Tetrapterys acutifolia Cav. (fam. Malpighiacae) stands out among the most important toxic plants of the Brazilian Southeast Region. These plants are responsible for a significant number of deaths in over 1-year-old cattle, especially in the states of Rio de Janeiro and São Paulo. This study aims to demonstrate that T. acutifolia is also able to induce abortion in cattle and to characterize the clinic-pathological alterations in cows and fetuses. Four cows, kept on pasture were used in the experiments which were performed on a farm in the county of Barra do Piraí, RJ, Brazil. The sprouts and young leaves of T. acutifolia were collected from the vicinity shortly before disposed in a trough. The experimental cows ingested the plant material at doses of 2.5g/kg/day (one cow), 5g/kg/day (two cows) and 10g/kg/day (one cow) until abortion occurred. All four cows aborted. The cows showed cardiac arrhythmia, muscular tremors, anorexia, ascites, distended jugular veins, edema of the sternal region and dewlap, and abortion (23 to 76 days after the beginning of ingestion of the plasnt) from the 5th to the 28th day of the experiment. Only one cow which received 10g/kg/day died with characteristic signs of heart failure, 36 days after she had aborted. Gross examination of the fetuses revealed hydrothorax, hydropericardium, hydroperitoneum, nutmeg appearance of the liver, few petechiae and ecchymoses in the epicardium, and pale areas in cross sections of the myocardium. The main postmortem findings in the cow that died were hydrothorax, hydropericardium and hydroperitoneum, engorged vessels at the heart base, exceedingly pale heart muscle with marked spots and stripes in cross sections. Distended jugular veins and severe edema in the sternal region and the abdominal wall were also observed. Histological examination of the fetal hearts revealed interstitial edema with incipient fibrosis and degenerative/necrotic changes of the myocytes. In the succumbed cow was found interstitial fibrosis, as well as necrotic areas and/or necrosis of individual myocytes in extensive portions of the heart, besides passive congestion of the liver. This study shows that Tetrapterys acutifolia can induce abortion in cattle and, depending on the dosage, can cause death.
Poisonous plants; Tetrapterys acutifolia; abortion; plant poisoning; cattle
