Plant Poisoning of Small Ruminants

Abstract

Sheep goats, llamas and alpacas are in general, capable of grazing or browsing a wide variety of toxic plants without any problem. So long as there are a variety of plants on which the animals can feed, they appear capable of varying the quantity of plants consumed, thereby avoiding a toxic dose of any one particular plant. However, small ruminants are susceptible to plant poisoning under conditions where there is overgrazing, drought, or access to areas where toxic weeds predominate. Historically, and even today, significant mortality in unadapted sheep can be associated with areas where plants such as Halogeton (Halogeton glomeratus) comprise the majority of the available forage. The Halogeton is palatable, and if it becomes the predominant forage, high sheep mortality results from the high level of oxalates in the plant. Small ruminants are susceptible to poisoning from plants that contain nitrates, cyanogenic glycosides, cardiac glycosides, photosensitizing agents and a variety of other plants toxins affecting the reproductive, urinary, hemic and nervous systems.