Influence of the Adrenal Cortex on Wool Growth and its Relation to ‘Break’ and ‘Tenderness’ of the Fleece

Lindner, H. R.; Ferguson, K. A.

doi:10.1038/177188b0

Cited by 42 publications

(23 citation statements)

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“…In fitting equation (1) to the experimental data, terms were included to estimate the seasonal variation in efficiency of wool growth and any possible time trend in efficiency, resulting from increased age of the sheep or possibly from reduced adrenal cortical activity (Lindner and Ferguson 1956) as the sheep became better adapted to their surroundings. The seasonal rhythm in wool growth observed under constant nutritional conditions is empirically more closely related to mean air temperature than to any simple function of day length (Ferguson, unpublished data).…”

Section: Resultsmentioning

confidence: 99%

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The Relation Between the Responses of Wool Growth and Body Weight to Changes in Feed Intake

Ferguson¹

1962

Aust. Jnl. Of Bio. Sci.

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SummaryThe wool growth responses to changes in feed intake are related to the changes produced in body weight. The relation is expressed by the equation W = Ei-kG, where W = wool growth rate, i = feed intake rate, G = rate of body weight change, and E and k are constants. The ratio of E to k in sheep of different productive efficiency was found to be constant.Evidence is presented that this equation indicates a relation between wool growth and metabolic rate, both possibly being responses to changes in endocrine secretion. An alternative interpretation that the equation reflects the effect of body weight change on the supply of amino acids limiting wool growth is also discussed but is considered less likely to be true.The bearing of the results on the evaluation of feedstuffs for wool produc. tion and on the definition of individual productive efficiency is discussed.

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Section: Resultsmentioning

confidence: 99%

“…The influence on wool growth of an increased metabolic rate resulting from muscular activity or exposure to cold similarly cannot be assessed from the present experiment. Furthermore under these conditions increased adrenocortical activity may suppress any rise in wool growth (Lindner and Ferguson 1956). …”

Section: Disoussionmentioning

confidence: 99%

The Relation Between the Responses of Wool Growth and Body Weight to Changes in Feed Intake

Ferguson¹

1962

Aust. Jnl. Of Bio. Sci.

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“…Depression of wool growth in sheep by the administration of adrenal glucocorticoid hormones was first reported by Lindner and Ferguson (1956) and has been confirmed both for cortisol (Chapman and Bassett 1970;Thwaites 1972) and for some synthetic analogues (Ferguson et al 1965;Panaretto et al 1975). The plasma concentrations of glucocorticoids and the time periods over which these must be maintained in order to inhibit wool growth is not known.…”

Section: Introductionmentioning

confidence: 99%

“…The plasma concentrations of glucocorticoids and the time periods over which these must be maintained in order to inhibit wool growth is not known. Most experimenters have administered hormones over prolonged periods; for example Lindner and Ferguson (1956) injected sheep with cortisone acetate for 10 weeks in order to depress wool growth, but technology at that time did not enable them to determine circulatory concentrations of the hormone. Chapman and Bassett (1970) reported that the retrogression of all components of the epidermis and dermis was maximal when plasma cortisol exceeded 3 p.g/100 m!.…”

Section: Introductionmentioning

confidence: 99%

Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Ba¹,

Wallace²

1978

Aust. Jnl. Of Bio. Sci.

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Plasma concentrations of dexamethasone have been measured in sheep during an 8-day infusion of dexamethasone-21-phosphate. The dexamethasone concentration profiles generally revealed a reproducible pattern with three phases-a peak during the first 48 h infusion which was followed by falling concentrations during the next 5 days, and a small increase in dexamethasone concentration during the final 24 h infusion was not uncommon. The pattern of dexamethasone concentrations was retained when dosage was arranged in such a way as to infuse increasing quantities of hormonal analogue as infusion progressed. Aspects of the metabolism of the analogue are discussed.Endogenous thyroxine and cortisol were significantly depressed during infusion. In these experiments wool was completely shed in three out of four animals dosed at a rate of 8·5 mg dexamethasone/kg o · 75 • The recovery of wool growth to its pretreatment values occurred by about one month after infusion. The consumption of food and body weight increases were satisfactory during the post-infusion period.

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“…The average fibre lengths, thicknesses, and densities are shown in (6). The hormones produced by the adrenal cortex appeared to have a direct action on the wool follicle-since the topical application of an ointment containing a corCisone analogue to a restricted area of the skin suppressed wool groivth, but only on the reated area (6).…”

Section: Fibre Charactersmentioning

confidence: 99%

Effect of Estradiol and Testosterone Injections and Thyroidectomy on Wool Growth in Shearling Sheep

Slen¹,

Connell²

1960

Can. J. Anim. Sci.

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The present study wai undertakeh ro der-ermine the effect on wool growth of l) liigh levels of estradiol and testosterone, and 2) thyroidectomy. MATERIALS AND METIIODSForty-eight grade Corriedale shearling sheep, half of which were ewes and half wethers, were used in this study. They were divided at randorn into three equal groups on the basis of #ool'production and body weight.Ewes and w6theri were disuibuted equally anh a further division i,rrr -id" !)' thyroidectomizing one-half of the ewes and wethers in each group 5 weeks before treatment was ,begun. Despite the fact that great care was taken in the extirpation of ihe thyroi-d For personal use only.[Vol. The use of testosterone on both intact and thyroidectomized wethers had no effect on wool growth when compared with the appropriare conrrols. Fibre CharactersThe average fibre lengths, thicknesses, and densities are shown in For personal use only.

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Influence of the Adrenal Cortex on Wool Growth and its Relation to ‘Break’ and ‘Tenderness’ of the Fleece

Cited by 42 publications

References 1 publication

The Relation Between the Responses of Wool Growth and Body Weight to Changes in Feed Intake

The Relation Between the Responses of Wool Growth and Body Weight to Changes in Feed Intake

Dexamethasone Concentrations in Ovine Plasma During its Intravenous Infusion, its Relation to the Production of Some Endogenous Hormones, and Some of the Effects on Wool Growth

Effect of Estradiol and Testosterone Injections and Thyroidectomy on Wool Growth in Shearling Sheep

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