Intoxicação por Crotalaria spectabilis em bovinos

Abstract

Epidemiological, clinical and anatomopathological findings of spontaneous intoxication by Crotalaria spectabilis in cattle are described. The planting of Crotalaria spp. in consortium systems aims to control the nematode population of the root lesions in crops, fix nitrogen to the soil and green manure. Seeds can remain viable after incorporation to the soil and predispose to regrowth and the permanence of this plant as invasive. Several species of crotalaria are reported to cause intoxication in several species of animals. The toxic principles are Pirrozolidinic Alkaloids (AP), and of these, monocrotaline (MC) is the main AP present in these plants. It is suggested that C. spectabilis has the greatest potential to cause intoxication among crotalaria species. The outbreak involved two properties located in distinct municipalities (A and B), and the animals consumed C. spectabilis at property A, where six showed clinical signs followed by death 20 days after introduction into the picket invaded by this plant. The animals were transferred to free sites of Crotalaria spp. After 45 days, 35 animals became ill at B property, 15 cattle died. The signs observed were weight loss, jaundice, decubitus, pedal movements and death. 1 bovine A and 2 were necropsied in property B, being the main alterations involving the liver directly that presented irregular parenchyma, yellow coloration with white areas and firm texture to the palpation. Microscopically, hepatic alterations involved centrilobular or diffuse fibrosis, disappearance of centrilobular hepatocyte, megalocytosis, microvacuolar degeneration and bilestase. Vascular lesions with different intensities are observed in lung and kidney of the 3 bovines. Status spongiosus was observed in the central nervous system of two cattle. The objective of this work is to describe the epidemiological, clinical and pathological aspects of subacute and chronic intoxication by Crotalaria spectabilis in cattle.