Plantas que causam morte súbita em ruminantes na Paraíba.

Abstract

Mascagnia rigida is the most important toxic plant for cattle in the Northeastern region of Brazil, causing sudden death during exercise. The objectives of this research were to report 3 outbreaks of intoxication by M. rigida in sheep and 1 in goats in the semiarid of the state of Paraíba, to reproduce experimentally the disease, and to determine if the active principle of the plant is eliminated through the milk. The outbreaks occurred at the start of the raining period, when the plant sprout before other forages, or after the end of the raining period, when M. rigida stays green and other forages dried. In the experimental reproduction of the poisoning doses of 10 and 20 g of M. rigida per kg body weight (g/kg bw) from two different regions were lethal to 3 goats and 3 sheep. One goat that ingested 20g/kg bw and a sheep that ingested 10g/kg bw recovered. Four animals that ingested 5 g/kg bw had mild clinical signs and recovered. Clinical signs of experimental and spontaneous cases were ingurgitation of the jugular veins, reluctance to move, sternal recumbence, incoordination, respiratory distress, depression, instability, and muscular tremors. Death occurred after a clinical manifestation period of approximately 4 minutes to 27 hours and 40 minutes. The main lesions were pulmonary edema and vacuolization and necrosis of epithelial cells in some renal tubules. To test if the active principle of M. rigida causes sudden deaths in newborn lambs and kids, 2g/kg bw of the plant were given daily to 2 goats and 5 sheep in the 15 days previous to the parturition. One sheep aborted 2 lambs, 5 days before parturition. The 4 lambs of the other 4 sheep ingested the colostrum without problems. The kid from one goat ingested the colostrum and died suddenly 5 minutes after. The kid from the other goat died immediately after parturition before the ingestion of colostrum. These results suggest that in goats, the active principle of M. rigida is eliminated through the milk at toxic doses for the kids. Management measures to prevent the poisoning are recommended.