W36 

 (leaf 2) 



In Wyoming, Beath and co-workers, 23 and Bruce 4 in British 

 Columbia, have reported on the poisonous properties of timber poi- 

 sonvetch and have contributed most of the available information 

 concerning the effects of this plant upon livestock. In the case of 

 sheep and cattle, females suckling their young are by far the most 

 susceptible ; ordinarily the death rate in horses is not high, although 

 in certain cases losses of from 10 to 40 percent or more have occurred. 

 However, horses once affected can never stand much work after- 

 ward. The greatest losses obtain among 1 animals which are new- 

 comers to the ranges ; in time, however, they seem to develop partial 

 (but never complete) immunity to the poison. Livestock suffer most 

 from this disease- during dry seasons, and the majority of range 

 losses attributable to the plant are intimately connected with short- 

 age of other forage. The toxic period of timber poisoiivetch is not 

 definitely known. Although a few livestock losses have occurred in 

 its earlier stages of growth, most poisonings have developed during 

 its flowering or seeding periods; after maturing and drying up it 

 has been eaten without apparent injury. 4 



There is an extensive local lingo for the cumulative symptoms 

 caused by timber poisonvetch, including such terms as alkali disease, 

 blind staggers, cracker-heel, knocking disease, mountain fever, roar- 

 ing disease, timber paralysis, and timber trouble. However, the first 

 two names are not limited to poisoning caused by timber poison- 

 vetch. 



The disease may be chronic, as commonly in Wyoming, 2 lasting 

 from several months to several years, or it may be acute, the symp- 

 toms appearing within a few days, and being rather quickly fatal. 

 In the chronic cases sjinptoms are varied and often difficult to rec- 

 ognize. They include general sluggishness and inactivity, weak- 

 ness, defective nutrition, often depraved appetite, impaired vision, 

 tendency to wander aimlessly, and varying degrees of paralysis, 

 especially in the hind legs. 



In acute cases one or more such characteristic symptoms are notice- 

 able, as sudden attacks in which the heart beats very rapidly and 

 spasmodically; impairment of vision (blind staggers); muscle in- 

 coordination which causes the animal to knock its heels together in 

 walking (knocking disease), or paralysis beginning in the hind legs, 

 with a tendency to spread to other parts; difficult breathing, often 

 accompanied by a wheezing or roaring (roaring disease). In addi- 

 tion there may be drooling, loss of voice, anemia, and a dangerous 

 decline in body temperature. In fatal cases death ordinarily results 

 from respiratory paralysis or from heart failure and may occur 

 within a few days after the first symptoms appear. Autopsy reveals 

 an enlarged and flabby heart with thin walls; the liver, lungs, 

 spleen, and various parts of the digestive tract are usually congested ; 

 there may be some nerve degeneration, especially of the vagus nerve. 



8 Beath, O. A., Draize, .T. H., and Gilbert, C. S. PLANTS POISONOUS TO LIVESTOCK. 

 Wyo. Agr. Expt. Sta. Bull. 200, 84 pp., illus. 1934. 



* Bruce, E. A. ASTRAGALUS CAMPESTRIS AND OTHER STOCK POISONING PLANTS OF 

 BRITISH COLUMBIA. Canada Dept. Agr. Bull. 88, 44 pp., illus. 1927. 



