Experimental poisoning by Nierembergia rivularis in sheep of Uruguay.

Abstract

The objective of this paper is to report the experimental poisoning in sheep ingesting N. rivularis in northern region of Uruguay. The experiment was conducted in the same farm where the natural intoxication occurred. Four Corriedale crossbred sheep were used, one as control. The animals, weighing an average of 20 kg, were raised in a field without any known toxic plants. Before the start of the experiment, the sheep were identified, clinically examined, dewormed with doramectin and closantel, and immunized against clostridial diseases. Faecal analyses for gastrointestinal nematodes were performed at 30 day intervals. Clinically the most significant symptom of N. rivularis ingestion was that the animals were unable to follow the flock as they were left behind during herd movement and showed dyspnea. When subjected to physical efforts, the signs of fatigue were more obvious. Calcium serum levels increased when ingestion of N. rivularis increased. X-rays showed an increased radiopacity of the aortic arch as the only anomaly. Ultrasonography revealed an increase in ecogenicity at the corticomedullary junction of the kidney.