ANATOMIC-PATHOLOGICAL STUDY OF DIGITAL DERMATITIS WOUNDS IN CATTLE ESTUDO ANATOMOPATOLÓGICO DE LESÕES DE DERMATITE DIGITAL EM BOVINOS

This essay had the scope of characterizing anatomic-pathological aspects of digital dermatitis wounds in distinct development phases. The essay was carried out from August 2004 and November 2005, using 40 cows distributed in four groups of ten animals each. Group I (GI) consisted of clinically healthy animals, and groups II (GII), III (GIII) and IV (GIV), consisted of animals bearing wounds in initial, erosive and proliferative phases, respectively. In GII histological observations were corneal stratus’ thickening, necrosis, hiperplasia, acanthosis, espongiosis and hyperqueratosis. In GIII it was observed hyperemia, ulcers, granulation tissue, hemorrhage and, microscopically, corneal layer thickening, paraqueratosis and multifocal necrosis. In GIV lesions of verrucous aspect, presence of fur, papillary projections were observed macroscopically, and, at histological examination, destruction of corneal layer and epidermis along with necrosis in all samples from the group. Concerning the microbiota, fungi were not observed in any group. As for bacteria, mixed flora was observed, especially spirochetes, in GII, GIII e GIV. Finally, it was concluded that histological alterations in distinct phases of digital dermatitis may commonly be present, differing in terms of severity. The presence of spiral microorganisms suggests their association with etiopathogenesis. KEY WORDS: Cattle, digital lesions erosives and proliferatives, histopathology. Este trabalho objetivou caracterizar os aspectos anatomopatológicos das lesões de dermatite digital em diferentes fases evolutivas. O estudo ocorreu entre agosto de 2004 e novembro de 2005, utilizando-se quarenta vacas alocadas em quatro grupos, contendo dez animais cada. O grupo I (GI) foi composto por animais clinicamente saudáveis e os grupos II (GII), III (GIII) e IV (GIV), com lesões na fase inicial, erosiva e proliferativa, respectivamente. No GII, à histologia observaram-se espessamento do estrato córneo, necrose tecidual, hiperplasia, acantose, espongiose e hiperqueratose. No GIII, observou-se a presença de hiperemia, úlcera, tecido de granulação, hemorragia e, microscopicamente espessamento, da camada córnea, paraqueratose e necrose multifocal. No GIV, lesões com aspecto verrucoso, presença de pêlos, projeções papilares foram observadas macroscopicamente e, ao exame histológico, destruição da camada córnea e da epiderme com necrose tecidual em todas as amostras do grupo. Em relação a microbiota, independente do grup