Is Preformed Gystine Essential to Sheep for Wool Production?

Remington, Claude; Bekker, J. G.

doi:10.1038/129687a0

Cited by 12 publications

(3 citation statements)

References 14 publications

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“…Of the two means whereby a sheep might secure a further supply of cystine for the production of wool which have been suggested, the surmise of Fraser and Roberts (3) that some of the tissues of the animal may elaborate cystine appears to me, from analogy with observations on the growth of body and hair in other animals, to be unlikely, but the view espoused by Rimington and Bekker (25) to account for an excess of cystine in wool over that in food is at first sight more attractive.…”

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confidence: 91%

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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

Marston

1935

J. Agric. Sci.

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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.

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confidence: 91%

“…Rimington and Bekker (25) suggest that the difference in their computation between the amount of cystine ingested and the output in the form of wool is derived from proteins formed by the bacteria in the rumen. Fraser and Roberts (3) attribute it to synthesis by the animal which they suggest occurs in the wool follicles.…”

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confidence: 99%

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

Marston

1935

J. Agric. Sci.

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“…The proteins of hair and wool differ in their composition from other animal proteins, particularly in having a high cystine content. It has been shown in the rat that cystine must be provided pre-formed in the food, but this is not necessarily true in the case of the sheep as suggested by Rimington and Bekker (7).…”

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confidence: 97%

Variation in the protein intake of sheep in relation to wool growth

Fraser¹,

Roberts

1933

J. Agric. Sci.

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Summary1. Two lots of twenty sheep each were fed indoors on rations known to produce satisfactory growth. The calorific value of the two diets was the same. One lot received 52 per cent, more digestible protein than the other. The diet of the low protein group was protein deficient according to the calculations of Wood.2. The sheep were shorn at the beginning of the experiment and again at its conclusion. Fibre measurements were made on samples taken at the same two periods from the same body area. The fleece and fibres grown during the experimental period were compared in each case with the fleece and fibres grown during the pre-experimental period. The fibre measurements included fineness, length and fibre weight.

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The Metabolism of Cystine and Methionine

Jackson

Block

1932

Journal of Biological Chemistry

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Is Preformed Gystine Essential to Sheep for Wool Production?

Cited by 12 publications

References 14 publications

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

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

Variation in the protein intake of sheep in relation to wool growth

The Metabolism of Cystine and Methionine

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