Changes in plasma amino acid patterns and wool growth during late pregnancy and early lactation in the ewe

1993 ◽  
Vol 44 (5) ◽  
pp. 945 ◽  
Author(s):  
DG Masters ◽  
CA Stewart ◽  
PJ Connell
Keyword(s):  
Amino Acids ◽  
Fibre Diameter ◽  
Late Pregnancy ◽  
Essential Amino Acids ◽  
Early Lactation ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Staple Strength ◽  
Animal House ◽  
Limiting Amino Acids

Pregnancy and lactation result in depressed growth, fibre diameter and tensile strength of wool. Competition for nutrients between wool follicles, maternal tissues and the foetus may cause these changes. Changes in the concentrations of individual free amino acids in plasma, during late pregnancy, were used as indicators of limiting amino acids in this experiment. A group of pregnant ewes was maintained in the animal house during late pregnancy and early lactation and measurements made on amino acids in plasma. Liveweight, wool growth and quality characteristics and sulfur in wool were also measured. Comparisons were made between the different time periods in pregnancy and lactation and between the reproducing ewes and a group of non-reproducing ewes maintained under the same conditions. During the last 3 weeks of pregnancy, there was a 31% decline in the concentration of the total, free essential amino acids in plasma. There was also a significant decline in the concentration of arginine (60%), lysine (55%) and threonine (48%). The concentrations of these amino acids increased during the first 3 weeks of lactation. There was no change in concentration of methionine or cystine. Wool growth rate was lowest in the last 3 weeks of pregnancy and the reproducing ewes had significantly lower wool growth, fibre diameter, staple strength and sulfur in wool than the non-reproducing ewes. The results indicate that a lack of the sulfur-containing amino acids is unlikely to be limiting, but a lack of arginine, lysine or threonine may be limiting wool growth and protein deposition in late pregnancy.

Grazing management of reproducing ewes affects staple strength

2000 ◽  
Vol 40 (6) ◽  
pp. 783 ◽  
Author(s):  
S. M. Robertson ◽  
G. E. Robards ◽  
E. C. Wolfe
Keyword(s):  
Fibre Diameter ◽  
Late Pregnancy ◽  
Staple Fibre ◽  
Grazing Management ◽  
Nutritional Management ◽  
Early Lactation ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Staple Strength ◽  
Lamb Growth

A grazing study was conducted on irrigated pastures to assess the influence of manipulating the availability of green pasture at different stages of pregnancy and lactation on the staple strength of broad-wool Merino ewes lambing in July. Sheep subjected to different treatments produced wool ranging between 14 and 48 N/ktex for single-rearing and 22 and 53 N/ktex for non-lambing ewes. Single-bearing/rearing ewes produced wool of strength +4.7 (P>0.05) to –23 N/ktex (P<0.001) in comparison with non-lambing ewes. Reproduction was associated with a reduction in staple strength of 51, 24 and 9% for ewes grazed throughout the experiment at low, medium and high pasture levels, respectively. A staple strength greater than 40 N/ktex was achieved in single-rearing ewes which grazed high pasture mass throughout pregnancy and lactation, during late pregnancy and early lactation, or during mid-pregnancy. Single-rearing ewes, which grazed low pasture biomass throughout either mid, late or all of pregnancy, or during lactation, produced wool with staple strength less than 30 N/ktex. In comparison to grazing the medium pasture allowance throughout the experiment, manipulation of pasture availability had relatively small effects on lamb growth and average fleece measurements, compared with the effects on staple strength. The exception was ewes grazing only the low pasture allowance. The interaction between reproduction and nutritional management influenced staple strength by altering the minimum fibre diameter and the uniformity of along-staple fibre diameter and rate of wool growth. It was concluded that managing pasture availability to promote a uniform along-staple fibre diameter or rate of wool growth can prevent reductions in staple strength associated with reproduction.

Effects on wool production during pregnancy and lactation of twice daily abomasal supplementation with casein or methionine and cystine

1978 ◽  
Vol 18 (90) ◽  
pp. 52 ◽  
Author(s):  
AJ Williams ◽  
RN Tyrrell ◽  
AR Gilmour
Keyword(s):  
Amino Acids ◽  
Fibre Diameter ◽  
Late Pregnancy ◽  
Similar Response ◽  
Early Lactation ◽  
Wool Production ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Sulphur Amino Acids ◽  
Sorghum Grain

The responses in wool production of Merino ewes to abomasal supplements of casein (56 g day-1) and of a mixture of methionine and cystine were measured during late pregnancy and early lactation. The mixed supplement provided equal quantities of the sulphur amino acids as the casein. The ewes were offered sufficient quantities of a diet of sorghum grain/lucerne hay (in the ratio 7 : 3 by weight) to maintain maternal liveweight. During the final four weeks of pregnancy and the first six weeks of lactation, the cassin supplement increased wool growth (826 vs. 639 g cm-2 day-1). A similar response was observed for fibre diameter (1 9.7 vs. 18.5 pm : P < 0.05). Wool production and fibre diameter did not differ between the ewes supplemented with methionine and cystine and the control ewes during this same period. The ewes supplemented with methionine and cystine produced wool with the greatest sulphur content, and this trait was least in the wool from the control ewes (3.84 vs. 3.64 vs. 3.49: P < 0.05). We concluded that the availability of the sulphur amino acids was not primarily limiting wool production in pregnant/lactating ewes.

Responses in wool and live weight when different sources of dietary protein are given to pregnant and lactating ewes

1996 ◽  
Vol 62 (3) ◽  
pp. 497-506 ◽  
Author(s):  
D. G. Masters ◽  
C. A. Stewart ◽  
G. Mata ◽  
N. R. Adams
Keyword(s):  
Amino Acids ◽  
Birth Weight ◽  
Live Weight ◽  
Late Pregnancy ◽  
Early Lactation ◽  
Foetal Growth ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Staple Strength ◽  
Different Sources

AbstractWool growth, staple strength and fibre diameter are reduced during pregnancy and lactation. This may be due to the increased requirement for protein for foetal growth, udder development and milk production causing a lack of amino acids for wool. Responses in wool production, ewe live weight, lamb birth weight and growth, plasma amino acids and levels of cortisol, insulin and growth hormone were measured when different sources of protein were offered. Either lupin seed (L), fish meal (F) or formaldehyde-treated egg white (E) were included in an oaten hay-based diet offered during the final 3 weeks of pregnancy and first 3 weeks of lactation. Provision of diets containing E or F resulted in significant (P < 0·001) increases in wool growth and trends towards increased staple strength (4 to 6 N/ktex) and clean fleece weights (0·17 to 0·38 kg) compared with the sheep given L. Feeding the E diet increased the concentration of cystine in plasma and sulphur in wool in late pregnancy. Feeding the F diet increased the concentrations of arginine, histidine, lysine and threonine in plasma in early lactation. Ewes given E had higher circulating insulin and increased insulin resistance, compared with sheep given L, on 2 of the 4 days of sampling during pregnancy and lactation during the treatment period. There were no treatment effects on lamb birth weight or growth but ewes given the E diet were significantly (P < 0·05, 3·3 kg) heavier than the ewes given L after 3 weeks of lactation. The results indicate that a lack of protein available for absorption in the small intestine causes reduced wool growth during late pregnancy and early lactation. Wool growth is more sensitive to a reduced protein supply than foetal growth, maternal weight or milk production.

Changes in plasma amino acid patterns and wool growth in response to abomasal injections of amino acids during late pregnancy and early lactation

1993 ◽  
Vol 44 (5) ◽  
pp. 959 ◽  
Author(s):  
CA Stewart ◽  
DG Masters ◽  
IH Williams ◽  
PJ Connell
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Late Pregnancy ◽  
Early Lactation ◽  
Growth Responses ◽  
Specific Amino Acid ◽  
Protein Deposition ◽  
Wool Growth ◽  
Limiting Amino Acids ◽  
Sulfur Containing

Provision of sulfur-containing amino acids into the abomasum has increased wool production in non-reproducing sheep and, on the basis of such studies, they have generally been considered as the primary limiting nutrients for wool growth. The specific amino acid needs of reproducing ewes were investigated in the current study. Three groups of pregnant ewes were fitted with temporary abomasal fistulae. For the last 3-4 weeks of pregnancy and the first 3 weeks of lactation, solutions containing sodium hydroxide (as a carrier) or methionine or a mixture of valine, arginine, lysine and threonine (VALT) were injected into the abomasum twice per day. The injection of methionine did not increase protein deposition during pregnancy; this was indicated by the failure of the treatment to lower the concentration of other amino acids in plasma, or increase liveweight, lamb birth weight or wool growth. Responses in early lactation were different with the methionine injected sheep having a lower concentration of free lysine, valine, alanine and serine in plasma, indicating an increased rate of protein deposition, and a faster growth rate in the ewes. Injections of VALT caused a decrease in the concentration of cystine and methionine in plasma and depressed wool growth and tensile strength. Theresults indicate that a lack of methionine was not limiting protein deposition during late pregnancy, but may have been during early lactation. Valine, arginine, lysine and threonine were not the primary limiting amino acids in late pregnancy or early lactation.

Responses in wool growth, liveweight, glutathione and amino acids, in Merino wethers fed increasing amounts of methionine protected from degradation in the rumen

1995 ◽  
Vol 46 (6) ◽  
pp. 1189 ◽  
Author(s):  
G Mata ◽  
DG Masters ◽  
D Buscall ◽  
K Street ◽  
AC Schlink
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Linear Relationship ◽  
Reduced Glutathione ◽  
Fibre Diameter ◽  
Essential Amino Acids ◽  
Sulfur Amino Acid ◽  
Wool Growth ◽  
Amino Acid Intake ◽  
Animal House

The aim of the experiments reported was to evaluate the protection from microbial breakdown of two methionine formulations (Lactet and Mepron) and to measure responses in wool production, liveweight, amino acids and glutathione in blood and tissues when one of these forms of methionine (Lactet) was supplied to merino wethers fed at maintenance. Lactet was well protected against microbial breakdown in the rumen. Peak values for concentrations of methionine in plasma, following administration of the different forms of methionine into the rumen, were 574, 148 and 143pmol L-1 for Lactet, DL-methionine and Mepron. Production responses to dosed levels of Lactet (0, 1, 2, 3, 5, 8 g methionine dayw1) were measured over 63 days in the animal house. Significant linear responses were obtained for wool growth (4-38%), fibre diameter (0.5-2 8m) and liveweight gain (30-1 15%). Concentrations of reduced glutathione in blood, liver and skin were increased, at some times during the experiment, by provision of Lactet. However, responses were inconsistent and highly variable among sheep, Glutathione was of limited use as an indicator of sulfur amino acid intake or status. Sulfate in plasma increased markedly at all levels of Lactet intake, and there was a linear relationship between Lactet intake and the concentration of sulfur in wool. Plasma free methionine and the ratio of methionine to total essential amino acids showed significant linear responses to the supplements. It was concluded that Lactet was an effective method of supplying rumen-protected methionine to ruminants.

Effect of time of joining and rate of stocking on the production of Corriedale ewes in southern Victoria. 3. Wool growth and the composition and availability of pasture

1975 ◽  
Vol 15 (73) ◽  
pp. 159 ◽  
Author(s):  
PA Kenney ◽  
IF Davis
Keyword(s):  
Fibre Diameter ◽  
Late Pregnancy ◽  
The Other ◽  
Early Lactation ◽  
Stocking Rate ◽  
Wool Production ◽  
Wool Growth ◽  
The Mean ◽  
Brome Grass ◽  
Stocking Rates

A study was made during a three year period (1 968-1 970) of wool production by a flock of 540 ewes grazing annual pasture at Werribee, Victoria. The ewes were stocked at three rates (5, 7 1/2 and 10 ewes ha-1) and lambed between July 6 and August 20 or between September 10 and October 29 each year. Fibre diameter and length of wool samples were measured in 1968, 1969 and 1970 ; in 1970 growth of greasy wool was calculated from staples of dye-banded wool. Wool growth was reduced in all ewes during late pregnancy and early lactation but was not affected during late lactation in ewes lambing in September. The proportion of tender fleeces from all ewes was greater in 1970 and the weight of fleeces from only those ewes bearing single lambs was less in all years for ewes lambing in July than for ewes lambing in September. More ewes were barren and fewer ewes had twins in July and consequently the mean fleece weights of all ewes from both groups were similar. Fleeces from ewes stocked at 10 ha-1 were lighter, shorter and finer than fleeces from ewes stocked at 5 and 7 1/2 ha-1, but the proportion of tender fleeces did not differ between the groups. Wool production of ewes stocked at 5 and 7 1/2 ha-1 increased from 1968 to 1970, whereas that of ewes at 10 ha-1 did not. This was associated with differences in pasture availability and composition. At 10 ewes ha-1 less pasture was present in winter and spring in 1970 than in 1968, whereas at the other stocking rates it was greater. In 1970 the density of weeds in autumn was greater and in spring more silver grass (Vulpia spp.) and less brome grass (Bromus spp.) was available at the high stocking rate.

Whole wheat grain feeding of Merino ewes. 3. Influence of level of wheat and vitamin A on wool growth in pregnancy and lactation

1976 ◽  
Vol 16 (78) ◽  
pp. 49 ◽  
Author(s):  
WR McManus ◽  
JA Reynolds
Keyword(s):  
Growth Rate ◽  
Vitamin A ◽  
Fibre Diameter ◽  
Late Pregnancy ◽  
Control Group ◽  
Whole Wheat ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Wool Yield ◽  
The Relationship

In experiment 1, ewes were fed three levels of wheat in pens, with or without vitamin A, from joining to weaning. The wheat levels ranged from 3.4 to 4.6 kg head-1 week-1. Control groups were run on native pasture. In experiment 2 three levels of wheat, which ranged from 3.9 to 7.1 kg head-1 week-1. were fed to ewes from joining to weaning. At each wheat level two groups were fed wheat in pens (wheat/ pen); another group was fed wheat in small paddocks (wheat/paddock). One of the wheat/pen groups received vitamin A. A control group was run at pasture. Vitamin A had no effect on wool traits except on wool yield in experiment 2. Clean wool weight and staple length increased linearly with increasing wheat intakes in both experiments. The relationship between fibre diameter and wheat level was linear in experiment 1 and curvilinear in experiment 2. In experiment 2 there were differences between wheat/pen and wheat/paddock groups in all the wool traits measured. In experiment 1, wool growth rate was reduced by 40 per cent in the wheat groups and by 44 per cent in the pasture groups during late pregnancy and lactation. In experiment 2, compared with early pregnancy, wool growth rate was reduced by 11 per cent and 31 per cent in the wheat groups during late pregnancy and lactation respectively.

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 The wool production and reproduction of Merino ewes can be predicted from changes in liveweight during pregnancy and lactation

2011 ◽  
Vol 51 (9) ◽  
pp. 763 ◽  
Author(s):  
M. B. Ferguson ◽  
A. N. Thompson ◽  
D. J. Gordon ◽  
M. W. Hyder ◽  
G. A. Kearney ◽  
...  
Keyword(s):  
Fibre Diameter ◽  
Late Pregnancy ◽  
Reproductive Rate ◽  
Breeding Cycle ◽  
Wool Production ◽  
Condition Score ◽  
Pregnancy And Lactation ◽  
Influence Of Food ◽  
Staple Strength ◽  
Fleece Weight

Defining the nature of the relationship between change in liveweight throughout a breeding cycle and ewe wool production and reproduction would be useful for developing management guidelines for Merino ewes. In this paper we tested the hypotheses that (1) feed on offer has variable effects on liveweight profiles of individual ewes; and (2) liveweight profiles of individual ewes can be used to predict their fleece wool production and reproductive performance. At sites in Victoria and Western Australia in 2001 and 2002, pregnant Merino ewes were exposed to 10 nutritional treatments. In each of the four experiments, ewes in average condition score 3 at artificial insemination were fed to achieve either maintenance or loss of a condition score over the first 100 days of pregnancy before grazing one of five levels of feed on offer between Day 100 and lamb weaning. Across all four experiments, the average difference in ewe liveweight between extreme treatments was: 7.0 kg (range 4.7–8.7 kg) at Day 100 of pregnancy; 11.9 kg (range 4.9–17.8 kg) at lambing; and by weaning was 13.9 kg (range 8.8–22.7 kg). Liveweight at joining and liveweight change during pregnancy and lactation of individual Merino ewes were significantly related to their clean fleece weight, fibre diameter and staple length and thus the second hypothesis was supported. Heavier ewes at joining produced more wool that was longer and broader and this effect was consistent across both sites and years. A 10-kg loss in ewe liveweight between joining and mid pregnancy, mid pregnancy and lambing or during lactation reduced clean fleece weight by 0.4–0.7 kg and fibre diameter by 0.5–1.4 um. At the Victorian site, where ewes were shorn in summer, a loss of 10 kg in liveweight between joining and Day 100 of pregnancy reduced staple strength by 5 N/ktex. As expected the influence of food on offer on changes in ewe liveweight was different between years and sites and between late pregnancy and lactation due to a complex group of pasture and animal factors. Therefore, managing changes in ewe liveweight itself rather than feed on offer will achieve more predictable outcomes. A higher liveweight at joining resulted in a predictable improvement in ewe reproductive rate and liveweight at joining was more important than the liveweight profile leading up to joining. This paper has shown that it is possible to predict the differences in wool production and reproductive rate of flocks of Merino ewes if ewe liveweight records at key times are known.

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.

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