Cashmere Growth Research Articles

Fibre growth of cashmere-bearing goats given melatonin in late autumn and winter

Abstract At monthly intervals from May to August 1986, groups of 20 reproducing cashmere-bearing does began treatment with continuous-release melatonin implants, with the aim of avoiding winter shearing by prolonging cashmere growth and/or delaying shedding. Treatment groups, plus a group of 20 untreated goats starting in May, were fibre-sampled on the mid-side until 17 November to determine changes in staple fibre length, time of shedding (monthly intervals), and fibre growth rate (bimonthly intervals). Goats treated in May had significantly more cashmere growth on the mid-side than untreated goats in the period July–September, indicating that their cashmere growth rate was higher or that the period of cashmere growth had been prolonged. However, there was no significant increase in total cashmere production or any detectable delay in shedding of cashmere. There was no prolonging of cashmere growth or delaying of shedding in other treatment groups.

Fibre growth cycles of cashmere-bearing, reproducing does in Southern Hawkes Bay, New Zealand, over a 30-month period

Abstract Fibre growth was measured in reproducing, cashmere-bearing does by sampling fibre and skin monthly from a mid-side position to give length of both cashmere and guard hair, hair follicle activity, and rate of fibre regrowth following shaving. New cashmere was first detected in the fleece of individual goats in January, February, or March and new guard hair in September, October, or November. By June each year, average cashmere staple length was close to maximum. Cashmere staple length was 54, 44, and 43 mm in June 1986 1987, and 1988, respectively. Average staple guard hair length reached a maximum of c. 45 mm each year and was never less than 24 mm because of the overlap of guard hair cycles. Growth rates were greatest for cashmere from February to May and for guard hair from December to April. Secondary (cashmere-producing) hair follicles grew short (0.6-2.3 mm) fibres during spring when mean secondary follicle activity reached 30%. Cashmere growth started around December–January, with mean secondary follicle activity increasing rapidly to reach more than 90% by February where it remained until late May. Activity of primary (guard hair-producing) hair follicles increased rapidly from October and remained high until late March. Cashmere growth was close to completion by June and histological findings indicated that shedding was beginning in August. Consequently optimal cashmere returns should be achievable by shearing in June–July although winter shearing may create management difficulties.

Hormonal manipulation of cashmere growth and shedding

Cashmere goats exhibit seasonal cycles in hair growth and moulting which are an evolutionary response to seasonal changes in temperature. The winter coat of the cashmere goat consists of two types of fibre, a coarse outer coat of guard hair produced by the primary hair follicles and a dense Insulating undercoat of cashmere (<19 microns diameter) produced by the smaller and more numerous secondary follicles. In the Spring, under the influence of Increasing daylength, both guard hairs and cashmere are shed from the follicles and a sparse coat of guard hair remains.The efficiency of harvesting fibre from cashmere goats is limited by the season of the moult, the long duration of the moulting period and by the variability between individual animals in the timing of the moult. Lynch & Russel (1989) reported that an earlier rise in plasma prolactin was associated with an advance In the onset of the spring moult in the cashmere goat.

Grazing management studies with Australian cashmere goats. 1. Effect of stocking rate on the growth and fleece production of weaner goats grazing tropical pastures

Australian cashmere weaner goats were continuously grazed on either nitrogen (N) fertilised Pangola grass or mixed tropical legume-pangola grass pastures at 3 stocking rates (15, 30, 60 goats/ha). Grazing commenced in January and was terminated in May (18 weeks). Three parasite control treatments (Seponver, Avomec, Systemex) were superimposed on each treatment. Parasite egg counts, liveweight change, cashmere growth and changes in pasture components were measured. Intestinal parasite burdens were low (<400 eggs/g faeces) in all animals throughout the trial, and there were no significant effects of parasite control treatment on goat productivity. The liveweight gain of goats decreased with increasing stocking rate and time on pasture. Mean values for the liveweight change of goats on the legume-grass pasture were 66, 37 and 14 g/day at stocking rates of 15, 30 and 60 goats/ha, respectively. Comparable values for goats grazing N-fertilised pangola grass were 40, 39 and 23 g/day for stocking rates of 15, 30 and 60 goats/ha. Goats grazing the legume-grass pastures at the lowest stocking rate (15 goats/ha) had significantly higher liveweight gains than did goats on all other treatments. There were no significant effects of stocking rate, pasture type or worm control treatment on fleece growth in these goats. Mean values were 191 g, 39 g and 15.0 �m for fleece weight, cashmere weight and mean cashmere fibre diameter respectively. The major legume in the legume-grass pasture was siratro, with axillaris, greenleaf desmodium and cassia forming minor components (10-300 kg/dry matter (DM)/ha). During the first 6 weeks of grazing, all legume components increased under stocking rates of 15 and 30 goats/ha. Thereafter, there was a significant decline in siratro yield to less than 200 kg DMha at all stocking rates. During this same period, the yields of the other legumes generally increased, suggesting that at low stocking rates the goats preferred grass to legume, and when grass was limiting, siratro was the legume preferred over all others. Weed yields increased with time in all except the high stocking rate treatments. It was concluded that weaner goat growth can be maximised on tropical legume-pangola grass pastures when stocking rates and intestinal parasite burdens are low. Protein intake may be limiting growth on N-fertilised grass pastures.

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.

Effect of DL-methionine supplementation on fleece growth by Australian cashmere goats

Australian feral goats have recently been found to produce commercially viable quantities of the luxury fibre cashmere (Smith, Clarke & Turner, 1973). Cashmere is the fine down produced by secondary follicles as an undercoat during winter. Fibre diameter ranges from 8 to 24 μm with a mean diameter of 16 μm. Unlike modern breeds of sheep such as the Merino which exhibit almost continuous wool growth, cashmere growth is distinctly seasonal with fibre growth commencing in summer (long daylength) and reaching a maximum length in early winter (short daylength) (McDonald, 1985). The cashmere is cast in spring with growth recommencing again in summer.

Productivity of Australian cashmere goats grazing Pangola grass pastures and supplemented with untreated and formaldehyde treated protein meals

The liveweight change and fleece growth Of Australian cashmere goats were studied in a 14 week grazing experiment (Mar.-June) in south-eastern Queensland. Weaner goats grazed nitro-fertilised Pangola grass (Digitavia decumbens Stent.) pastures and were supplemented every second day with a range of protein meals (60 g crude protein/goat.day), i.itht.1. untreated or fomialdehyde treated. Following high growth rates (> 90 g 1iveweight.day) by all kids early in the experiment, control animals experienced severe weight loss (-40 g/day). Goats given protein supplements performed significantly (P<0.05) better, though they only maintained weight. There were no differences (P> 0.05) in liveweight change between the untreated and formaldehyde treated protein groups. The poor growth of goats in this study was associated with declining feed availability under the high stocking rates used (80 goats/ha) and possibly with a seasonal depression in appetite. Total fleece growth was significantly (P<0.05) increased by protein supplementation, except for sunflower meal. However, cashmere growth (mean � s.e., 16.3 � 2.1 g) was largely unaffected by supplementation, with greater hair growth (64 v. 54 g) being responsible for the improved fleece weight in those goats receiving protein supplements. Kids supplemented with formaldehyde treated protein tended to grow more fleece than did kids given untreated protein meals but the differences were not significant.

Effect of photo-translation on fleece growth in cashmere goats

Cyclical changes in fleece parameters were studied in mature feral doe goats exposed to either natural light (NL) followed by continuous light (CL) then NL, or CL followed by NL then CL.Results show that both initial translocations (NL-CL and CL-NL) were recognized immediately and reflected in changes in volume growth rate, length, diameter, brush end fibres of cashmere and cashmere : hair ratio. Cyclic activity continued after the change in photoperiod. Progressive alterations in cycle amplitude, period and frequency appeared in CL following the initial NL-CL change. Following the initial CL-NL change, cycles of some cashmere fleece parameters continued to be influenced by previous CL exposure and did not immediately adopt NL cyclicity. Mean cycle periods of 252-261 days were common to all CL photoperiods and to NL following CL. This suggests that CL exposes a unique cycle of fleece growth, which is independent of photoperiod and retained for some time after the cessation of CL, owing to transient modification of pineal function. Differences between the response to the first and second translocation may be a function of interactions between the cycle status and translocation, rather than solely the change from one photoperiod to another.The NL-CL change resulted in two cycles of cashmere growth in the 392 days following the initial translocation. This would allow two fleeces to be harvested during that time compared with the one expected in NL alone. Exploitation of this principle may represent an opportunity to increase cashmere production.

The sedimentation rate in angina pectoris and coronary thrombosis: Riseman, Joseph E., and Brown, Morton G.: Am. J. M. Sc. 194: 392, 1937

This study was designed to investigate the effects of tryptophan (Trp) supplementation on cashmere fiber characteristics and on serum Trp, melatonin (MEL), prolactin (PRL), insulin-like growth factor 1 (IGF-1), triiodothyronine (T3), and thyroxine (T4) concentrations in cashmere goats during the cashmere fast-growth period. Thirty-six Liaoning cashmere wether goats were stratified on the basis of body weight (28 ± 0.8 kg) and assigned randomly to 1 of the following 4 rumen-protected Trp treatments: 0, 2.0, 4.0, and 6.0 g per goat per day. The experimental period lasted 137 d. Blood samples were collected monthly during the daytime (8:00 AM) and at night (8:00 PM). Tryptophan supplementation improved cashmere growth rates, cashmere weight, and body weight (P = 0.001) and increased serum Trp levels, nighttime MEL concentrations, IGF-1, and T3 and T4 concentrations (P < 0.05). Across the treatments and sampling months, a highly positive correlation between cashmere growth rate and nighttime serum MEL concentrations was observed (r = 0.879, P = 0.001). A moderately negative correlation between cashmere growth rates and serum PRL concentrations during the day and at night (rday = –0.645, P = 0.007; rnight = –0.583, P = 0.018) was observed. A moderately positive correlation between the cashmere growth rate and the daytime serum IGF-1 concentration (r = 0.536, P = 0.032) was observed, and no correlation was found between the cashmere growth rate and the other serum hormone concentrations. These data indicate that changes in serum concentrations of MEL, IGF-1, and PRL are related to cashmere growth in Liaoning cashmere goats during the cashmere fast-growth period. Under the experimental conditions of the current trial, we suggest that Trp may promote cashmere growth by increasing daytime IGF-1 and nighttime MEL secretion.