PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

RESUMO.- Saturnino K.C., Mariani T.M., Barbosa-Ferreira M., Brum K.B., Fernandes C.E.S. & Lemos R.A.A. 2010. [Experimental poisoning by Brachiaria decumbens in feedlot sheep.] Intoxicação experimental por Brachiaria decumbens em ovinos confinados. Pesquisa Veterinária Brasileira 30(3):195-202. Departamento de Medicina Veterinária, Faculdade de Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS 79070-900, Brazil. E-mail: rlemos@nin.ufms.br Foi realizado estudo experimental de intoxicação por Brachiaria decumbens em ovinos confinados que receberam apenas esta forrageira como alimento. Os animais foram avaliados em três períodos do ano, com duração de 60 dias cada. As análises incluíram exame clínico e amostras de sangue para mensuração da atividade sérica das enzimas gama glutamiltransferase e aspartato aminotransferase com o objetivo de avaliar sua importância e utilidade no diagnóstico de fotossensibilização hepatógena causada pela planta. Foram descritos ainda, achados de necropsia e histopatológicos. Dos vinte e quatro animais confinados, cinco morreram no primeiro período (fevereiro a abril), quatro no segundo (junho a agosto) e dois no terceiro (outubro a dezembro), tendo como principais sinais clínicos anorexia, icterícia, fotofobia, dermatite leve, além de desidratação e apatia. Nos achados de necropsia foram constatados icterícia generalizada, vesícula biliar repleta e distendida, padrão lobular hepático evidente e, em dois casos, opacidade de córnea. As alterações microscópicas foram mais significativas no fígado com bilestase, tumefação e vacuolização de hepatócitos, sinusóides com macrófagos, proliferação de ductos e dúctulos biliares com infiltração linfocítica, que variaram na sua severidade conforme o tempo decorrido da ingestão da planta, além de imagens negativas de cristais no citoplasma de macrófagos presentes nos sinusóides hepáticos e no espaço periportal e cristais refringentes oticamente ativos, ocluindo a luz de ductos biliares. Os achados foram característicos de fotossensibilização hepatógena por B. decumbens, principalmente pela presença de fotofobia, mesmo quando os animais não apresentaram fotodermatite. O aumento da atividade sérica da gama glutamiltransferase teve alta correlação com a morte dos animais. O surgimento da elevação da atividade sérica de gama glutamiltransferase foi, em média, 11 dias antes da constatação dos sinais clínicos, validando sua importância no diagnóstico e na prevenção. A aspartato aminotransferase teve resultados inconsistentes. Treze animais não apresentaram sinais clínicos, apesar de serem constatadas significativas elevações nos níveis séricos das enzimas em questão, sugerindo a existência de indivíduos tolerantes/resistentes dentro do intervalo estabelecido. O modelo experimental foi adequado na caracterização da intoxicação de ovinos por B. decumbens, oferecendo subsídios para estimar preventivamente o risco de morte de ovinos intoxicados pela planta, além de ser útil para a realização de novos estudos da intoxicação por B. decumbens.

• Brachiaria decumbens photosensitization

Abstract in Portuguese:

ABSTRACT.- Saturnino K.C., Mariani T.M., Barbosa-Ferreira M., Brum K.B., Fernandes C.E.S. & Lemos R.A.A. 2010. [Experimental poisoning by Brachiaria decumbens in feedlot sheep.] Intoxicação experimental por Brachiaria decumbens em ovinos confinados. Pesquisa Veterinária Brasileira 30(3):195-202. Departamento de Medicina Veterinária, Faculdade de Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS 79070-900, Brazil. E-mail: rlemos@nin.ufms.br Brachiaria decumbens was fed as exclusive source of food to feedlot sheep. Sheep were evaluated in three periods of the year, of 60 days each, regarding their clinical status and was performed collection of blood samples to measure enzymatic activity of gamma glutamyltransferase and aspartate aminotransferase to evaluate their diagnostic importance and usefulness besides the clinical signs, necropsy and histopathology finds in hepatogenous photosensitization Brachiaria related. Out of 24 feedlot sheep, five died in the first period (February-April), four in the second (June-August) and two in the third (October-December). Main clinical signs were anorexia, jaundice, photophobia and two cases of slight dermatitis, besides dehydration, apathy and corneal opacity. Necropsy revealed generalized jaundice, distended gall bladder and liver with evident lobular pattern. The histological changes varied in severity according the time after the beginning of the plant ingestion; they were more significant in the liver and included bilestasis, swelling and vacuolation of hepatocytes, foammy macrophages, bile duct proliferation and mononuclear inflammatory cell infiltration, further crystal negative images were found within cytoplasm of macrophages present inside of hepatic sinusoid and in the periportal space and also optically active refringent crystal in the lumen of bile tubules. These finds are characteristic of hepatogenous photosensitization, mainly by presence of photophobia, even when the sheep did not present photodermatitis. The results of serum biochemistry activity, during the course of poisoning with strong relation between increased gamma glutamyltransferase activity, and lethality. Onset of arising gama glutamyltransferase activity was 11 days, in average, before beginning of clinical signs. Aspartate aminotransferase had increased activity only close to the beginning of clinical signs. Serum biochemistry results of GGT suggest that they are useful for a precocious diagnosis preventing deaths caused by ingestion of B. decumbens. Thirteen sheep didn’t show clinical signs despite significant increases on serum enzyme activity, suggesting the existence of tolerant/resistant individuals. The experimental model of feedlot was adequate to study B. decumbens toxicosis in sheep.

Abstract in English:

ABSTRACT. Riet-Correa F., Haraguchi M., Dantas A.F., Burakovas R.G., Yokosuka A., Mimaki Y., Medeiros R.M.T. & Matos P.F. 2009. Sheep poisoning by Panicum dichotomiflorum in northeastern Brazil. Pesquisa Veterinária Brasileira 29(1):94-98. Hospital Veterinário, Centro de Saúde e Tecnologia Rural, Universidades Federal de Campina Grande, Patos, PB 58700-000, Brazil. E-mail: franklin.riet@pq.cnpq.br Different species of Panicum, including P. dichotomiflorum, have been reported as a cause of photosensitization in sheep, horses, cattle and goats. An outbreak of hepatogenous photosensitization occurred in 3 flocks of hair sheep in the Brazilian semiarid region. Eighty one out of 365 sheep were affected and 39 died. The main affected animals were nursing lambs and sheep younger than one year old. Donkeys, goats and cattle grazing in the same pasture were not affected. Clinical signs were edema of the head, followed by dermatitis, mainly in the face, ears, and croup, ocular discharge, corneal opacity with blindness, and redness of the coronary band and hoof. At necropsy of one affected lamb the liver was yellowish. Upon histologic examination scattered necrotic hepatocytes were observed in the liver and focal areas of necrosis of myocytes appeared in the heart. Samples of P. dicotomiflorum were analyzed by TLC and those containing saponins were isolated by HPLC using RP-C18 column and eluted with a mixture of MeOH and H2O. The isolated compounds were submitted to 1H and 13C NMR spectroscopy. Reactions were positive to furostanol saponins with the same Rf of the standard protodioscin (0.21) and methylprotodioscin (0.32). The spectroscopic results indicated a mixture of (25R)- and (25S)-protodioscin isomers in a proportion of 3:1, and methylprotodioscin.

• Lithogenic steroidal saponins Panicum dichotomiflorum photosensitization protodioscin

Abstract in Portuguese:

ABSTRACT. Riet-Correa F., Haraguchi M., Dantas A.F., Burakovas R.G., Yokosuka A., Mimaki Y., Medeiros R.M.T. & Matos P.F. 2009. Sheep poisoning by Panicum dichotomiflorum in northeastern Brazil. Pesquisa Veterinária Brasileira 29(1):94-98. Hospital Veterinário, Centro de Saúde e Tecnologia Rural, Universidades Federal de Campina Grande, Patos, PB 58700-000, Brazil. E-mail: franklin.riet@pq.cnpq.br Different species of Panicum, including P. dichotomiflorum, have been reported as a cause of photosensitization in sheep, horses, cattle and goats. An outbreak of hepatogenous photosensitization occurred in 3 flocks of hair sheep in the Brazilian semiarid region. Eighty one out of 365 sheep were affected and 39 died. The main affected animals were nursing lambs and sheep younger than one year old. Donkeys, goats and cattle grazing in the same pasture were not affected. Clinical signs were edema of the head, followed by dermatitis, mainly in the face, ears, and croup, ocular discharge, corneal opacity with blindness, and redness of the coronary band and hoof. At necropsy of one affected lamb the liver was yellowish. Upon histologic examination scattered necrotic hepatocytes were observed in the liver and focal areas of necrosis of myocytes appeared in the heart. Samples of P. dicotomiflorum were analyzed by TLC and those containing saponins were isolated by HPLC using RP-C18 column and eluted with a mixture of MeOH and H2O. The isolated compounds were submitted to 1H and 13C NMR spectroscopy. Reactions were positive to furostanol saponins with the same Rf of the standard protodioscin (0.21) and methylprotodioscin (0.32). The spectroscopic results indicated a mixture of (25R)- and (25S)-protodioscin isomers in a proportion of 3:1, and methylprotodioscin.

Abstract in English:

ABSTRACT.- Pimentel L.A., Riet-Correa F., Guedes K.M., Macêdo J.T.S.A., Medeiros R.M.T. & Dantas A.F.M. 2007. [Primary photosensitization in equidae and ruminants in the Brazilian semi-arid caused by Froelichia humboldtiana (Amaranthaceae).] Fotossensibilização primária em eqüídeos e ruminantes no semi-árido causada por Froelichia humboldtiana (Amaranthaceae). Pesquisa Veterinária Brasileira 27(1):23-28. Hospital Veterinário, CSTR, Universidade Federal de Campina Grande, Campus de Patos, Patos, PB 58708-110, Brazil. E-mail: franklin.riet@pesquisador.com.br Photosensitization is common in the Brazilian semiarid, affecting mainly horses, but also donkeys, mules, sheep and cattle. The dermatitis affects mainly non pigmented skin, and the animals recover after being withdrawn from the pastures. To demonstrate the etiology of the disease, Froelichia humboldtiana (Roem. et Schult.) Seub., collected in the field one or two times a week and kept in the refrigerator for 1-4 days, was administered for 30 or more days as the only food ad libitum to 2 donkeys and one white sheep, and as the only forage ad libitum, to one white horse. No clinical signs were observed in those animals, and serum activities of aspartate-aminotransferase (AST), alanine-aminotransferase (AST), and gamma-glutamyltransferase (GGT) were within normal ranges. In another experiment, one sheep was tied by a rope, during the day, in a pasture of exclusively F. humboldtiana for a 26 days period. Skin lesions characteristic of photosensitization appeared 4-5 days after the start of the experiment and became severe until day 26. After the withdrawal of the animal from the pasture on day 26 it fully recovered within 30 days. In another experiment, 4 sheep were tied by ropes in the same pasture, during the day, for a 29 days period. Another 4 control sheep were maintained in a neighboring pasture without F. humboldtiana. Skin lesions characteristic of photosensitization were observed after 11-25 days of F. humboldtiana grazing. Serum activities of AST and GGT, and serum levels of bilirubin were within normal ranges. At the end of the 29 days grazing F. humboldtiana, 2 sheep were euthanized, and 2 were withdrawn from the pastures. No gross or histologic liver lesions were observed on the 2 sheep euthanized; the other 2 sheep recovered within 17 and 20 days after the end of grazing. One mare and its foal grazed in the same pasture during 44 days. The mare that had a pigmented skin had no dermatitis, but the foal showed dermatitis on the white areas of the skin after 25 days of grazing. The two horses were withdrawn from the pastures after 44 days grazing, and the foal fully recovered within 15 days. These experiments indicate that F. humboldtiana causes primary photosensitization in domestic animals. The absence of lesions in animals ingesting the plant collected in the field and kept refrigerated suggests that F. humboldtiana lost toxicity after collection. The absence of lesions in the eyes of affected animal, which are characteristic of primary photosensitization caused by furocoumarins containing plants, suggests that F. humboldtiana contains a naphthodianthrone derivate, similar to those found in Fagopyrum esculentum and Hypericum perforatum which do not cause eye lesions.

• Primary photosensitization Froelichia humboldtiana Amaranthaceae equidae ruminants dermatitis

Abstract in Portuguese:

ABSTRACT.- Pimentel L.A., Riet-Correa F., Guedes K.M., Macêdo J.T.S.A., Medeiros R.M.T. & Dantas A.F.M. 2007. [Primary photosensitization in equidae and ruminants in the Brazilian semi-arid caused by Froelichia humboldtiana (Amaranthaceae).] Fotossensibilização primária em eqüídeos e ruminantes no semi-árido causada por Froelichia humboldtiana (Amaranthaceae). Pesquisa Veterinária Brasileira 27(1):23-28. Hospital Veterinário, CSTR, Universidade Federal de Campina Grande, Campus de Patos, Patos, PB 58708-110, Brazil. E-mail: franklin.riet@pesquisador.com.br Photosensitization is common in the Brazilian semiarid, affecting mainly horses, but also donkeys, mules, sheep and cattle. The dermatitis affects mainly non pigmented skin, and the animals recover after being withdrawn from the pastures. To demonstrate the etiology of the disease, Froelichia humboldtiana (Roem. et Schult.) Seub., collected in the field one or two times a week and kept in the refrigerator for 1-4 days, was administered for 30 or more days as the only food ad libitum to 2 donkeys and one white sheep, and as the only forage ad libitum, to one white horse. No clinical signs were observed in those animals, and serum activities of aspartate-aminotransferase (AST), alanine-aminotransferase (AST), and gamma-glutamyltransferase (GGT) were within normal ranges. In another experiment, one sheep was tied by a rope, during the day, in a pasture of exclusively F. humboldtiana for a 26 days period. Skin lesions characteristic of photosensitization appeared 4-5 days after the start of the experiment and became severe until day 26. After the withdrawal of the animal from the pasture on day 26 it fully recovered within 30 days. In another experiment, 4 sheep were tied by ropes in the same pasture, during the day, for a 29 days period. Another 4 control sheep were maintained in a neighboring pasture without F. humboldtiana. Skin lesions characteristic of photosensitization were observed after 11-25 days of F. humboldtiana grazing. Serum activities of AST and GGT, and serum levels of bilirubin were within normal ranges. At the end of the 29 days grazing F. humboldtiana, 2 sheep were euthanized, and 2 were withdrawn from the pastures. No gross or histologic liver lesions were observed on the 2 sheep euthanized; the other 2 sheep recovered within 17 and 20 days after the end of grazing. One mare and its foal grazed in the same pasture during 44 days. The mare that had a pigmented skin had no dermatitis, but the foal showed dermatitis on the white areas of the skin after 25 days of grazing. The two horses were withdrawn from the pastures after 44 days grazing, and the foal fully recovered within 15 days. These experiments indicate that F. humboldtiana causes primary photosensitization in domestic animals. The absence of lesions in animals ingesting the plant collected in the field and kept refrigerated suggests that F. humboldtiana lost toxicity after collection. The absence of lesions in the eyes of affected animal, which are characteristic of primary photosensitization caused by furocoumarins containing plants, suggests that F. humboldtiana contains a naphthodianthrone derivate, similar to those found in Fagopyrum esculentum and Hypericum perforatum which do not cause eye lesions.

Abstract in English:

ABSTRACT.- Brum K.B., Haraguchi M., Lemos R.A.A, Riet-Correa F. & Fioravanti M.C.S. 2007. Crystal-associated cholangiopathy in sheep grazing Brachiaria decumbens containing the saponin protodioscin. Pesquisa Veterinária Brasileira 27(1):39-42. Departamento de Patologia, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900, Brazil. E-mail: kbbrum@gmail.com An outbreak of hepatogenous photosensitization is reported in a flock of 28 sheep grazing Brachiaria decumbens in Mato Grosso do Sul State, Central-Western Brazil. Seven lambs and an adult sheep were affected and 6 of them died. Two surviving affected lambs and one lamb without clinical signs had increased serum values of gamma glutamyltransferase, bilirubin, and cholesterol. In two adult unaffected sheep those parameters were within normal values. An adult sheep submitted to necropsy presented moderate body condition, unilateral corneal opacity, drying of the muzzle, moderate jaundice, increased lobular pattern of the liver, and a distended gallbladder. Histological lesions were epithelial degeneration, necrosis, and hyperplasia of small bile ducts. Mild amounts of foamy macrophages were observed, mainly in the centroacinar zone. Diffuse swelling and vacuolation were observed in hepatocytes. Crystal negative images were found within bile ducts, foamy macrophages, and the lumen of some renal tubules. The heart showed multifocal areas of degeneration and necrosis of the muscle fibers. Pasture samples (Brachiaria decumbens) contained 2.36% of protodioscin. No Pithomyces chartarum spores were found in the pasture. Samples from a similar neighboring B. decumbens pasture grazed by cattle without photosensitization contained 1.63% of protodioscin isomers. Outbreaks of photosensitization caused by Brachiaria spp. are common in cattle in the Brazilian Cerrado (savanna) with about 51 million hectares of Brachiaria spp pastures. Sheep farming has been recently developed in this region, and the number of sheep is increasing significantly. Because sheep are more susceptible than cattle to lithogenic saponins, poisoning by Brachiaria should be an important limiting factor for the sheep industry.

• Sheep photosensitization Brachiaria decumbens protodioscin steroidal saponin cholangiopathy

Abstract in Portuguese:

ABSTRACT.- Brum K.B., Haraguchi M., Lemos R.A.A, Riet-Correa F. & Fioravanti M.C.S. 2007. Crystal-associated cholangiopathy in sheep grazing Brachiaria decumbens containing the saponin protodioscin. Pesquisa Veterinária Brasileira 27(1):39-42. Departamento de Patologia, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900, Brazil. E-mail: kbbrum@gmail.com An outbreak of hepatogenous photosensitization is reported in a flock of 28 sheep grazing Brachiaria decumbens in Mato Grosso do Sul State, Central-Western Brazil. Seven lambs and an adult sheep were affected and 6 of them died. Two surviving affected lambs and one lamb without clinical signs had increased serum values of gamma glutamyltransferase, bilirubin, and cholesterol. In two adult unaffected sheep those parameters were within normal values. An adult sheep submitted to necropsy presented moderate body condition, unilateral corneal opacity, drying of the muzzle, moderate jaundice, increased lobular pattern of the liver, and a distended gallbladder. Histological lesions were epithelial degeneration, necrosis, and hyperplasia of small bile ducts. Mild amounts of foamy macrophages were observed, mainly in the centroacinar zone. Diffuse swelling and vacuolation were observed in hepatocytes. Crystal negative images were found within bile ducts, foamy macrophages, and the lumen of some renal tubules. The heart showed multifocal areas of degeneration and necrosis of the muscle fibers. Pasture samples (Brachiaria decumbens) contained 2.36% of protodioscin. No Pithomyces chartarum spores were found in the pasture. Samples from a similar neighboring B. decumbens pasture grazed by cattle without photosensitization contained 1.63% of protodioscin isomers. Outbreaks of photosensitization caused by Brachiaria spp. are common in cattle in the Brazilian Cerrado (savanna) with about 51 million hectares of Brachiaria spp pastures. Sheep farming has been recently developed in this region, and the number of sheep is increasing significantly. Because sheep are more susceptible than cattle to lithogenic saponins, poisoning by Brachiaria should be an important limiting factor for the sheep industry.

Abstract in English:

ABSTRACT.- Barbosa J.D., Oliveira C.M.C., Tokarnia C.H. & Peixoto P.V. 2006. [Hepatogenous photosensitization in horses caused by Brachiaria humidicola (Gramineae) in the State of Pará.] Fotossensibilização hepatógena em eqüinos pela ingestão de Brachiaria humidicola (Gramineae) no Estado do Pará. Pesquisa Veterinária Brasileira 26(3):147-153. Escola de Medicina Veterinária, Campus Castanhal, Universidade Federal do Pará, Rua Maximino Porpino 1000, Castanhal, PA 68743-080, Brazil. E-mail: diomedes@ufpa.br Data on the clinical-pathological aspects and on the epidemioloy of a disease in horses, characterized by phototsensitization, which occurs in northeastern of Pará, Brazil, are presented. Of a total of 40 horses examined clinically, post-mortem examination was performed on seven. Due to the characteristic lesions found on the non-pigmented skin, the macroscopic and histological alterations in the liver, and knowing that Brachiaria grasses contain saponins with toxic properties, which cause liver lesions and photosensitization in cattle and sheep, it is concluded that this disease in horses is caused by grassing exclusively Brachiaria humidicola.

• Poisonous plants Brachiaria humidicola plant poisoning photosensitization saponins horses

Abstract in Portuguese:

ABSTRACT.- Barbosa J.D., Oliveira C.M.C., Tokarnia C.H. & Peixoto P.V. 2006. [Hepatogenous photosensitization in horses caused by Brachiaria humidicola (Gramineae) in the State of Pará.] Fotossensibilização hepatógena em eqüinos pela ingestão de Brachiaria humidicola (Gramineae) no Estado do Pará. Pesquisa Veterinária Brasileira 26(3):147-153. Escola de Medicina Veterinária, Campus Castanhal, Universidade Federal do Pará, Rua Maximino Porpino 1000, Castanhal, PA 68743-080, Brazil. E-mail: diomedes@ufpa.br Data on the clinical-pathological aspects and on the epidemioloy of a disease in horses, characterized by phototsensitization, which occurs in northeastern of Pará, Brazil, are presented. Of a total of 40 horses examined clinically, post-mortem examination was performed on seven. Due to the characteristic lesions found on the non-pigmented skin, the macroscopic and histological alterations in the liver, and knowing that Brachiaria grasses contain saponins with toxic properties, which cause liver lesions and photosensitization in cattle and sheep, it is concluded that this disease in horses is caused by grassing exclusively Brachiaria humidicola.

Abstract in English:

ABSTRACT.- Tokarnia C.H., Armién A.G., Barros S.S., Peixoto P.V. & Döbereiner J. 1999. [Complementary studies on the toxicity of Lantana camara (Verbenaceae) in cattle.] Estudos complementares sobre a toxidez de Lantana camara (Verbenaceae) em bovinos. Pesquisa Veterinária Brasileira 19(3/4):128-132. Projeto Sanidade Animal Embrapa/UFRRJ, Km 47, Seropédica, RJ, 23851-970, Brazil. An outbreak of poisoning by Lantana camara var. aculeata in cattle was diagnosed in the county of Quatis, State of Rio de Janeiro. The animals, after travelling by foot, were put, hungry, for a few days, on a pasture highly infested by the plant. The toxicity of the plant was proved experimentally in cattle; also experiments to see how far the plant has cumulative properties, were performed. The plant caused Iethal poisoning when given as a single dose of 40 g/kg; 20 g/kg caused severe poisoning, 10 g/kg slight or no poisoning and 5 g/kg failed to provoke symptoms. A lethal result was produced also when 10 g/kg per day was given over 4 days. The administration of 5 g/kg per day caused severe poisoning when fed over 5 days to two calves. The dose of 2.5 g/kg fed daily over 7 or 9 days also produced severe poisoning in two calves; in another calf, severe symptoms were produced only after feeding 2.5 g/kg per day for 19 days; still another calf showed no symptoms after 32 days of feeding 2,5 g/kg per day, although twice the lethal dose had been fed by this time. A dose of 1.25 g/kg per day over . 34 days also failed to produce any symptoms.

• Poisonous plants plant poisoning photosensitization Lantana camara Verbenaceae pathology cattle Plantas tóxicas intoxicação por planta fotossensibilização patologia bovinos.

Abstract in Portuguese:

RESUMO.- Tokarnia C.H., Armién A.G., Barros S.S., Peixoto P.V. & Döbereiner J. 1999. [Complementary studies on the toxicity of Lantana camara (Verbenaceae) in cattle.] Estudos complementares sobre a toxidez de Lantana camara (Verbenaceae) em bovinos. Pesquisa Veterinária Brasileira 19(3/4):128-132. Projeto Sanidade Animal Embrapa/UFRRJ, Km 47, Seropédica, RJ, 23851-970, Brazil. Descreve-se, no município de Quatis, RJ, a ocorrência de um surto de intoxicação por Lantana camara var. aculeata em bovinos, caracterizado por acentuada icterícia, lesões de fotossensibilização, constipação e edema subcutâneo dos membros. A reprodução experimental da doença, com êxito letal, através da administração de dose única de 40 g/kg de L. camara var. aculeata, confirmou a planta como causa do surto; doses únicas de 20 g/kg, 10 g/kg e 5 g/kg causaram respectivamente, grave intoxicação, leve intoxicação e ausência de sintomas. Experimentos com doses repetidas permitem concluir que essa planta apresenta efeito acumulativo, quando ingerida em doses diárias de 10 g/kg (1/4 da dose letal); a administração de quatro doses de 5 g/kg (1/8 da dose letal) ou de oito doses de 2,5 g/kg (1/16 da dose letal) reproduziram o quadro grave de intoxicação. Subdoses menores, de 1,25 g/kg (1/32 da dose letal), administradas durante 34 dias, não produziram quaisquer sinais clínicos. Os exames histológicos dos casos naturais e experimentais revelaram, além de bilestase, alterações regressivas nos hepatócitos e no epitélio dos túbulos renais.

Abstract in English:

An outbreak of primary photosensitization in cattle, grazing on a pasture invaded by Ammi majus, in Southern Brazil, is described. The disease occurred during December and January in a herd of 14 cows and 14 calves. Clinical signs were characterized by dermatitis in the udder of the cows and keratoconjuntivitis in the calves. Regression of the lesions was observed after the withdrawel of the animals from the pasture. The disease was reproduced in calves by the administration of A. majus seeds at a dosis of 1.7 to 8 g/kg of body weight. The experimental animals showed ocular discharge, oedema of the eyelids, keratitis and dermatitis of the muzzle.

• Poisonous plants plant poisoning primary photosensitization Ammi majus Umbelliferae cattle

Abstract in Portuguese:

Descreve-se um surto de fotossensibilização primária em bovinos no município de Bagé, Rio Grande do Sul, em uma pastagem invadida por Ammi majus. A doença ocorreu nos meses de dezembro e janeiro em um grupo. de 14 vacas e 14 terneiros da raça Hereford. Os animais apresentaram fotossensibilização, caracterizada por dermatite no úbere das vacas e ceratoconjuntivite nos terneiros, que regrediram após a retirada dos animais da pastagem. A doença foi reproduzida experimentalmente, em 6 terneiros, com sementes de A. majus, nas doses de 1,7 a 8 g/kg de peso vivo, observando-se corrimento ocular, edemas das pálpebras, ceratite e dermatite no focinho.

• Plantas tóxicas intoxicação por planta fotossensibilização primária Ammi majus Umbelliferae bovinos