In experiments in bovines, which received repeated daily sublethal doses of Asclepias curassavica (2.5 and 5.0 g/kg/day during 12 days) till reaching the lethal dose or more, the fresh leaves of the plant did not show a cumulative effect. One animal developed tolerance against a dose which previously caused symptoms (5 g/kg), but not against a larger one (10 g/kg) which was given subsequently. The dried plant continued toxic up to 2 months after collection, but after 6 months had lost its toxicity. A mixture of the hacked fresh plant with fresh hacked grass, was not eaten by the animals in amounts that possibly could cause symptoms of poisoning, when given in proportions that varied from 1:2 to 1:6, plant:grass. A mixture of the recently dried hacked plant with dried hacked grass, in the proportion of 1:3, was eaten only by one of four bovines in amounts that possibly could cause symptoms; but even that animal did not show symptoms of poisoning.
Poisonous plants; plant poisoning; Asclepias curassavica; Asclepiadaceae; pathology; cattle
