Bovine cutaneous streptothricosis and demodicosis : studies on the defects and economic losses on crust leather resulting from damage caused by these diseases / Mukhtar Taha Abu-Samra in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 73 (Année 1989)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 73 (Année 1989) . - p. 74-87 Titre : Bovine cutaneous streptothricosis and demodicosis : studies on the defects and economic losses on crust leather resulting from damage caused by these diseases Type de document : texte imprimé Auteurs : Mukhtar Taha Abu-Samra, Auteur ; K. E. E. Ibrahim, Auteur Année de publication : 1989 Article en page(s) : p. 74-87 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Défauts Cuirs et peaux de bovins Démodécie Peau -- Maladies Streptothricose Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In the Sudan, 16,540 cattle were surveyed for bovine cutaneous streptothricosis and 48,000 were surveyed for bovine demodicosis. The incidence of cutaneous streptothricosis ws 4.5 %, while the incidence of bovine demodicosis among the total number of the animals (48,000) surveyed was 34-3 % and its incidence among slaughtered animals (1535) was 38.8 %. These results show that slaughterhouse surveys for demodicosis are more reliable than clinical surveys because many cattle with demodectic mange might have no visible cutaneous lesions and can only be detected after careful examination, flaying of the hides or during tanning. In both cutaneous streptothricosis and demodicosis many forms of lesions, were encountered. The lesions were localised, confluent or generalised involving extensive areas or the wholehide of infested cattle. Dermatophilus congolensis was demonstrated in smears and isolated in pure culture from affected material obtained from cattle infested with cutaneous streptothricosis. Numerous demodex bovis mites were demonstrated and isolated from caseated ("cheesy") waxy material obtained from demodectic mange lesions. Severe and advanced histopathological changes were seen in skin sections from the lesions of both diseases. Leather sections from cutaneous stre ptothricosis showed a badly damaged grain surface with many scars and depressions. The fibres were distorted and had lost their contour ; the whole thickness of the crust leather was fibrosed. Leather sections from bovine demodicosis showed, at the site of lesions, a ragged cavity with no definite boundaries. The fibres round the cavity were distorted, thinner than normal and compressed. In some sections, the grain surface was found to be separated from the corium. Hides affected by cutaneous streptothricosis and demodicosis were gree-graded as rejects. During the tanning procedure, both diseases causes difficulty in soaking, plumping, splitting, scudding or shaving. At the site of lesions there was uneven distribution of chemicals leaving unsightly blemishes. Both diseases caused a marked reduction in the aesthetic appeal and cutting area of the leather. Cutaneous streptothricosis resulted in a course and rough grain surface and, in severely affected areas, the leather was pitted. Bovine demodicosis caused depressions, cavities or holes in the crust leather. Cutaneous streptothricosis and bovine demodicosis caused a marked reduction in the tensile strength, apparent density and flexing endurance. Bovine demodicosis was found to have the more deleterious effect on crust leather because the percentage decrease in tensile strength, apparent density and flex endurance in the former disease was greater. Hides affected by cutaneous streptothricosis and demodicosis were completely rejected or fetched low prices resulting in serious economic loss. En ligne : https://drive.google.com/file/d/1IvbDq-HWnYitKRRj0WlU3HiIUk9OUTj6/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8830 [article]

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Bovine demodicosis : leather from the raw material to the finished product / Mukhtar Taha Abu-Samra in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 99, N° 2 (03-04/2015)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 99, N° 2 (03-04/2015) . - p. 80-90 Titre : Bovine demodicosis : leather from the raw material to the finished product Type de document : texte imprimé Auteurs : Mukhtar Taha Abu-Samra, Auteur ; Yassir Adam Shuaib, Auteur Année de publication : 2015 Article en page(s) : p. 80-90 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Analyse Cuirs et peaux de bovins Démodécie Parasitoses Peau -- Maladies chez les animaux Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Demodex bovis mites and associated bacteria produced lesions ranging from 25 to 3618 per hide. Infected hides were compared to non-infected ones, from the raw material to the finished product. Infected hides showed the following defects: (1) Severely infected hides were green-graded as rejects. (2) The curing time was longer than non-infected ones. (3) The rate of water absorption was reduced by more than 50% (4) Liming resulted in dark blue precipitate on the lesions due to uneven distribution of the sulphide. (5) Scudding was very difficult. (6) Deliming and pickling resulted in circuler white blemishes on the grain surface. (7) Slipping-off of the grain surface over severely infected areas. (8) The degree of plumping was only 12-22%. (9) Splitting was very difficult, and when split, holes and cavities were evident. (10) Shaving resulted in detachment of all the lesions on the flash side leaving numerous pits and holes. (11) The aesthetic appeal and cutting areas of the leather were markedly reduced. (12) Severely infected hides were difficult to finish, required more effort in buffing and utilized more dye without producing a drastic improvement in acceptability, and the grain surface was unsightly, uneven, full of elevations and depressions. Leather sections revealed ragged cavities with no definite boundaries. The fibres round those cavities were distorted, thinner than normal and compressed. The grain of the leather showed many small shallow depressions and separation of the grain surface from the corium in areas with large lesions. Severely affected leather showed complete damage and distortion of bath the grain surface and corium. Bovine demodicosis infected hides resulted in a significant reduction at (p<0.01) in the cure-index, tensile strength, tearing load, percentage elongation, correlation coefficient of tensile strength versus tearing load, apparent density, flexing endurance, distension at grain crack, hide substance, moisture, fat and ash contents compared to non-infected ones. However, the distension at grain burst of infected specimens showed a significant reduction at (p<0.05) over non-infected ones. The deleterious effects of bovine demodicosis revealed in this study ; would definitely culminate in serious economic losses in the national economy of the Sudan. The government, veterinarians and research workers should devote more time to the prevention and control of the disease. They should create awareness of the cattle owners regarding the damaging effects of demodectic mange in the quallty of cattle hides, animal health and production. Tanneries should avoid selecting infected bides, involving unnecessary expenditure on the production of otherwise reject finished product because the deleterious effects of this disease persists in any leather goods manufactured from the leather produced. Note de contenu : - MATERIALS AND METHODS : Animals - Laboratory investigations - Preparation of crust leather - Physical tests of crust leather - Chemical analysis of crust leather - Statistical analysis - RESULTS : Findings recorded during the preparation of crust leather - Microscopic examination of crust leather - Physical testing and chemical analysis of crust leather En ligne : https://drive.google.com/file/d/1AvBEdjQ-mMyMPNZpdCzY4-WsK4rfGKY8/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23744 [article]

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Effect of demodectic mange on the leather-making quality of indian goatskins / R. A. Venkatesan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXIII (Année 1978)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXIII (Année 1978) . - p. 422-432 Titre : Effect of demodectic mange on the leather-making quality of indian goatskins Type de document : texte imprimé Auteurs : R. A. Venkatesan, Auteur ; M. Sugumar, Auteur ; S.-C. Nandy, Auteur Année de publication : 1978 Article en page(s) : p. 422-432 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Analyse Cuirs et peaux -- Défauts Cuirs et peaux de chèvres Démodécie Parasitoses Peau -- Maladies chez les animaux Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Caprine demodecosis is causing great concern to the Indian leather trade as goatskins are considerably affected in quality by this defect. Demodectic mange mites were found to be lodged within subsurface nodules of the skin surrounded by dense fibrous tissue. In raw skin the nodules were bulged out on the flesh side only. The changes in appearance, variations in the number and distribution of nodules, and the effect on pelt and leather quality were studied af ter liming and after chrome or vegetable tanning for comparison with fresh skins. Histo¬pathological study revealed fibrous encapsulation around the nodules with no secondary bacterial infection. A few cases of the acute (squamous) form of demodecosis were noted in raw skin resembling sarcoptic mange infestation. Variations in number of nodules at different anatomical locations were significant. Amino acid composition of the skin in the affected area was compared with that in the unaffected area. Note de contenu : - MATERIALS AND METHODS : Vegetable tanning - Chrome tanning - Histopathology - Microscopical study of the etiological agent - Counts of demodectic nodules - Variation in anatomical distribution of nodules - Amino acid analysis - Procedure for analysis of nodule contents - RESULTS : Observations on demodecosis in untanned skins - Observations on crust leathers - Histopathological observations on demodectic nodules - Counts of demodectic nodules in skin sduring processing - Amino acid composition - Table 1 : Counts of demodectic nodules on 35 goatskins during lether processing - Table 2 : Anatomical distribution of demodectic nodules on limed pelts En ligne : https://drive.google.com/file/d/1dKtcFZCzGPOFg3b9vbRrmaGT4F8cDFhM/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=41160 [article]

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Effects of some important ectoparasites on the grain quality of cattlehide leather / A. L. Everett in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXII (Année 1977)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXII (Année 1977) . - p. 6-24 Titre : Effects of some important ectoparasites on the grain quality of cattlehide leather Type de document : texte imprimé Auteurs : A. L. Everett, Auteur ; R. W. Miller, Auteur ; W. J. Gladney, Auteur ; Mary V. Hannigan, Auteur Année de publication : 1977 Article en page(s) : p. 6-24 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acariens Cuirs et peaux -- Défauts Cuirs et peaux de bovins Démodécie Ectoparasites Evaluation Mouches Parasitoses Poux Taons Tiques Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Hides and leather from 23 cattle exposed to massive infestations of bloodsucking external parasites were evaluated for grain damage in a co-operative series of tests over an eight-year period. In tests under controlled conditions, horn flies, and two species of mosquitoes caused no significant damage to leather grain ; four species of hard ticks caused severe damage in every case, with no apparent differences among the species. Damage from the lone star tick is illustrated at different healing stages. In tests of cattle exposed to severe infestations of parasites under natural conditions, the shortnosed cattle louse caused no significant grain damage inleather ; horse flies and deer flies caused slight but consistent, and possibly significant, damage ; and incidentally occuring demodectic mites caused moderate to severe damage to some of the hides. The detailed nature of the damage is illustrated. Investigation of the mite infestations provided useful information on the transmission of demodectic (follicular) mange, or demodicosis. Note de contenu : - EXPERIMENTAL PROCEDURES : Test organisms - Test cattle - Test hides - Fly andmosquito test - Louse test - Tick test - RESULTS AND DISCUSSION : Effects of flies, mosquitoes, and lice - Effect of demodectic mites - Effects of ticks - Table 1 : Identification of ectoparasites tested on cattle - Table 2 : Treatments applied to cattle in four separate tests - Table 3 : Biting flies counted on test steers - Table 4 : Deer and horse flies trapped at remote pasture in 1973 - Table 5 : Evaluation of hide and leather damage from ectoparasites En ligne : https://drive.google.com/file/d/1cduH7h7Bdt4FIMzI62TxgBqsZrmaRmZz/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38254 [article]

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