Kemp Fibres Research Articles

Effect of Blending Ratio and Sewing Characteristics on Performance Properties for Barki Wool/Polyester Fabrics

ABSTRACT The coarse wool breeds have a very small share in the clothing market due to the difficulty of their weaving and sewing. Herein, we propose a new method for utilization of coarse wool fibers (Barki), after grading and sorting according to handle, fineness, and kemp content to separate the class of fine fleeces and patches with no kemp fibers. Barki wool fibers were then blended with woolen polyester fibers to produce 30:70% and 45:55% wool/polyester woven fabric. The properties of the produced fabrics from Barki wool/polyester yarns were compared with those of Merino wool/polyester fabric 45:55%. The effects of wool type, nature of sewing threads, stitch type, and the number of stitches per centimeter, on the seam slippage as well as other inherent properties of the fabrics, were studied. The results indicate that a fine soft grade of Barki wool could be used in apparel, and the least seam slippage was obtained upon using fabric and stitch from the same type of yarns using 5 stitches/cm. As the ratio of polyester fibers in the blended fabric increases, the seam slippage as well as, crease recovery, and tear strength get better except that for pilling resistance and drapeability.

The effects of nutrition and parity on the development and productivity of Angora goats: 2. Effects of six combinations of mid pregnancy and postnatal nutrition on energy intake and doe live weight, body condition and mohair production

There is little research on the nutrient requirements and the effects of nutrient manipulation on the productivity of lactating Angora does. The study design investigated the combined effects of 3 levels of mid pregnancy nutrition (MPN)×2 levels of postnatal nutrition during lactation (PNN) with both single and twin bearing does, providing 6 nutrition patterns. Following artificial insemination and pregnancy scanning, does were fed pelleted rations in individual pens in an outdoor feedlot from day 47 of pregnancy until 13 weeks following kidding. MPN treatments commenced from day 47 as follows: Control (C), fed to lose live weight (–67g/day); Maintenance (M), does fed to maintain live weight; Supplemented (S), does fed to gain live weight at 102g/day. From days 105 of pregnancy until 4days postpartum the feeding level was ad libitum for all treatments. From 4days postpartum PNN treatments were: ad libitum (AL) to allow maximum ME intake; Restricted (R) to 70% of AL. This report is concerned with the responses from kidding to weaning for energy intake, live weight, body condition score (BSC) and mohair production. In AL treatments, maximum ME intake was reached during weeks 5–10 of lactation as follows: twin rearing does 3.88×maintenance; single rearing does 3.25×maintenance. No interaction occurred between MPN and PNN in affecting doe live weight. PNN significantly affected doe live weight from week 2 until weaning with AL does gaining 97g/day from kidding to week 5 and thereafter 28g/day. R fed does lost 40g/day from kidding to week 10 and thereafter gained 38g/day. By week 4 of lactation twin rearing does were 4kg lighter than single rearing does. The change in BCS from just prior to kidding to day 90 of lactation was affected by an interaction between MPN and PNN. BSC of does fed M-R and S-R declined to a greater extent than does fed C-R, while the BCS for C-AL and M-AL increased to that of S-AL, which had remained constant at a high BCS. By day 21 of lactation the effects of PNN were significant, with AL does having significantly higher BCS than R does and the differences increased as lactation progressed. The BCS of single rearing does fed AL increased progressively, while the BCS of all other does declined. By the end of lactation, R does had significantly lower BCS than twin rearing does fed AL, which in turn had a significantly lower BCS compared with single rearing AL fed does. Significant interactions between MPN and PNN affected mohair growth, clean washing yield, mohair fibre diameter, incidence of medullated non kemp fibres and staple length. For fleece weight, S-AL and M-AL had heavier greasy and clean fleece weight compared with S-R and M-R with the other treatments intermediate. Similarly, the mean fibre diameter of S-AL was 2.4μm coarser than that of M-R, with other treatments being intermediate. For both greasy and clean fleece weight, twin rearing does produced 14% less mohair than single rearing does. For R fed twin rearing does, the mohair had greater fibre diameter variability compared with other does. Overall, PNN had a greater number of and larger effects on measured parameters than MPN. Restricting nutrition in lactation was shown to depress doe live weight, BCS and the growth of mohair. Lactating Angora does rapidly changed their live weight and BCS in response to ME provision. To maintain live weight during lactation ME intakes of 3×maintenance were required. Twin rearing does required an additional 0.5×maintenance ME requirement compared with single rearing does. Does can gain live weight and BCS during lactation provided they are fed sufficiently. The preferred nutritional practice should allow maximum ME intake at least until week 6 of lactation.

Genetic parameters of objectionable fibers and of their associations with fleece traits in Corriedale sheep.

The aim of this research was to assess the variability and genetic relationships among binary traits denoting the presence or absence of objectionable fibers, namely pigmented (BINPPF), medullated (BINPMED), and kemp fibers (BINPK), and of fleece traits (fiber diameter [FD] and clean fleece weight [CFW]) in Corriedale sheep. Additionally, the total response to selection against objectionable fibers and indirect responses when selecting for fleece traits were evaluated. Fiber records from 679 animals and fleece records from 795 animals obtained from 2 experimental flocks (from 2005 to 2007) were used; the pedigree file included a total of 3,792 animals. Heritability and genetic correlations among the traits were estimated with a multivariate animal model under a Bayesian setting. Heritability estimates (posterior SD) for BINPPF, BINPMED, and BINPK were 0.35 (0.08), 0.37 (0.10), and 0.63 (0.09), respectively; for CFW and FD, estimates were 0.42 (0.09) and 0.43 (0.08), respectively. The genetic correlations between CFW and the 3 types of objectionable fibers were very low (i.e., <0.2). Thus selection for CFW is not expected to affect the number of such fibers in any direction. The same occurred for the genetic correlation between BINPK and FD. Genetic correlations between FD and BINPMED and FD and BINPPF were positive and favorable (0.50 and 0.56, respectively). Selecting for lower FD would decrease the numbers of objectionable fibers. The expected correlated responses in BINPPF, BINPMED, and BINPK when selecting for CFW were -0.03 (0.11), 0.03 (0.11), and -0.05 (0.18), respectively; when selecting for FD, the correlated responses were -0.26 (0.11), -0.26 (0.11), and -0.14 (0.16). Overall, this study reports novel information on genetic parameters for the presence of objectionable fibers and their associations with fleece traits in sheep. Our findings suggest that it could be possible to improve FD while at the same time reducing the content of BINPMED and BINPPF in wool; however, improvements in CFW are likely to have no effect on the numbers of objectionable fibers.

Identification of quantitative trait loci for wool traits in Iranian Baluchi sheep

Regions on 3 ovine chromosomes (OAR1, 5 and 25) were selected to study quantitative trait loci (QTL) segregating for wool traits in Baluchi sheep, an indigenous sheep breed in Iran. Progenies (503) from 13 half-sib families were genotyped for 15 microsatellite markers. The average number of progeny per sire was 38 and ranged between 16 and Wool traits (14) were analyzed and phenotypes were corrected for fixed effects of birth year, sex, flock, litter size and shearing date (year and season). The QTL analyses were performed using regression-based interval mapping. The results revealed 4 QTL on OAR1 for fibre type traits (hetero-type and Kemp fibres type per cent in fleece), coefficient of variation of fibre diameter and greasy fleece weight, one QTL on OAR5 for clean fleece weight and 7 QTL on OAR25 for fibre type traits (Hetro-type, Kemp and True wool fibres per cent), greasy and clean fleece weight, coefficient of variation of average fibre diameter and the per cent of fibre diameter between 40 and 50 µm.

Evaluation certain environment factors on wool characteristics of Arabi sheep breeds

Evaluation and grading of wool based on sex and age can help to improve economic value of wool. This study was conducted to investigate the wool production and fleece characteristics of Arabi sheep in Khuzestan province The right mid-side wool samples were taken from 90 Arabi sheep (1 - 4 years; 16 male and 74 female) by hand shearing. The staple length of shoulder, flank and rump were 13.18 ± 0.27, 13.31 ± 0.22 and 14.27 ± 0.25 cm, respectively. The greasy fleece weight, wool wax, vegetable matter, yield percentage, fiber diameter and its coefficient variation measures were 1.72 ± 0.06 Kg; 2.77% ± 0.12%; 0.54% ± 0.07%; 73.36% ± 0.68%; 30 ± 0.41 μm; 30.23% ± 0.3% respectively. Correspondingly, the medulated fibers, true wool fiber and Kemp fibers were 21.6% ± 1.9%, 76.1% ± 2.04% and 2.5% ± 0.57% respectively. Age and sex had a significant influence on staple lengths. Fleece weight (P < 0.01) and wool wax were (P < 0.05) affected by sex. There was no significant interaction between age and sex groups for fiber characteristics, but it was important for staple between body location (P < 0.05). There were a low considerable kemp and CV of wool diameter percentage on Arabi sheep in comparison with the other Iranian native sheep. The wide variation in fleece weight (0.8 - 3.9 kg); mean staple lengths (8.8 - 19.2 cm); medulated and kemp (0 - 84.04 and 0% - 30.22%); fiber diameter (24.9 - 37.43 μm) suggest potential for improvement of economical traits.

Comparison of four European endangered red sheep based on fleece characteristics

Patterns of wool variations found in modern sheep breeds may shed some light on the history of circum-Mediterranean migrations, which at present are still largely unknown. In this study, the characteristics of wool from five different local European breeds were investigated. Wool samples were taken from the following sheep breeds: Aranese, Roussillon Red, Castillonnais, Levant Red and Majorcan Red. Specimens were collected from 88 animals in different herds for each breed. The following sheep fleece characteristics were investigated: length of long-coarse, short-fine and kemp (medullated) fibres; their proportion within the staple; yield after scouring with isoalcohol; and fibre diameter. The amount of short-fine fibres was lower in the Levant Red and Majorcan Red breeds, with an inversely proportional amount of kemp fibres. Clean yield with isoalcohol was about 80 percent in all these breeds. Fleece characteristics offer a glimpse of possible morphologic relationships between the Levant Red and Majorcan Red that moreover exhibit a similarity in colour and a geographical proximity. Because very little is still known about the nature of the patterns of the fleece of Atlantic West and North African sheep, the importance of the African influence on existing European Mediterranean red sheep breeds remains to be clarified. A plausible hypothesis is that different influences would have left different traces, with a lesser impact on Pyrenean breeds.

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

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.

Chromosomal segments underlying quantitative trait loci for mohair production in Angora goats

SummaryThis study reports the results obtained in the search of chromosomal regions affecting fleece traits in a population of Angora goats in the Argentinean Patagonia. Six hundred thirty-four offspring from 14 parental half-sib families were used. Nine phenotypic fleece traits were recorded at 4 and 11 months of age. A genome examination using 85 informative molecular markers was conducted. A linkage analysis was performed using a regression interval analysis. Our study identified 10 genomic regions affecting the average fibre diameter, coefficient of variation of the average fibre diameter, percentage of fibres with diameters over 30 µm, greasy fleece weight, staple length, average curvature of fibres, percentage of continuous medullated fibres and percentage of kemp fibres located on five goat chromosomes (1, 2, 5, 13 and 19). These results show that the average size of the quantitative trait loci effect was 1.6 phenotypic standard deviations for different traits and families. The aims of quantitative trait loci detection is the potential use of these molecular markers to increase accuracy in predicting the genetic merit of breeding and its implementation in animal breeding schemes through marker-assisted selection.

Assessment of contamination of wool by dark and medullated fibres using near infrared spectroscopy

Increased crossbreeding of Merino sheep in Australia, involving coloured or highly medullated sire breeds, has increased the risk of dark and highly medullated fibres in wool lots. Commercial implementation of the Dark and Medullated Fibre Risk Scheme, based on producer information, is identifying to buyers some of these risks and technology is sought to provide an inexpensive method for routine presale testing of greasy wool lots. One measurement concept assessed the ability of near infrared spectroscopy (NIRS) to predict variation in levels of pigmented fibres or highly medullated fibres in wool. The project used either ‘seeded’ wool samples or naturally contaminated samples with measured reference values as well as different methods of sample preparation of wool fibre (in air or immersed in benzyl alcohol) or the solutions from alkali hydrolysis of wool fibre and NIRS measurement (reflectance v. transmission). NIRS can predict variation in trace levels of pigmented fibre or highly medullated white fibres (kemp) in wool and, among the methods assessed, reflectance analysis of wool fibre in air was generally better than the other options considered. Calibration models for NIRS reflectance measurement of 5 g wool samples ‘seeded’ with 1–50 black-pigmented, tan-pigmented or white kemp fibres gave coefficients of determination (R2) of 0.96, 0.88 and 0.82 with standard errors of cross-validation (SECV) of 4.34, 6.97 and 7.17 fibres per 5 g sample, respectively. However, these calibration equations generally did not predict variations in the reference values for 3 other sets of naturally contaminated samples. New calibration equations determined for each of the sets of naturally contaminated samples also predicted variation in the pigmented fibre reference values, with the extent of agreement depending on the accuracy of the reference data as well as sample preparation and method of measurement. Calibration models for NIRS reflectance measurement of wool fibre from the 3 sets of naturally contaminated samples produced R2 = 0.99, 0.71 and 0.92 with SECV = 0.923, 6.43 and 4.54 pigmented fibres per 5 g sample, respectively. However, these calibrations and those obtained from various combinations of the wool sets also had limited ability to predict variation in pigmented fibre reference values in other independent or excluded samples. Refinement of the technique and development of calibrations with extensive and reliable reference data, representing all of the wool variation likely to be encountered, may allow this NIRS potential to become relevant in the presale testing of wool as an inexpensive measurement procedure for estimating dark and medullated fibre content.

A STUDY ON FLEECE CHARACTERIZATION OF HAMADANI SHEEP IN ERBIL PLAIN

This study was undertaken on 196 Hamadani sheep (179 ewes & 17 rams) to characterize the fleece quantitatively and qualitatively and to determine the effect of flock ( 1 – 4 ), ewe age (1.5 to ≥ 5.5 years) and ewe status (barren, rearing single and twin lambs) on the studied traits besides the relationships among these traits. The results indicated that the overall means were: body weight 59.4 kg, greasy fleece weight 2.3 kg, staple length 11.9 cm, fiber length 18.3 cm, fiber diameter 37.2 μm, crimps 0.65 crimps/cm, medullated fibers 3.4 %, hairy fibers 59.4 %, fine fibers 36.7 %, heterotype fibers 1.1 % and kemp fibers 2.8 %. Furthermore, it was noticed that the grease content in greasy and scoured wool were 1.73 and 0.86 % respectively. Statistical analysis revealed a significant effect of flock on body weight, greasy fleece weight, staple length, fiber length, fiber diameter, crimps, medullated fibers, heterotype fibers and kemp fibers whereas, age of ewe affected only greasy fleece weight, staple length, fiber length and fiber diameter significantly.Non of the studied traits were affected significantly by ewe status.

A genetic analysis of wool characteristics and lamb performance traits in Scottish Blackface sheep

AbstractGenetic parameters were estimated for wool quality, fleece characteristics and lamb production traits for Scottish Blackface sheep reared under extensive hill conditions in the UK. In two separate studies, heritabilities and genetic correlations were estimated for wool quality traits measured on lambs at 5 months of age and again on the shorn fleece a year later. The wool traits included birth coat length (BCT), 10-point scores for proportion of grey and kemp fibres present in the fleece (grey, kemp), British Wool Marketing Board (BWMB) recommendation (REC), greasy fleece weight (FLWT), BWMB fleece grade (FLGR), and average staple length (ASL). Genetic and phenotypic correlations were estimated between lamb wool traits and lamb live weights at birth (BWT), marking (at mid lactation with an average age of 7 weeks) (MWT), weaning (at an average age of 17 weeks) (WWT) and slaughter (SLWT), average fat depth (AVFD) and average muscle depth (MD). Individual lamb carcass measurements included Meat and Livestock Commission (MLC) conformation score (CONF) and fat class (FATC). Heritability estimates measured on 2524 or more live lambs were 0·69, 0·52, 0·26, 0·42 and 0·31 for BCT, ASL, grey, kemp and REC respectively. Heritability estimates for traits measured on the shorn fleece a year later for 1415 ewes were 0·37, 0·02, 0·57, 0·43, 0·46 and 0·14 for ASL, grey, kemp, REC, FLWT and FLGR respectively. Genetic correlations between FLWT in hoggets and other wool were positive and moderate to high in magnitude, ranging from 0·22 for kemp in lambs to 0·48 for grey in hoggets. Genetic correlations between REC and live-weight traits were 0·39 for MWT, 0·37 for WWT and 0·44 for SLWT. Genetic correlation between ASL and ultrasonic fat depth was 0·15 and for ASL and ultrasonic muscle depth was -0·30. The results indicate that the simple scoring systems derived to assess these traits are useful indicators of fleece quality, are highly repeatable over time and are a good gauge of likely future wool production. The results indicate that selection for heavier, leaner lambs should not compromise fleece quality, as assessed in this study.

Variation in fleece characteristics of Awassi sheep at different ages

Fleece characteristics have economic significance in sheep. When assessing fiber characteristics, the importance of sex, age of sheep and the body location of the sample taken are important considerations. Triplicate fleece samples were obtained from the shoulder, right mid-side and hip of 12 male and 17 female lambs (6–10 months), 62 yearling ewes (14–20 months) and 235 mature ewes (28–84 months) by hand shearing. The greasy fleece weight, staple length, fiber length and fiber diameter measures were 2.1±0.03 kg, 14±0.18 cm, 24±0.26 cm and 36±0.33 μm, respectively. Correspondingly, the medullated fibers, inner coat, outer coat and kemp fibers were 11.6±0.33, 59.7±0.29, 34.0±0.23 and 6.3±0.16%, respectively. Age had a significant influence on body weight and greasy fleece weight, but male and females were similar. Body location of the sample had a significant effect on the fiber diameter, and percentages of medullated fibers, kemp fibers, and inner coat fibers. The finest fibers and a lower percentage of medullated fibers were found on the shoulder and mid-side, whereas, the percentage of inner coat fibers was highest on the hip. Although there was no significant interaction between body location and age–sex groups for fiber characteristics, it was important for staple and fiber length ( P<0.05). The wide variation in fiber diameter and percentage of medullated fibers suggest potential for improvement of economical traits.

Prediction of clean mohair, fiber diameter, vegetable matter, and medullated fiber with near-infrared spectroscopy.

Four experiments were conducted in three separate years to test the utility of near-infrared spectroscopy (NIRS) to predict the clean mohair content of Angora goat fleece. Mohair fleece samples were obtained each year from yearling billies at the conclusion of the Angora Goat Performance Test conducted at the Texas A&M University Research Station, Sonora. In Exp. 1 (n = 293) and Exp. 2 (n = 256), fleeces were scanned with a Pacific Scientific (Silver Spring, MD) near-infrared spectrometer fitted with a fiber-optic probe, and calibrations were developed for clean mohair content. In Exp. 3, 59 mohair fleeces collected at the Texas A&M Research Station in San Angelo were sampled four times each. Each sample was scanned with the same spectrometer in reflectance mode fitted with a transport mechanism. This mechanism allowed the instrument to scan a 15-cm2 segment of the fleece sample. Conventional procedures to determine reference values for mohair yield, vegetable matter content, fiber diameter, and percentage of medullated and kemp fibers were conducted. Prediction equations were developed that related NIR spectra to reference values for yield and diameter parameters and were used to predict mohair characteristics for each fleece sample. The predicted and reference values were subjected to a simple analysis of variance to determine variation within and across samples. In Exp. 1, mohair base was related to NIR spectra with R2 = .46 and standard error of calibration (SEC) = 2.84%. In Exp. 2, similar repeatability errors for mohair base could be obtained for both reference- and NIRS-derived values. Fiber diameter and medullated fibers were poorly related to NIR spectra. When samples were scanned using the transport mechanism (Exp. 3), R2 and SEC were .82 and 1.19% for mohair base and .93 and .98 microm for fiber diameter, respectively. The CV for mohair base and diameter were 1.0 and 1.4%, whereas those for predicted mohair base and diameter were 1.4 and 3.4%, respectively. The increased variation within samples for predicted values represents sampling error and lack of fit between NIRS and the laboratory determined values. When the samples from Exp. 1 and 2 were rescanned with the NIRS transport (Exp. 4), R2 and SEC were .79 and 2.03% for mohair base and .52 and 3.49 microm for fiber diameter. The fiber optic probe would facilitate real-time analysis on the shearing floor, but our data indicate that the spectral limitations so far are too severe. A large sample device such as the transport gave excellent results for predicting mohair base and fiber diameter.

Influence of effects on quality traits and relationships between traits of the llama fleece

Differences owing to age, sex and coat color on fleece traits, and relationships between traits, were investigated in fiber samples of llama fleece. Fiber samples were obtained from five fleece regions of 143 llamas: withers; shoulder; ribs; loin-rump and thigh. The fleece composition was heterogenous and consisted of different proportions of unmedullated (20.2%), fragmented med (36.7%), continuous med (39.4%), and kemp (3.7%) fibers. Average diameter, diameter of coarse fibers, diameter of fine fibers, medullation percentage, average length, undercoat length, guard hair length, clean fleece yields and crimps per 2.54 cm averaged 31.6 μm, 40.8 μm, 25.5 μm, 43.1%, 5.01 cm, 8.34 cm, 6.67 cm, 82.3% and 6.1 crimps, respectively. Age was the most important differentiating factor ( P < 0.05) for all traits. Medullation percentage and average diameter significantly increased with the age of the animal. The fleece of two-year-old llamas was the finest, averaging a similar diameter and medullation (25.5 μm and 27.5%) to that of Medium Adult alpaca fiber. Average diameter was significantly associated with medullation percentage ( r = 0.78). It also appeared that the degree of medullation induced important changes in fiber diameter, determining larger diameters as the proportion of medullated fibers increased at a linear change rate of b = 0.195 μm per unit of percentage of medullation ( P < 0.01). Diameters of finer unmedullated and fragmented med fibers were highly correlated to coarse continuous med fibers (0.60 and 0.74, respectively); thus animals having finer undercoats also would tend to have finer guard hairs. Fiber lengths and crimps per 2.54 cm decreased with age ( P < 0.01). Although of a magnitude with no practical implications, differences owing to sex ( P < 0.01) were found on diameter of coarse fibers, undercoat length, medullation percentage, clean fleece yields and crimps per 2.54 cm. The coat color was a factor of differences ( P < 0.01) for medullation percentage. Colored fleeces were less medullated than white fleeces (36 versus 47%, respectively). Relative to the five sampled regions, samples from withers and ribs were more representative because of their better homogeneity (lower variation coefficients) and degree of association with the mean of all sampled regions

Contamination of white wool by melanin-pigmented fibres when pigmented and white sheep graze together.

Various densities of black sheep (0, 2%, 9.5%, 21.4% and 50%) were run with white sheep for a period of 10 weeks. The groups were yarded on average once weekly. The number and lengths of melanin-pigmented wool and kemp fibres were measured in carded wool samples from the white fleeces. All groups containing black sheep produced white wool with higher levels of pigmented fibres (an increase of 8- to 64-fold) than the control group (P&lt; 0.05). The extent of contamination of white wool by pigmented fibres increased with the density of black sheep. Both pigmented wool and pigmented kemp fibres occurred frequently in the contaminated wool samples and the fibres mainly had lengths less than 10 mm. The results provide evidence of the risks involved in the practice of including pigmented sheep in white sheep flocks.

A study of some wool traits in two coarse wool breeds and their reciprocal crosses

SummaryIn a study of two coarse wool breeds (Awassi and Karadi) and their reciprocal crosses, data were obtained on the mean fibre length, mean fibre diameter, fibre type ratio, medullation and on the effect of some environmental factors on these traits. Reciprocal crosses showed intermediate values, in growth rate of fibres, percentages of fibre types and medullation, between those of the parental breeds. Sex exhibited a significant effect at weaning only, on fibre length. Heterosis in fibre length, at the two ages, was small and negative. Maternal influence on fibre length was small and not significant. Fibre length in Karadi sheep showed the highest frequency of bimodal distribution whereas Awassi showed the lowest. Awassi × Karadi was closer to Karadi and Karadi × Awassi had greater affinity to Awassi in the frequency of samples showing bimodal distribution.Reciprocal crosses had larger diameter, at weaning, than those of the parental breeds. At 1 year of age they assumed an intermediate position between the pure bred parents.At weaning, the two reciprocal crosses showed a highly significant heterosis in fibre diameter; its value decreased with advancing age and it showed no significant effect at 1 year of age.Maternal influence on fibre diameter was very small and not significant.Karadi × Awassi and Karadi samples had the highest percentage of samples showing bimodal distribution of fibre diameter.Samples with bimodal distribution of both length and diameter, indicating two coats, had the highest frequency in Karadi followed by Karadi × Awassi; Awassi showed the lowest value.Percentages of fine, coarse and kemp fibres were significantly affected by breed and age of dam. Type of birth showed a significant effect only on percentage of coarse fibres.Karadi wool might be more suitable for carpet manufacturing. It excelled the other groups in the bimodal distribution of both length and diameter as well as in medullation. Cross-breeding increased the bimodality of fibre distribution.

The Structure of, and Growth Cycles in, the Coat of Wild Mouflon Sheep (Ovis musimon) and their Crosses

The double coat of the Mouflon comprised ketnp fibres 50 mm long, and underwool that was shorter than the kemp until the end of the winter. Some Mouflon × Merino sheep had a similar coat, but the wool was always longer than the kemp and denser, the S/P (wool/kemp) follicle ratio being about 12/1 compared with 20/1 in the Merino parent and about 5/1 in the Mouflon parent. Fleece casting took place during June, but the Mouflon × Merino animals shed only their kemp fibres and cast the fleece only from the belly. New growth of kemp was evident as early as March and was most rapid during spring and early summer. The rate of growth then fell until the maximum length was reached in late autumn. Wool was often not evident until late summer and its maximum rate of growth occurred during autumn. The skin showed that there was a basic annual cycle of follicle activity from March to September and inactivity during the winter 6 months. Although not evident in the coat, subsidiary peaks of follicle inactivity occurred at 2 to 4 month intervals throughout the year. These occurred in similar months to those that have been observed in the goat and in other breeds of sheep.

The study of variability in some wool traits in a coarse wool breed of sheep

SummaryWool samples from 47 Barki yearlings were taken from five positions during two years to study the variability in the fleece, the cause of variability and associations between different fleece traits. Statistical analysis has indicated the following significant points.An antero-posterior gradient occurred in the different traits under study. When medullation was discarded, though it was of a low magnitude (3·9%), a reduction of 5·89% in the mean fibre diameter and of 18·33% in its standard deviation occurred.The position most representative of the whole fleece varied with the trait. It is recommended to take three sampling positions forming a triangle, withers, mid-side and hip, to represent the Barki fleece.The animals contributed the major part in the variability of mean fibre diameter (1), the standard deviation of fibre diameter (S.D.1), percentage medullation, mean fibre diameter after discarding the medullated fibres (2), the standard deviation of fibre diameter after discarding the medullated fibres (S.D.2), the contribution of medullation to the total variability, percentage fine fibres and percentage coarse fibres. The positions were the main contributor to the variability of percentage kemp fibres, staple length, medullation index and to a certain extent to that of the kemp score. The year played a significant part in the variability except for 2 and S.D.2.The highest correlations with the standard deviation of fibre diameter were those of percentage medullation and kemp score. These three variables when considered separately accounted for 0·47, 0·35 and 0·31 respectively of the variability in S.D.Equations were obtained to predict the standard deviation from both the mean fibre diameter and the percentage medullation and to predict the mean fibre diameter from the staple length and the kemp score. The coefficient of determination of the first set of equations ranged from 0·47 to 0·56 while that of the second set ranged between 0·07 and 0·51 for different positions.

Preliminary Results on the Elastic Moduli of Wool, Mohair, and Kemp Fibers by Ultrasonic Pulse Techniques

The preliminary difficulties involved in exciting single animal fibers to act as elastic waveguides at 0.5 MHz have been overcome. Propagation constants of the lowest-order vibration modes were used to calculate the respective elastic constants of the fibers.

Comparison of Young's Modulus for Bending and Extension of Single Mohair and Kemp Fibers

The bending and extension moduli of single mohair and kemp fibers have been deter mined and compared. Previous results are not consistent—bending moduli values rang ing from larger-than to smaller-than the values obtained by stretching. Moduli for bending and stretching of mohair were found not to differ significantly, while kemp fibers can be divided into two distinct bending moduli groups, depending, ap parently, on the structure of the medulla. The medulla of these kemp fibers may be solid or hollow (semi-solid), yielding two different results for bending. Stretching moduli for all kemp fibers do not differ significantly and are comparable with the bend ing moduli of hollow fibers only.