Effect of selection for wool growth on seasonal patterns of yield, fibre diameter, and colour in Romney lines

1995 ◽  
Vol 35 (1) ◽  
pp. 27 ◽  
Author(s):  
T Wuliji ◽  
IL Weatherall ◽  
RN Andrews ◽  
KG Dodds ◽  
PR Turner ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fibre Diameter ◽  
Seasonal Patterns ◽  
Control Line ◽  
Wool Growth ◽  
Growth Decline ◽  
Selection For ◽  
Staple Strength ◽  
Fleece Weight

Seasonal wool growth and associated wool characteristics were measured in a Romney line selected for high fleece weight and an unselected control line in 1990 and 1991. Both had a significant (P<0.01) decline in wool growth rate in winter compared with summer. The wool growth rate advantage (P<0.001) of the selected line over the control averaged 19 and 33% for ewes, and 24 and 36% for hoggets, in summer and winter, respectively. Staple strength, yield, and fibre diameter differences were closely associated with wool growth. Colour analysis showed no difference between lines in either brightness (Y) or yellowness (Y - Z). However, both the Y and Z values were lower in spring and summer, while Y - Z was highest in summer. The results suggest that selection for high fleece weight also improves major wool characteristics and reduces the relative winter wool growth decline in Romneys.

Fibre diameter and staple strength of sheep selected for divergent clean fleece weight when subjected to an increase in intake or an increase in intake and diet change

2005 ◽  
Vol 56 (2) ◽  
pp. 195 ◽  
Author(s):  
M. A. Friend ◽  
G. E. Robards
Keyword(s):  
Growth Rate ◽  
Stepwise Regression ◽  
Fibre Diameter ◽  
Dietary Treatment ◽  
Diet Change ◽  
Wool Growth ◽  
Ad Libitum ◽  
Staple Strength ◽  
Fleece Weight ◽  
Ad Libitum Feeding

Merino wethers with a high (fleece plus, Fl+) or low (fleece minus, Fl–) potential for wool growth were offered a restricted intake of either oat grain or lucerne chaff for 8 weeks followed by ad libitum lucerne chaff for 4 weeks. The Fl– sheep that were fed oats then lucerne had a lower (P < 0.05) intake during the first 2 weeks of ad libitum feeding than all other groups. Staple strength of Fl+ sheep (37.5 ± 2.2 N/ktex) was less (P < 0.05) than that of Fl– sheep (44.5 ± 2.4 N/ktex), and dietary treatment did not significantly affect staple strength. Wool growth rate was unaffected by dietary treatment, but was greater (P < 0.001) for Fl+ (6.4 ± 0.2 µg/mm2.day) than for Fl– (4.0 ± 0.2 µg/mm2.day) sheep. Along-fibre variation in diameter was greater (P < 0.001) in Fl+ (15.6 ± 0.5%) than in Fl– (9.9 ± 0.5%) sheep. Between-fibre variation in diameter was greater (P < 0.001) in Fl+ (16.5 ± 0.5%) than in Fl– (13.2 ± 0.5%) sheep, and between-fibre variation in diameter was affected (P < 0.05) by dietary treatment in Fl+ sheep. Staple strength was significantly correlated (P < 0.05) with along-fibre variation in diameter (r = –0.48), and stepwise regression analysis indicated that along-fibre variation in diameter, wool growth rate during early restricted feeding, and minimum fibre diameter explained 63% of the variance in staple strength. The results are discussed in relation to the lower staple strength of Fl+ sheep.

Supplementation of young Merino sheep grazing annual pastures with lupin, barley grain, or silage

1993 ◽  
Vol 33 (4) ◽  
pp. 403 ◽  
Author(s):  
JJ Gardner ◽  
PT Doyle ◽  
JB Rowe ◽  
R Hetherington ◽  
P Spicer ◽  
...  
Keyword(s):  
Growth Rate ◽  
Energy Levels ◽  
Fibre Diameter ◽  
Barley Grain ◽  
Sheep Grazing ◽  
Merino Sheep ◽  
Wool Growth ◽  
Metabolisable Energy ◽  
Staple Strength ◽  
Fleece Weight

We examined the effects on liveweight change and wool production of supplements of lupin, barley grain, or silage given to Merino weaners (age 5-7 months; starting weight about 30 kg) grazing dry annual pastures. In experiment 1, each supplement was offered at 5 rates (g/sheep.day): lupin, air-dry, 75-450; barley, air-dry, 80-480; silage, fresh, 430-2580. Sheep on all treatments gained weight in the first 29 days of supplementary feeding, with no effect of rate of supplementation (lupin 97 g/day; barley 57 g/day; silage 74 g/day). Those receiving no supplement also gained weight (40 g/day). Different supplements were not compared because the energy levels of lupin and barley were not measured. Over the next 48 days, liveweight changes increased (P<0.001) linearly with rate of feeding of lupin (25 � 2.1 g/100 g) and barley (12 � 0.8 g/100 g). The trend with silage (11 � 5.0 g/kg) was not significant. Taken over the 77 days, liveweight changes increased (P<0.01) linearly with rate of feeding for lupin (20 �. 1.8 g/100 g), barley (8 �. 1.7 g/100 g), and silage (10 �. 2 g/kg). There were no significant (P>0.05) differences associated with the rate of supplementation for annual clean fleece weight (lupin 3.43 kg, barley 3.37 kg, silage 3.30 kg) or mean fibre diameter of the 12-month fleece (lupin 22.2 �m, barley 22.6 �m, silage 22.1 �m). In experiment 2, sheep were given no supplement, lupin, barley, or lupin and barley mixtures (metabolisable energy ratio, 1:3,1:1,3:1). All supplements increased liveweight change (P<0.01) and clean wool growth rates (P<0.05) compared with no supplement. There was also a trend towards an increase in total wool grown by supplemented sheep (3.8 - 4.00 v. 3.73 kg). Liveweight change during the first 71 days of feeding increased (P<0.01) as the proportion of lupin in the supplement increased, with no effects in the final 70 days of supplementation. During supplementation, clean wool growth rate increased (P<0.05) as the proportion of lupin in the mixture increased, but there was no significant effect on the total amount of wool grown over 12 months or on mean fibre diameter. Supplements resulted in increased (P<0.001) staple strength when compared with controls (21-25 v. 14 N/ktex).

Influence of liveweight, liveweight change, and diet on wool growth, staple strength, and fibre diameter in young sheep

1998 ◽  
Vol 49 (2) ◽  
pp. 269 ◽  
Author(s):  
D. G. Masters ◽  
A. D. Peterson ◽  
G. Mata ◽  
S. M. Liu
Keyword(s):  
Management Strategy ◽  
Fibre Diameter ◽  
Experimental Period ◽  
Canola Meal ◽  
Wool Growth ◽  
Lupin Seed ◽  
Staple Strength ◽  
Wool Yield ◽  
Fleece Weight

The effects of initial liveweight, liveweight change, and composition of the diet on wool growth and staple strength in weaner sheep were investigated. Weaner wethers (64) were allocated to treatments in a factorial design (23). The factors were initial liveweight (heavy, 33 kg; light, 25 kg), liveweight change (fed at maintenance for 56 days, or 28 days at 0 ·6×maintenance then 28 days at 1·6×maintenance), and diet (lupin seed based diet or canola meal based diet). The heavier weaners grew approximately 1·9 g/day more wool than the light sheep during the experimental period and this resulted in a higher clean fleece weight (1·8 v. 1·4 kg), staple strength (37 v. 27·4 N/ktex), and fibre diameter (18·0 v. 17·4 µm). Substituting canola meal for lupin seed increased wool growth during the experiment and clean wool yield, but did not affect clean fleece weight or staple strength. The weaners fed to lose and then gain weight grew wool with a lower staple strength than the weaners fed to maintain weight through the experiment (28·6 v. 35·8 N/ktex), but there were no differences in any of the other fleece characteristics. The ratio of wool growth to dry matter intake (DMI) was higher in the sheep fed canola meal than those fed lupins (by approximately 1·5 g/kg DMI) and higher in weaners losing weight than those fed to maintain weight (by approximately 4·5 g/kg DMI). From a practical perspective, these results indicate that initial liveweight and liveweight change both influence staple strength and wool growth and need to be included in any management strategy to improve wool quality of young sheep.

Supplementation of young sheep with lupins plus sulfur and a complete mineral mix

1992 ◽  
Vol 32 (3) ◽  
pp. 267
Author(s):  
PT Doyle ◽  
RA Love ◽  
RH Dunlop ◽  
CL White
Keyword(s):  
Fibre Diameter ◽  
Potassium Sulfate ◽  
Feeding Period ◽  
Merino Sheep ◽  
Mineral Supplements ◽  
Wool Growth ◽  
Average Intake ◽  
Staple Strength ◽  
Fleece Weight ◽  
Mineral Lick

Young Merino sheep (7-8 months of age, weighing about 40.5 kg) were given weekly supplements of 1050 gfsheep of lupins, lupins coated with potassium sulfate (25 g/kg lupins), lupins and access to a mineral lick (offered at 175 g/sheep.week), or lupins coated with potassium sulfate and access to the lick. The sheep grazed an annual pasture at a stocking rate of 15 sheepha and were given the supplements between 14 December and 5 April. The amount of pasture on offer in mid December exceeded 3000 kg DMha but declined to 1500 kg DMha in late March.There were significant amounts of green feed present in December and March (>20% of pasture DM), a small amount in January, and no green feed in February. Despite this the percentage of sheep licking the minerals was over 70% in January , February; and March, with average intake being about 10 g/sheep.day. No significant differences occurred between treatments for liveweights of sheep during the feeding period or at shearing. Over the feeding period sheep lost weight at about 30 g/day. Neither the additional sulfur nor the mineral lick had any significant effects on fleece weight, mean fibre diameter of the fleece, staple length, or staple strength. Wool growth rates were not different between treatments during the feeding period. These results indicate that under good pasture conditions with some green feed available, and when lupins are supplied, responses to mineral supplements are unlikely.

Protein metabolism in skin and muscle of sheep selected for or against staple strength

2000 ◽  
Vol 51 (5) ◽  
pp. 541 ◽  
Author(s):  
N. R. Adams ◽  
S. M. Liu ◽  
J. R. Briegel ◽  
J. C. Greeff
Keyword(s):  
Growth Rate ◽  
Protein Synthesis ◽  
Synthesis Rate ◽  
Deuterated Water ◽  
Feeding Level ◽  
Fractional Rate ◽  
Wool Growth ◽  
Fractional Synthesis ◽  
Selection For ◽  
Staple Strength

Two experiments were carried out to determine the mechanisms underlying the reduced effect of nutritional status on wool growth rate in Merino sheep that have been selected for high staple strength (SS). In Expt 1, each group of 6 young sheep of SS+ and SS– genotypes were fed at 0.4 or 1.1 times maintenance, and in Expt 2, groups of 8 sheep of each genotype were fed at 1.1 and 1.8 times maintenance. In both experiments, rates of protein synthesis in skin, muscle, gut, rumen, and liver were determined using a flooding dose of labelled phenylalanine. Feed intake and the digestibility of feed were not affected by genotype. Neither dissection of the carcasses at slaughter, nor deuterated water analysis in Expt 1, detected any differences between the genotypes in body composition. The feeding level affected the total daily amount of protein synthesised in all the organs examined, and the fractional rate of protein synthesis was affected by feeding level in all organs except the liver. The fractional synthesis rate of protein was less responsive to feeding level in the SS+ sheep in both skin and muscle (P < 0.05), but not in the liver, jejunum, or rumen. Total protein synthesis in muscle, and the estimated rate of protein degradation, were also less responsive to feeding level in the SS+ sheep (P < 0.05). We conclude that sheep genetically selected for high or low SS have altered local mechanisms in both skin and muscle that control the way they respond to nutrition. These findings provide a mechanism by which selection for wool growth rate also affects body metabolism.

Effects of shearing time and time of lambing on wool growth and processing characteristics

1984 ◽  
Vol 24 (126) ◽  
pp. 337 ◽  
Author(s):  
GW Arnold ◽  
AJ Charlick ◽  
JR Eley
Keyword(s):  
Growth Rate ◽  
Seasonal Pattern ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Lower Percentage ◽  
Dominant Factor ◽  
Lower Yield ◽  
Merino Sheep ◽  
Wool Growth ◽  
Fleece Weight

Wool growth rate, seasonal pattern of fibre diameter, clean fleece weight, quality and the processing characteristics of wool were measured on medium-wool Merino sheep shorn in March (autumn) or October (spring) coupled with March or June lambing. These four management systems were compared under two nutritional regimes in the medium rainfall area of Western Australia. The sheep grazed annual pastures only, or had lupin grain and stubble during summer in addition to the pasture. The study ran for two shearing periods. Time of shearing was the dominant factor. Sheep shorn in March produced 14% more clean wool and fewer tender fleeces than sheep shorn in October. The autumn wool had a lower yield, higher fibre diameter and when processed had a higher card loss, lower percentage noil and lower top and noil yield. However, mean fibre length in the top was substantially higher and the variation in fibre length lower. Vegetable matter was higher in autumn shorn wools. There were some interacting effects of lambing time and type of feed regime. Sheep fed lupins had lower yielding wool but this effect was more pronounced in June lambings and was reflected in differences in top and noil yield. From measurements of wool growth rate, it was found that the extra wool was produced in autumn after shearing, due possibly to stimulated appetite that cannot occur after spring shearing because the sheep are too fat.

Strip grazing to control wool growth rate of sheep grazing green annual pastures

1999 ◽  
Vol 39 (3) ◽  
pp. 247 ◽  
Author(s):  
J. Young ◽  
P. T. Doyle ◽  
P. Booth
Keyword(s):  
Growth Rate ◽  
Production Systems ◽  
Fibre Diameter ◽  
Matter Content ◽  
Stocking Rate ◽  
Merino Sheep ◽  
Wool Growth ◽  
Staple Strength ◽  
Sheep Production ◽  
Strip Grazing

We compared strip grazing (SG) as a means of controlling wool growth rate, reducing variation in fibre diameter along the staple, and of carrying more Merino sheep through winter on green annual pastures, with set stocking (SS) in 3 experiments. In experiments 1 and 2, SG involved grazing to a residual feed on offer (FOO) of 400 kg DM/ha with an estimated intake of about 0.8 kg DM/day for each sheep. Treatments commenced after pasture establishment in autumn–winter, with both treatments stocked at 20 wethers/ha until late spring. During spring, average liveweight changes were lower (P<0.01) under SG than SS (55 v. 153 g/day experiment 1; –16 v. 217 g/day experiment 2). Strip grazing, compared with SS, reduced (P<0.01) the variation in wool growth rate and fibre diameter along the staple leading to lower (P<0.01) clean wool weights (3.54 v. 3.94 and 2.97 v. 4.12 kg), but finer (P<0.01) (20.9 v. 22.0 and 19.5 v. 21.5 mm), stronger (P<0.01) (28.6 v. 25.3 and 39.9 v. 35.5 N/ktex) wool. However, there was also an increase in vegetable matter content of the wool. The effects on annual pastures were to increase grass (79 v. 48 and 59 v. 25%) and reduce legume (12 v. 36 and 22 v. 54%) content at the end of spring. In experiment 3, two strip grazing treatments were used: SGl with a residual FOO of about 400 kg DM/ha and a stocking rate of 28 wethers/ha; and SGh with a residual FOO of about 800 kg DM/ha and stocking rate of 14 wethers/ha. The stocking rate for SS was 12 wethers/ha. SGl, following an autumn deferment, enabled a stocking rate of 28 wethers/ha to be sustained through winter without supplementary feeding. This is substantially higher than the district average stocking rate of about 7 sheep/ha. Strip grazing reduced (P<0.01) liveweights at the completion of treatments (SGl 41.9 v. SGh 47.9 v. SS 60.3 kg), reduced (P<0.01) clean wool weights (3.40 v. 3.72 v. 4.54 kg) and mean fibre diameter (19.1 v. 19.0 v. 20.9 m), but increased staple strength (21.3 v. 19.0 v. 16.9 N/ktex). These results are discussed in relation to opportunities to utilise strip grazing in sheep production systems on annual pastures in south-western Australia.

Effects of differential grazing of annual pastures in spring and age of sheep on pasture and sheep production

1997 ◽  
Vol 37 (7) ◽  
pp. 727 ◽  
Author(s):  
A. N. Thompson ◽  
M. W. Hyder ◽  
P. T. Doyle
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Fibre Diameter ◽  
Wool Growth ◽  
Period 2 ◽  
Significant Difference ◽  
Condition Score ◽  
Staple Strength ◽  
Sheep Production ◽  
Curvilinear Relationships

Summary. The effects of controlled grazing through spring on the production of young (age 1 year; liveweight 38.3 ± 0.09 kg; condition score 3.0 ± 0.03) and mature (age 3 years; liveweight 61.9 ± 0.36 kg; condition score 3.1 ± 0.04) Merino wethers was examined. The grazing treatments involved adjusting sheep numbers to maintain green feed on offer near target amounts of 800, 1200, 1600, 2000, 2400 and 2800 kg dry matter/ha. Liveweight and wool growth measurements were made on 8 sheep per plot, with additional animals added or removed as necessary to maintain pasture near the target feed on offer. Changes in wool-free liveweight were linear between days 0 and 42 (period 1), and days 42 and 111 (period 2) for both classes of sheep grazing low feed on offer treatments. Hoggets lost less liveweight than mature animals while grazing low feed on offer during period 1 and gained liveweight faster (P<0.05) than mature animals for any feed on offer during period 2. Curvilinear relationships existed between feed on offer and clean wool growth rate and fibre diameter, with feed on offer accounting for 65 and 81% of the variations in wool growth rate, and 65 and 73% of the variations in fibre diameter, for hogget and mature sheep respectively. There was no significant difference in wool growth rate between animal classes. Annual clean wool production, fibre diameter and staple length increased linearly (P<0.05) with increasing feed on offer. Staple strength was higher (P<0.05) in mature sheep compared with hoggets, but was greater than 30 N/ktex for both classes of sheep irrespective of feed on offer. These results indicate that intensive grazing in spring to predetermined feed on offer is a useful tactic for manipulation of wool growth and fibre diameter, but factors other than feed on offer also contribute to liveweight change and wool growth.

Efficiency of conversion of food to wool in selected and unselected Merino types

1972 ◽  
Vol 23 (1) ◽  
pp. 117 ◽  
Author(s):  
DG Saville ◽  
GE Robards
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Surface Area ◽  
Fibre Diameter ◽  
Response To Selection ◽  
Gross Efficiency ◽  
Wool Growth ◽  
Selection For ◽  
Fleece Weight ◽  
Growth Differences

Comparisons were made between Collinsville, Bungaree, and Peppin Merino ewes in efficiency of conversion of food to wool. The effect of selection for some characters on efficiency of conversion within the Peppin Merino was also investigated. The Collinsville ewes grew 14% more wool and had an 8% lower food intake at maintenance than did the Peppins. Differences in wool growth between the Peppin and Collinsville types fed ad lib. were mainly due to efficiency and body weight differences. Efficiency, intake, and body weight each had a similar influence on wool growth differences between Peppins and Bungarees. Peppin ewes selected for wool production, either alone or together with crimp frequency, had a higher gross efficiency than unselected sheep fed below maintenance (13 and 8%) or ad lib. (14 and 13%). The efficiency difference between selected and unselected sheep increased, then decreased, with increasing intake. The decrease in efficiency differences at higher intakes did not appear to influence the ranking of selected or unselected sheep. The response to selection for clean fleece weight was shown to develop a plateau after about one generation of selection. Selection had resulted in the elimination of a relationship between efficiency and wool growth. The present results indicate that further progress in fleece weight is unlikely to be made either by selecting for fleece weight with some control on fibre diameter or by selecting for increased surface area.

Selection for ultrafine Merino sheep in New Zealand: heritability, phenotypic and genetic correlations of live weight, fleece weight and wool characteristics in yearlings

2001 ◽  
Vol 72 (2) ◽  
pp. 241-250 ◽  
Author(s):  
T. Wuliji ◽  
K. G. Dodds ◽  
J. T. J. Land ◽  
R. N. Andrews ◽  
P. R. Turner
Keyword(s):  
New Zealand ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Live Weight ◽  
Production Traits ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Staple Strength ◽  
Fleece Weight ◽  
Staple Length

AbstractMerino yearling records from 1988 to 1992 birth years in ultrafine wool selection and random control flocks at Tara Hills High Country Station, New Zealand were analysed for live weight, fleece weight and wool characteristics. Estimates of heritability, genetic and phenotypic correlations among traits using REML methods are presented. Heritabilities (h2) of birth, weaning, autumn, spring and summer live weights and greasy and clean fleece weights were estimated as being 0·35, 0·34, 0·44, 0·43, 0·49, 0·24 and 0·28 respectively; while h2 of yield, fibre diameter, coefficient of variation in fibre diameter, staple crimp, staple length, staple strength, position of break, resistance to compression, bulk, CIE Y and CIE Y-Z were estimated to be 0·58, 0·59, 0·60, 0·45, 0·71, 0·13, 0·18, 0·46, 0·38, 0·38 and 0·42 respectively. Genetic correlations were found to be high among the live weights but low to moderate among fleece weight and wool characteristics. Heritability estimates of fibre diameter, fibre diameter variation and staple length were found to be higher in New Zealand fine wool Merinos than most of those reported in the literature. The results indicate that selection for reduced fibre diameter will have little effect on other major production traits such as live weight and fleece weight.

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