UNITED STATES DEPARTMENT OF AGRICULTURE 



I BULLETIN No. 575 



(Contribution from the Bureau of Animal Industry 

 JOHN R. MOHLER, Chief 



jj\J%*^wL 



Washington, D. C. 



July 23, 1918 



STOCK-POISONING PLANTS OF THE RANGE 



By C. D. Marsh, Physiologist, Pathological Division. 



CONTENTS. 



Prefatory note 1 



Introduction 2 



Loco plants 4 



Larkspurs 8 



Cicuta (water hemlock) 13 



Death camas 14 



Lupines 15 



Laurels 16 



Fern 17 



Wild cherry 17 



Milkweed '. 18 



Woody aster 18 



Colorado rubber plant 18 



Western sneezeweed 19 



Oak 20 



Psoralea tenuifolia 20 



Prevention of losses 21 



Conclusion 24 



PREFATORY NOTE. 



It is well known that poisonous plants cause heavy losses of range animals. Statis- 

 tics in regard to these losses are not available, but from estimates made in many locali- 

 ties it seems probable that the average loss must be as great as 3 to 5 per cent, while in 

 some range States it rises to much higher figures. For example, it has been estimated 

 that in Colorado the losses amount to a million dollars annually, while sheep growers 

 in Wyoming have estimated their annual loss as 14.6 per cent. 



These losses, too, are to a large extent of mature animals, those that are ready or 

 nearly ready for the market, and for the rearing of which large sums have already been 

 spent. The importance of these severe losses has been recognized by the United 

 States Department of Agriculture and extended investigations and experiments have 

 been undertaken to determine what plants were poisonous and under what conditions 

 poisoning took place, and to formulate methods for preventing these deaths. This 

 work has involved prolonged study, and is still in progress. Some very definite results 

 have been obtained, however, and it has been shown that the heaviest losses are due 

 to a comparatively small number of plants. If the stockmen and herders can recog- 

 nize these plants and will act upon the information contained in the bulletins which 

 have been published on the subject, there is no doubt that most of these losses can be 

 avoided. 



Presumably, for the sake of their own material interests, the owners of live stock will 

 be glad to do all in their power to reduce the fatalities from these plants. At the 

 present time, however, when it is a matter of supreme concern to conserve the national 

 food supply, one of the most important elements of which is meat, it is especially 



106738°— Bull. 575—17 1 



