The influence of abomasal supplements of methionine on wool growth of wheat-fed sheep

1974 ◽  
Vol 25 (6) ◽  
pp. 919 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Blood Plasma ◽  
Fibre Diameter ◽  
Length Growth ◽  
Wool Growth ◽  
Abomasal Infusion ◽  
Mineral Mixture ◽  
In Blood Plasma

Sheep receiving a diet consisting solely of wheat (500 g/day), supplemented with a mineral mixture, were given abomasal infusions of varying amounts of DL-methionine (1.5–6.0 g/day) or of L-cystine (5 g/day). Other sheep received DL-methionine as a supplement to a roughage diet. All levels of methionine infused caused a decrease in the mass of wool grown by sheep consuming the wheat diet. This effect was greatest with 6 g methionine and was due mainly to a considerable depression of fibre diameter. Smaller amounts of methionine decreased fibre diameter and increased length growth rate. The infusion of methionine caused a considerable weakening of the wool grown by most of the sheep, with the result that a 'break' was observed in the fleece after about 1 week of methionine administration. This effect occurred with all levels of methionine but was more pronounced with 6 g/day. The abomasal infusion of cystine (5 g/day) caused little change in the mass of wool grown, but fibre diameter was decreased slightly. There were no appreciable effects on the strength of wool fibres and no wool was shed. Supplementation of the roughage diet (400 g/day) with methionine at 2 g/day stimulated wool growth, whereas with 6 or 10 g/day the mass of wool grown was unchanged but fibre diameter was markedly reduced. The strength of wool fibres was not markedly influenced by methionine infusions on this diet. The levels of amino acids in blood plasma and in abomasal digesta indicated that the mixture of amino acids absorbed was similar with both the roughage and the wheat diets.

The influence of abomasal supplements of zein and some amino acids on wool growth rate and plasma amino acids

1976 ◽  
Vol 86 (3) ◽  
pp. 475-482 ◽  
Author(s):  
P. J. Reis ◽  
D. A. Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Volume Growth ◽  
Fibre Diameter ◽  
Essential Amino Acids ◽  
Fibre Volume ◽  
Plasma Amino Acids ◽  
Leucine Supplementation ◽  
Length Growth ◽  
Wool Growth

SummaryMerino sheep were given abomasal infusions of (i) zein (80 g/day), (ii) zein (80 g/day) supplemented with L-lysine (6 g/day), L-tryptophan (1 g/day) or lysine and tryptophan together, or (iii) L-leucine (20 g/day). Effects on wool growth (length growth rate, fibre diameter, fibre volume growth rate and mass of wool grown) and on plasma amino acids were measured.Zein increased length growth rate and decreased fibre diameter; on average the volume growth rate and mass of wool grown were not significantly altered. The addition of tryptophan to the infusion of zein did not significantly alter wool growth, whereas the addition of lysine significantly increased all aspects of wool growth. The responses to these treatments were rapid and were adequately assessed during 12-day infusion periods. The infusion of leucine did not cause any appreciable changes in wool growth.Leucine supplementation increased the concentration of leucine in blood plasma about six-fold. Zein decreased the concentration of lysine and ornithine in plasma and increased the concentration of several essential amino acids; leucine was increased about seven-fold. The addition of tryptophan to zein had no effects on plasma amino acids, whereas lysine decreased the concentration of several amino acids in plasma and markedly increased lysine.

Effects on wool growth of the infusion of mixtures of amino acids into the abomasum of sheep

1978 ◽  
Vol 90 (1) ◽  
pp. 173-183 ◽  
Author(s):  
P. J. Reis ◽  
D. A. Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Volume Growth ◽  
Fibre Diameter ◽  
Essential Amino Acids ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Standard Mixture ◽  
Wool Growth

SUMMARYMerino sheep were given abomasal infusions of either mixtures of amino acids or protein during periods of 8 or 12 days. Effects on wool growth were measured using autoradiography and a clipping procedure which allowed time for the emergence of the wool fibres. Estimates of volume growth rate, from the autoradiographic measurements, and of mass of wool grown, from clipping, were in good agreement.An infusion of a standard mixture of 13 amino acids, which included ten essential amino acids in approximately the proportions in casein, consistently stimulated wool growth. The mean increases in volume and mass of wool grown, during 30 infusions, were 66 and 67% respectively. A mixture of ten essential amino acids alone appeared to be as effective as the standard mixture for stimulating wool growth, and there were no significant differences between the effects on wool growth of casein and the standard mixture of amino acids.The omission of methionine from an infusion of the standard mixture of amino acids, or from a mixture of essential amino acids only, inhibited wool growth rate; both fibre diameter and length of wool grown per day were reduced to below the control values. In addition, the strength of the fibres was considerably reduced.Infusions of zein and of an amino acid mixture simulating the essential amino acid composition of zein both inhibited wool growth rate, due to a reduction in fibre diameter. Similar effects on wool growth were observed when any one of three essential amino acids (lysine, isoleucine or leucine) was omitted from an infusion of the standard mixture of amino acids. The omission of five other essential amino acids (arginine, histidine, phenylalanine, threonine or valine) from the infusion, or variations in the proportions of leucine, lysine or methionine, had no appreciable effects on wool growth.

scholarly journals Metabolic Fate of Parenterally Administered Sulphur-Containing Amino Acids in Sheep and Effects on Growth and Composition of Wool

1970 ◽  
Vol 23 (4) ◽  
pp. 1077 ◽  
Author(s):  
RN Murdoch
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Parenteral Administration ◽  
Metabolic Fate ◽  
Length Growth ◽  
Wool Growth

Intravenous or intraperitoneal infusions of either L-cysteine (2, 0 gjday) or L-methionine (2�5 gjday) for 20 days increased wool diameter and its length growth rate, the main increases occurring during the first 8 days of infusion. Thus parenteral administration of these amino acids is effective in stimulating wool growth.

Intake and long-term cysteine supplementation change wool characteristics of Romney sheep

2001 ◽  
Vol 52 (1) ◽  
pp. 29 ◽  
Author(s):  
R. G. Sherlock ◽  
P. M. Harris ◽  
J. Lee ◽  
G. A. Wickham ◽  
J. L. Woods ◽  
...  
Keyword(s):  
Growth Rate ◽  
Treatment Period ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Amino Acid Supplementation ◽  
Sulfur Concentration ◽  
Treatment Groups ◽  
Length Growth ◽  
Wool Growth ◽  
Pre Treatment

Sulfur amino acid supplementation increases wool production in sheep at low planes of nutrition but it is unclear whether there is any benefit of supplementation at planes of nutrition above maintenance and what implications this might have for wool quality characteristics. This experiment directly investigated the interaction between sulfur supplementation and plane of nutrition in terms of wool growth and fibre characteristics. Twenty-four Romney ewes, acclimatised in individual metabolism units over a 7-week pre-treatment period, were allocated to 1 of 4 treatment groups based on a 22 factorial arrangement. Groups were low (L) or high (H) intake (0.8 or 1.3 maintenance, respectively) with continuous intravenous infusion of either saline (–Cys) or cysteine (+Cys, 2 g/day). During the 3-month treatment period, measurements were obtained for liveweight, plasma cysteine concentration, wool sulfur concentration and output, clean wool growth, mean fibre diameter (MFD), length growth rate (LGR), colour, loose wool bulk, handle, and crimp frequency and character. Clean wool growth response (P < 0.05) to cysteine supplementation was greater for the L sheep (6.06 v. 4.31 g/100 cm2) than the H sheep (7.20 v. 6.13 g/100 cm2). The response to supplementation in LGR (P < 0.01) was similar in both H (14%) and L (20%) sheep. There was no response in MFD due to sulfur supplementation, although fibre diameter measurements made along the fibres suggest that there was a response in L but not H sheep (P < 0.1). Wool sulfur concentration and output increased as a result of cysteine supplementation but concentration increased more in L (30.6 v. 24.5 mg S/g; P < 0.01) than in H sheep (28.4 v. 26.2 mg S/g). Qualitative electrophoresis analyses suggested that the increase in wool sulfur was achieved primarily by an increase in ultra-high-sulfur proteins. Crimp frequency and character were both significantly (P < 0.01) enhanced by cysteine supplementation. It is concluded that cysteine supplementation, at feed intakes that commonly occur in the commercial situation, can produce a useful increase in wool growth. This growth increase is primarily accomplished by increasing length growth rate rather than fibre diameter, which should also improve the value of the wool fibre produced.

The rate of response of wool growth to abomasal supplements of casein

1971 ◽  
Vol 76 (1) ◽  
pp. 173-176 ◽  
Author(s):  
P. J. Reis ◽  
A. M. Downes
Keyword(s):  
Growth Rate ◽  
Daily Ration ◽  
Growth Responses ◽  
Length Growth ◽  
Wool Growth ◽  
Abomasal Infusion ◽  
Rate Of Response

SUMMARYCasein in amounts ranging from 10 to 124 g/day was administered as an abomasal infusion to seven Merino wethers whose daily ration comprised 600–700 g of either chopped wheaten hay alone or a mixture of chopped wheaten and lucerne hays. Increases in both the length growth rate and diameter of the wool occurred at all levels of supplementation tested. When casein was infused at the rate of 100 g/day for a 20-day period the biggest increases in wool growth occurred during the first 4 days and there was little further change after the first 8 days.There were marked wool growth responses to the infusion of up to 80 g casein per day. The results suggest that little further increase could be expected with the infusion of more than 120 g/day.

Effects of experimentally produced local subdermal temperature changes on skin temperature and wool growth in the sheep

1970 ◽  
Vol 74 (1) ◽  
pp. 83-90 ◽  
Author(s):  
A. G. Lyne ◽  
M. Jolly ◽  
D. E. Hollis
Keyword(s):  
Growth Rate ◽  
Fibre Diameter ◽  
Slight Reduction ◽  
Environmental Disturbances ◽  
Temperature Changes ◽  
Merino Sheep ◽  
Cooling Period ◽  
Length Growth ◽  
Wool Growth ◽  
Change In Mean

SUMMARYA heat-exchange chamber made of perspex was inserted beneath the skin of a Merino sheep. By passing water at predetermined temperatures through the chamber, the normal subdermal temperature of 37°C was raised approximately 4°C for 4 days, then lowered approximately 5°C for 4 days.In response to heating, the animal's temperature regulating mechanism was able to maintain a fairly constant subdermal temperature. However, it was unable to maintain as constant a subdermal temperature in response to cooling. There was, during the cooling period, an obvious nervous response to environmental disturbances manifested by sudden transient decreases in subdermal temperature over the chamber.During the cooling period there was a decrease of 12% in mean length growth rate of wool over the chamber but mean fibre diameter was unchanged. Heating produced a small decrease in mean fibre diameter, but no change in mean length growth rate. Heating appeared to produce a slight reduction in pigmentation of some fibres but neither heating nor cooling produced demonstrable changes in crimping.

The response of skin and wool growth to local subdermal temperature changes in a sheep

1970 ◽  
Vol 75 (3) ◽  
pp. 501-515 ◽  
Author(s):  
M. Jolly ◽  
A. G. Lyne
Keyword(s):  
Growth Rate ◽  
Marked Reduction ◽  
Fibre Diameter ◽  
Progressive Decrease ◽  
Epidermal Thickness ◽  
Sebaceous Glands ◽  
Temperature Changes ◽  
Length Growth ◽  
Heating And Cooling ◽  
Wool Growth

SUMMARYHeat-exchange chambers, one for heating and one for cooling, were surgically embedded beneath the skin of a sheep. The intensity of heating and cooling was progressively increased, producing average subdermal temperatures up to 50·3 °C over one chamber and down to 21·0 °C over the other. The normal subdermal temperature was 37·7 °C.Moderate heating produced a small increase in the length growth rate of wool over the hot chamber. Higher temperatures caused a marked reduction and with still further heating there was almost complete cessation of wool growth.In contrast to heating, cooling always caused a suppression of wool growth which became more pronounced as the degree of cooling was intensified. The length growth rate decreased to half of normal at one stage but it never ceased.There was evidence of a slight but progressive decrease in fibre diameter with increasing subdermal temperatures up to 45 °C but at a temperature of 48 °C many of the fibres exhibited a marked thickening. Cooling the skin had little effect on fibre diameter. Pigmentation of the fibres was unchanged throughout the whole range of temperatures used and there was no evidence of change in crimping of the fibres.Heating in the range 45–50 °C produced an increase in epidermal thickness. Sweat and sebaceous glands, and erector muscles appeared unchanged after heating or cooling but innervation of the skin appeared to be reduced by extreme heating.The skin and wool growth over a dummy chamber were normal and similar in all respects to that in other control areas.

The influence of nutrition on the effectiveness of mimosine for defleecing sheep

1978 ◽  
Vol 29 (5) ◽  
pp. 1057 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Intravenous Infusion ◽  
Continuous Intravenous Infusion ◽  
High Intake ◽  
Wool Growth ◽  
Abomasal Infusion ◽  
High Feed ◽  
Standard Rate ◽  
Small Intestines

The effectiveness of mimosine as a chemical defleecing agent was assessed in adult sheep that were subjected to a variety of nutritional treatments prior to administration of mimosine, and in lambs receiving relatively high feed intakes. Mimosine was given as a continuous intravenous infusion over a period of 2 days. Sheep receiving 600 g of a roughage-based diet per day were consistently defleeced following an infusion of mimosine at the rate of 80 mg/kg/day (designated the standard infusion). The prior feeding of a reduced intake of this diet (300 g/day) did not alter the amount of mimosine required to defleece sheep. Likewise, the prior abomasal infusion of an imbalanced mixture of amino acids, which depressed the wool growth rate, did not allow defleecing with a reduced amount of mimosine. A 4-day fast, commenced 3 days before the start of mimosine infusion, approximately halved the amount of mimosine required to defleece sheep. The provision of a high intake of energy, together with large amounts of amino acids available for absorption from the small intestines (supplied by casein), for at least 1 week prior to mimosine infusion, completely prevented defleecing with the standard infusion of mimosine. The effects of these nutritional treatments could be obviated by a 4-day fast as described above. Also, increasing the rate of infusion of mimosine to 120 mg/kg/day largely overcame the effects of previous high nutrition. Relatively greater amounts of mimosine were required to defleece lambs than adults. The concentration of mimosine in plasma was related to the rate of infusion of mimosine. However, fasting and a low dietary intake tended to enhance the concentration of mimosine in plasma for a given rate of infusion. Infusion of mimosine at the standard rate resulted in plasma mimosine concentrations of the order of 100 µmoles/l, but this concentration did not ensure that defleecing would be possible.

Wool growth regulation by local skin cooling

1967 ◽  
Vol 9 (3) ◽  
pp. 393-397 ◽  
Author(s):  
J. M. Doney ◽  
J. G. Griffiths
Keyword(s):  
Heat Transfer ◽  
Growth Rate ◽  
Blood Flow ◽  
Growth Regulation ◽  
Fibre Diameter ◽  
Systemic Response ◽  
Local Cooling ◽  
Local Skin ◽  
Wool Growth ◽  
Skin Cooling

Local cooling of the skin, produced by exposure to wind was shown to depress the rate of length growth of wool. The depression was associated with reductions in skin temperature and blood flow and with increases in heat transfer in the exposed regions. Fibre diameter did not appear to be affected and there were no indications of a systemic response of wool growth rate to exposure.

Effects of defaunation of the rumen and supplementation with amino acids on the wool production of housed Saxon Merinos. 2. Methionine and protected methionine

1988 ◽  
Vol 28 (2) ◽  
pp. 179 ◽  
Author(s):  
DJ Cottle
Keyword(s):  
Amino Acids ◽  
Fibre Diameter ◽  
High Energy ◽  
Previous Trial ◽  
Growth Responses ◽  
Wool Production ◽  
Low Protein ◽  
Wool Growth ◽  
Protein Diets ◽  
Ciliate Protozoa

In experiment 1, 6 groups, each of 10 superfine Merino wethers, were individually penned indoors and hand-fed oats, wheat straw and whole lupins, either alone or with 2 g/day of DL-methionine or 6.6 g/day of fatty acid coated methionine (Ketionin) for 23 weeks. Following shearing the 6 groups were hand-fed lucerne-chopped hay in experiment 2 either alone or with hydroxymethyl-methionine (Mepron) or Ketionin for 23 weeks. In both experiments the rations were fed at maintenance level and were offered 3 times a week. Half of the sheep had no rumen ciliate protozoa following treatment in a previous trial. In experiment 1, defaunated sheep produced an additional 6.5%clean wool on the supplemented oats plus lupins rations. Inclusion of Ketionin in the ration of defaunated sheep resulted in an 11% increase in clean wool growth, without affecting wool quality. In experiment 2 defaunated sheep produced an additional 6% clean wool on the lucerne-chopped hay ration. No responses to defaunation occurred on the supplemented rations. Inclusion of both forms of protected methionine in the ration (providing 2 g methionine/sheep.day) resulted in 23% and 13% higher clean wool production in the faunated and defaunated sheep respectively. Fibre diameter of wool was increased by 0.7 pm in sheep receiving Mepron and 0-5 pm in sheep receiving Ketionin. The wool grown by suppiemented sheep remained suitable for the 'Sharlea' trade (< 17.5 �m). It is concluded that wool growth responds more to defaunation on high energy-low protein diets. Wool growth responses to supplementation with protected methionine were greater on 100% roughage diets than on high grain diets. Further study is needed before an optimal ration for superfine wool production is formulated.

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