Clean Fibre Research Articles

On-farm paddock-scale comparisons across southern Australia confirm that increasing the nutrition of Merino ewes improves their production and the lifetime performance of their progeny

Experiments conducted by Lifetimewool at plot-scale have shown that differences in the maternal liveweight during pregnancy and lactation (liveweight profiles) of individual Merino ewes influences their wool production and reproductive rate as well as the birthweight, survival, weaning weight and lifetime wool production of their lambs in a predictable manner. This study determined whether these impacts of nutrition of the ewe on ewe and progeny performance are measurable on commercial properties across southern Australia at a paddock-scale where ewes were aggregated into flocks with a greater spread of the date of conception and where the liveweight profile of the flocks were managed based on random samples of 100 ewes and liveweight was uncorrected for fleece weight or conceptus. Eighteen paddock-scale experiments at 15 sites were conducted in cooperation with wool producers across Victoria, Western Australia, New South Wales, South Australia, and Tasmania. Each co-operator joined up to 1000 mixed aged adult Merino ewes. The flock was scanned using ultrasound at Day 50 from the start of joining to identify those ewes that conceived during the first 21 days of joining. These ewes were then split at random into two treatments and fed to achieve a target difference in liveweight of 10 kg or ~1 condition score/fat score at lambing. The production of ewes during their year of pregnancy and following their next joining was measured as was the performance of their progeny up to their third shearing. Only the 13 paddock-scale experiments that achieved a difference in liveweight profile at lambing of at least 4 kg were included in the final analysis. In these 13 experiments, increasing the nutrition of Merino ewes during pregnancy clearly increased the clean fleece weight and fibre diameter in ewes and the survival and lifetime wool production of their lambs. In most cases the size of the effect was not significantly different to that predicted by the relationship derived using individual liveweight profiles in the plot-scale experiments. This confirms that managing average ewe liveweight or condition score/fat score profile through better nutrition will lead to predictable increases in the performance of ewes and their progeny performance under commercial conditions and validates the use of the plot-scale relationships in economic analyses.

Managing the nutrition of twin-bearing ewes during pregnancy using Lifetimewool recommendations increases production of twin lambs

The effect on ewe and lamb production by differential management of single- and twin-bearing Merino ewes during pregnancy and lactation was examined. The hypothesis that the survival and productivity of single- and twin-born progeny is not affected by differential management of single- and twin-bearing ewes was tested. To test this hypothesis, two ewe flocks were monitored on a commercial property in the south-east of South Australia. The body condition score of one flock of ewes was managed according to Lifetimewool recommendations for southern Australian (Lifetimewool flock; n = 464). Lifetimewool recommendations are that body condition score should be 3.0 at mating and then allowed to decline to an average of 2.7, which is maintained until lambing. Twin- and single-bearing ewes were managed as separate mobs after pregnancy scanning to meet their energy requirements. The second flock was managed similarly to the commercial ewe flock and was representative of ewe management practices in the region (normal-practice flock; n = 464). At lambing, the condition score of the Lifetimewool flock was 0.7 condition scores units greater than the normal-practice flock. Ewe clean fleece weight and fibre diameter were greater in the Lifetimewool flock and their lambs had higher survival rates to weaning. Over three shearings, progeny from Lifetimewool ewe flocks produced more clean wool (P < 0.0001) but there was no consistent effect on fibre diameter, staple length or staple strength. Twin-born lambs from ewes managed to Lifetimewool guidelines had a similar liveweight and produced similar quantity and quality of wool to single-born lambs managed to Lifetimewool guidelines, but still suffered higher rates of mortality to weaning. This suggests that it is possible to manage ewes pregnant with twins to ensure that their surviving progeny perform at a level similar to single-born progeny managed under similar targets.

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

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

Effect of Coriander Seeds (Coriandrum Sativum) on Wool Growth and It's Traits and Some Haematological Traits of Awassi Ewes

This study was conducted to find out the effect of coriander seeds as feed additive on some hematological traits and wool growth and it's physical traits of Awassi ewes, blood samples were taken biweekly for blood picture, and wool samples were taken every 2.5 months for wool growth and its physical traits. Eighteen Awassi ewes at the age of 2-3 years were randomly divided equally into three groups (6each ) "body weight was considered".Ewes in the first group kept as control and daily fed on concentrate diet (350 g/ head), while the second group was fed on the same diet contain (2.5%) of coriander seeds, while the third group was fed on same diet contain (5%) of coriander seeds. Also all animals were allowed to graze. Blood samples were taken from jugular vein for blood traits viz (PCV) packed cell volume, (Hb) hemoglobin, (MCHC) mean cell hemoglobin concentration. Wool samples (5×5) cm2 were clipped from the last six ribs of the right chest for measuring wool growth and its traits (creasy and clean wool, samples weights, clean wool ratio, staple and fiber lengths and diameters and wool fiber crimps in 1cm of length). The results of blood parameters revealed that the second and third groups were significantly (p<0.05) recorded higher values in their PCV ,Hb, MCHC during most studied periods compared with the control group ,While the second and third groups were significantly (P<0.05) recorded higher values than the first group (control) in their creasy and clean wool, fiber length, wool fiber crimps, while no differences where existed in other wool physical traits.

Characterization of Surface-Treated Coir Fiber Obtained from Environmental Friendly Bioextraction

This study presents an ecofriendly color improvement method for clean bioextracted coir fiber with biogas recovery. The fiber samples were subjected to treatment with hydrogen peroxide (H2O2)and were optimized at 0.08% with 1:10 fiber to water ratio for 24 h. Combination treatments with (nitric acid) HNO3 and H2O2 were also studied, and matching color of H2O2 treatment at 0.08% was resulted by the treatment of the fiber with 0.016 N HNO3 and 0.03% H2O2, respectively. There was no significant difference in mechanical properties of the samples. The scanning electron microscopic studies of the samples could show significant improvement of surface finish by the treatments.

Effects of level of feeding on energy utilization by Angora goats1

Twelve mature Angora does were used in a replicated 3 × 3 Latin square to determine effects of feeding level on energy utilization. Fiber growth and change in tissue (nonfiber) mass were determined in the first 4 wk of 6-wk periods, preceded by 14 or 18 d of adaptation. Determination of ME intake and gas exchange measures occurred in wk 4, followed by feeding near maintenance, then fasting in wk 5 and 6 to determine the ME requirement for maintenance (ME(m)). A 60% concentrate diet was fed at levels to approximate 100, 125, and 150% of assumed ME(m) [low, medium (med), and high, respectively]. Digestibilities and diet ME/GE were not affected by treatment with different amounts of feed offered and subsequent intake near ME(m). Heat energy during fasting (261, 241, and 259 kJ/kg of BW(0.75); SEM = 8.7) and efficiency of ME used for maintenance (71.6, 69.6, and 69.2%; SEM = 2.29) were similar among treatments, although ME(m) differed (P < 0.04) between med and high (365, 344, and 377 kJ/kg of BW(0.75) for low, med, and high, respectively; SEM = 10.3). Tissue gain was less (P < 0.01) for low than for the mean of med and high (MH; -0.6, 23.7, and 29.8 g/d), although clean fiber growth only tended (P < 0.09) to differ between low and MH (5.60, 6.57, and 7.36 g/d for low, med, and high, respectively; SEM = 0.621). Intake of ME was greater (P < 0.01) for MH than for low (6.87, 8.22, and 8.41 MJ/d for low, med, and high, respectively). Total heat energy was less (P < 0.02) for low vs. MH and tended (P < 0.07) to be greater for high than for med (6.03, 6.31, and 6.77 MJ/d); mobilized tissue energy was low but greater (P < 0.02) for low vs. MH (0.16, 0.01, and 0.04 MJ/d for low, med, and high, respectively). Efficiency of ME use for fiber growth was similar among treatments (17.2, 16.3, and 17.7% for low, med, and high, respectively; SEM = 1.61). In conclusion, efficiency of ME use for fiber growth was similar to the NRC recommendation regardless of feeding level, although ME(m) was decreased perhaps because of experimental conditions used. Energy appeared partitioned to fiber growth, but preferential usage was not complete possibly because energy metabolism for tissue accretion reached a plateau with the greatest feeding level.

Recovery in Viscid Line Fibers

The development of a reliable procedure for removing the viscous coating of viscid silk has allowed the accurate characterization of the tensile behavior of clean flagelliform silk (i.e., silk of the flagelliform gland without the viscous coating synthetised in the aggregate gland). For comparison, tensile tests on native viscid silk (with the viscous coating) fibers were also performed. It was found that viscid silk, either native or clean, has an elastomeric behavior when kept wet, either by immersion in water (clean fibers) or by the effect of the viscid coating (native fibers). When tested in dry environments (35% RH, relative humidity, for clean fibers and 10% RH for native fibers), their mechanical behavior was no longer elastomeric, with it being more similar to other silk fibers. Furthermore, it was noticed that flagelliform silk fibers show a ground state to which they can return independent of the previous loading history.

Fibre production by beef cows

Cattle grow and shed fibre which assists them adapt to seasonal changes in the environment. In the absence of cattle fibre production data for southern Australia, Angus, Hereford, Simmental and Limousin cows and crosses between these breeds grazing perennial pastures at Hamilton, Victoria were sampled in late winter. The fibre-growing area on the sides of cattle was measured, fibre sampled at the mid-side site and the sampling area determined. Fibre was tested for fibre diameter distribution, clean washing yield and fibre length measured. Cows were 3–7 years of age, liveweights were 412–712 kg and the mean fibre-growing area was 2.2 m2. This produced an average 682 g of total fibre (range 346–1175 g). The mean fibre diameter of all fibres was 51.7 µm (range 43–62 µm) and 18% of fibres were &lt;36 µm (range 6–39%). The clean washing yield was 92.4% (range 87.4–95.8%). Fibre length averaged 21 mm. Increasing the age, liveweight and condition score of cows and increasing weight of clean fibre were associated with significant increases in mean fibre diameter. Breed of cattle did not affect fibre production (P &gt; 0.1) but did affect mean fibre diameter (P &lt; 0.05). The quantity of fibre production indicates potential for low value textile production. The high level of total fibre production, twice that of an earlier report, and fibre shedding from cattle suggests that white fibre-producing animals such as Merino sheep, Angora and cashmere goats and alpaca should avoid using cattle-handling facilities, particularly in the month before shearing.

Gross margins in Australian mohair enterprises and relationships with farm inputs, productivity and mohair quality

In the absence of financial information on Australian mohair enterprises we aimed to determine the gross margins (per dry sheep equivalent, DSE) and their relationships with farm inputs, productivity and mohair quality in Australian mohair enterprises. Using established Victorian Farm and Sheep Monitor Project protocols we collected data for the financial years 2004–05, 2005–06 and 2006–07 from farmers in south-eastern Australia and made comparisons with data from wool enterprises of similar farm area. Over 3 years the financial returns from mohair exceeded that from wool in terms of $/DSE ($23.0 v. 11.3) and $/ha ($132 v. $116). This result was achieved despite the mohair enterprises grazing their goats far less intensively compared with the grazing intensity of sheep (5.9 v. 10.3–11.1 DSE/ha) and by using far less phosphate fertiliser than used in the wool enterprises (2.2 v. 4.6–6.1 kg P/ha). These differences were counterbalanced by higher prices for mohair compared with fine wool ($13.15/kg v. $8.35/kg clean fibre). Gross margin for the mohair enterprise did not increase as stocking rate increased. Income from mohair sales declined as the proportion of does in the flock increased. Increasing the proportion of does in the flock was associated with a decline in the average price of mohair ($16/kg greasy at 42% does to $8/kg greasy at 83% does in the flock). This decline was closely associated with the increasing proportion of the total amount of mohair coarser than 34.0 µm (either fine hair or hair) plus stained mohair. The variation in profitability between farms indicates significant scope for many mohair enterprises to increase profit. A focus on producing finer quality mohair will increase mohair profitability.

Influence of stocking rate and mixed grazing of Angora goats and Merino sheep on animal and pasture production in southern Australia. 3. Mohair and wool production and quality

The effects of animal species (AS; Angora goats, Merino sheep, mixed-grazed goats and sheep at the ratio of 1 : 1) and stocking rate (SR; 7.5, 10 and 12.5 animals/ha) on fibre production and quality were determined in a replicated experiment on improved annual temperate pastures in southern Australia from 1981 to 1984. Separately grazed sheep produced the most total clean fibre/ha at each SR. Mixed-grazed treatments produced amounts of clean fibre/ha similar to the arithmetic mean of sheep and goat treatments at 7.5/ha (21.9 versus 21.3 kg/ha), 10% more at 10/ha (28.3 versus 25.3 kg/ha, P &lt; 0.05) and 7% more at 12.5/ha (31.6 versus 29.6 kg/ha, P &lt; 0.10). Clean wool production/head was affected by AS and SR but not year. Clean mohair production was affected by SR and year but not AS. Variation in mean fibre diameter (MFD) accounted for 67 and 71%, respectively, of the variation in clean wool and clean mohair production/head. There was an AS × SR interaction for clean fibre production/t pasture. Growth rate of mohair was highest in autumn and least in summer. In each season, an increase in the SR reduced the clean mohair growth rate. Growth rate of wool was highest in spring and least in summer. Wool and mohair MFD were affected by an AS × SR interaction. Mohair MFD was also affected by year and season. At 10/ha, wool from mixed-grazed sheep had a greater MFD than wool from separately grazed sheep (20.2 versus 18.9 μm) and mixed-grazed goats grew mohair 1 μm coarser than separately grazed goats. At 12.5/ha mixed-grazed goats grew mohair 1.9 μm finer than separately grazed goats. Mohair MFD was predicted by a multiple regression that included average liveweight for the period of fleece growth, season of growth (summer 1 µm finer than winter) and year (range 1.27 µm). Mohair MFD increased 4.7 µm/10 kg increase in average fleece-free liveweight (P = 6.4 × 10–14). Fleece-free liveweight alone accounted for 76.4% of the variation in mohair MFD. There was an AS × SR interaction for the incidence of kemp and medullated fibres; under severe grazing pressure their incidence was suppressed. This experiment indicated that the principles associated with the effects of SR on wool production on annual temperate pastures apply to mohair production. Mixed grazing of Merino sheep and Angora goats produced complementary and competitive effects depending on the SR. Angora goats should not be grazed alone or mixed-grazed with sheep on annual temperate pastures at SR greater than that recommended for Merino sheep.

Effect of adding Eruca Sativa Seeds and Vit.E.on the diet of mal Awassi lambs on same production traits

The aim of this study was to find out the effect of adding Eruca Sativa seed in concentrate diet alone orwith Vit.E administration on productivity of male Awassi lambs.This study was conducted onVeterinary College,Baghdad University.Fifteen Awassi ram lambs at age of 5-6 months ,were dividedequally in to three groups accordingly and treated as followed :The frist group A(G)was fed onconcentrate diet containing Eruca Sativa seeds (5%)at a rate of 400g/day /haed,The second groupB(G+E) was fed on the same ration mentioned above with Vit.E with a dose of 400mg/head was givenorally bimonthly ,The animals in the third group C (control)were fed on a concentrate diet free ofEruca Sativa at a rate of 400g/day.All animals offered 0.5kg alfalfa/day/head and freely grazing for 3-6h daily. The results revealed the followings:Body weight was increased in all animal progressively.Animals in group (G)and (G+E)were significantly (p&lt;0.05) or mathematically increased comparedwith the control groups especially in late perieds.The absolute gains of the first and second groups weresignificantly (p&lt;0.05) higher than the control group .Body skeletal measurements of all animalsincreased progressively .The first and second groups showed better values as compared with the controlgroup.Testes measurements progressively increased with age for all animals .Testes circumferencesrecorded significantly (p&lt;0.05) hiyher in group G and G+E at the end period of the experimentcompared with the control group.By using Eruca Sativa seeds caused an improvement in wool yieldand its traits viz.;greasy and clean wool,staple length and fiber length and diameter.However,thesecond group recorded better values in some productivity traits such as body weight and woolproduction compared with the first group.There fore ,it was concluded that adding Eruca Sativa seeds in concentrate diet caused an improvementin productivity traits. Vit.E.administration with Eruca Sativa seeds caused more improvement in someproductive traits.

Chemical recycling of carbon fibers reinforced epoxy resin composites in oxygen in supercritical water

The carbon fibers in carbon fibers reinforced epoxy resin composites were recovered in oxygen in supercritical water at 30 ± 1 MPa and 440 ± 10 °C. The microstructure of the recovered carbon fibers was observed using scanning electron microscopy (SEM) and atom force microscopy (AFM). The results revealed that the clean carbon fibers were recovered and had higher tensile strength relative to the virgin carbon fibers when the decomposition rate was above 85 wt.%, although the recovered carbon fibers have clean surface, the epoxy resin on the surface of the recovered carbon fibers was readily observed. As the decomposition rate increased to above 96 wt.%, no epoxy resin was observed on the surface of the carbon fibers and the oxidation of the recovered carbon fibers was readily measured by X-ray photoelectron spectroscopy (XPS) analysis. The carbon fibers were ideally recovered and have original strength when the decomposition rates were between 94 and 97 wt.%. This study clearly showed the oxygen in supercritical water is a promising way for recycling the carbon fibers in carbon fibers reinforced resin composites.

Genetic correlations between early growth and wool production of crossbred ewes and their subsequent reproduction

Genetic correlations between reproductive and productivity traits of ewes and their early growth, wool production and worm resistance traits were estimated among 2460 crossbred ewes. The ewes were progeny of 74 maternal breed sires and mainly Merino dams. The ewes were born over 3 years and had three joinings with a total of 6824 ewe joining records. The reproductive and ewe productivity traits included: (i) fertility (ewes lambing per ewe joined); (ii) litter size (number of lambs born per ewe lambing); (iii) rearing ability or lamb survival (lambs weaned of lambs born for lambing ewes); (iv) number of lambs born (NLBj) per ewe joined; (v) number of lambs weaned (NLWj) per ewe joined; (vi) total litter weight weaned (TWWj) per ewe joined; and (vii) the component trait average lamb weaning weight in the litter (AWW). The growth traits included the weight of the ewe at birth (BWT), weaning (WWT) and postweaning (PWWT), as well as growth rate pre- and postweaning. The wool traits included greasy (GFW) and clean fleece weight (CFW), yield and average fibre diameter (FD) at their first adult shearing. Worm egg count (WEC) during their first year was also recorded. Bivariate mixed models analyses using ASReml procedures were used to estimate the genetic correlations. The genetic correlations between TWWj and growth traits were positive and moderate to high and ranged from 0.34 for BWT to 0.61 for PWWT. Those for the other composite reproductive traits were slightly lower and ranged from 0.27 to 0.54 for NLWj and from 0.07 to 0.46 for NLBj. The genetic correlations between the overall measures of reproduction (NLBj, NLWj and TWWj) and GFW, CFW and FD were negative and generally low to moderate (–0.21 to –0.52). The correlations were generally larger for NLBj than for NLWj and TWWj. The genetic correlations between the reproductive traits and WEC were close to zero, except between AWW and WEC (0.42). The phenotypic correlations between the reproductive traits and the growth, wool and WEC traits were all close to zero. The genetic correlations were generally favourable between ewe reproduction and growth, with early selection for traits such as WWT and PWWT likely to give some improvement in subsequent reproduction and ewe productivity. In contrast, there appears to be a slight antagonism between reproduction and wool production. This study provides estimates of genetic correlations from crossbred ewes that add to the limited knowledge of these parameters that will improve the accuracy of genetic evaluation and prediction of the outcomes from breeding programs for meat and wool objectives that include reproduction.

A morphology-related study on photodegradation of protein fibres

The wool fibre has a complex morphology, consisting of an outer layer of cuticle scales surrounding an inner cortex. These two components are hard to separate effectively except by using harsh chemical treatments, making it difficult to determine the susceptibility of the different components of the fibre to photoyellowing. An approach to this problem based on mechanical fibre modification is described. To expose the inner cortex of wool to different degrees, clean wool fibres were converted into ‘powders’ of various fineness via mechanical chopping, air-jet milling, ball milling or their combination. Four types of powdered wool (samples A, B, C and D) were produced with reducing particle size distributions and an increasing level of surface damage as observed using SEM. Sample A contained essentially intact short fibre snippets and sample D contained a large amount of exposed cortical materials. Samples B and C contained a mixture of short fibre snippets and cortical materials. Solid wool discs were then compressed from the corresponding powder samples in a polished stainless steel die to enable colour measurement and UV irradiation studies. ATR-FTIR studies on powder discs demonstrated a small shift in the amide I band from 1644 cm −1 for disc A to 1654 cm −1 for disc D due to the different structures of the wool cuticle and cortex, in agreement with previous studies. Similarly an increase in the intensity ratio of the amide I to amide II band (1540 cm −1) was observed for disc D, which contains a higher fraction of cortical material at the surface of the disc. Discs prepared from sample D appeared the lightest in colour before exposure and had the slowest photoyellowing rate, whereas discs made from powders A–C with a higher level of cuticle coverage were more yellow before exposure and experienced a faster rate of photoyellowing. This suggests that the yellow chromophores of wool may be more prevalent in cuticle scales, and that wool photoyellowing occurs to a greater extent in the cuticle than in the cortex. Photo-induced chemiluminescence measurements showed that sample D had a higher chemiluminescence intensity after exposure to UVA radiation and a faster decay rate than samples A and B. Thus one of the roles of the wool cuticle may be to protect the cortex by quenching of free radical oxidation during exposure to the UV wavelengths present in sunlight.

Genetic parameters for bodyweight, wool, and disease resistance and reproduction traits in Merino sheep. 1. Description of traits, model comparison, variance components and their ratios

Both wool and sheep meat industries are interested in sheep that have a high reproduction performance and are resistant to internal parasites, in addition to the traditional traits. There is considerable interest in breeding sheep for wool, carcass, reproductive and internal parasite resistance traits simultaneously. The objective of this study was to estimate single trait genetic parameters for 40 traits recorded in Merino sheep, covering bodyweight, carcass, wool, reproduction and internal parasite resistance traits. This also involved determining the appropriate models. The results from this study will be used to review the genetic parameters used in the routine genetic evaluations conducted by Sheep Genetics. The most appropriate models included a maternal genetic effect and covariance between direct and maternal genetic effects for most of the bodyweight traits, greasy and clean fleece weight, fibre diameter and coefficient of variation of fibre diameter. The permanent environment due to the dam was not included for any trait. There was considerable genetic variation in most traits analysed; lowest heritabilities (0.09–0.10) were found for number of lambs born and weaned per lambing opportunity, and highest heritabilities (0.62–0.77) for fibre diameter. The estimated heritabilities and genetic variances, in combination with the estimated correlations, indicate that there is potential to make genetic improvement in most traits currently recorded in Australian Merino sheep.

Frequency of shearing increases growth of fibre and changes objective and subjective attributes of Angora goat fleeces

SUMMARYThe impact of genotype and of frequency and timing of shearing, on mohair attributes and production of modern Angora goats was studied. Goats in the southern hemisphere grazed pastures between February 2004 and 2006. There were seven shearing treatments by three genetic strains with four or eight replicates of individual goats. Treatments were: three different 6-month shearing intervals and two of 12-month shearing intervals with different months of shearing, a 7-month winter shearing interval and a 3-month shearing interval. Genetic strain was based on sire line: 1·0 South African; 1·0 Texan; and Mixed 0·5 South African and 0·5 Texan. Annual greasy mohair production was 5·08 kg, and average clean fleece production was 4·37 kg. The Angora goats produced an annual clean fleece equivalent to 0·122 of their mean fleece-free live weight which was equal to 0·34 g/kg/day. Measurements were analysed over the period of spring 2004 shearing to spring 2005 shearing, excluding the June–December shearing treatment. Increased frequency of shearing increased fleece growth and affected 13 objective and subjective attributes of mohair that were evaluated including clean washing yield, fibre diameter and fibre diameter variation, incidence of medullated fibres, staple length, fibre curvature, crimp frequency, style, staple definition, staple fibre entanglement and staple tip shape. The direction of these effects were generally favourable and for most attributes the magnitude of the response was linear and commercially important. Each additional shearing resulted in an additional 149 g of clean mohair representing 0·034 of the annual clean mohair production. This increase was associated with a 0·6 cm increase in staple length and 0·32 μm increase in mean fibre diameter. In conclusion, Angora goats shorn less frequently grew less mohair that was more likely to be entangled in spring. Managers of Angora goats should take note of these findings.

Fleece Phenotype Influences Susceptibility to Cortisol-induced Follicle Shutdown in Merino Sheep

This experiment was conducted to determine the extent to which susceptibility to cortisol-induced follicle shutdown is influenced by fleece phentotype. Twenty Finewool (10 sheep low fibre diameter, low coefficient of fibre diameter-LL and 10 low fibre diameter, high coefficient of variation of fibre diameter-LH) and twenty Strongwool (10 low fibre diameter, low coefficient of variation of fibre diameter-HL and 10 high fibre diameter and high coefficient of variation of fibre diameter-HH) sheep of 9 months of age were individually penned in an animal house and were injected intramuscularly with an aqueous suspension of hydrocortisone acetate at a rate of 1.42 mg/kg body weight for a period of two weeks. Fibre diameter was measured from clipped tattooed patch wool samples. Follicle activity was measured by histological changes in skin biopsies taken weekly. Blood samples were collected at two-week intervals and plasma cortisol measured. Increased plasma cortisol concentration significantly (p<0.05) reduced clean wool production and mean fibre diameter dropped to its lowest level four weeks after commencement and two weeks after the cessation of cortisol injection. Elevation of plasma cortisol concentration significantly (p<0.0001) increased the percentage of inactive follicles two weeks after injection started. High fibre diameter groups (Strongwool sheep; i.e. HL+HH) had significantly (p<0.0001) higher percentage of follicle shutdown than low fibre diameter groups (Finewool sheep; i.e. LL+LH). Average percentage of shutdown follicles for Finewool (LL+LH) and Strongwool (HL+HH) Merino sheep was 9.8±0.9 and 13.5±0.9 respectively. Shutdown of primary follicles was more pronounced in Finewool than Strongwool sheep. There was no significant effect of coefficient of variation of fibre diameter on propensity to follicle shutdown induced by exogenous cortisol. It is concluded that elevation in plasma cortisol concentration is inhibitory to the normal activity of follicles in Strong-wool sheep but that variation in fibre diameter has little or no effect.

Structure‐Dependent Electrical Properties of Carbon Nanotube Fibers

Spun carbon nanotube (CNT) fibers have great potential for conducting and sensing applications owing to their unique, tunable electrical properties. Here we report the electron transport properties of neat, well-aligned CNT fibers spun from arrays of millimeter-long CNTs. The conductivity of asspun CNT fibers is around 595.2 S cm at room temperature, and its variation with temperature shows a semiconductive behavior from 300 to 75.4 K. The electron transport was found to follow a three-dimensional (3D) hopping mechanism. Importantly, it was found that chemical treatments may significantly affect the conductivities of as-spun fibers. Oxidizing the CNT fibers in air or HNO3 increased the conductivities, while covalent bonding of Au nanoparticles to the CNT fibers remarkably improved conductivity and changed conduction behavior. Conversely, annealing CNT fibers in Ar+ 6% H2 at 800 °C or under the CNT array growth conditions at 750 °C led to a dramatic decrease in conductivity. Owing to their conjugated and highly anisotropic 1D structures, carbon nanotubes (CNTs) are a fascinating new class of electronic materials from both theoretical and applied standpoints. The excellent conductivities of CNTs and their ability to carry very high current density, along with their high thermal conductivity, chemical stability, and mechanical strength, make CNTs uniquely promising for a broad range of applications, including building blocks for nanoscale electronic devices, microsensors for bio-agents and chemicals, and power cables for space shuttles. The electrical resistivity q of individual CNTs has been measured under ballistic conductions to be as low as 10 X cm for single-walled and 3× 10 X cm for multiwalled CNTs, respectively, indicating that CNTs may be better conductors than metals such as copper at room temperature. However, in most cases, due to the presence of various defects or impurities formed during the CNT growth, the conductivities of individual CNTs are often much lower than those under ballistic conduction with nanotubes free of defects. The electron transport in CNT assemblies is different from that in individual nanotubes. It has been reported that singlewalled carbon nanotube (SWNT) fibers, either synthesized directly by vertical floating chemical vapor deposition (CVD) methods or extruded from a super-acid suspension, exhibit room-temperature resistivities in the range of 1 × 10 to 7 × 10 X cm, which is nearly 100 times higher than the resistivities of single nanotubes. The resistivities of multiwalled carbon nanotube (MWNT) fibers are typically one or two orders of magnitude higher than that of SWNT fibers. Such large differences between single nanotubes and fiber assemblies may arise from a high impurity content (such as amorphous carbon and catalytic particles) in the fibers, which may profoundly affect electron transport by causing significant scattering, and contact resistances between nanotubes. Therefore, two approaches can be used to improve the electrical conductivity of CNT fibers: 1) minimize the contact resistances between nanotubes by improving the alignment of CNTs and by increasing the lengths of individual tubes; 2) improve the conductivity of individual CNTs by post-synthesis treatments. Itwas the objective of the study reported here to use these two approaches to produce CNT fibers with high conductivity and to study the fundamental conduction mechanisms of the CNT fibers. Thin and clean CNT fibers (typically 3 lm in diameter) were spun from arrays of well-aligned, millimeter-long CNTs, which were synthesized using ethylene CVD on a Fe catalyst film. By measuring the resistance of CNT fibers at temperatures from 300 K to 75.4 K, we investigated the electronic properties of as-spun fibers and their possible conducting mechanisms. It was also found that the conductivity of CNT fibers could be tuned through mild post-treatments. The spun CNT fibers were post-treated with five different procedures: 1) Annealing in air at 480 °C for half an hour in an attempt to clean off the amorphous carbon, whose oxidation temperature is often around 400 °C. 2) Oxidizing in dilute 5 M HNO3 solution at 40 °C to cause a weak chemical C O M M U N IC A TI O N

Giant magnetoresistance of Fe3O4-polymethylmethacrylate nanocomposite aligned fibers via electrospinning

This paper describes the results of investigations on giant negative magnetoresistance (GMR) in nanocomposite aligned fibers prepared using electrospinning. The nanocomposite contains polymethylmethacrylate (PMMA) matrix and the nanoparticles of polymer (PMMA) grafted magnetite, Fe3O4 (PGM). Even for the low magnetic field (1T) a GMR of about 50% was observed for low loading (5wt%) of PGM at room temperature. The fibers were characterized using scanning electron microscope and high resolution transmission electron microscope. X-ray diffraction (XRD) patterns were recorded for clean PMMA fibers, PMMA granules, and PGM nanoparticles. The dc conductivity was calculated from the I-V characteristics for the fibers at room temperature.

Simultaneous Removal of Organic Matter and Nitrogen Compounds in Autoaerated Biofilms

This paper describes the simultaneous removal of organic matter and nitrogen compounds carried out using an autoaerated multispecies biofilm growing on gas-permeable hollow-fiber membranes. In order to perform the aerobic heterotrophic oxidation and nitrification processes, the biofilm absorbs atmospheric oxygen through the inside walls of hollow fibers and consumes substrate from the bulk liquid. A mass balance calculated the consumed oxygen. Depending on the removed organic and nitrification rates, the oxygen flux through the hollow fibers can reach up to 90% of the total oxygen consumed, whereas the remaining 10% pertains to the dissolved oxygen from the influent wastewater. Without the biofilm the oxygen transfer rate through clean hollow fibers is 3.5gm−2day−1, whereas the oxygen transfer rate through the biomembrane (hollow fiber+biofilm) achieves a maximum value of 25gm−2day−1. The enhanced oxygen transfer using the biological pathway may be attributed, among many other factors, to the mobility of the microorganisms generating microturbulence, which produces more active bioturbulent diffusiveness than the molecular diffusion in the biofilm. It has also shown that the oxygen utilization efficiency was affected by the substrate utilization rate.