Poisonous plants to livestock interest in the Amazonia and Savanna ecotone region Part I: Bico do Papagaio, North of Tocantins, Brazil

Abstract

Extensive grazing systems and sediment erosion as pastures degrade, induces the exposition to poisonous plants causing economic losses to livestock production. Thus, this study aimed to determine the poisonous plants of livestock interest in the Bico do Papagaio, North of Tocantins state, Brazil. Based on reports of 85 farmers in 20 counties the most important poisoning in order of occurrence involved Brachiaria decumbens and Palicourea marcgravii. Sporadic outbreaks of poisoning occurred due consumption of Ipomoea asarifolia, Manihot esculenta, Enterolobium contortisiliquum, Manihot spp and Pteridium aquilinum. Additionally, Manihot glaziovii was also mentioned by the producers as a toxic plant. Dimorphandra mollis, Ipomoea carnea subsp. fistulosa, Lantana spp, Palicourea juruana, Ricinus communis, Stryphnodendron obovatum, and Sorghum vulgare although known by the interviewees, did not trigger poisoning outbreaks in the study area. On the other hand, Arrabidaea bilabiata, A. jupurensis and Brachiaria radicans were unknown by farmers. Parkia pendula, a plant with unknown toxicity, was mentioned by farmers at Ananas and Tocantinópolis counties as a toxic plant, causing inapetence, weight loss and apathy in cattle. Hypolytrum pungens, another plant with unknown toxicity, promoted two poisoning outbreak at Tocantinópolis county causing incoordination in cattle, in agreement with farmers. It is concluded that the region of the study presents particular characteristics in relation to the poisonous plants for livestock found in other regions of Brazil, and also that there is lack of research on plants not yet reported in the literature that may have significant toxicity to livestock. Keywords: Toxicology, poisoning, ruminant, cattle, Amazon, ecotone.