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PubMed1988

Effects of growth hormone administration on wool growth in merino sheep.

The effects of daily administration of 10 mg of highly purified ovine growth hormone (GH) for a period of 4 weeks on wool growth have been measured in 12 Merino ewes fed either a calculated maintenance energy intake or 1.6 times this amount (six on each ration). Concentrations of hormones, glucose, urea, alpha-amino N and amino acids in the blood were monitored and faeces and urine collected for measurement of nitrogen balance. Wool growth rate decreased by 20% during the 4 weeks of GH treatment in sheep fed the high energy diet, largely because of reduced wool fibre diameter. This was followed by restoration of normal growth and then an increase of up to 20% above control levels, a response which persisted for 12 weeks following cessation of GH administration, and which was due to increases in both fibre length and diameter. GH administration caused marked increases in plasma concentrations of GH, insulin and somatomedin C, glucose and free fatty acids, all of which returned to basal levels following cessation of GH administration. No consistent changes in plasma concentration of T3, T4, cortisol, prolactin or alpha amino N were detected. Plasma urea and methionine levels decreased during GH treatment and returned to, or were raised above, basal levels after the GH treatment period. GH injection also resulted in a net retention of N during treatment, followed by a transient period of net N loss. The GH-induced changes in wool growth may be caused by a change in the partitioning of amino acids between the muscle mass and the skin. No other contributing factor(s) were identified.

Animals↗
PubMed1991

Chronic treatment with long-acting bromocriptine does not affect duration of the breeding season, voluntary food intake, body weight, or wool growth in the Scottish blackface ewe.

The aim of this study was to determine whether suppression of the seasonal increase in prolactin concentrations by chronic treatment with the dopamine agonist bromocriptine would affect onset of anoestrus, voluntary food intake, body weight, and wool growth in a seasonal breed of sheep. Groups of eight Scottish Blackface ewes were injected i.m. each week with either the vehicle (Group A) or 2.0 mg (Group B), 6.0 mg (Group C), or 18.0 mg (Group D) of bromocriptine in a long-acting formulation, commencing on 18 January and terminating on 25 July (midwinter to midsummer in the northern hemisphere). Immediately before the bromocriptine injection, blood samples were taken for progesterone and prolactin determination. Voluntary food intakes were measured daily, and body weights were recorded every fortnight. Estimates of wool growth were made by weighing wool clipped from a measured area of skin once a month. Treatment had no effect on onset of anoestrus, voluntary food intake, body weight, or wool growth. Plasma prolactin concentrations increased significantly in all groups during the treatment period. From January to April, all doses of bromocriptine significantly reduced prolactin concentrations but later in the study (May and June) prolactin was significantly suppressed in Group D only, although even in this group prolactin concentrations increased between March and June. Pituitary prolactin content, measured at the end of the study in July, was also suppressed by bromocriptine. The gradual increase in prolactin concentrations in ewes receiving chronic bromocriptine was further investigated by treating a fifth group of ewes (Group E) with 18.0 mg of long-acting bromocriptine each week, commencing on 20 June.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

The role of condensed tannins in the nutritional value of Lotus pedunculatus for sheep. Rates of body and wool growth.

Lotus pedunculatus (cv. Grasslands Maku) grown on acid low-fertility soil and containing high concentrations of condensed tannin (76-90 g/kg dry matter (DM] was grazed by growing sheep for 31-42 d periods in three experiments. In Expt 2 an additional group of lambs grazed areas oversown with white clover (Trifolium repens) and red clover (Trifolium pratense). Lambs were transferred from grazing ryegrass (Lolium perenne)-white clover straight on to lotus in all experiments (unconditioned sheep). In Expt 3 a second group was included which had grazed high-tannin lotus for a pre-experimental period of 8 weeks (conditioned sheep). Effects of condensed tannin on body and wool growth were assessed by studying responses to daily oral administration of polyethylene glycol (PEG; molecular weight 3350, 75-100 g/d). PEG forms a complex with condensed tannin, which is assumed to be inert in its passage through the digestive system, and so effectively reduces the nutritional effects attributable to high condensed-tannin concentrations. Live-weight gain (LWG) in the absence of PEG was low (27-125 g/d) for sheep grazing high-tannin lotus, and PEG administration increased LWG by 41-61 g/d and increased wool growth. In Expt 3, responses to PEG supplementation tended to be less with conditioned than with unconditioned sheep, indicating that conditioned sheep had partially adapted to the high-tannin diet. PEG supplementation had no effect on either LWG or wool growth of sheep grazing areas oversown with mixed clovers, confirming its effects as specific to forages containing condensed tannins. These experiments therefore conclusively show that high concentrations of condensed tannin induced by growing Lotus pedunculatus under low soil fertility conditions prevent maximum expression of LWG and wool growth in grazing sheep. These results contrast with high LWG (153-315 g/d) observed in growing sheep grazing the same lotus cultivar grown in high fertility soil and containing 20 g condensed tannin/kg DM, a level considered to be nutritionally beneficial.

Administration, Oral↗
PubMed2006

Influence of temperature on stability of multilamellar liposomes in wool dyeing.

Liposomes are lipid vesicles that are composed of amphiphile molecules and can carry hydrophobic and hydrophilic materials. In this research work liposomes used as carrier for transfer of dye molecules into wool fibers. The preparation and production of multilamellar liposomes (MLV) from Soya lecithin were carried out and the behavior of liposomes at different temperature was studied. The effect of different concentration of liposomes in the dye exhaustion profile of two dyes (Namely, Irgalan Blue FBL and Lanaset Blue 2R) at two different temperatures of 85 degrees C and 95 degrees C on the wool fabric was investigated. The results showed that presence of liposomes in the dye-bath helps to increase the dye absorption on the wool fabric before 80 degrees C. Dyeing at higher temperature and longer time leads to a decrease in the final exhaustion along with increase in the liposomes concentration. Liposomes at high temperature converted to the disperse phospholipids unimers that may deposited on the fabric surface and may produce a hydrophobic barrier against absorption of dye. The presence of 1% o.w.f. (on weight of fabric) of liposomes at 85 degrees C improved the dye exhaustion of Irgalan Blue FBL on the wool fabric. The wash fastness properties of samples which dyed in the dye-bath containing liposomes also improved.

Animals↗
PubMed1998

Wool production in transgenic sheep: results from first-generation adults and second-generation lambs.

In sheep transgenic for a sheep insulin-like growth factor 1 (IGF-1) cDNA driven by a mouse keratin promoter, we assessed wool production and properties in 51 adults of the first generation (G1) and in 56 lambs of the second generation (G2). Transgenic G1 sheep had an increased rate of wool production during spring and summer of year 2 compared with nontransgenic half-sibs, with a maximum increase of 17% in December, but during the winter nadir rates were similar. At second- and third-year shearing, however, fleece weights were not significantly different. There was a trend for transgenic animals to have coarser wool of lower staple strength. A controlled feeding trial revealed no significant differences in feed intake. The transgene was expressed not only in skin but also in a wide range of other tissues. Circulating IGF-1 concentrations were not significantly different between transgenic and nontransgenic animals, suggesting that local mechanisms were more important than systemic mechanisms for wool production, but were significantly higher in males than in females. In the G2 sheep, transgenic fleece weight did not differ significantly from nontransgenic either as lambs or at the end of the lamb year. Although the transgene was inherited in Mendelian fashion and was widely expressed, the production advantage seen in animals of the first generation did not persist in the second generation.

Animal Husbandry↗
PubMed2006

Dyeing of wool fibres with natural dyes: effect of proteolytic enzymes.

In spite of the widespread use of proteins (casein, peptone, etc.) and protein fragments as a substrate for the proteolytic enzymes, a substrate prepared from dyes that adsorb onto appropriate materials, such as wool and cotton, are also used for enzyme activity determination. In the point of view of this thought, it was our aim to develop the substrates which are easily and economically obtainable and also environmentally safer for the frequently used proteolytic enzymes, such as subtilisin carlsberg, trypsin, chymotrypsin, and protease type XVI and, if possible, to prepare the specific substrate at least for one of these enzymes. For this aim, wool was dyed with natural dyes such as juglone, lawsone, berberine, and quercetin. The optimum pH, incubation time, and agitation rate were determinated. The results indicate that, of all the tested enzymes on wool-dye complex as an insoluble substrate, the most appropriate complex was found to be wool-lawsone complex.

Animals↗
PubMed1986

Localization of low-sulfur keratin proteins in the wool follicle using monoclonal antibodies.

Monoclonal antibodies that recognize components of the low-sulfur keratin proteins extracted from Merino wool have been used to locate these components within the wool follicle. Immunoblotting procedures showed that all of the monoclonal antibodies bound more than one of the eight low-sulfur protein components, indicating that these proteins have antigenic determinants in common. Immunofluorescence studies showed that those antibodies specific for the component 7 family of the low-sulfur proteins bound to the developing wool fiber, whereas those antibodies recognizing the component 8 family bound to areas throughout the wool follicle, particularly the inner and outer root sheaths, but also to the fiber, the cuticle, and the epidermis. One of the monoclonal antibodies also bound to intermediate filament networks of cultured human epithelial cells.

Animals↗
PubMed1999

Wool follicle matrix cells: culture conditions and keratin expression in vitro.

Wool follicle matrix cell cultures were initiated as explants from Tukidale (carpet wool) sheep primary follicle bulbs after removal of the outer root sheath. Successful explantation required coculture on collagen with intact dermal papillae. Cells had a typical epidermal morphology (pavements of flattened. polyhedral cells). Extracellular matrix from dermal papillae, conditioned media, separation of dermal papilla from bulb matrices by tissue culture inserts and feeder layers were unable to support matrix cell explantation. Cultures could be maintained for up to 14 passages during which time the cells became larger with an increased cytoplasmic/nuclear ratio and irregular outline. Proliferation of matrix cells was greater on laminin than with either collagen type I or type IV. Proliferation was considerably reduced under serum-free conditions. This was most apparent at low calcium (0.09 mmol/L). By Northern hybridization matrix cells were found to express keratin K18 at all stages of culture. Keratin K 1.15 expression was evident by the tenth passage. The wool-specific keratin K2.10 was not detected. The data demonstrate that successful wool matrix cell culture is achievable. Keratin gene expression occurs in these cells and varies with the stage of culture.

Animals↗
PubMed1991

myc protooncogenes of wool and hair growth.

The growth of hard keratin fibers such as wool and hair is dependent on the proliferation of cells in the follicle bulb. If the cells leaving the bulb could be induced to undergo an extra division, then fiber growth should increase. The cellular division within the follicle is complex and probably involves one or more growth factors, which act by altering the expression of transcription factors and other nuclear proteins. We propose that the expression of the myc protooncogenes is a central part of this mechanism. In support of this hypothesis we have detected the mRNAs for TGF-beta 1, basic FGF, TGF-alpha, and c-myc in plucked wool follicles using PCR amplification. We have also shown that the TGF-beta 1, TGF-beta 2, TGF-beta 3, EGF, TGF-alpha, basic FGF, N-myc, and c-myc genes are expressed in mouse skin, and we looked for changes during the hair cycle. The PCR data suggest that in whole skin the levels of mRNA for TGF-beta 1, TGF-beta 2, TGF-alpha, and c-myc do not change. In Quackenbush mice the levels for N-myc, TGF-beta 3, and basic FGF mRNA appear to be lower at the end of the hair cycle. We have confirmed in CBA/C57 black mice that lower levels of N-myc mRNA are detected when hair growth ceases in catagen and telogen. To test our hypothesis further and to assess its practical application, we are making transgenic mice in which the N-myc gene is overexpressed in the hair follicle by way of a wool keratin promoter. The transgene consists of 3.3 kb of 5' sequence from an ovine type 1 IF gene, the murine N-myc genomic coding sequence, and an SV40 polyadenylation signal. The native keratin type 1 IF gene is expressed exclusively in the wool follicle, as shown by in situ hybridization. However, in mice the injection of the transgene has resulted in high embryonic mortality and some embryos with large body size and head malformations. Since these mice were not transgenic, this is likely to be an effect of transient expression of the transgene during embryogenesis. The two transgenic mice produced so far have a normal phenotype.

Aging↗
PubMed1988

The effects of caseous lymphadenitis on wool production and bodyweight in young sheep.

Two hundred Merino wether hoggets were used to examine the effect of Corynebacterium pseudotuberculosis infection (caseous lymphadenitis) on wool production and bodyweight. Sheep which were challenged with C. pseudotuberculosis (artificially infected) and not vaccinated against this disease produced 0.20 kg less clean wool than unchallenged controls during the following 12 months. The incidence of sheep with lesions in the group that was vaccinated prior to challenge was 55% lower than in unvaccinated challenged sheep but their wool production was not significantly different from either the controls or the unvaccinated challenged sheep. Vaccinated sheep were also heavier than unvaccinated sheep 12 months after challenge. These results indicate that caseous lymphadenitis infection may reduce wool production.

Animals↗
PubMed1997

Changes in productivity and profitability of wool-growing farms that follow recommendations from agricultural and veterinary studies.

OBJECTIVE: To estimate the changes in productivity and profitability in a group of wool-growing farms as they adopted major recommendations from agricultural and veterinary studies. FARMS: Four wool-growing farms in south western Victoria were selected from the clients of the Mackinnon Project, a farm consultancy service run from the University of Melbourne. Each farm had closely followed recommended procedures, kept comprehensive financial and physical records and had been clients for at least 5 years. The comparison group was the South Western Victoria Monitor Farm Project (SWVMFP), about 45 farms in the same region as the study farms that were monitored annually by Agriculture Victoria. PROCEDURE: For a 7-year period, the financial and physical performance of both groups of farms was estimated. Stocking rate, wool production, gross farm income, farm operating costs, net farm income and return on assets were compared. RESULTS: Mean gross farm income of the four study farms steadily rose from 86% of the average SWVMFP farm before the adoption of recommendations to an average of 155%. During the same period, net farm income rose from 70% to 207% of the average of the SWVMFP. Return on asset of the four farms rose irregularly from 26% to 145% of the average of the SWVMFP. Farm operating costs on the four farms were higher than for the SWVMFP group, but the ratio of costs remained relatively constant. CONCLUSION: The adoption of proven research results was associated with large increases in net farm income. An increase in gross income, rather than a reduction in costs was the main reason for this. Research results offer a way to increase the financial viability of wool-growing farmers, many of whom are currently unable to maintain their lifestyle, resources and infrastructure.

Agriculture↗
PubMed1998

Trends in the use of pesticides and pesticide residues on Queensland wool.

OBJECTIVE: To determine the amounts of organophosphorous and synthetic pyrethroid residues on Queensland wool sampled between 1995 and 1997, and to study if pesticide use changed during the period. DESIGN: Estimated amounts of residues were obtained from a survey of Queensland wool clips and information on pesticide use was obtained from a trace-back postal survey of flock managers. PROCEDURE: Trends in amounts of residues over time were assessed using analysis of variance and simple linear regression models, and changes in pesticide use was assessed using chi 2 tests. RESULTS: Significant linear reductions in organophosphorous (P = 0.0012), synthetic pyrethroid (P = 0.0044) and total (P = 0.0002) residues were detected. The proportion of wool-growers treating for louse infestation (P = 0.0046) treating twice or more (P = 0.0006) and treating more than 4 months after shearing (P = 0.0001) decreased between 1994 and 1997. However, the proportion of growers who treated for blowfly strike (P = 0.0124) and used insect growth regulator pesticides increased (P < 0.0001). The use of handjetting to apply pesticides for blowfly strike control increased and the use of dips decreased (P < 0.0001). CONCLUSION: Residues of organophosphorous compounds and synthetic pyrethroids reduced in Queensland wool between 1994 and 1997. Although woolgrowers treated for louse infestation less, pesticide use to control blowfly strike increased. The increasing use of insect growth regulators in the industry needs to be monitored.

Animals↗
PubMed2005

Some physiological responses associated with reduced wool growth during blowfly strike in Merino sheep.

OBJECTIVE: To examine the effect on wool growth of physiological changes associated with experimental flystrike in superfine Merino wethers. DESIGN: An animal house study comparing experimentally fly struck sheep with non-infected control groups that were pair fed or fed ad libitum. PROCEDURE: Sheep in the blow fly larval challenge group were each artificially infected with 500 first instar larvae per day for 8 days. Infections were terminated with insecticide on day 10. For all sheep, live weight change, feed intake and body temperature were monitored and blood collected for analysis of haematology, cortisol, serum haptoglobin, serum amyloid A and the pro-inflammatory cytokines, TNFa, IL-1 b, IL-6 and IL-8. Wool growth and staple strength were examined 4 months after infection. RESULTS: Experimental fly strike included moderate fever, depressed feed intake, and elevated cortisol, IL-6, serum amyloid A and haptoglobin. Staple strength was significantly decreased in struck sheep and did not differ between wool from sites adjacent to and remote from strike lesions. CONCLUSIONS: The results suggest that depression in feed intake alone is not sufficient to account for the decline in staple strength seen during fly strike. Cortisol, IL-6 and metabolic consequences of the acute phase response are likely to be major contributors to the systemic effects of blowfly strike on wool.

Animals↗
PubMed1965

COMPARISON OF THE ELUTION AND ADSORPTION OF PICORNAVIRUSES BY COTTON AND CALCIUM ALGINATE WOOL SWABS.

The recovery of picornaviruses by cotton and calcium alginate wool swabs was studied by use of prototype strains of poliovirus 1, echovirus 1, coxsackievirus A9, and rhinovirus 16/60. No significant differences in recovery of viruses by the two types of swabs could be demonstrated. It is suggested that use of cotton swabs in the virus laboratory be continued, since wool swabs may favor the recovery of undesirable bacterial contaminants. Adsorption of viruses by cotton and wool swabs was similar from virus-buffer mixtures at pH 4.0, 7.0, and 8.0 at 24 and 37 C. Elution of virus from cotton and wool swabs was also studied. There was no significant difference in the amount of virus eluted at pH 5.5, 7.1, or 8.4.

Adsorption↗
PubMed1982

Plasma concentrations and urinary excretion of mouse epidermal growth factor associated with the inhibition of food consumption and of wool growth in Merino wethers.

Twenty-four adult Merino wethers were given mouse epidermal growth factor (mEGF) subcutaneously at doses ranging from 0.02 to 0.12 mg/kg body weight or intravenously in the dose range 0.10 to 0.14 mg/kg body weight for periods ranging from 3 to 48 h. Plasma concentrations of mEGF were measured by radioimmunoassay and effects of treatment on food consumption and wool growth were observed. Plasma concentrations of the protein sustained for 15-24 h at about 20 ng mEGF/ml (or exceeding this) almost invariably caused feed rejection and casting of the fleeces. This last result clearly indicated disruption of proliferative activity among the replicating cells in wool follicles which regulate wool growth. The inhibitory effects on appetite and wool growth of smaller doses of the protein and of plasma concentrations equal to those above which were sustained for shorter periods have also been examined. Approximately 10% of the dose of mEGF appeared in the urine of three sheep 1 to 3 days after the start of s.c. infusions of 5 mg for 7 h.

Animals↗
PubMed1991

A deterministic computer simulation model of life-cycle lamb and wool production.

A deterministic mathematical computer model was developed to simulate effects on life-cycle efficiency of lamb and wool production from genetic improvement of performance traits under alternative management systems. Genetic input parameters can be varied for age at puberty, length of anestrus, fertility, precocity of fertility, number born, milk yield, mortality, growth rate, body fat, and wool growth. Management options include mating systems, lambing intervals, feeding levels, creep feeding, weaning age, marketing age or weight, and culling policy. Simulated growth of animals is linear from birth to inflection point, then slows asymptotically to specified mature empty BW and fat content when nutrition is not limiting. The ME intake requirement to maintain normal condition is calculated daily or weekly for maintenance, protein and fat deposition, wool growth, gestation, and lactation. Simulated feed intake is the minimum of availability, DM physical limit, or ME physiological limit. Tissue catabolism occurs when intake is below the requirement for essential functions. Mortality increases when BW is depressed. Equations developed for calculations of biological functions were validated with published and unpublished experimental data. Lifetime totals are accumulated for TDN, DM, and protein intake and for market lamb equivalent output values of empty body or carcass lean and wool from both lambs and ewes. These measures of efficiency for combinations of genetic, management, and marketing variables can provide the relative economic weighting of traits needed to derive optimal criteria for genetic selection among and within breeds under defined industry production systems.

Animals↗
PubMed1991

Simulation of life-cycle efficiency of lamb and wool production for genetic levels of component traits and alternative management options.

A deterministic computer model was used to predict effects of genetic improvements in performance and of management options on life-cycle flock TDN input per unit of empty body weight (EBW) or carcass lean (CLN) equivalent value of market lamb, cull ewe, and wool output from a pure breeding system of sheep production for sheep fed to maintain normal weight. Relative values per kilogram for market lambs, cull ewes, and clean wool were 1 to .33 to 2.04 in lamb empty body equivalent, but 1 to .33 to 1 in lamb carcass lean equivalent. A 10% increase in lamb viability improved TDN/EBW or CLN by -15 to -20% for high to low lambing rates. Corresponding smaller gains were -7 to -11% for fertility, -3 to -13% for lambing rate, -1 to -3% for wool growth rate, -1 to -5% for milk production without creep feeding, -2 to -1% for mature size to about 70 kg, and -.6 to -.9% for precocity of fertility. Increasing leanness 10% improved TDN/CLN by -3 to -1% but increased TDN/EBW 3% because of higher maintenance requirements of leaner sheep. Higher protein requirements for increased lambing rate, milk production or leanness, or greater increases in non-feed than in feed costs, would mean only slightly less reduction of TDN/output than shown. Creep feeding was beneficial only for prolific, low-milking stock. Flushing reduced adverse effects of restricted feeding. Different values for wool vs meat or for costs of feed vs non-feed inputs would change results. These estimates for relative economic importance of traits apply to derivation of optimum criteria for selection among breeds or crosses, or within-breeds used in rotation crossbreeding, but would differ for specialized terminal-sire or maternal breed roles.

Animal Husbandry↗
PubMed1996

Lifetime lamb and wool production of targhee or Finn-Dorset-Targhee ewes managed as farm or range flock: I. Average annual ewe performance.

Lifetime (5 yr) lamb production and wool production from 207 straightbred Targhee (T) and 474 1/4 Finn-1/4 Dorset-1/2 Targhee (FDT) crossbred ewes managed in a range or farm flock system were evaluated for ewe fertility, prolificacy, ewe fleece weight, and total lamb weight weaned per ewe exposed. Data included 2,620 ewe exposures, 2,384 parturitions, 4,638 lambs born, and 3,498 lambs weaned. Ewes were born in 1984 through 1987 and lambed the first time as 2-yr-olds. Expressed as mean annual values, ewe fertility rates were similar (92.2 vs 91.0%, P = .30) for FDT and T ewes. Finn-Dorset-Targhee ewes had higher (P < .001) prolificacy (2.11 vs 1.75), weaned more lambs per ewe exposed (1.41 vs 1.18), produced more total lamb weight weaned per ewe exposed (33.8 vs 29.9 kg), and lambed 2 d earlier than T ewes. Targhee ewes produced more (P < .001) wool (4.5 vs 3.5 kg) than FDT ewes. Range flock ewes had a higher (P < .001) fertility rate (94.5 vs 88.7%), higher number of lambs weaned per ewe exposed (1.38 vs 1.22), and higher total lamb weight weaned per ewe exposed (34.7 vs 29.0 kg) than farm flock ewes. Farm flock ewes had a higher (P < .001) prolificacy (2.00 vs 1.86) and produced more wool (4.2 vs 3.8 kg) than range flock ewes. Targhee ewes had heavier lambs at birth (5.2 vs 4.6 kg; P < .001) and at weaning (25.8 vs 25.4 kg; P < .05). Range flock lambs were heavier (P < .001) at weaning than farm flock lambs (26.2 vs 24.9 kg). Lambs from FDT dams had a higher (P < .01) survival rate than lambs from T dams (75.6 vs 71.4%). Lamb survival from birth to weaning was higher (P < .001) for range flock lambs than for farm flock lambs (76.6 vs 70.4%). Incorporation of Finnsheep and Dorset breeding increased the reproductive performance in both management systems but decreased wool production.

Aging↗