Neuronal vacuolation of the trigeminal nuclei in goats caused by ingestionof Prosopis juliflora pods (Mesquite beans)

Three groups of 6 goats each were fed a ration containing 30, 60, or 90%, o n a dry matter base, of Prosopis juliflora pods. A control group of 4 goats ingested only the basic ration. Two hundred and ten days after the start o f the experiment 3 goats that ingested 60% pods in and 4 that ingested 90% had mandibular tremors, mainly during chewing. All animals were killed afte r 270 d of ingestion. No grass lesions were observed. Histologic lesions we re characterized by fine vacuolation of the pericaryon of neurons from the trigeminal nuclei. Occasionally neurons of the oculomotor nuclei were also affected. Wallerian degeneration was occasionally observed in the mandibula r and trigeminal nerves. Denervation atrophy of the masseter, temporal, hyo glossus, genioglossus, styloglossus, medial pterygoid and lateral pterygoid muscles was seen. The clinical signs from Feeding the P juliflora pods wer e caused by a selective toxicity to neurons of some cranial nerve nuclei.