Poisoning by Marsdenia hilariana and Marsdenia megalantha (Apocynaceae) in ruminants.

Neurological signs were observed in cattle consuming the roots of Marsdenia hilariana and sheep consuming leaves of Marsdenia megalantha. Similar nervous signs to those observed in spontaneous poisoning were induced experimentally by the administration of roots of M. hilariana to goats, and by the administration of leaves and roots of M. megalantha to sheep. No lesions were observed at necropsies and on histological examination of the nervous system and other tissues.