Estrategias para la prevención y el control de intoxicaciones naturales por plantas fotosensibilizantes en bovinos Strategies for the prevention and control of natural intoxication by photosensitizing plants in cattle
The study was conducted at the Livestock Production Enterprise Bacuranao, of the Habana del Este municipality (La Habana province, Cuba), in order to establish a strategy for the prevention and control of natural intoxications by photosensitizing plants in cattle. For such purpose, a presumptive diagnosis on photosensitization was carried out, through the floristic inventory of the plants present in grazing and with the use of the clinical method. Diverse plants which cause hepatogenous photosensitization in the animals were identified, with Ageratum houstonianum Mill., Lantana camara L., Crotalaria retusa L. Crotalaria incana L. and Crotalaria spectabilis Roth standing out. The density of cattle per quadrant, the areas with higher incidence of this type of plants and the animals with dermatitis were determined through the Epidemiological Surveillance System (SIVE), by quadrants and grids. In the evaluation of the relative risk (RR) with and without the presence of the sun and with regards to the green forage intake, it was found that the animals exposed to sunlight and those that consumed forage had 1,85 and 3,17 times more incidence, respectively, of clinical signs associated to the hepatogenous photodynamic dermatitis, with higher levels for the ones that ingested the toxic plant A. houstonianum Mill along with the forage. From these results a plan of general and specific measures was elaborated for the control of toxicosis in the areas contaminated with these plants. It is concluded that the use of SIVE, the botanical census, the support treatments to animals with severe symptoms and the management and feeding measures can improve the efficacy in the control of toxicosis and, in turn, the protection of the animals at risk.
Fotossensibilização hepatógena em eqüinos pela ingestão de Brachiaria humidicola (Gramineae) no Estado do Pará
Data on the clinical-pathological aspects and on the epidemioloy of a disease in horses, characterized by phototsensitization, which occurs in northeastern of Para, 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.
Intoxicações por plantas em ruminantes no Brasil e no Uruguai: importância econômica, controle e riscos para a saúde pública
As intoxicacoes por plantas em animais de producao, no Brasil e no Uruguai sao conhecidas desde que os pioneiros Espanhois e Portugueses introduziram as primeiras cabecas de gado em pastagens naturais da regiao. As perdas economicas ocasionadas pelas intoxicacoes por plantas podem ser definidas como diretas ou indiretas. As perdas diretas sao causadas pelas mortes de animais, diminuicao dos indices reprodutivos (abortos, infertilidade, malformacoes), reducao da produtividade nos animais sobreviventes e outras alteracoes devidas a doencas transitorias, enfermidades subclinicas com diminuicao da producao de leite, carne ou la, e aumento a susceptibilidade a outras doencas devido a depressao imunologica. As perdas indiretas incluem os custos de controlar as plantas toxicas nas pastagens, as medidas de manejo para evitar as intoxicacoes como a utilizacao de cercas e o pastoreio alternativo, a reducao do valor da forragem devido ao atraso na sua utilizacao, a reducao do valor da terra, a compra de gado para substituir os animais mortos, e os gastos associados ao diagnostico das intoxicacoes e ao tratamento dos animais afetados (Riet-Correa et al. 1993, James 1994). As perdas economicas causadas pelas intoxicacoes por plantas sao dificeis de se estimar por que nao existem dados confiaveis sobre todos esses componentes, no entanto, as perdas causadas por mortes sao faceis de determinar quando dispomos de dados elaborados por laboratorios de diagnostico, sobre a frequencia das causas de mortes dos animais numa determinada regiao.