Timpanismo gastrointestinal em equídeos alimentados com Panicum maximum com alto conteúdo de amido

Cecal dilatation in cattle ingesting Megathyrsus maximus (syn. Panicum maximum) cv. Mombaça and cv. Tanzânia

Nine outbreaks of cecal dilatation are reported in cattle in rotationally-grazed pastures of Megathyrsus maximus during the rainy season with one day grazing and rest intervals of 23-28 days. Clinical signs, observed 6-24 h after entering the pasture, were inappetence, long periods in sternal recumbency, rough hair coat, arched back, tenesmus with difficult defecation, dry stools, reduced ruminal movements, intestinal tympany with right abdominal distention, and decreased milk production. The animals recovered 8-12 h after their removal from the pastures. All pastures were fertilized at 80-120 kg/ha of urea/year. In six farms, in addition to urea, chicken litter (CL) was also added. Water-soluble carbohydrates (WSC), non-fiber carbohydrates (NCF) and starch concentrations in the pastures causing tympany were higher (P < 0.05) than in control pastures. To demonstrate the relationship of the disease with fertilization of the pastures, a pasture of M. maximus was divided into five blocks of 16 m2 and each block subdivided into four plots each, totaling 20 plots. One plot of each block was randomly chosen for 1 of 4 different treatments: 1. fertilized with 8 t/ha of CL; 2. fertilized with 16 t/ha of CL; 3. fertilized with 180 kg/ha urea; 4. control without fertilization. In general, plots fertilized with urea or with CL had higher NFC and starch concentrations (p < 0,05) than the control plots. In another experiment a pasture of M. maximus was divided into 23 paddocks and rotationally grazed. Ten paddocks were fertilized with 180 kg/ha of urea and five fertilized with 8 t/ha of CL. The concentration of NFC and starch were significantly higher (p < 0.05) in the pastures fertilized with urea and with urea plus CL. These results suggest that cecal dilatation may be caused by the high concentrations of NFC and starch in the pastures fertilized with urea and/or poultry litter.

Plants causing poisoning outbreaks of livestock in South America: A review

This paper reviews toxic plants for livestock in South America. We included 219 plants in this review, considering only the plants that caused at least one demonstrated outbreak of poisoning. Plants reported as toxic in other regions and present in South America, but with no confirmed outbreaks of poisoning in this region, are not included. We report the main aspects of the epidemiology, clinical signs, pathology and economical importance of the poisonings. Initially, the toxic plants are described based on their toxic compounds, but because the toxic compound is unknown in 92 (42%) of the plants we also classify them according to the affected system. This review highlights the great diversity of toxic plants capable of affecting livestock in South America, and for this reason studies in this regard should be intensified.

Poisoning by Megathyrsus maximus (Sin. Panicum maximum) cv. Colonião in horses in the state of Rio de Janeiro

ABSTRACT: Colic outbreaks in horses have been associated with the grazing of several Megathyrsus maximus (Sin. Panicum maximum) cultivars in the North and Central-West regions of Brazil. In this paper, we report a horse colic outbreak in the Southeast region of Brazil caused by ingestion of the “Colonião” cultivar of M. maximus, which has not previously been considered as toxic. The five affected horses belonged to the Veterinary Platoon based at the Central Ammunition Deposit of the Brazilian Army in the city of Paracambi, Rio de Janeiro state, Brazil. The horses had access to treated water and commercial concentrate, and were located in a field of M. maximus at the time of the outbreak. All horses exhibited clinical signs of colic and bloat, and three of them died. The extend of the clinical course ranged from four to five days in the three animals that died; in the two animals that recovered from the colic episodes, the extend of the clinical courses were 10 and 15 days. Necropsy findings revealed intestinal and gastric bloating and hemorrhages involving the intestinal wall. Light microscopy showed moderate diffuse lymphoplasmacytic and eosinophilic enteritis with multifocal erosions, in addition to submucosal edema associated with multifocal vasculitis. The pathogenesis of colic caused by M. maximus ingestion in horses has not yet been elucidated. Some authors have suggested that higher starch concentrations in M. maximus during the rainy season may be responsible for the toxicity of this plant. However, the findings of this study do not support this hypothesis. As a prophylactic measure, it is suggested that horses do not graze exclusively M. maximus at the beginning of rainy periods, in which regrowth of this grass occurs. In Brazil, outbreaks of horse colic associated with ingestion of varieties of Megathyrsus can also occur outside the North and Midwest regions, under specific climate conditions.