Clinical and histopathological study of the phototoxic dermatitis in Zebu calves in grazing of Brachiaria decumbens

Objetivo . El objetivo del trabajo fue estudiar los aspectos clinicos e histopatologicos de la Dermatitis Fototoxica Secundaria (DFS), debidos a la ingestion de Brachiaria decumbens en terneros cebu (Bos indicus) del departamento de Cordoba, Colombia. Materiales y metodos . Se estudiaron doce terneros Cebu, machos, de 12 a 18 meses de edad, con DFS diagnosticados clinica, histopatologicamente y examenes de laboratorio. Resultados. Clinicamente, se evidenciaron signos de fotofobia, deshidratacion, emaciacion progresiva, mucosas ictericas y lesiones cutaneas como res-quebramiento de la piel con aspecto apergaminado, desprendimiento cutaneo y formacion de costras en grandes extensiones. Las lesiones se ubicaron bilateralmente en diferentes areas de la piel en orejas, region perineal, epigastrica y costal. La pruebas serologicas arrojaron elevada actividad catalitica de las enzimas hepaticas GGT y AST indicando lesion hepatica compatible con colestasis. Histopatologicamente, se observo en hematoxilina eosina, dermatitis necrotica cronica, en tricromico de gomori, se observo escasa proliferacion dermica de fibroblastos desorganizados, escasa presencia de tejido conjuntivo difuso y fibras de colageno desorganizadas y en picrosirius red/polarizacion, se observo areas de birrefringencia rojiza y verde-amarillenta, indicando moderada presencia de colageno maduro tipo I (color rojo brillante en la polarizacion) y de tipo III (color verde-amarillento brillante en la polarizacion). Conclusiones . El diagnostico definitivo de la enfermedad se fundamento en las caracteristicas clinicas, en los resultados de laboratorio y en los hallazgos histopatologicos, siendo concluyentes como metodos de diagnostico de la DFS. En la literatura consultada no existen reportes de estudios de DFS en terneros Cebu del departamento de Cordoba y en Colombia. Objective . The objective was to study the clinical and histopathological aspects of Phototoxic Dermatitis Secondary (PDS), secondary to ingestion of Brachiaria decumbens in Zebu calves (Bos indicus) department of Cordoba, Colombia. Materials and methods. Twelve calves Zebu, male, 12 to 18 months, PDS diagnosed with clinical, histopathologically studied and laboratory exams. Results . 5367 Clinically, signs of photophobia, dehydration, progressive emaciation, icteric mucous membranes and skin lesions as res-breaking with leathery skin appearance, skin peeling and scabbing over large areas were evident. The lesions were located bilaterally in different areas of the skin in ears, perineal region, epigastric and costal. Serological tests gave the high catalytic activity of the liver enzymes AST and GGT indicating liver injury consistent with cholestasis. Histopathologically was observed in hematoxylin eosin, chronic necrotic dermatitis, in trichrome Gomori poor dermal proliferation disorganized fibroblasts, low presence of diffuse connective tissue and collagen fibers disorganized and picrosirius red / polarization areas reddish birefringence was observed was observed and greenyellow, indicating moderate presence of mature collagen type I (bright red in polarization) and Type III (bright yellowish-green polarization). Conclusions . The definitive diagnosis of the disease was based on clinical features, laboratory findings and histopathological findings, being conclusive as diagnostic methods of the PDS. In the literature there are no reports of studies PDS in Zebu calves department of Cordoba and Colombia.