Effect of cysteine ethyl ester supplements on wool growth rate

Abstract

L-Cysteine ethyl ester hydrochloride (CEE) was evaluated as a dietary sulfur amino acid supplement for increasing wool growth rate. In Experiment 1, eight sheep were offered 800 g chopped lucerne hay daily and wool growth was measured over a three-week control period. These sheep were then given a continuous infusion of either CEE per rumen, CEE per abomasum, cysteine per abomasum or continued on the basal diet alone, for three weeks, and wool growth was measured again. All supplements were equivalent to 25 mmol/day. Wool growth rate on tattooed patches in sheep given CEE per rumen or abomasum increased 67% and 75% respectively above the rates prior to infusion, while that of animals given cysteine increased 45%. Wool growth rate in the control sheep increased by only 15% in the same period. In Experiment 2, wool growth was measured in 24 sheep offered 800 g/day lucerne chaff, and again when CEE, cystine, or Na2SO4, each providing 21 mmol S/day, were combined with mineral mix and offered with the feed. CEE and cystine increased wool production by 1.9 g/sheep/day (P < 0.01) and 1.0 g/day (P < 0.05), respectively, above that measured in the control groups (nil- or Na2SO4- supplemented) which did not differ.