Introduction

Livestock poisoning by plants has been a problem to livestock producers since earliest times. Wasting of livestock is a common occurrence on rangelands, but difficult to trace to a cause. Much of the emphasis on the problem of livestock poisoning by plants has been placed on determining the toxic effects of the plants on livestock and less on the plant aspect of the interaction. Livestock poisoning by plants can usually be traced to problems of management, overall range condition, or both, rather than the mere presence of poisonous plants. Direct effects of poisonous plants on livestock and factors influencing these effects, though difficult to assess, are most obvious. Management decisions require a thorough understanding of costs and benefits associated with shifts in programs to avoid problems like poisonous plants. An additional purpose of the symposium was an attempt to put dollar values on the adverse effects of poisonous plants on livestock production.