Effects of Experimentally Induced Fleece-rot on the Structure of the Skin of Merino Sheep

1982 ◽  
Vol 35 (5) ◽  
pp. 545 ◽  
Author(s):  
DE Hollis ◽  
RE Chapman ◽  
JA Hemsley
Keyword(s):  
Histological Examination ◽  
Merino Sheep ◽  
Trunk Region ◽  
Simulated Rain ◽  
Skin Samples ◽  
Experimentally Induced

Four medium- and six strong-wool Merino sheep were exposed to continuous simulated rain (4'5 mm/h) for periods ranging from 3 to 9 days. In response, the sheep developed characteristics typical of fleece-rot lesions such as exudative encrustation' and bacterial discoloration of the fleece. Skin samples were taken periodically for histological examination from the trunk region of the sheep prior to, during, and after wetting.

Studies in fleece-rot of sheep.

1953 ◽  
Vol 4 (4) ◽  
pp. 430 ◽  
Author(s):  
RH Hayman
Keyword(s):  
Microscopic Examination ◽  
Similar Condition ◽  
Unit Area ◽  
Skin Surface ◽  
Climatic Conditions ◽  
Field Station ◽  
Merino Sheep ◽  
Naturally Occurring ◽  
Sufficient Intensity ◽  
Experimentally Induced

Occasions of unduly heavy and prolonged rainfall during the period April 1946 – July 1951 resulted in the occurrence of fleece-rot in sheep of the Field Station flock in each of the six years. Data obtained from periodic examinations of the flock have been related to the nature of climatic conditions associated with outbreaks of the disease. They show that when rain occurs in falls of sufficient intensity and frequency to wet sheep to the skin for a period of a week or more, fleece-rot may be expected to develop in some of them. The longer the period for which the sheep are kept wet, the greater the number in a flock which will be affected. Fleece-rot was experimentally induced in four out of five Merino sheep known to be susceptible to the condition, whereas five animals known to be resistant were unaffected by the same treatment. Microscopic examination of skin sections taken from naturally occurring cases revealed the presence of a dermatitis. A similar condition was observed in skin sections from the animals in which fleece-rot was experimentally induced. Young sheep were found to be more susceptible than old. There was no association between degree of wrinkling and susceptibility or between 'grip' and susceptibility. When subjectively-appraised attributes of the fleece were related to the occurrence of fleece-rot, confusing results were obtained. However, when measured fleece data, obtained from a group of Merino sheep which had been under observation for four consecutive years, were considered, it was found that those for clean-scoured yield, wax and suint ratio, and density of fibre population per unit area of skin surface, were related to resistance or susceptibility. Nevertheless, a number of animals were found which were susceptible or resistant to the disease despite the nature of their fleece attributes. Differences in susceptibility were found between families of Merino sheep. These are associated with between-family differences for the fleece attributes found to be important in fleece-rot reaction.

scholarly journals Studies of Autofluorescence in Experimentally Induced Cerebral Necrosis in Pigs

1980 ◽  
Vol 17 (2) ◽  
pp. 226-233 ◽  
Author(s):  
J. Y. S. Lee ◽  
P. B. Little
Keyword(s):  
Liquid Nitrogen ◽  
Histological Examination ◽  
Necrotic Focus ◽  
Ultraviolet Illumination ◽  
Cerebral Necrosis ◽  
Selection Of ◽  
Experimentally Induced

Lesions of cerebrocortical necrosis experimentally induced in pigs by transcalvarial freezing with liquid nitrogen were slightly fluorescent 48 hours after surgery. Fluorescence increased greatly thereafter and was most marked grossly under ultraviolet illumination with a wavelength of 366 nm at 7 days. Fluorescence of the necrotic focus persisted up to 35 days after surgery. Detection of cerebrocortical necrosis by ultraviolet illumination of fresh specimens during gross inspection is useful in determining the extent and distribution of lesions. This would aid more accurate selection of brain sections for histological examination in various encephalopathies.

scholarly journals Quantitative Fraction Evaluation of Dermal Collagen and Elastic Fibres in the Skin Samples Obtained in Two Orientations from the Trunk Region

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Naveen Kumar ◽  
Pramod Kumar ◽  
Satheesha Nayak Badagabettu ◽  
Keerthana Prasad ◽  
Ranjini Kudva ◽  
...  
Keyword(s):  
Image Analysis ◽  
Healing Process ◽  
Wound Healing Process ◽  
Elastic Fibres ◽  
Trunk Region ◽  
Analysis Technique ◽  
Significant Difference ◽  
Dermal Collagen ◽  
Lateral Chest ◽  
Skin Samples

Background. Histomorphic evaluation of dermal collagen and elastic fibres was analysed by image analysis technique. The quantification of dermal elements was performed in skin tissues, collected in horizontal and vertical directions from trunk region and discussed under the perspective of consequences of scar related complications.Materials and Method. Total number of 200 skin samples collected from 5 areas of trunk region were processed histologically and subjected to tissue-quant image analysis. Statistical analysis involving mean with SEM and pairedttest by SPSS were employed to the percentage values obtained from image analysis.Result. Among the chosen 5 areas of trunk region, abdomen showed the statistically significant difference for both collagen and elastic content between horizontal and vertical orientations (P< 0.05), whereas upper back, presternal, and lateral chest areas showed significant difference (P< 0.05) only for collagen and groin only for elastic content.Conclusion. The differences in the distribution of dermal collagen and elastic fibres in 2 directions of the samples from the same areas might be attributed to final outcome of wound healing process by influencing the appearance and behaviour of scar related complications in the region of trunk.

Development of the skin follicle population in Merino sheep.

1954 ◽  
Vol 5 (4) ◽  
pp. 737 ◽  
Author(s):  
AS Fraser
Keyword(s):  
Merino Sheep ◽  
Skin Samples

Skin samples were taken at intervals from birth to several months of age, and counts made of the ratio of secondary to primary follicles. This ratio, which is of the order of 2-4 at birth, increases to about 13-18 by 30-40 days after birth and then increases slowly to the mature value of 18-24 over several months.

scholarly journals Morphological Changes in the Skin and Wool Fibres of Merino Sheep Infused with Mouse Epidermal Growth Factor

1983 ◽  
Vol 36 (4) ◽  
pp. 419 ◽  
Author(s):  
DE Hollis ◽  
RE Chapman ◽  
BA Panaretto ◽  
GPM Moore
Keyword(s):  
Electron Microscope ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Scanning Electron Microscope ◽  
Intravenous Infusion ◽  
Morphological Changes ◽  
Merino Sheep ◽  
Epidermal Growth ◽  
Skin Samples ◽  
Scanning Electron

Intravenous infusion of 4�5-4�7 mg of mouse epidermal growth factor (mEGF) into nine castrated male Merino sheep for 26 h resulted in complete casting of the fleeces 6-8 days later. The morphological changes which occurred in the skin were studied in skin samples taken before infusion and at intervals between 1 hand 42 days after the infusion had begun. Wool fibres from the shed fleeces were examined with the scanning electron microscope.

scholarly journals Erratum to “Quantitative Fraction Evaluation of Dermal Collagen and Elastic Fibres in the Skin Samples Obtained in Two Orientations from the Trunk Region”

2015 ◽  
Vol 2015 ◽  
pp. 1-1
Author(s):  
Naveen Kumar ◽  
Pramod Kumar ◽  
Satheesha Nayak Badagabettu ◽  
Keerthana Prasad ◽  
Ranjini Kudva ◽  
...  
Keyword(s):  
Elastic Fibres ◽  
Trunk Region ◽  
Dermal Collagen ◽  
Skin Samples

scholarly journals Pigmented Spots in the WoolBearing Skin of White Merino Sheep Induced by Ultraviolet Light

1986 ◽  
Vol 39 (2) ◽  
pp. 125 ◽  
Author(s):  
JW Forrest ◽  
MR Fleet
Keyword(s):  
Ultraviolet Light ◽  
Histological Examination ◽  
Outer Root Sheath ◽  
Merino Sheep ◽  
Local Tissue ◽  
Naturally Occurring ◽  
Root Sheath ◽  
Induced Changes

Black-grey pigmented skin spots, some of which contained pigmented wool fibres, were observed in a flock of 8� 5-year-old white Merino ewes. The spots were concentrated along the backline and increased in number following shearing, suggesting exposure to sunlight to be of importance in the development of these non-congenital pigmented skin spots in genetically white Merino sheep. To test the effect of ultraviolet light, white Merino sheep, ranging in age from 3 to 8 years, had a closely clipped mid side area of wool-bearing skin irradiated on each of 28 consecutive days. Pigmented skin spots developed in 6 of the 16 white Merino sheep irradiated. Spots first appeared after 10 days of irradiation, the number subsequently increasing with time, and two skin spots were found to contain sparse numbers of blackgrey pigmented wool fibres. Histological examination showed both the naturally occurring and irradiationinduced pigmented skin spots resulted from an increase in both number and activity of melanocytes localized along the epidermal-dermal border of the epidermis. With time, the melanocytes were observed to have entered, to varying depths, the outer-root sheath of follicles still producing white wool fibres. These ultraviolet-light-induced changes to epidermal melanocytes in white Merino sheep presumably occur due to alterations within the local tissue environment in which the melanocytes lie.

scholarly journals Investigating the depth of thermal burns in elephants

2006 ◽  
Vol 77 (3) ◽  
Author(s):  
A. Shakespeare ◽  
J. Steyl ◽  
S. Strydom
Keyword(s):  
Histological Examination ◽  
Clinical Observation ◽  
Burn Injuries ◽  
Thermal Burns ◽  
Partial Thickness ◽  
Burn Depth ◽  
Skin Samples

Histological examination of burn injuries in elephants revealed that the depth was not as severe as expected from clinical observation. Although the actual burn depth was deep, the thickness of elephant skin, especially the dermis, resulted in the lesions being classified as less severe than expected. Examination of skin samples from selected areas showed that most lesions were either superficial (1st degree) or superficial partial-thickness (superficial 2nd degree) burns with the occasional deep partial thickness (deep 2nd degree) wound. These lesions however, resulted in severe complications that eventually led to the death of a number of the elephants.

Relationships between skin follicle characteristics and fibre properties of Suri and Huacaya alpacas and Peppin Merino sheep

2012 ◽  
Vol 52 (7) ◽  
pp. 442 ◽  
Author(s):  
M. B. Ferguson ◽  
B. A. McGregor ◽  
R. Behrendt
Keyword(s):  
Negative Correlation ◽  
Fibre Diameter ◽  
Variable Number ◽  
Primary Follicle ◽  
Merino Sheep ◽  
Secondary Follicle ◽  
The Mean ◽  
Fibre Traits ◽  
Fibre Characteristics ◽  
Skin Samples

We aimed to quantify the number, type and arrangement of skin follicles in Huacaya and Suri alpaca skin and correlate their follicle characteristics with fibre traits of harvested fibre and compared these relationships with those of Merino sheep. Fibre and skin samples were collected from the mid-side of 12 Huacaya alpacas, 24 Suri alpacas and 10 Merino sheep. The mean fibre diameter (MFD ± s.e.) of the Huacaya and Suri were: 35.5 ± 0.9 and 28.3 ± 1.0 μm, respectively. The follicle groups found for alpacas were very different from the normal trio of primary follicles found in sheep and goats. The follicle group of the alpacas consisted of a single primary follicle surrounded by a variable number of secondary follicles. The mean ± s.e. primary follicle density was 3.1 ± 0.3 and 2.7 ± 0.1 follicles/mm2 for Huacaya and Suri, respectively. The mean ± s.e. secondary follicle density (SFD) was 13.7 ± 1.2 and 17.5 ± 0.6 follicles/mm2 for Huacaya and Suri, respectively. The mean ± s.e. ratio of secondary to primary follicles (S/P ratio) was 5.1 ± 0.5 for the Huacaya and 7.3 ± 0.2 for the Suri alpacas. The sheep had higher S/P ratios and SFD, lower MFD and produced significantly heavier fleeces. The key correlations found between traits in alpacas include a negative correlation between SFD and MFD (r = –0.71, P = 0.001) and a negative correlation between S/P ratio and MFD (r = –0.44, P = 0.003) and a positive correlation between S/P ratio and total follicle density (r = 0.38, P = 0.010). The study revealed that important relationships exist between alpaca skin follicle characteristics and fibre characteristics. It was the number of secondary follicles in a group that imparts density and a corresponding reduced MFD.

scholarly journals Characterization of Melanocytes in Wool-bearing Skin of Merino Sheep

1985 ◽  
Vol 38 (3) ◽  
pp. 245 ◽  
Author(s):  
JW Forrest ◽  
MR Fleet ◽  
GE Rogers
Keyword(s):  
Electron Microscopy ◽  
Copper Deficiency ◽  
Light And Electron Microscopy ◽  
Outer Root Sheath ◽  
Merino Sheep ◽  
Root Sheath ◽  
Experimentally Induced

The distribution and character of melanocytes in the wool-bearing skin of Merino sheep of known genotypes were examined by light and electron microscopy. In black Merino sheep (ww, homozygous recessive), melanocytes were localized within three regions of the skin: epidermal-dermal border, outer root sheath and follicle bulb. Melanocytes within these regions were found to be actively producing melanin, had numerous dendritic extensions and were able to transfer melanin to adjacent keratinocytes. In a black Merino sheep whose fibres were white due to an experimentally induced copper deficiency the melanocytes were amelanotic. In contrast, for both WW (homozygous dominant) and Ww (heterozygous) white Merino sheep melanocytes were observed only at the epidermal-dermal border of the epidermis. The melanocytes appeared also to differ in character containing less melanin, appearing less dendritic in shape and having a reduced ability to transfer melanin to adjacent keratinocytes. The gene for white fleece (W), therefore, appears able to regulate pigmentation in Merino sheep, at least in part, by controlling the location and activity of melanocytes within the wool-bearing skin.

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