Nutritional Factors Influencing Hair and Wool Growth

Ryder, M. L.

doi:10.1016/b978-1-4832-3287-4.50020-9

Cited by 44 publications

(36 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The first was that, as observed for the blood bicarbonate pool, there was about a 3-h time lag between the dietary change and the incorporation of new dietary components (amino acids in this case) into the blood. Furthermore, it was assumed that, after entry into the blood, the hairforming amino acids would first be laid down in the keratinous zone of the hair follicles in detectable quantities within~8 h. This assumption is justified on the basis of the results of a study by Ryder (1958) who found that it took~8 h for 35 S labeled cystine injected into the blood of lambs to appear in the prekeratinization zone of the hair follicles. If hair formation of horses is similar to that of sheep, then the overall time lag from the start of the dietary isotope change to incorporation of dietary amino acids into hair keratin will bẽ 12 h. Errors were assigned to the chronologies derived for the horse tail hairs according to the uncertainty of correctly identifying the position of each isotope transition within the relevant tail hair segments.…”

Section: Breath and Hair Samplesmentioning

confidence: 98%

Turnover of carbon isotopes in tail hair and breath CO 2 of horses fed an isotopically varied diet

et al. 2004

View full text Add to dashboard Cite

Temporal stable isotope records derived from animal tissues are increasingly studied to determine dietary and climatic histories. Despite this, the turnover times governing rates of isotope equilibration in specific tissues following a dietary isotope change are poorly known. The dietary isotope changes recorded in the hair and blood bicarbonate of two adult horses in this study are found to be successfully described by a model having three exponential isotope pools. For horse tail hair, the carbon isotope response observed following a dietary change from a C3 to a C4 grass was consistent with a pool having a very fast turnover rate ( t1/2 approximately 0.5 days) that made up approximately 41% of the isotope signal, a pool with an intermediate turnover rate ( t1/2 approximately 4 days) that comprised approximately 15% of the isotope signal, and a pool with very slow turnover rate ( t1/2 approximately 140 days) that made up approximately 44% of the total isotope signal. The carbon isotope signature of horse blood bicarbonate, in contrast, had a different isotopic composition, with approximately 67% of the isotope signal coming from a fast turnover pool ( t1/2 0.2 days), approximately 17% from a pool with an intermediate turnover rate ( t1/2 approximately 3 days) and approximately 16% from a pool with a slow turnover rate ( t1/2 approximately 50 days). The constituent isotope pools probably correspond to one exogenous and two endogenous sources. The exogenous source equates to our fast turnover pool, and the pools with intermediate and slow turnover rates are thought to derive from the turnover of metabolically active tissues and relatively inactive tissues within the body, respectively. It seems that a greater proportion of the amino acids available for hair synthesis come from endogenous sources compared to the compounds undergoing cellular catabolism in the body. Consequently, the isotope composition of blood bicarbonate appears to be much more responsive to dietary isotope changes, whereas the amino acids in the blood exhibit considerable isotopic inertia.

show abstract

Section: Breath and Hair Samplesmentioning

confidence: 98%

Turnover of carbon isotopes in tail hair and breath CO 2 of horses fed an isotopically varied diet

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Skin samples were removed from the fixative within 12 h and stored in 70% ethanol until histological processing. Skin samples were embedded in paraffin wax and sectioned at 6 um thickness transverse to the plane of the follicle and stained using haematoxylin and eosin (Auber 1952;Ryder & Stephenson 1968). Sections containing primary (P) and secondary (S) follicles were selected at the level of the sebaceous gland in the skin, and were examined using a light microscope.…”

Section: Lambsmentioning

confidence: 99%

The effect of maternal shearing and thyroid hormone treatments in mid pregnancy on the birth weight, follicle, and wool characteristics of lambs

Kenyon

Sherlock

Parkinson

et al. 2005

New Zealand Journal of Agricultural Research

View full text Add to dashboard Cite

Mid pregnancy shearing of ewes has been associated with a short-to medium-term increase in maternal thyroid hormone concentrations. To determine the role of this elevation in the observed changes in lamb birth weight and fibre characteristics, ewes in mid pregnancy were either: shorn at day 70 of pregnancy with thyroid glands left intact (Shorn), unshorn with intact thyroid glands (Unshorn), thyroidectomised but left unshorn with a short-term elevation in thyroxine (T4) concentrations in mid pregnancy (Tx+T4), or unshorn with intact thyroid gland and prolonged elevation in T4 concentrations (+T4). The Tx+T4 regime successfully increased maternal thyroid hormone for a short period post-treatment, while the +T4 regime increased maternal thyroid hormone levels for a prolonged period during mid to late pregnancy. Lambs born to Shorn ewes were significantly (P < 0.05) heavier than those born to Tx+T4 and +T4 ewes and tended to be heavier than those born to Unshorn ewes (P = 0.10). Birth weights of lambs born to Tx+T4 and +T4 ewes did not differ from those born to Unshorn ewes. Ewe treatment had no effect on lamb wool follicle characteristics or fibre diameter, coefficient of variation of mean fibre diameter, yield, or loose wool bulk; but treatment tended to affect colour (P = 0.05) and staple length (P = 0.09). These results suggest that an elevation in A04064; maternal thyroid hormones is not the sole endocrine mechanism responsible for either the birth weight effect or changes in fibre characteristics observed in lambs born to mid pregnancy shorn ewes. However, it is still possible that an elevation of T4 and T3 concentrations in conjunction with other factors are required to achieve the observed effects.

show abstract

“…Nutrition, photoperiod, hormones, genotype, and other factors can affect wool production (Ryder & Stephenson 1968;Black & Reis 1979;Nagorcka 1979;Wallace 1979;Black 1987), but little is known of their specific eJects on fibre diameter and length-growth rates. Two techniques have been used to obtain information on fibre growth characteristics.…”

Section: Introductionmentioning

confidence: 99%

Seasonal variations in the dimensions of individual Romney wool fibres determined by a rapid autoradiographic technique

Woods¹,

Orwin²

1988

New Zealand Journal of Agricultural Research

View full text Add to dashboard Cite

A technique for radio-labelling short regions of growing wool fibres was modified by using intradermal injections of 3H-cystine and a rapid detection method. This technique allowed emergence times and dimensional changes of individual wool fibres to be rapidly and precisely monitored. Seasonal changes in fibre dimensions were determined for five sheep on maintenance nutritional levels following monthly injections over 12 months. Fibre diameter and length-growth varied seasonally, maximum and mimimum values occurring in summer and winter respectively. However, the amplitude and timing of each of these cycles differed between sheep and between fibres from individual sheep. As a consequence, the seasonal cycle in wool production (i.e., fibre volume) may be brought about by different combinations of fibre diameter and length-growth changes. Monthly diameter and length-growth measurements were often poorly correlated, suggesting that the cellular/physiological mechanisms determining these parameters in the follicle are complex.

show abstract

Nutritional Factors Influencing Hair and Wool Growth

Cited by 44 publications

References 79 publications

Turnover of carbon isotopes in tail hair and breath CO 2 of horses fed an isotopically varied diet

Turnover of carbon isotopes in tail hair and breath CO 2 of horses fed an isotopically varied diet

The effect of maternal shearing and thyroid hormone treatments in mid pregnancy on the birth weight, follicle, and wool characteristics of lambs

Seasonal variations in the dimensions of individual Romney wool fibres determined by a rapid autoradiographic technique

Contact Info

Product

Resources

About