Relationship of feed intake with cystine availability and wool growth in Merino wethers

1993 ◽  
Vol 44 (5) ◽  
pp. 973 ◽  
Author(s):  
GJ Lee ◽  
AJ Williams
Keyword(s):  
Sulfur Content ◽  
Fibre Diameter ◽  
Kinetics Model ◽  
Similar Proportion ◽  
Standard Diet ◽  
Growth Responses ◽  
Irreversible Loss ◽  
Wool Growth ◽  
Saturation Kinetics ◽  
The Relationship

Two experiments were conducted to characterize the relationship between nutrient supply and the rate of wool growth. We concentrated on the accepted view that the rate of wool growth in Merino sheep is primarily limited by the availability of sulfur amino acids, which are largely determined by diet intake and its interaction with microbial fermentation in the reticulo-rumen. In the first experiment, the effects of variable intakes of two diets (one including 10% fishmeal) by sheep on the rate of irreversible loss of cystine and plasma cystine concentration were investigated. Nitrogen intake (N) was positively and linearly related to both the irreversible loss rate and the plasma concentration of cystine, with no effects of diet per se. In the second experiment, the same dietary treatments were imposed on 39 wethers for 16 weeks following an 8 week pre-experimental period. The monthly rates of wool growth, average fibre diameter and sulfur content of the wool were measured and related to various components of intake. The rate of wool growth responded in a positive curvilinear decreasing manner to changes in intake, the response requiring 2 months to stabilize. There was no significant effect of diet when daily intake was expressed as g N kg-0.75 liveweight. Including the covariate (wool growth when fed the standard diet), the quadratic linear model accounted for 90% of the total variation in wool growth. Responses in fibre diameter and its variation, and wool sulfur content were similar to those of wool growth, in that they were positive and did not equilibrate quickly. A saturation kinetics model of the relationship between daily N intake (g N kg 0.75 liveweight) and wool growth accounted for a similar proportion of the variation as did a linear (with quadratic term) model without the covariate. It is concluded that the saturation kinetics model may be useful for more comprehensive comparisons of both the genetic potential and the sensitivity of wool growth to environmental changes.

Liveweight and wool growth responses to a Mediterranean environment in three strains of Merino sheep

1998 ◽  
Vol 49 (8) ◽  
pp. 1187 ◽  
Author(s):  
N. R. Adams ◽  
J. R. Briegel
Keyword(s):  
Body Composition ◽  
Fibre Diameter ◽  
The Other ◽  
Wool Fibre ◽  
Growth Responses ◽  
Mediterranean Environment ◽  
Protein Loss ◽  
Broad Group ◽  
Wool Growth ◽  
Sources Of Variation

The present study examined changes in wool growth, liveweight, and body composition in groups of fine, medium, and broad wool Merino wethers grazed together at pasture in the highly seasonal Mediterranean environment, to determine the sources of variation in wool growth that may affect staple strength (SS). Seasonal changes in wool growth were measured using 6 dyebands placed at times of seasonal change in the nutrient supply from pasture, and liveweights were recorded fortnightly. Dilution of deuterated water was used to determine changes in body composition between the beginning of summer and the end of autumn. The sheep lost liveweight over this period, but loss of protein relative to fat over this period was unexpectedly high (7 : 1). The relative changes in liveweight, and loss of its components (fat and lean) during summer and autumn, were similar in all 3 groups, even though the Broad group was heavier than the other 2 genotypes at all times (P < 0·01). In contrast to the similar pattern of liveweight change, wool growth rates and changes in the fibre diameter were less variable throughout the year in the Broad group than the other 2 groups (P < 0·001). Stepwise regression indicated that the characteristics related to SS were standard deviation in fibre diameter (SDfd; P < 0·001), mean fibre diameter (P < 0·001), and variation in diameter within a 200-mm length of wool fibre (Sdfdwithin; P < 0·05). However, the relative importance of different factors for SS differed within each group. The most important factors were mean fibre diameter in the Fine group, the variation in fibre diameter along the staple (SDfdalong) in the Medium group, and the variation in diameter between fibres (SDfdbetween) in the Broad group. It is concluded that SS is a complex characteristic, depending on both the fibre diameter and several sources of variation in fibre diameter, all of which can differ among flocks. Protein loss made a disproportionate contribution to liveweight loss over summer and autumn, but the amino acids made available did not contribute substantially to wool growth or SS.

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.

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.

Factors differentiating between high and low wool producing sheep in western Queensland

1992 ◽  
Vol 43 (6) ◽  
pp. 1367
Author(s):  
DA Pritchard ◽  
PK O'Rourke
Keyword(s):  
Linear Growth ◽  
Phenotypic Expression ◽  
Fibre Diameter ◽  
Live Weight ◽  
Unit Surface Area ◽  
Growth Responses ◽  
Wool Production ◽  
Pasture Quality ◽  
Wool Growth ◽  
Commercial Flock

Four experiments were carried out to examine factors which may influence the phenotypic expression of wool growth. High wool producing sheep (HPS) and low wool producing sheep (LPS) were selected from a commercial flock and studied under grazing and controlled feeding conditions. Results are discussed in relation to management of HPS for increased wool production. In the paddock experiment, advantages to HPS in wool growth per unit surface area were least (7%) when pasture quality was low (11 g N/kg DM) and greatest (20%) when pasture quality was best (21 g N/kg DM). Despite the greater live weight of HPS compared with LPS (16%), the HPS produced 25% more clean wool per unit of live weight. Daily clean wool production was always greater in HPS than in LPS. Values ranged from 9.1 v. 7.5 g/day to 15.1 v. 11.6 g/day. During the period following the peak in nitrogen content of the pasture, HPS produced a greater volume of fibre than LPS (194 v. 167 8m3/dayx103), this difference being primarily associated with the greater fibre diameter of wool from HPS (25.4 v. 24.6 8m). In pen experiment 1, the efficiency of conversion of feed to wool was determined under controlled feeding conditions. Differences in wool growth between HPS and LPS at maintenance (M) and above maintenance (M+) were 21% and 49% respectively. Relative efficiency of conversion of feed to wool was 5% higher for HPS during the period immediately following the change in ration and greatest (38-48%) after sheep had made liveweight gains. Wool growth differences between HPS and LPS in pen experiment 2 could not be attributed to either differences in follicle density (66 v. 64 follicles/mm2) or the ratio of secondary to primary follicles (24 : 1 v. 22 : 1). The efficiency of retention of apparently absorbed nitrogen was similar (21.4 v. 20.8%) for HPS and LPS at below maintenance (M-) but differed at M-t (26.8 v. 11.7%). Rumen dry matter turnover time at M- was faster in HPS than in LPS (29.8 v. 38.4 h) but similar at M+ (30.4 v. 34.4 h). At M-, volumetric fibre production of HPS increased from 79 to 106 ,8m3/dayx 103 and from 59 to 75 ,8m3/day x103 for LPS following the subcutaneous administration of the sulfur containing amino acid methionine. These increases were associated with increases in both fibre diameter (1.5 8m) and fibre linear growth (42 8m/day) in HPS, but only linear growth (52 ,8m/day) in LPS. At M+, when basal wool growth was high, there was little increase in wool growth by either group following supplementary methionine. Wool growth responses to methionine were 25 and 19% for HPS and LPS respectively at M+ in pen experiment 3.

Nutritional responses in wool growth by four Merino genotypes of differing wool growth performance

1994 ◽  
Vol 45 (6) ◽  
pp. 1171 ◽  
Author(s):  
GJ Lee ◽  
AJ Williams
Keyword(s):  
Organic Matter ◽  
Nutrient Intake ◽  
Regression Coefficient ◽  
Unit Area ◽  
Fibre Diameter ◽  
The Other ◽  
Wool Growth ◽  
Per Se ◽  
Relationship Of ◽  
The Relationship

Sheep from four Merino flocks, different in annual clean fleece production when grazed together, were offered a range of nutritional treatments to compare their ability to digest dietary organic matter (experiment 1) and to compare the relationships of wool growth and fibre diameter with nutrient intake (experiment 2). The sheep were selected from a finewool (Fl), a strong wool (S), and two medium-Peppin (MP6 and MP10) flocks. The nutritional treatments varied intakes of two pelleted diets-B and F. Diet B consisted of oat grain, lucerne chaff, and oaten straw, while diet F was as for B but fortified with fishmeal. The digestibility of both diets was negatively related to the level of intake, and there were some differences between the flocks in their ability to digest organic matter. Clean wool growth per unit area of skin was curvilinearly related (P < 0.001) to N intake, but was not influenced by diet per se. The regression coefficient for the relationship of clean wool growth with N intake and the estimated maximum wool growth rate of flock F1 were less than the other flocks. However, flock MP10 grew less wool than flocks S and MP6 at any given intake. Variation in (fibre diameter)2 accounted for 0.6 of the variation in wool growth, with responses in fibre diameter to intake being similar to those observed in wool growth. The responses in plasma cystine of the flocks to N intake differed, with the relationship for flock F1 being curvilinear and reaching a maximum at an intake of 27 g N day-1, while the responses of the other flocks were essentially linear. The relationships between plasma cystine level and wool growth differed between the flocks such that wool growth of sheep from flocks S and MP6 was more responsive to increased plasma concentration of cystine.

Effects of defaunation of the rumen and supplementation with amino acids on the wool production of housed Saxon Merinos. 4. Cottonseed meal, analogues of methionine and avoparcin

1988 ◽  
Vol 28 (6) ◽  
pp. 707 ◽  
Author(s):  
DJ Cottle
Keyword(s):  
Amino Acids ◽  
Cottonseed Meal ◽  
Fibre Diameter ◽  
Cost Effective ◽  
Wool Fibre ◽  
Growth Responses ◽  
Wool Production ◽  
Wool Growth ◽  
Fleece Weight ◽  
Ciliate Protozoa

Ten groups, each of 6 superfine Merino wethers were individually penned indoors and hand-fed at maintenance level a ration of 70% oats and 30% chopped lucerne hay (w/w). The groups of sheep were fed 3 different supplementary pellets rotationally during three 9-week periods. Each group received 3 of the following 7 pellets: (1) control, (2) cottonseed meal (CSM), (3) CSM plus hydroxymethyl-methionine (MEP), (4) CSM plus methionine hydroxy analogue (MHA), (5) CSM plus avoparcin (AV), (6) CSM plus MEP plus AV, and (7) CSM plus MHA plus AV. The rations were offered 3 times a week. Half of the sheep had no rumen ciliate protozoa. Wool production was measured during the 7-month period. Defaunation resulted in a 6.9% increase in greasy fleece weight and a 7.7% increase in clean wool production. Average wool fibre diameter increased by 0.6 pm in defaunated sheep. The clean wool growth responses compared with sheep fed the control pellets were 4, 5, 12, 0, 3 and 9% respectively for sheep fed pellets 2-7. The most cost-effective supplement was the CSM plus MHA pellet, which increased clean wool production by 0.5 glday compared with sheep fed the CSM pellet but did not significantly affect wool quality. It was concluded that supplements containing MHA could be economically fed to housed superfine Merino wethers ('Sharlea'), but MHA appears to be relatively inefficient in supplying methionine to the intestines.

Effects of defaunation of the rumen and supplementation with amino acids on the wool production of housed Saxon Merinos. 3. Cottonseed meal and hydroxymethyl-methionine

1988 ◽  
Vol 28 (6) ◽  
pp. 699 ◽  
Author(s):  
DJ Cottle
Keyword(s):  
Amino Acids ◽  
Cottonseed Meal ◽  
Growth Response ◽  
Fibre Diameter ◽  
Diameter Ratio ◽  
Design Experiment ◽  
Growth Responses ◽  
Wool Production ◽  
Wool Growth ◽  
Ciliate Protozoa

In experiment 1 six groups, each of 10 superfine Merino wethers were individually penned indoors and hand-fed chopped lucerne hay with either control pellets, cottonseed meal pellets (CSM) or cottonseed meal plus hydroxymethyl-methionine pellets (CSMEP). Following their shearing, the 6 groups in experiment 2 were hand-fed 1 of 3 chopped lucerne hay:oat rations [75: 25,50: 50,25: 75% (w/w)]. Each sheep was also fed either control pellets (25 g/day) or CSMEP pellets (75 g/day) in a cross-over design experiment. 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. In experiments 1 and 2, wool production was measured during a 4 and 6 month period respectively. In experiment 1, defaunation resulted in a 6% increase in clean wool production on the unsupplemented chopped lucerne hay ration. Inclusion of CSM and CSMEP pellets resulted in clean wool growth responses of 16% and 19% respectively. Unacceptable increases in fibre diameter were associated with the increased wool production. In experiment 2, the clean wool response to defaunation was highest (12%) on the 75% chopped lucerne hay ration, when the control pellet was fed. Inclusion of the CSMEP pellet resulted in clean wool growth responses of 0.73, 0.98 and 0.99 g/day in sheep fed on the 75,50 and 25% chopped lucerne hay rations respectively. The wool production responses due to the CSMEP pellet were associated with increases in fibre diameter (0.3 �m), length (4 mm/year) and length/diameter ratio (0.4 �m/day.�m) of the wool grown. It was concluded that CSMEP pellets are best fed with a mixed ration containing more grain than chopped lucerne hay. The wool growth response to feeding hydroxymethyl-methionine was considered uneconomic.

scholarly journals Nutritional Factors Involved in Wool Production by Merino Sheep I. The Influence of Fodder Intake on the Rate of Wool Growth

1948 ◽  
Vol 1 (3) ◽  
pp. 362 ◽  
Author(s):  
Hedley R Marston
Keyword(s):  
Fibre Diameter ◽  
Cross Sectional ◽  
Nutritional Factors ◽  
Merino Sheep ◽  
Wool Growth ◽  
Mean Diameter ◽  
The Mean ◽  
Four Levels ◽  
The Individual ◽  
The Relationship

The rate of wool growth (weight of wool produced per unit time), determined in seven sheep subjected to four levels of food intake, ncreased 400-600 per cent. from the lowest to the highest level of feeding and this change was reflected in both the mean length and in the mean diameter of the fibres, the relationship between these variables being characteristic of the individual sheep. The fibre diameter distribut!ons were also affected, the individual fibres responding up to the limit of their capacities in proportion to their cross-sectional areas.

Wool growth of pregnant and lactating Merino ewes

1985 ◽  
Vol 105 (3) ◽  
pp. 613-622 ◽  
Author(s):  
V. H. Oddy
Keyword(s):  
Organic Matter ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Total Plasma ◽  
Wool Growth ◽  
Digestible Organic Matter ◽  
Pregnancy And Lactation ◽  
The Difference ◽  
The Relationship ◽  
Growth Deficit

SUMMARYThe wool production of pregnant, lactating and non-pregnant, non-lactating (dry) Merino ewes eating one of three diets: chaffed oaten hay (OH), chaffed lucerne hay (LH), and a 50/50 (w/w) mixture of OH and LH, was determined. Measurements were made for 2 months prior to mating, during pregnancy and for 3 months after lambing, and for the dry ewes over the same period.Production of clean wool (Y, g/day) by dry ewes was linearly related to digestible organic matter intake (X, g/day):Y = 0·0301 X - 3·34, r = 0·97.Clean wool growth was significantly less (P < 0·01) than dry ewes in the 4th and 5th month of pregnancy and throughout lactation. During pregnancy the total deficit in clean wool growth (calculated as the difference between observed wool growth and that expected on the basis of the relationship between feed intake and clean wool growth of dry ewes) was 456 g for ewes bearing a single lamb and 578 g for those bearing twins, with no difference between diets. In lactation the total clean wool growth deficit increased as milk production increased, and for every litre of milk produced there was a deficit of 12 g clean wool.Wool fibre diameter was reduced during the 1st month of lactation. There was no consistent effect of pregnancy or lactation on the number of wool follicles per mm2, the ratio of primary plus secondary to primary wool follicles, or on the thickness of skin on the midside.Digestibility of dietary organic matter (DOM) was reduced during the last 3 months of pregnancy, and the first 2 months of lactation. However, this was insufficient to account for the magnitude of the decrease in wool growth seen during pregnancy and lactation.Wool sulphur content increased during pregnancy (P < 0·001), but not during lactation. The relationship between total plasma cyst(e)ine concentration and DOM intake during pregnancy was similar to that in dry ewes, but during lactation total plasma cyst(e)ine concentration was less than expected. It was calculated that during pregnancy the amount of sulphur saved through reduced wool growth was greater than that deposited in the conceptus, and during lactation the amount of sulphur saved in reduced wool growth matched that excreted as milk.These results are discussed in relation to control of wool growth during pregnancy and lactation.

Wool growth responses to DL-methionine administration and factors affecting the value of supplementation

1991 ◽  
Vol 31 (4) ◽  
pp. 471 ◽  
Author(s):  
RGA Stephenson ◽  
GR Suter ◽  
CJ Howitt
Keyword(s):  
Fibre Diameter ◽  
Growth Responses ◽  
Rhodes Grass ◽  
Factors Affecting ◽  
Net Return ◽  
Wool Production ◽  
Wool Growth ◽  
Treatment Analysis ◽  
Positive Correlations ◽  
The Cost

Wool growth responses to methionine administration were assessed using Peppin Merino wethers on various planes of nutrition. In experiment 1, sheep were fed 700 g/day of lucerne pellets to maintain liveweight. DL-methionine (5.8 g) administered subcutaneously resulted in 0.29 mg/cm2.day (36%) more wool (P<0.01) and a 2.5 �m (15.2%) increase in fibre diameter (P<0.05). In experiment 2, two levels (700 and 1400 g/day) of lucerne pellets were offered, with and without methionine administered subcutaneously (5.8 g). Main treatment analysis indicated a significant (P<0.01) effect of nutrition on wool growth and fibre diameter, with no effect of methionine, except for a reduction (P<0.05) in liveweight gain. Methionine administration was associated with a non-significant increase (39%) in wool growth for the 700 g diet and no change for the 1400 g diet. In experiment 3, two levels (1.75 and 2.5 g/day) of methionine were infused (4 h daily) when sheep were fed a submaintenance ration of Rhodes grass chaff, supplemented with nitrogen and sulfur. Significant (P<0.05) wool growth responses at both levels of methionine infusion were similar, with absolute (0.21 and 0.23 mg/cm2.day) and percentage (52 and 58%) increases for 1.75 and 2.5 g/day methionine treatments, respectively. Methionine administration only increased wool production at nutritional levels of liveweight maintenance or below when wool growth values for control treatments were 0.63,0.59 and 0.40 mg/cm2.day for experiments 1, 2 and 3. Fibre diameters of sheep in untreated groups were 16.4 and 18.8 pm for experiments 1 and 2. These wool growth and fibre diameter values are 25-40% below what might be expected for this strain of Merino. The values of positive correlations between wool growth and fibre diameter were increased with increased nutrition and the administration of methionine in experiment 2. This result and the nil response at high basal wool growth, together with the low potential net return on the cost of methionine, suggest that the use of methionine could be unprofitable.

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