment and had a higher rate of protein synthesis in the skin than weaners fed lupins. The r esponse to canola meal of wool and skin was the same whether feeding was co ntinuous or alternated with oats-barley, indicating that the benefits from feeding partially protected proteins continues after feeding has stopped.