Studies on the relationship between nutrition and wool production of Merino sheep. II. The effect of the administration of cystine, cystein, sulphur and of methionine on the growth of wool of a Merino ewe on a protein-poor ration

Abstract

1. The question whether the amount of cystine in the wool grown may exceed that in the diet is discussed.2. When 1 gm. of laevo-cystine was added to the daily ration of a ewe on a low protein diet, the wool grown upon a circumscribed area was 14 per cent, more than that grown during a similar period immediately preceding. Four-fifths of the sulphur in the added cystine was absorbed, about half of which was excreted in the urine during the period the cystine was being fed.3. When 1 gm. of laevo-cystein was injected subcutaneously each day for 10 days, a 34 per cent, increase in wool growth occurred. During three succeeding periods, of 10 days each, immediately after the injections had been discontinued, the increases were 30, 18 and 7 per cent, respectively. Of the 2.6 gm. of sulphur in the cystein injected during the 10 days, 1.7 gm. was retained and could be accounted for by the extra amount of wool grown during that and the succeeding periods.