Affiliation:
1. Senior Information Scientist, Veterinary Poisons Information Service (VPIS), 2nd Floor, Godfree Court, 29-35 Long Lane, London, SE1 4PL
Abstract
Poisoning can be seasonal. Potential toxic hazards in the spring include adders, which emerge from hibernation as the weather warms. Adders may not be seen to bite a horse, but envenomation should be considered in a horse with localised limb swelling that spreads up the leg. There are several spring-flowering plants which contain toxic compounds such as cardiogenic glycosides (foxglove, lily of the valley, oleander), protoanemonin (Hellebore) and grayanotoxins (Pieris and Rhododendron). Saplings of sycamore are a spring source of hypoglycin A which causes atypical myopathy in horses. Treating plant poisoning in horses generally involves removing the plant, providing good quality food and giving supportive care. Managing the effects of adder bite is supportive, centring around administration of specific antivenom.