Transient treatment of pregnant Merino ewes with modulators of cortisol biosynthesis coinciding with primary wool follicle initiation alters lifetime wool growth

2013 ◽  
Vol 53 (10) ◽  
pp. 1101 ◽  
Author(s):  
M. L. McDowall ◽  
N. S. Watson-Haigh ◽  
N. M. Edwards ◽  
H. N. Kadarmideen ◽  
G. S. Nattrass ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Gene Families ◽  
Transforming Growth Factor Β ◽  
In Utero ◽  
Skin Development ◽  
Merino Sheep ◽  
Wool Follicle ◽  
Critical Phases

The economically important characteristics of the adult fleece of Merino sheep, such as increases in clean fleece weight, fibre length, fibre diameter and crimp characteristics are determined during critical phases of fetal development of the skin and its appendages. Genetics plays a major role in the development of traits, but the maternal uterine environment could also influence development. Treatment of pregnant ewes with cortisol and its analogues has previously been shown to produce changes in wool follicle morphology. The aim of this study was to determine the effect of transient manipulation of maternal cortisol status during critical phases of wool follicle initiation and development in utero. From Days 55–65 post-conception, singleton-bearing Merino ewes were treated with metyrapone (cortisol inhibitor) or betamethasone (cortisol analogue). Lambs exposed to metyrapone in utero were born with hairier birthcoats than the control or betamethasone treatment groups (P < 0.05), displayed a 10% increase in staple length and a reduction in crimp frequency for the first three shearings (P < 0.05). Co-expression network analysis of microarray data revealed up-regulation of members of the transforming growth factor-β and chemokine receptor superfamilies, gene families known to influence hair and skin development. These experiments demonstrate that presumptive transient manipulation of maternal cortisol status coinciding with the initiation of fetal wool follicle development results in long-term alteration in fleece characteristics, namely fibre length and fibre crimp frequency. These results indicate it is possible to alter the lifetime wool production of Merino sheep with therapeutics targeted to gene expression during key windows of development in utero.

Response to selection in Australian Merino sheep. VII. Phenotypic and genetic parameters for some wool follicle characteristics and their correlation with wool and body traits

1975 ◽  
Vol 26 (5) ◽  
pp. 937 ◽  
Author(s):  
N Jackson ◽  
T Nay ◽  
HN Turner ◽  
Turner H Newton
Keyword(s):  
Control Systems ◽  
Genetic Control ◽  
Genetic Parameters ◽  
Unit Area ◽  
Fibre Diameter ◽  
Environmental Correlations ◽  
Merino Sheep ◽  
Wool Follicle ◽  
Australian Merino

Four numerical characteristics-follicle depth, follicle curvature, number of follicles per unit area of skin, and ratio of number of secondary to number of primary follicles-describing the size, shape, and arrangement of wool follicles have been measured in Peppin Merino sheep at 4-5 months (weaning), 15-16 months (two-tooth shearing) and at later ages ranging from 2 1/2 to 7 1/2 years. Estimates of their repeatability, heritability and phenotypic, genetic, and environmental correlations with 10 wool and body characteristics are reported. All four follicle characteristics were found to be highly inherited and sufficiently correlated with wool characteristics to be of interest to both the wool biologist and the sheep breeder. Fixed environmental effects influenced the expression of some follicle characteristics, while others, notably follicle curvature at any age, were unaffected, and therefore potentially more useful as practical selection aids. Groups of sheep selected for clean wool weight with control of (i) fibre diameter and wrinkle score, and (li) crimp frequency and wrinkle score, exhibited changes in the four follicle characteristics, which agreed with what the genetic correlation estimates would predict. The role of follicle characteristics in the biology of genetic control of wool growth is portrayed by fitting causal models invoking follicle characteristics as intermediates between the gene and the wool character. The analysis separates three independent genetic control systems, the identity of which corresponds closely to factors postulated in previous theoretical studies.

Lifetime changes in wool production of Merino sheep following differential feeding in fetal and early life

2006 ◽  
Vol 57 (8) ◽  
pp. 867 ◽  
Author(s):  
R. W. Kelly ◽  
J. C. Greeff ◽  
I. Macleod
Keyword(s):  
Detrimental Effect ◽  
Fibre Diameter ◽  
Feed Restriction ◽  
Gestation Length ◽  
Merino Sheep ◽  
Wool Production ◽  
Free Weight ◽  
Wool Follicle ◽  
Pregnant Ewe

In commercial Merino farming, a major determinant of profitability is quantity and quality of wool production. We tested the hypothesis that the level of feed restriction commonly encountered by autumn/early winter lambing Merino ewes in southern Australia was sufficient to have a detrimental effect on their progeny’s lifetime wool production. Two periods of feed restriction of the dams were tested, viz. from day 50 to 140 of gestation (Expt 1), and from day 50 of pregnancy to weaning at 12 weeks of age (Expt 2). In order to reduce the numbers of experimental animals required, identical twin lambs were produced by cloning embryos. There was a total of 35 and 22 pairs of clones in Expts 1 and 2 that were recorded to 6.4 and 4.4 years of age, respectively. In Expt 1 it was estimated (i.e. conceptus-free weight) that the submaintenance (Sub-M) ewes lost 18 kg in weight compared with 9 kg by the Control (C) ewes over the period of differential feeding. In Expt 2 the Sub-M ewes lost 10 kg during pregnancy and 10 kg during lactation, compared with a loss of 3 kg and a gain of 4 kg over the same period in the C ewes. Gestation length was 1.3 days shorter (P < 0.01) in the Sub-M than C ewes in Expt 1. Birthweights of the Sub-M lambs were 0.5 kg lighter than the C lambs in Expts 1 (P < 0.01) and 2 (P < 0.05). At 12 weeks of age, liveweights of the lambs in the Sub-M and C treatments were 24.2 and 25.9 kg in Expt 1 (P < 0.01) and 14.0 and 25.0 kg in Expt 2 (P < 0.001). Corresponding liveweights at 4 months of age were 30.9 and 32.5 kg (P < 0.01) and 19.9 and 29.7 kg (P < 0.001), the Sub-M animals producing less clean wool (0.1 and 0.4 kg, P < 0.01 and < 0.001, Expts 1 and 2, respectively), that was finer in Expt 2 (2.7 μm, P < 0.001) than their C counterparts. Throughout the rest of the study the Sub-M animals in Expt 2 (but not Expt 1) were on average 3.2 kg lighter (P ranging from < 0.05 to < 0.001) than C animals. In both experiments the ratio of secondary to primary wool-producing follicles was lower (1.1–2.6 units, P < 0.001) in the Sub-M than C animals. These differences led to (P < 0.05) lower significantly adult clean wool production of 0.17 kg (Expt 1) and 0.24 kg (Expt 2) per annum. There was no significant interaction between nutritional treatment and age of the animal for clean wool production. Within experiments there were no significant differences between nutritional treatments in any of the wool quality measurements. However, when fibre diameter data for both experiments were combined for 3.4 and 4.4 years of age, the Sub-M animals were significantly broader (0.3 μm, P < 0.01) when compared with the C animals. We conclude that Sub-M feeding of the pregnant ewe will permanently affect liveweight, the wool follicle population, and wool production and quality, in Merino sheep. Extension of the period of under feeding into lactation (Expt 2) appears to increase the amplitude of the differences in young animals, which is largely overcome by the time the animal reaches 2.4 years of age.

Controls of Hair Follicle Cycling

2001 ◽  
Vol 81 (1) ◽  
pp. 449-494 ◽  
Author(s):  
K. S. Stenn ◽  
R. Paus
Keyword(s):  
Growth Factor ◽  
Hair Follicle ◽  
Cell Biology ◽  
Transforming Growth Factor ◽  
Gene Families ◽  
Transforming Growth Factor Β ◽  
Follicle Growth ◽  
Modern Biology ◽  
Hair Follicle Growth

Nearly 50 years ago, Chase published a review of hair cycling in which he detailed hair growth in the mouse and integrated hair biology with the biology of his day. In this review we have used Chase as our model and tried to put the adult hair follicle growth cycle in perspective. We have tried to sketch the adult hair follicle cycle, as we know it today and what needs to be known. Above all, we hope that this work will serve as an introduction to basic biologists who are looking for a defined biological system that illustrates many of the challenges of modern biology: cell differentiation, epithelial-mesenchymal interactions, stem cell biology, pattern formation, apoptosis, cell and organ growth cycles, and pigmentation. The most important theme in studying the cycling hair follicle is that the follicle is a regenerating system. By traversing the phases of the cycle (growth, regression, resting, shedding, then growth again), the follicle demonstrates the unusual ability to completely regenerate itself. The basis for this regeneration rests in the unique follicular epithelial and mesenchymal components and their interactions. Recently, some of the molecular signals making up these interactions have been defined. They involve gene families also found in other regenerating systems such as fibroblast growth factor, transforming growth factor-β, Wnt pathway, Sonic hedgehog, neurotrophins, and homeobox. For the immediate future, our challenge is to define the molecular basis for hair follicle growth control, to regenerate a mature hair follicle in vitro from defined populations, and to offer real solutions to our patients' problems.

scholarly journals Expression of transforming growth factor-β isoforms and their receptors in utero-vaginal junction of hen oviduct in presence or absence of resident sperm with reference to sperm storage

Reproduction ◽  
2006 ◽  
Vol 132 (5) ◽  
pp. 781-790 ◽  
Author(s):  
Shubash Chandra Das ◽  
Naoki Isobe ◽  
Masahide Nishibori ◽  
Yukinori Yoshimura
Keyword(s):  
Growth Factor ◽  
Western Blot ◽  
Reverse Transcriptase ◽  
Mrna Expression ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
In Utero ◽  
Sperm Storage ◽  
Reverse Transcriptase Pcr ◽  
Sperm Storage Tubules

Our goal was to determine whether transforming growth factor β (TGFβ) isoforms were involved in the process of sperm survivability in the sperm-storage tubules (SST) in the utero-vaginal junction (UVJ) of hen oviduct. The birds were artificially inseminated. The mRNA expressions of three types of TGFβ isoforms (TGFβ2, TGFβ3, and TGFβ4) and three types of receptors (TβR1, TβR2, and TβR3) were examined in the presence or in the absence of resident sperm in SST by semi-quantitative reverse transcriptase-PCR. The mRNA expression of TGFβs and TβRs in sperm was also examined. Immunocytochemistry and western blot were performed for TβR2 to confirm its localization in UVJ. The sperm were observed at least 10 days after insemination by histology. The mRNA expressions of TGFβs and TβRs were significantly increased in UVJ in the presence of resident sperm in SST. The mRNA expressions of TGFβs and TβRs were also observed in sperm. Immunohistochemistry revealed that TβR2 were located in lymphocytes in UVJ and SST cells. The presence of TβR2 in UVJ was also confirmed by western blot. These results suggest that enhanced expressions of TGFβs and TβRs in UVJ may protect sperm in SST, probably by suppressing anti-sperm immunoreactions.

Environmental responsiveness of fibre diameter in grazing fine wool Merino sheep

2005 ◽  
Vol 56 (7) ◽  
pp. 673 ◽  
Author(s):  
D. J. Brown ◽  
B. J. Crook
Keyword(s):  
Seasonal Variation ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Skin Thickness ◽  
Merino Sheep ◽  
Length Growth ◽  
Environmental Responsiveness ◽  
Diameter Fibre ◽  
Staple Strength ◽  
Profile Characteristics

Fibre diameter, fibre length, and the ratio of fibre length growth to mean fibre diameter (L/D), fibre diameter profile characteristics, and staple strength were examined in 16 fine wool Merino wethers in a 12-month field experiment. Variations in fibre diameter, fibre length, and L/D were shown to be associated with fibre diameter profile characteristics and staple strength. At constant fibre diameter, L/D was significantly positively related to variation in fibre diameter along the staple. A positive correlation between seasonal variation in L/D and variation in diameter between fibres was also observed. Staple length was significantly positively correlated with along-staple variation in fibre diameter and negatively correlated with variation in fibre diameter among fibres. Among-fibre variation in fibre diameter was not significantly correlated with along-staple variation in fibre diameter. Seasonal variation in fibre length growth, fibre diameter, and the ratio of length to diameter throughout the year was associated with increased variation in fibre diameter along the fibre diameter profile and reduced staple strength in grazing sheep. Seasonal variation in fibre diameter was mostly related to mean fibre diameter, L/D, and seasonal variation in fibre length growth rate. Changes in fibre diameter throughout the year were also related to seasonal changes in body weight, fat depth, and skin thickness.

scholarly journals Evidence of a unique developmental mechanism specifying both wool follicle density and fibre size in sheep selected for single skin and fleece characters

1989 ◽  
Vol 53 (1) ◽  
pp. 57-62 ◽  
Author(s):  
G. P. M. Moore ◽  
N. Jackson ◽  
J. Lax
Keyword(s):  
Fibre Diameter ◽  
Statistical Association ◽  
Merino Sheep ◽  
Developmental Mechanism ◽  
Negative Linear Correlation ◽  
Foetal Life ◽  
Wool Follicle ◽  
Fleece Weight ◽  
The Relationship ◽  
Staple Length

SummarySkin and fleece traits have been characterized in four lines of Merino sheep selected for high- and low-fibre diameter (D±) and staple length (L±) from a medium-woolled flock. Over a period of 20 years, each line responded in the desired direction, producing fleeces composed of thick or thin fibres and long or short wool staples. However, variations in the amounts of wool grown that might be expected from these procedures were compensated by changes in unselected characters. Thus a predicted difference in fleece weights between high and low staple length lines was reduced by an increase in fibre crimp frequency in L− sheep. Similarly, changes induced in fibre diameter in the D lines resulted in small effects on fleece weight in comparison to the large (and inverse) effects on follicle numbers. Towards the end of the selection regime, mean follicle density in D− sheep was twice that of D+ sheep. This intriguing response within the follicle population was examined further: an analysis of the relationship between follicle density and fibre diameter amongst the four lines revealed a highly significant, negative linear correlation. The implication of this statistical association is that the numbers of follicles initiated in skin during foetal life had a direct bearing on the sizes of wool fibres eventually produced. It was concluded that both features must be under the control of a single developmental mechanism. Since the expression of each of the characters is separated in time, the mechanism must be activated during the earlier event, i.e. at or before the phase of follicle initiation.

Tunicamycin reduces wool growth by slowing the mitotic activity of wool follicles

1997 ◽  
Vol 48 (3) ◽  
pp. 331 ◽  
Author(s):  
S. C. Davies ◽  
I. H. Williams ◽  
C. L. White ◽  
J. E. Hocking Edwards
Keyword(s):  
Direct Effect ◽  
Vascular System ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Annual Ryegrass ◽  
Wool Growth ◽  
Wool Follicle ◽  
Low Levels ◽  
A Minor ◽  
Annual Ryegrass Toxicity

Reductions in wool growth have previously been observed in ewes exposed to low levels of corynetoxins, the causal agents of annual ryegrass toxicity. In this experiment, tunicamycin, a commercially available and closely related toxin, was infused into an isolated area of skin on the abdominal flank. Eleven sheep were continuously infused for 5 days with saline on one side and a total dose of either 35 or 350 µg tunicamycin/kg affected skin on the other side. Both fibre length (P < 0·05) and fibre diameter (P < 0·01) were reduced by tunicamycin treatment. Cell division in the wool follicle bulb was also reduced by tunicamycin (P < 0·005), indicating that the toxin is able to have a direct effect on the follicles and their ability to produce wool. The permeability of the vascular system increased in the skin tissue treated with tunicamycin, but only at the highest toxin dose (P < 0·05); therefore, poor nutrient supply to the follicle may be a minor contributor to reduced wool growth. The direct effect of tunicamycin on the wool follicle explains why wool growth is reduced by low levels of corynetoxins independently of, and prior to, effects on the whole animal.

Effects of shearing time and time of lambing on wool growth and processing characteristics

1984 ◽  
Vol 24 (126) ◽  
pp. 337 ◽  
Author(s):  
GW Arnold ◽  
AJ Charlick ◽  
JR Eley
Keyword(s):  
Growth Rate ◽  
Seasonal Pattern ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Lower Percentage ◽  
Dominant Factor ◽  
Lower Yield ◽  
Merino Sheep ◽  
Wool Growth ◽  
Fleece Weight

Wool growth rate, seasonal pattern of fibre diameter, clean fleece weight, quality and the processing characteristics of wool were measured on medium-wool Merino sheep shorn in March (autumn) or October (spring) coupled with March or June lambing. These four management systems were compared under two nutritional regimes in the medium rainfall area of Western Australia. The sheep grazed annual pastures only, or had lupin grain and stubble during summer in addition to the pasture. The study ran for two shearing periods. Time of shearing was the dominant factor. Sheep shorn in March produced 14% more clean wool and fewer tender fleeces than sheep shorn in October. The autumn wool had a lower yield, higher fibre diameter and when processed had a higher card loss, lower percentage noil and lower top and noil yield. However, mean fibre length in the top was substantially higher and the variation in fibre length lower. Vegetable matter was higher in autumn shorn wools. There were some interacting effects of lambing time and type of feed regime. Sheep fed lupins had lower yielding wool but this effect was more pronounced in June lambings and was reflected in differences in top and noil yield. From measurements of wool growth rate, it was found that the extra wool was produced in autumn after shearing, due possibly to stimulated appetite that cannot occur after spring shearing because the sheep are too fat.

scholarly journals Polymorphisms and association of FAT1 gene with wool quality traits in Chinese Merino sheep

2020 ◽  
Vol 65 (No. 1) ◽  
pp. 31-39
Author(s):  
Guang-Wei Ma ◽  
Xin You ◽  
Hua Yang ◽  
Xiao-Hong Yan ◽  
Fang Mou ◽  
...  
Keyword(s):  
Planar Cell Polarity ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Wool Fibre ◽  
Pcr Analysis ◽  
Quality Trait ◽  
Quality Traits ◽  
Exon 2 ◽  
Merino Sheep ◽  
Wool Quality

FAT atypical cadherin 1 (FAT1) is a member of the atypical cadherin superfamily and is involved in the planar cell polarity signalling pathway which regulates hair follicle morphogenesis, cycling, and orientation. The purpose of this study was to investigate the sheep FAT1 gene expression, polymorphisms and its association with wool quality traits in Chinese Merino sheep. Quantitative real-time PCR analysis showed that the FAT1 mRNA was differentially expressed in the adult skin of Chinese Merino and Kazak sheep. Seven SNPs (termed SNPs 1–7) were identified in exon 2 of sheep FAT1 gene by Sanger sequencing. SNPs 2 and 7 (novel SNPs) were significantly associated with wool crimp (P &lt; 0.05). SNPs 4 and 5 (rs161528993 and rs161528992) were significantly associated with wool fibre length (P &lt; 0.05). SNP 7 was highly significantly associated with average wool fibre diameter (P &lt; 0.01). Similarly, FAT1 haplotypes were significantly associated with wool crimp (P &lt; 0.05), and the haplotypes H1–H3 and H5 were significantly associated with higher wool crimp (P &lt; 0.05). Bioinformatics analysis showed that the wool quality trait-associated SNPs (SNPs 2, 4, 5 and 7) might affect the pre-mRNA splicing by creating or abolishing the binding sites for serine/arginine-rich proteins, and in addition, SNPs 2 and 4 might alter the FAT1 mRNA secondary structure. Our results suggest that FAT1 influences wool quality traits and its SNPs 2, 4, 5 and 7 might be useful markers for marker-assisted selection and sheep breeding.

Some properties of the wool from copper-starved Merino sheep

1949 ◽  
Vol 39 (3) ◽  
pp. 265-273 ◽  
Author(s):  
R. C. Palmer
Keyword(s):  
Tensile Strength ◽  
Amino Acid ◽  
Fibre Diameter ◽  
Fibre Length ◽  
South Australia ◽  
Fibre Strength ◽  
Research Association ◽  
Merino Sheep ◽  
Special Skill ◽  
The Mean

The mean fibre length, mean fibre diameter, mean fibre crimp ratio (i.e. ratio of length of the fibre under 2·5 mg. load to its length stretched), and a quantity approximately proportional to the ultimate tensile fibre strength, have been measured for twenty-five skirted Merino fleeces clipped from sheep that had been grazed at Robe (South Australia) on copperdeficient land and fed by mouth with amounts of copper varying from zero to 100 mg./day. Sulphur analyses and qualitative amino-acid analyses were carried out on some of the fleeces. The fleeces were processed one by one on the worsted system into yarn. The results show an increase in fibre diameter, an increase in ultimate tensile strength and an improvement in behaviour in processing with increasing dietary supplement of copper.A contribution to these experiments through special skill or knowledge has been made by almost everyone on the staff at Torridon, and especially by the late W. L. Semple, J. G. Martindale and H. Beevers. Thanks are due to Messrs Isaac Holden and Sons Ltd. for their generous co-operation in carrying out part of the work at their mill and to Mr A. Prescott, Mr F. Sharp and Mr G. W. Owen of the Wool Control, and Mr F. R. Emmett of Messrs Laycock, Son and Co. Ltd., for their assistance in judging tops. The author would like to thank Mr B. H. Wilsdon, the Director of Research, for suggestions and encouragement during this work, and the Council of the Wool Industries Research Association for permission to publish this paper.

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