Drought associated poisoning of cattle in south texas by the high quality forage legume Leucaena leucocephala

Approximately 80 head of yearling cattle grazing on 680 acres exhibited sig ns of Leucaena leucocephala toxicosis, which was confirmed in 3 animals by detection of 3-hydroxy-4 (IH)-pyridone, the metabolite of the poisonous pri nciple mimosine, in their urine. The animals had grazed leucaena almost exc lusively due to lack of alternative forage resulting from drought condition s. Toxicosis from this otherwise high Quality forage would likely not have occurred had animals consumed lower amounts of leucaena acid could probably have been prevented, as it has been elsewhere, had the animals been coloni zed with Synergistes jonesii, a beneficial ruminal bacterium capable of deg rading the toxic metabolites.