Mohair research update 18 : the importance of the live weight of Angora goats on husbandry and production

The live weight of farm animals is strongly associated with production, profitability, management requirements and animal survival (Table 1). The mature live weight of farm animals and of goats is positively associated with their potential to grow rapidly. Live weight is directly related to the nutrient requirements of goats, irrespective of their productive state.

For Angora goats in particular, live weight is associated with mohair production and mohair fibre diameter, age at puberty, reproductive performance and ovulation rate, carcass attributes, meat production and sale value at the end of their productive life. Live weight also affects the timing of the eruption of incisor teeth.

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

The 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.

Influence of energy and polymer-escapsulated methionine supplements on mohair growth and fibre diameter of Angora goats fed at maintenance

We studied the fleece production of Angora wether goats provided with energy, to maintain liveweight, and polymer-encapsulated methionine while they were fed on poor quality roughage rations in early summer. Forty goats (mean fleece-free liveweight 28.5 kg) were randomly allotted to 5 treatments and housed individually for 12 weeks. The treatments were: control, fed to lose 5 kg liveweight; M, fed to maintain liveweight; and 3 maintenance rations with either 0.5, 1 or 2 g day-1 of polymer-encapsulated methionine. The basal ration was oaten chaff (56.8% digestible dry matter) and all maintenance- fed goats received a supplement of 150 g day- 1 gristed barley. Goats required an estimated 267 kJ ME kg-0.75 day-1 to maintain liveweight. Goats fed the control diet grew less mohair (P<0.05) with reduced mean fibre diameter (P< 0.05) than maintenance-fed goats (4.9 g day-1, 30.0 pm compared with 5.8 g day-1, 31.9 pm). For maintenance-fed animals, the addition of 1 g day- methionine (0.15% of dry matter intake) increased mohair growth by 0.8g day-1 (P<0.075). Feeding barley to prevent liveweight loss and feeding polymer-encapsulated methionine at maintenance is unlikely to result in economic responses in mohair production of goats grazing low quality summer pastures

Growth of Australian shortfin eel (Anguilla Australis) elvers given different dietary protein and lipid levels

The Australian shortfin eel, Anguilla australis is a potential candidate for intensive aquaculture. The present study was undertaken to evaluate the growth of elvers (5.4 g ± 0.1 initial weight) fed with diets of varying protein and lipid content, and to assess the potential of using soya-bean meal as a dietary ingredient. A 10 week experiment was conducted at 24 (±1.0) °C by rearing fish, in 60 L conical fibre glass tanks using a closed recirculation system. Diets having protein concentrations of 40 or 50% (by dry weight) were tested at three lipid levels (15, 20, 25%); diets being designated P₄₀L₁₅, P₄₀L₂₀, P₄₀L₂₅, P₅₀L₁₅, etc. All these diets contained 5% soya-bean meal. In addition P₅₀L₂₀ diets were formulated to contain 10 and 20% soya-bean meal in the diet (Diets S1 & S2). Shortfin eel grew best on the P₅₀L₁₅ diet, with an average specific growth rate of 2.26%. Food conservation ratio (FCR) and Protein efficiency ratio (PER) ranged from 1.21 (P₅₀L₁₅) to 2.12 (P₄₀L₂₅), and 0.92 (P₅₀L₂₅) to 1.65 (P₅₀L₁₅), respectively. Based on all criteria the best growth performance of shortfin eel was on the P₅₀L₁₅ diet, followed by P₄₀L₂₀ and P₄₀L₁₅. At both protein levels fish reared on diets with 25% lipid performed poorly. The performance of shortfin eel was not affected by the amount of soya-bean meal in the diet, up to a maximum of 20% dietary inclusion. No significant differences in muscle protein were evident in shortfin eel reared on different dietary treatments, nor was the lipid content of muscle related to dietary lipid level.

Nutrition, growth and production of Cherax Destructor Clark, 1936 (Decapoda, Parastacidae)

In this study the nutrition, growth and production of C. destructor was examined. Selected nutritional requirements of juvenile animals were determined under controlled conditions with the aim of developing a pelleted diet for use in hatcheries, nurseries and growout situations. The best developed diet was assessed for its potential as a supplementary feed for animals cultured in earthen environments. The protein requirements were first determined simultaneously with an evaluation of the effect of replacing animal protein (fishmeal) by soybean meal. Juveniles were reared communally for 59 d on isoenergetic diets containing 15-30% protein and graded levels of soybean meal (0-60%, of protein). When soybean meal was included at a level of 40-60%, growth was reduced relative to that achieved with control diets containing 15% and 20% protein, but this was not the case at a 20% soybean meal substitution level. A two-way interaction occurred between dietary protein and soybean meal content. Higher protein feeds enabled higher soybean meal inclusion levels without significantly affecting growth. Protein increases of 5% produced better growth at the 40% and 60% soybean meal substitution levels. This effect was less pronounced in the control and the 20% soybean meal diets. Carcass %protein increased and %lipid decreased as dietary protein increased. A similar effect occurred by increasing the soybean meal level to 60%. No obvious trend in carcass moisture, energy, and ash occurred. A protein requirement of 30% was apparent when fish meal and soybean meal were included in diets at levels of 20% and 24% (dry matter) respectively. Alternative protein sources to soybean meal were subsequently identified. Juveniles were maintained for 12 weeks on isoenergetic diets containing 30% protein and differing in the primary source of protein used, with meat, snail, soybean, yabby, and zooplankton meals comprising the major protein ingredient. No significant difference occurred in mean weight (MW), percentage weight gain (%WG), SGR or survival among diets. Food conversion ratios (FCR) were low, with a minimum value of 0.95 for the snail-based diet. The apparent net protein utilisation (ANPU) varied from 29.6% (zooplankton-based diet) to 41.2% (snail-based diet). Carcass composition varied with diet, with the greatest difference occurring in carapace colour. Animals fed the zooplankton-based diet developed the strongest, most natural pigmentation. A new combination of previously used protein-based ingredients was subsequently tested with reference to two yabby species, Cherax albidus and Cherax destructor, that were grown simultaneously in identical conditions. Juvenile male animals were reared individually for 20 weeks on isoenergetic diets containing 15% or 30% protein with fish meal, soybean meal, yabby meal and wheat products forming the basis of the diets. C albidus grew the fastest and utilised the food the most effectively. Carcass composition was influenced by diet with the 30% protein diet resulting in an increase in carcass protein and ash and a decrease in carcass lipid and energy relative to the low protein diet. Carcass moisture and calcium were not affected by diet. The intermoult period (IP) was highly dependent on the premoult weight (W) but the mean moult increment (WI, as weight) was independent of the PM. The orbital carapace length (OCL) and the abdominal length (ABL) %moult increments generally declined with an increase in PM whereas the propus length (PL) %moult increment generally increased. The IP, WI, %OCL, %ABL, and %PL moult increments varied according to diet and to species. Elevated dietary protein caused a reduction to the IP (for similar sized animals) by 11 d and 7 d and an increase to the WI by 85% and 81% in C. albidus and C destructor respectively. Dietary induced morphological changes also occurred. Animals of a standard OCL (both species) had significantly larger abdomens when fed the higher protein diet. Growth on the best developed diet was compared to the growth obtained on a natural diet of freshwater zooplankton. Juveniles were reared individually for 12 weeks on the two diets. The MW, %WG and SGR were higher for the zooplankton diet. Carcass composition was influenced by diet and the zooplankton fed animals had a higher carcass %protein, %lipid, %ash and %fibre content and were more richly pigmented than animals fed pellets. The IP and the WI were highly dependent on the PM and varied according to diet; feeding with zooplankton reduced the IP by 1.2 days and increased the WI by 13.7% compared to pellets. Nutrient digestibility was determined for the pelleted diets evaluated in the growth trials. Protein digestibility (PD) and dry matter digestibility (DMD), using chromic oxide (Cr2O3) as an exogenous marker, were high for all diets, at around 93% and 83% respectively. Ash digestibility varied considerably from 17% to 73% for the snail and yabby meal diets respectively. Crude fibre digestibility was around 50% and probably indicates cellulase activity. Alternative markers to Cr2O3 were evaluated. Ash was considered to be the most suitable alternative to Cr2O3, providing a reasonable, albeit lower, estimate of nutrient digestibility. Cr2O3 and ash were preferentially excreted whereas fibre was retained in the digestive system for a longer period, consequently, the collection of a particular fraction of the deposited faeces (late or early) substantially affected the digestibility coefficients. In earthen-based environments, animals fed the best developed diet were compared to animals cultured using a forage crop of clover (Trifolium repens). Three supplementary feeding strategies representing varying levels of management intensity were evaluated in a series of trials conducted in ponds and pond microcosms. Growth on pellets consistently exceeded that obtained with the forage crop, with final MW being 67-159% higher than that using clover and appeared to be the result of direct pellet consumption and from a pellet fertiliser effect (on the sediment). Within-pond DMD and PD were high and similar for each treatment (DMD = 51-58%; PD = 89-92%). In the control pond, DMD and PD increased with each successive flood. The faecal egestion rate (PER) decreased with each successive flood in all ponds, and is negatively related to animal weight and to foregut fullness (FF) according to power curves. FF was consistently lowest in the control pond. Mean FF was 48.5%, 62.3%, and 26.7% for the pellet, crop and control ponds respectively. FF increased to the third flood in each pond. The foregut protein content was high in all samples and the mean values were 33.9%, 32.7% and 35.6% for the pellet, crop and control ponds respectively. Foregut ash was highly variable within each pond and is inversely related to the foregut protein content. In the control and pellet ponds the highest foregut ash content occurred during flood 1. The culture system (aquaria or pond) strongly influenced the composition of the foregut content. The foregut of animals fed the manufactured diet (B2) in ponds contained approximately 176% more ash and 5% more protein than the foregut of animals fed in bare-bottom tanks. The FF of the tank fed animals was approximately 45% higher than the FF of pond fed animals after a similar feeding period. Base-line yields for extensive production systems appeared to be around 400kg ha-1. The supplementary addition of T. repens produced yields of approximately 635kg ha-1 (in ponds) to around 1086kg ha-1 (in tanks). The sequential addition of cut-clover to tanks stimulated growth to levels approaching those achieved on pellets. Yabbies stocked into ponds at 15-20 m-2 with a mean weight of 2.67g and fed a 30% protein pelleted diet for 100 d, resulted in a yield of approximately 1117kg ha-1, but only 2% of the population were above a marketable size of 50g. The feed utilisation indices were better for animals reared on pellets in bare-bottom tanks than in earthen environments, indicating some degree of pellet wastage when natural feeds are simultaneously present. High apparent food conversion ratios and low protein efficiency ratios occurred when the forage crop was provided. A considerable quantity of the dry matter and protein content of the forage crop was either inefficiently utilised or directed into other production pathways. Sowing a forage crop into pond microcosms to which a pelleted diet was also provided, did not enhance growth performance. Pelleted feed inputs at a rate of approximately 129g m-2 to 198g m-2 (dry matter) and 38g -2 to 64g m-2 (protein) over 70-100 d resulted in acceptable growth and feed utilisation indices for animals reared in ponds and pond microcosms. Forage crop inputs of approximately 533g m-2 to 680g m-2 (as dry matter) or 84g m-2 to 177g m-2 (as protein) over a 70-100 d period produced reasonable growth rates but poor feed utilisation indices. Low inputs of dry matter (from 113-296g m-2) and protein (from 24-54g m-2) from clover were sufficient to maintain high growth rates in pond microcosms for around 28 d. In ponds, a very low level of 21g m-2 (dry matter) and 4.3g m-2 (protein) was sufficient for around 3 weeks. Forage depletion appeared to occur beyond week 3-4 and was probably a major growth limiting factor. The mean hepatosomatic index (HSI) was 9.44, 7.68, and 6.79 for the pellet, crop, and control ponds respectively. The relationship between hepatopancreas weight and overall animal weight was significantly different between treatments. The hepatopancreas of pellet-fed animals had the highest %lipid and lowest %ash, %protein, %carbohydrate and %moisture content. In terms of absolute quantities, the only major difference in hepatopancreas composition between treatments occurred for lipid and dry matter content. The hepatopancreas of the pellet-fed animals was a cream/cream-yellow colour and was very fragile, whereas in the other ponds it was a more ‘natural’ bright yellow colour and was structurally more robust. C. destructor has a capacious foregut, being approximately 5 times the volume of similar sized Penaeids. The foregut volume (V, ml) of the yabby is related to animal weight (W, g) according to V = 0.048 W0.9543. Animals that were starved for 96 h and then fed diet B2 were almost completely foil after 30 min. The ‘apparent enzymatic response’ of animals fed various natural and artificial diets in tanks was evaluated. Nutrient processing time and the enzymatic response following ingestion appeared to be regulated by the chemical and physical properties of the diet. For the natural feeds, foregut protein was 1.2% higher (for zooplankton) and up to 300% higher (for detritus) than dietary protein, whereas ash was 7.5% higher (zooplankton) and 46-63% lower (detritus) than dietary ash. For animals fed diet B2 after 48 h without food, FF was approximately half that of 96 h starved animals after a similar feeding period but foregut protein and ash contents were similar. Finally, the physiological and morphological attributes elucidated in this study are discussed with reference to the ecology of the yabby. High growth rates, excellent feed utilisation indices and high digestibility coefficients for a wide range of diet-types illustrate nutritional flexibility. A capacious foregut, a large hepatopancreas with a high energy storage capacity, the ability to partition and preferentially excrete the low nutrient value inorganic component of the diet, the capacity to alter body form, nutrient processing time and enzymatic secretions in relation to diet-type, and modified behaviour according to feed availability also demonstrate plasticity/adaptability/flexibility. The combined effect of these important characteristics ensures survival in environments that may be adverse and highly variable in terms of nutrient availability. Collectively the morphological and digestive traits elucidated in this study reflect the generalist-type nature of C destructor and indicate that a polytrophic classification still seems appropriate. Several priority areas for further nutrition research are identified and recommendations are made regarding the best-practices to use in the commercial culture of the yabby. Of paramount importance is the further clarification of the nutritional requirements and feeding preferences of animals in various phases of development.

The trophic effect of dietary fibre is not associated with a change in total crypt number in the distal colon of rats

Soluble fibres, such as guar gum, promote and wheat bran or methylcellulose protect from chemically induced colon carcinogenesis, relative to the effect of a fibre-free diet in rats. Mechanisms are poorly understood. Whereas all fibres are trophic to the colonic epithelium, the heterogeneity of effects on carcinogenesis may reflect different effects on the total number of crypts and, therefore, the size of the stem cell population. This study aimed to assess this hypothesis. Sprague–Dawley rats were fed one of fibre-free diets with or without 10% wheat bran, methylcellulose or guar gum for 4 weeks. The distal colons were stained with methylene blue and quantified for the number and density of crypts using an image analysis system. Epithelial proliferative kinetics was measured stathmokinetically. Methodology for quantifying crypts was valid and reproducible. Rats fed a fibre-free diet had atrophic distal colon, as shown by a decrease in crypt column height and a lower mitotic index. Fibre supplementation prevented the atrophy and was associated with crypt mouth areas that were 30–60% larger than those in the fibre-free group (P < 0.001, ANOVA), with the methylcellulose group being the largest (1.16 µm2). The crypt density of the fibre-free group was 16–19% greater than those in fibre fed groups (P + 0.006), due to the smaller size of the crypts. However, there was no difference in the total number of crypts across the four dietary groups (P > 0.1). Distal colons in all of the dietary groups contained ~105 crypts. In conclusion, although variation in the amount or type of dietary fibre exerts heterogeneous effects on the growth of the colonic epithelium and on colon carcinogenesis, the total number of crypts in the distal colon remains constant. It is, therefore, unlikely that fibres influence carcinogenic events by altering the size of the stem cell population.

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 3461-175 g). The mean fibre diameter of all fibres was 51.7 μm (range 43-62 μm) and 18% of fibres were 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 > 0.1) but did affect mean fibre diameter (P < 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.

Influence of grain supplements during winter on liveweight, mohair growth and mohair quality of weaner Angora goats

To identify methods to improve growth and mohair production of weaned Angora goats (mean liveweight 18-20 kg) during their first winter, two supplementary feeding experiments using whole-grain barley and lupins were conducted on a farm in southern New South Wales, in a region where weaner illthrift had been reported. Experiment 1 was a 2×2 + 1 factorial with 16 replicate goats; two feeding levels (115 or 230 g/day of whole-barley grain)× two periods of feeding (4 or 8 weeks) + Control (grazing only). Experiment 2 had five treatments × 13 replicate goats; three treatments fed 230 g/day of whole-barley grain for periods of 2 or 3 months and two treatments fed a 50:50 mixture of lupin and barley grain at 350 g/day for 2 or 4 months. Goats were individually fed and then all returned together for grazing. There were no effects of feeding in Experiment 1 and variations of feeding 230 g/day of barley in Experiment 2 provided no benefit. Feeding lupin/barley for 4 months increased liveweight (gain 59 g/day), mohair production, mohair fibre diameter and the incidence of medullated fibre. About 25% of this ration was not eaten by eight goats, reducing treatment average intake to 295 g/day. By the end of spring, there was no difference in treatment liveweights. Regression constants indicated that for each 1 μm increase in mean fibre diameter, greasy fleece weight increased 35 g and for each 1 kg increase in pre-shearing liveweight, greasy fleece weight increased 26 g. The results show that Angora weaner goats can grow during winter, provided their energy and protein needs for growth are met. Improved pasture management and higher levels of supplementary feeding to weaned Angoras are indicated compared with current practices on farms in Australia.

Three dimensional scaffolds from multilobal fibres for enhanced cell growth

Multilobal fibres are irregularly shaped fibres with several surface channels or grooves. Scaffolds created from these fibres have high surface area which may enhance cell density. This study compared the cell growth of dermal fibroblasts and osteoblast-like SaOS2 cells on multilobal fibre nonwoven scaffolds to the conventional fibre scaffolds. Cells were cultured on round nylon, trilobal nylon, round polyethylene terephthalate (PET) and multilobal PET scaffolds for 14 days. There were more cells growing on trilobal nylon and PET multilobal scaffolds than their round counterparts. The preference to the type of multilobal scaffolds was cell dependent. The density of fibroblast increased 37% on trilobal nylon compared to round nylon scaffolds after 14 days of culture. SaOS2 cells preferred the multilobal PET scaffolds, exhibiting a 66% increase in cell number after 14 days of culture. Scaffolds manufactured from multilobal fibres have the ability to accommodate a high number of cells, demonstrating a great potential in tissue engineering applications.

Electrospinning of nanofibres with parallel line surface texture for improvement of nerve cell growth

Nanofibres having a parallel line surface texture were electrospun from cellulose acetate butyrate solutions using a solvent mixture of acetone and N,N'-dimethylacetamide. The formation mechanism of the unusual surface feature was explored and attributed to the formation of voids on the jet surface at the early stage of electrospinning and subsequent elongation and solidification of the voids into a line surface structure. The fast evaporation of a highly volatile solvent, acetone, from the polymer solution was found to play a key role in the formation of surface voids, while the high viscosity of the residual solution after the solvent evaporation ensured the line surface to be maintained after the solidification. Based on this principle, nanofibres having a similar surface texture were also electrospun successfully from other polymers, such as cellulose acetate, polyvinylidene fluoride, poly(methyl methacrylate), polystyrene and poly(vinylidene fluoride-co-hexafluoropropene), either from the same or from different solvent systems. Polarized Fourier transform infrared spectroscopy was used to measure the polymer molecular orientation within nanofibres. Schwann cells were grown on both aligned and randomly oriented nanofibre mats. The parallel line surface texture assisted in the growth of Schwann cells especially at the early stage of cell culture regardless of the fibre orientation. In contrast, the molecular orientation within nanofibres showed little impact on the cell growth.

The allometric relationship between mean fibre diameter of mohair and the fleece-free liveweight of Angora goats over their lifetime

As mean fibre diameter (MFD) is the primary determinant of mohair price we aimed to quantify the lifetime changes in mohair MFDas Angora goats aged and grew. Measurements were made over 12 shearing periods on a population of Angora goats representing the current range and diversity of genetic origins including South African, Texan and interbred admixtures of these and Australian sources. Records of sire, dam, birthweight, birth parity, liveweight, fleece growth and fleece quality were taken for does and castrated males (wethers) (n = 267 animals). Fleece-free liveweights (FFL_wt) were determined for each goat at shearing time by subtracting the greasy fleece weight from the liveweight recorded immediately before shearing. A restricted maximum likelihood growth curve model was developed for relating MFD to FFL_wt, age and other measurements.Asimple way of describing the results is:MFD= k (FFL_wt)b E; where k is a parameter that can vary in a systematic way with shearing(age), breed, weaning weight, sire, dam and individual; b is a parameter that is the same for nearly the whole study; and E are independent errors from a log-normal distribution. The analysis shows that ^b = 0.34, with s.e. (^b) = 0.021. Thus, mohair MFD was allometrically related to the cube root of FFLwt over the lifetime of Angora goats. However, the allometric proportionality constant differed in a systematic way with age at shearing, genetic strain, weaning weight, sire, dam and individual. For Texan-breed goats, MFD decreased as weaning weight increased (P = 0.00016). The findings indicate that management factors that affect liveweight and weaning weight have lifetime effects on mohair fibre diameter and therefore the value of mohair and the profitability of the mohair enterprise.

Effects of different nutritional regimens on the productivity of Australian Cashmere goats and the partitioning of nutrients between cashmere and hair growth

The influence of energy or protein supplementation or energy restriction on cashmere growth was studied in 35 highly productive cashmere wether goats. The goats were shorn on 3 December and randomly allocated to 3 levels of energy intake: M, goats fed to maintain liveweight; 0.8M, goats fed to lose 5 kg liveweight from December to April and then fed ad libitum; and >M, goats fed to gain liveweight. Nested within >M were ADLIB (goats offered feed ad libitum), and 1.25M and l.5M (goats fed M plus 25 or 50% of the difference in mean intake between M and ADLIB). The metabolisable energy requirement to maintain liveweight was 250 kJ kg-0.75 day-1 but to maintain body condition (l.25M) it was 3 12 kJ kg-0.75 day-1. Goats fed 0.8M had a mean intake of 0.68M and lost 26 g day-1 liveweight until April, but when fed ad libitum consumed 2.15M in June and grew rapidly in late autumn and winter at 93 g day-1. Goats fed ADLIB consumed 2.30M in February and gained 87 g day-1 from December to February, but intake declined to 1.61 M in June and they gained 20 g day-1 from April to June. Cashmere growth and fibre diameters of fleeces shorn on 17 June of goats fed >M (221g, 17.69 pm) were significantly greater (P< 0.02) than those of goats fed 0.8M (146 g, 16.67 ¦m), with levels of M-fed goats being intermediate. Within >M, there were no significant differences in cashmere growth. Protein supplementation within M (27 or 54 g day -1 formaldehyde- treated casein) resulted in 40% more wool growth in sheep (P<0.001), but no increase in cashmere or hair growth in goats. Goats fed ADLIB had significantly reduced cashmere yields (P < 0.05) and grew more hair (P<0.05) than did goats in other treatments. About 4 weeks after energy supplementation, fibre diameter of previously energy-deprived goats increased (P< 0.01). Midside patches indicated that energy-deprived goats, which lost liveweight, diverted nutrients preferentially to cashmere growth, while goats fed ADLIB partitioned nutrients towards hair growth. To maximise cashmere growth, supplementary energy should be supplied to avoid liveweight loss from December to April. Goats that had small (1-2 kg) liveweight gains and maintained body condition achieved near maximal levels of cashmere growth.

Weathering, fibre strength and colour properties of processed white cashmere

Weathering refers to the degradation of wool fibres that occur during growth from exposure of the fleece to sunlight, water and air. Weathering damage to Merino wool reduces quantities of fibre that are harvested, reduces length in both raw and processed wools, reduces spinning performance and dyeing outcomes. This work aimed to aimed to quantify if and to what extent weathering occurred in 38 lots of commercial dehaired white cashmere and cashmere top sourced from traditional and new origins of production and the extent of any association between weathering and tensile strength properties of the dehaired cashmere and cashmere top. The cashmere was tested for physical properties, bundle tenacity and extension, tristimulus values brightness (Y) and yellowness (Y-Z) and reflectance. Dye uptake was used as an index of weathering. Linear models, relating to weathering, bundle tenacity and Y-Z were fitted to origin and other objective measurements. Mean attributes (range) were: mean fibre diameter, 17.0 μm (13.5–21.3 μm); bundle tenacity of tops, 10.3 cN/tex (8.3–12.9 cN/tex), for dehaired fibre, 10.1 cN/tex (9.1–11.4 cN/tex). Stain uptake varied from 0.92 to 6.34 mg/g fibre indicating a six-fold variation in the extent of weathering. Both the extent of weathering and the bundle tenacity of commercial lots of cashmere were affected by the origin of the cashmere. Increased weathering reduced bundle tenacity, bundle extension, increased the yellowness and reduced reflectance of white cashmere. Bundle tenacity of cashmere declined as fibre diameter variability increased from 20 to 22.5%. For the samples tested, the cashmere from China, Mongolia, Afghanistan and Iran showed more weathering than cashmere from Australia, New Zealand and the USA. The differences in the extent of weathering and of bundle tenacity between cashmere from different origins were of commercial significance.