In the Amazon region, sprouting pastures of Panicum maximum cause colic and death in horses and mules. To produce the disease two experiments were performed with growing P. maximum cv. 'Mombaça' in penned horses. In Experiment 1, at the beginning of the raining season, 10 horses were fed with recently harvested sprouting P. maximum. Two horses showed colic on the 5th and 11th day after start of the ingestion. In Experiment 2, also during the raining season, the same 10 horses used in Experiment 2 were divided into two groups of 5 horses each. Group 1 received sprouting P. maximum immediately after harvested and Group 2 received the grass 24 hours after harvested. The control group consisted of four animals which were placed in individual pens and fed with Pennisetum purpureum and commercial ration twice a day. One horse from Group 2 showed colic on day 13th after the start of feeding. The other horses of both groups showed intestinal bloat. In both experiments affected horses recovered after the end of the administration. The control group did not showed clinical signs. These results demonstrated that the disease is caused by the ingestion of sprouting P. maximum during the rainy season. The results in experiment 2 showed that P. maximum do not loss toxicity 24 hours after harvesting. Clinical signs suggest that primary alteration caused by P. maximum is intestinal fermentation followed by bloat.
acute abdomen; equidae; intestinal disorders; Panicum maximum