CIRCUMSTANCES INCREASING DANGER OF POISONING. 27 



INFLUENCE OF SNOWSTORMS. 



Many serious cases of stock poisoning' have occurred after late 

 spring and earh' autumn snowstorms. In ail cases which we have 

 been al)le to investigate the explanation seems to be that the grass 

 was covered bv snow and nothing remained visible for the stock to 

 eat except certain plants which happened to l>e poisonous. On some 

 of the high ranges in the so-called mountain basins spring snowstorms 

 frequently occur as late as the first of June. Sometimes the snow 

 falls to a depth of 1 foot during these storms, and this depth is suf- 

 ficient to cover all grass at that season of the year. The tall species 

 of larkspur {Delphinium glaucum) usually stands about 2 feet high 

 at that time. This plant is greedil}" eaten by cattle under these cir- 

 cumstances, largely, perhaps, for the reason that nothing else is to be 

 obtained without digging under the snow. Cattle and horses are the 

 onl}^ animals which suffer from poison aftei- late snowstorms, for the 

 reason that sheep are not allowed to graze on the mountain ranges 

 until considerably later in the season, when the danger from snow- 

 storms is past. A number of disastrous cases of sheep poisoning- 

 have occurred, however, immediately after early fall snowstorms. 

 In all such cases which we had opportunit}" to investigate the plant 

 which was responsible for the poisoning was lupine. The conditions 

 were about the same in all cases. The lupine pods had failed to open 

 as couipletely as they ordinarily do, and a considerable portion of the 

 seeds were, therefore, retained in the pods. The lupine was the only 

 edible material which was left stimding above the snow. The influ- 

 ence of snowstorms upon stock poisoning depends, therefore, upon 

 the fact that the late spring and early fall snowstorms frequently 

 cover all forms of vegetation on the range with the exception of some 

 poisonous plants. 



DANGER ARISING FROM DRIVING OR TRAILING SHEEP. 



Attention has already been called to the fact that many serious cases 

 of poisoning among sheep have occurred while the bands were being 

 driven from one locality to another. The suggestion has already been 

 made b}" way of explanation that sheep can not make the same choice 

 of forage plants while being hurried over the range as they can under 

 conditions of rest. In following bands of sheep under the.se different 

 conditions it was observed that a much greater variety of plants and 

 even of noxious plants were eaten by sheep when on the trail than 

 when left to eat at leisure. The more indiscriminate grazing observed 

 under these conditions is perhaps due parti}' to sheep being worried 

 and partly to their being unable to satisfv their hunger so quickly as 

 under more normal conditions. It would seem highly desirable that, 

 where possible, two herders be detailed with each band of sheep while 



