EFFECTS OF ABOMASAL SUPPLEMENTS OF METHIONINE ON WOOL GROWTH OF GRAZING SHEEP

Seven experiments are reported in which methionine supplements were given directly into the abomasum of Merino wethers grazing either improved or native pasture at Armidale, New South Wales. In 4 experiments where initial wool growth was 0.4-0.8 mg/cm2.day of clean dry wool, significant increases in wool growth (at 2.4 g methionine/day in 3 experiments and 0.6-4.8 g/day in the fourth) and fibre diameter were obtained when methionine was given once daily in capsules. In the fourth experiment the response to methionine was quadratic, with a maximum at 2.4 g/day. In the remaining 3 experiments, where initial wool growth was greater-than-or-equal-to 1.1 mg/cm2.day, no significant response to methionine was obtained, whether it was given once daily or infused continuously.