Medullated fibres and fleece characteristics in Corriedale hoggets from two flocks in Uruguay

2011 ◽  
Vol 51 (11) ◽  
pp. 1034 ◽  
Author(s):  
I. Sienra ◽  
K. Neimaur ◽  
R. Kremer ◽  
J. I. Urioste
Keyword(s):  
Genetic Variation ◽  
Fibre Diameter ◽  
High Variability ◽  
Fibre Content ◽  
Strongly Correlated ◽  
Veterinary Science ◽  
Wool Sample ◽  
Staple Strength ◽  
Wool Yield ◽  
Fleece Weight

The incidence of medullation in 549 Corriedale hoggets from two experimental flocks, its association with other characteristics of the fleece, and the sire effect were evaluated. The investigation was carried out during 2005–06 in hoggets from the Faculty of Agriculture and Faculty of Veterinary Science experimental flocks. Fleeces were weighed and samples were taken at shearing by picking 104 staples from fleeces to measure medullation. A mid-side wool sample was taken to determine wool characteristics (fleece weight, wool yield, mean fibre diameter, staple strength and length). A Dark Fibre Detector was used to identify total medullated fibres and fibre type: medullated fibres (med) and kemp, which were confirmed by light microscope. Mean total medullated fibres, med and kemp content per 10 g of clean wool were 4.2 ± 11.2; 2.0 ± 8.9 and 2.3 ± 4.9, and median values were 0.9, 0.0 and 0.7, respectively, in 549 fleeces. A high variability between samples and a higher proportion of hoggets with kemp fibres than those with med were observed. There were significant differences between sire families for total medullated fibre content/10 g, med fibre content/10 g and kemp fibre content/10 g, but there were no significant effects between flocks, years or interaction between them. Phenotypic correlations between medullated fibre content and wool characteristics were generally low (less than 0.19). In conclusion, medullated fibre content was highly variable between samples and was not strongly correlated with other fleece characteristics. Medullation varied between sire groups, suggesting genetic variation, which could be exploited to improve wool quality.

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.

Staple strength of fine, medium and strong wool Merino wethers under drought conditions

2006 ◽  
Vol 46 (9) ◽  
pp. 1123
Author(s):  
M. A. Friend ◽  
G. E. Robards
Keyword(s):  
Coefficient Of Variation ◽  
Management Strategies ◽  
Fibre Diameter ◽  
Summer Rainfall ◽  
Arid Environment ◽  
Strongly Correlated ◽  
Rainfall Events ◽  
Treatment Groups ◽  
Effect Of Treatment ◽  
Staple Strength

Fine, medium and strong wool Merino wethers (n = 72, 4 years old) were grazed together on drought-affected pastures in a semi-arid environment. In order to examine the hypothesis that restricting liveweight gains at the break of drought would improve staple strength, sheep were allocated to restricted grazing in a 5-ha paddock (drought group), or unrestricted grazing in a 20-ha paddock (drought-break group) when it was judged that the drought had broken in the region. Wool staples from all sheep broke at a point coinciding with summer rainfall events before allocation to treatment groups, and staple strength did not differ between treatments. Medium wool sheep (22.0 ± 1.6 N/ktex) produced wool of lower (P<0.001) staple strength than fine (30.0 ± 1.6 N/ktex) or strong (30.2 ± 1.6 N/ktex) wool sheep. Restricting the measurement of staple strength to the period when treatments were applied revealed no effect of treatment on staple strength, despite the fact that wethers in the drought-break group experienced a greater (P<0.001) liveweight gain (6.62 ± 0.37 kg) after allocation to their treatment than those in the drought group (–3.24 ± 0.37 kg). Staple strength was most strongly correlated with coefficient of variation of fibre diameter (r = –0.65; P<0.001); a result that was observed for all strains and treatment groups. The results indicate that coefficient of variation of fibre diameter is correlated with staple strength regardless of strain, and that management strategies designed to limit fibre diameter variability during a drought need to be applied not only at the break of a drought.

Studies on Western Australian Merino sheep. 1. Stud, strain and environmental effects on hogget performance

1992 ◽  
Vol 43 (6) ◽  
pp. 1381 ◽  
Author(s):  
RP Lewer ◽  
RR Woolaston ◽  
RR Howe
Keyword(s):  
Fibre Diameter ◽  
Strain Differences ◽  
Average Fibre Diameter ◽  
Weaning Age ◽  
Average Fibre ◽  
Males And Females ◽  
Wool Yield ◽  
Fleece Weight ◽  
Western Australian ◽  
Australian Merino

A 6 year study is reported of Merino studs and strains (Peppin, Collinsville and Bungaree) in Western Australia. Wool and body traits of males and females were measured, with additional subjective traits assessed on females. The effects of strain, stud (within strain), birth year, dam age, birth rearing rank, weaning age and their interactions were estimated using least squares procedures. When tested against studs, strain differences were significant for fibre diameter (both sexes), clean wool yield and about half of the subjective traits (females) but for none of the liveweights. Stud and year effects were significant for all traits, as was their interaction for most traits. Some studs were more stable between years than others in both clean fleece weight and average fibre diameter. Of the remaining effects, birth rearing rank influenced the greatest number of traits, while dam age only affected yield in ewes and some early liveweights. Peppins produced wool 2.0-2.3 microns finer than Bungarees, but not significantly different from Collinsvilles. Peppins also had the best subjective wool scores, but had the highest wrinkle scores and scored poorly on other subjective body traits. Twin-born hoggets produced 0.05-0.15 kg less clean wool than their single-born contemporaries, and their fleeces were about 0.4 microns coarser with poorer subjective qualities. Twins were also lighter from birth (by 23%) up to 17 months (by 5%) in females. Late-born lambs had higher birth weights, but lower subsequent weights, persisting until 12 months in females.

Increasing lamb output by crossing commercial Merino ewes with South African Meat Merino rams

2000 ◽  
Vol 40 (1) ◽  
pp. 11 ◽  
Author(s):  
S. W. P. Cloete ◽  
A. Durand
Keyword(s):  
Survival Rate ◽  
South African ◽  
Coefficient Of Variation ◽  
Fibre Diameter ◽  
Combined Effect ◽  
Weaning Weight ◽  
Slaughter Weight ◽  
Ram Lambs ◽  
Staple Strength ◽  
Fleece Weight

Commercial Merino ewes were randomly allocated to 1 of 2 groups, which were joined either to commercial Merino or South African Meat Merino rams during October 1996 and 1997. Merino rams were involved in 161 joinings, and South African Meat Merino rams in 157 joinings. The proportions of ewes that lambed were independent of the breed of the sire when expressed relative to the number of ewes joined (0.809 and 0.801 in ewes joined to South African Meat Merino and Merino rams, respectively). The proportion of multiple lambs was similarly not affected by the breed of the service sire. Lambs sired by South African Meat Merino rams were on average ( s.e.) heavier (4.17 0.07 v. 3.86 0.07 kg; P<0.01) at birth. They also tended to have a better (0.69 v. 0.59; P<0.10) survival to weaning, and were heavier (26.9 0.6 v. 22.8 0.6 kg; P<0.01) at weaning than purebred Merino contemporaries. The combined effect of the tendency towards an improved survival rate as well as the increased lamb weaning weight resulted in a 36% increase (P<0.01) in lamb output in Merino ewes joined to South African Meat Merino ewes compared with ewes joined to Merino rams. Higher (P<0.01) proportions of ram lambs sired by South African Meat Merino rams reached slaughter weight (about 40 kg) before the onset of the dry Mediterranean summer than purebred Merinos. Two-tooth ewes sired by South African Meat Merino rams were heavier (P<0.01) at 2-tooth age (53.0 0.6 v. 52.0 0.6 kg) than purebred Merinos. The 2-tooth greasy fleece weight of South African Meat Merino sired 2-tooth ewes were lower (3.85 0.08 v. 4.66 0.09 kg; P<0.01), with a lower (66.8 0.6 v. 70.5 0.7 %; P<0.01) clean yield than that of purebred Merinos. This resulted in a marked difference in clean fleece weight between the 2 types (2.56 0.06 v. 3.28 0.06 kg, respectively). Wool produced by South African Meat Merino sired 2-tooth ewes was generally broader (21.8 0.3 v. 20.3 0.3 m; P<0.01) and shorter (87.3 1.3 v. 96.4 1.4 mm; P<0.01) than that of their purebred Merino contemporaries. The coefficient of variation of fibre diameter as well as staple strength was independent of the breed of the sire. Liveweight of adult ewes and wool traits were independent of the breed of the service sire.

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.

Fleece rot and body strike in Merino sheep. IV. Experimental evaluation of traits related to greasy wool colour for indirect selection against fleece rot

1990 ◽  
Vol 41 (1) ◽  
pp. 139 ◽  
Author(s):  
HW Raadsma ◽  
BR Wilkinson
Keyword(s):  
Fibre Diameter ◽  
Selection Criterion ◽  
Indirect Selection ◽  
Objective Measurement ◽  
Genetic Potential ◽  
Wool Yield ◽  
Fleece Weight ◽  
Colour Development ◽  
The Cost

The potential for using indicators of greasy wool colour as indirect criteria for selection of sheep genetically resistant to fleece rot and body strike was examined. Nine traits based on the subjective grading of wool samples (1 trait), objective reflectance (6 traits) and colour development during incubation (2 traits) were evaluated for their genetic potential, ease and reliability of measurement, and relationship with other major production characteristics. The colour of wool was assessed in 949 Merino ewe hoggets representing the progeny of 134 sires before the induction of fleece rot. All colour traits were moderately heritable, ranging from 0.25 � 0.13 for subjective colour score to 0.40 � 0.14 (h2�.s.e.) for an objective reflectance index. Based on the combined estimate of the heritability of the indicator trait and its genetic correlation with fleece rot, indices based on the objective measurement of colour reflectance and colour development following incubation showed the highest genetic potential for indirect selection. Objective measurement of colour reflectance also showed a high genetic potential for indirect selection against body strike. Subjective colour assessment prior to the induction of fleece rot showed the lowest potential for indirect selection against both fleece rot and body strike. The cost of objective measurement of colour was less than that of colour development during incubation, and the former was found to be the most reliable indirect selection criterion in this experiment. A consequence of selecting solely for decreased greasy wool colour on other production characters is likely to result in decreased fibre diameter, increased wool yield, with a potentially small decrease in greasy fleece weight. Further evaluation of colour indicators as additional selection criteria should first focus on the likely role of fleece rot and body strike resistance as part of (national) breeding objectives. Only then can the full impact of using colour variables on the overall breeding aggregate be established.

Wool yield and characteristics of Dorset, Leicester and Sunffolk breeds and their ‘DLS’ cross

1977 ◽  
Vol 88 (3) ◽  
pp. 651-653 ◽  
Author(s):  
M. H. Fahmy ◽  
J. A. Vasely
Keyword(s):  
First Generation ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Wool Production ◽  
Average Fibre Diameter ◽  
Average Fibre ◽  
Wool Yield ◽  
Fleece Weight

SUMMARYGreasy fleece weight (12 months growth) and wool samples from hip and shoulder regions were taken on 15 Dorset, 20 Leicester, 20 Suffolk and 17 DLS ewes (a cross of ½ Dorset, ¼ Leicester, ¼ Suffolk obtained by mating DL rams to DS ewes and DS rams to DL ewes). The purpose of the study was to compare wool production and characteristics of the first generation of DLS with that of the three breeds of origin. Wool production of DLS was 3·58 kg, 8·8 and 14% higher than that of Suffolk and Dorset, but 11% lower than that of Leicester (P< 0·01). The percentage of clean wool was highest in Leicester (78·3%), followed by DLS, Dorset and Suffolk (76·1, 74·3 and 70·5%, respectively). The average fibre diameter of the DLS and Leicester was 38 /m, 4 /m thicker than that for Suffolk and Dorset (P < 0·01). Average fibre length was 15 cm in DLS and Dorset, 6 cm shorter than in Leicester, and 3 cm longer than in Suffolk (P < 0·01). The variability in fibre diameter and length was highest in Leicester, followed closely by DLS.

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.

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.

Predicted responses in Merino sheep from selection combining visually assessed and measured traits

2010 ◽  
Vol 50 (10) ◽  
pp. 976 ◽  
Author(s):  
S. I. Mortimer ◽  
K. D. Atkins ◽  
S. J. Semple ◽  
N. M. Fogarty
Keyword(s):  
Fibre Diameter ◽  
Selection Combining ◽  
Breeding Programs ◽  
Dual Purpose ◽  
Merino Sheep ◽  
Merino Wool ◽  
Wool Quality ◽  
Staple Strength ◽  
Fleece Weight ◽  
Australian Merino

Visually assessed traits for wool quality and ease of management are important to Merino sheep breeders and need to be considered in breeding programs. The present study reports on the predicted correlated responses in visual traits from selection using a range of standard MERINOSELECT™ indices available for use in Australian Merino breeding programs. The effect of including a visual trait in the index is also reported. The visual scored traits were classer grade, wool quality (handle, character and colour), conformation (neck and body wrinkle, front and back leg structure) and fleece rot. The indices covered a range of micron premiums of varying emphasis on increasing fleece weight and reducing fibre diameter. The indices were for Merino wool enterprises (Merino 14%, Merino 7% and Merino 3.5%) and Merino dual purpose wool and meat enterprises (Dual Purpose 7% and Dual Purpose 3.5%). The breeding objectives for the indices included fleece weight, fibre diameter, coefficient of variation of fibre diameter, staple strength, bodyweight and reproduction. Selection over 10 years using the standard MERINOSELECT™ indices is predicted to result in a small correlated improvement in the wool quality traits and classer grade, with a slight deterioration in fleece rot score. The improvement in wool handle, character and colour are greater with those indices that have a greater emphasis on reducing fibre diameter than with those increasing fleece weight. Indices with more emphasis on increased fleece weight than on reduced fibre diameter are predicted to result in small increases in neck and body wrinkle scores and a slight deterioration in wool colour. Inclusion of classer grade, handle, character or colour provided slight extra gains in fleece weight for indices that emphasised reduced fibre diameter through increased accuracy of selection.

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