Spring poisoning hazards

Abstract

Poisoning in the spring may occur in livestock from exposure to glyphosate which is used prior to sowing of plant crops or from ingestion of poisonous plants. Glyphosate is of low toxicity but many products contain a carrier which is irritant to tissues. Plant poisoning may occur because other forage is unavailable and hungry animals will eat unpalatable toxic plants if other food sources are scare. Some plants such as bluebell (Hyacinoides species) and ransom (wild garlic, Allium urinsum) grow in profusion in the spring. Bluebells cause gastrointestinal and cardiac effects and Allium species cause anaemia. Some plants are more toxic in the spring as concentrations of toxic compounds are high compared with other times of the year. This is the case with hemlock (Conium maculatum) and water hemlock (Cicuta virosa). Both these plants cause neurological effects and water hemlock, in particular, causes very rapid onset of clinical signs. Spring flowering plants such as Rhododendron and Pieris species are commonly associated with poisoning, particularly in ruminants. Both these species contain grayanotoxins which cause gastrointestinal and cardiac effects. Access to areas where poisonous plants are known to grow should be restricted and good quality forage provided. Treatment options for management of poisoning in livestock are limited and, in some cases, the only sign of exposure is sudden death.