40 BULLETIlSr 405_, U. S. DEPARTMENT OF AGEICULTUEE. 



range cases, and the conditions under which poisoning may occur 

 seem now quite clear. 



It was early recognized that lupine poisoning ordinarily occurs 

 only when hungry sheep graze upon the plants. Well-fed bands 

 are rarely, if ever, poisoned. This statement, it may be said in 

 passing, can be made general and covers practically all poisonous 

 plants. If sheep are taken from the cars and turned into a pasture 

 abundantly supphed with lupine, disastrous results are likely to 

 occur. In July, 1914, 400 sheep, out of a band of 4,000, were lost 

 near Lakeview, Oreg. The matter was investigated by Mr. Norman 

 G. Jacobson, of the Forest Service, who found that the sheep had 

 been driven 34 miles in four days with a scarcity of forage. On 

 July 25, after a day's drive of 10 miles, they were turned into a 10- 

 acre pasture which, investigation showed, contained Httle but sage- 

 brush and lupines, and the lupines were in pod. The sheep, of course, 

 ate the lupines and with resulting loss. Many losses have occurred 

 in the fall when sheep are coming down from the mountain ranges 

 and have been caught by snow. On such occasions the fall of snow 

 may cover the grasses, but leave the lupines exposed. Hungry sheep 

 coming upon such an area may eat enough of the lupines to produce 

 poisoning. In the faU of 1913 a sheep owner in Montana lost 300 

 sheep in this way. 



An area in the Caribou National Forest was investigated where 

 annual losses have occurred. It was found that the sheep coming 

 from the mountains pass through thick patches of lupine and eat 

 it greedily. The fact that the lupines are in pod at the time of the 

 drive makes the matter worse. In 191 1 , an especially disastrous year, 

 one outfit lost 1,000 head in this locality. 



And yet, in spite of these known cases of severe loss, sheep some- 

 times graze on lupine through a good part of the season and with no 

 harm. Except as they are especially hungry sheep rarely, if ever, 

 eat enough of the lupine to cause trouble. Poisoning is much more 

 likely to occur if sheep are hurried over a lupine area, for then in 

 their eagerness and jealousy of each other they seize upon the lupines, 

 which are more easily reached than the grasses. Generally speaking, 

 it is much better to drift sheep over a lupine area than to drive them. 

 It may be noted that sheep that are new to a locaHty are much more 

 hkely to eat too much of the lupine than those that are accustomed 

 to the country. 



An attempt was made m 1912 to demonstrate in an experimental 

 way that hungry sheep may be poisoned when they feed upon lupine. 

 A bunch of 11 sheep were kept without food for 36 hours and then, 

 during one day, were driven 12 to 15 miles with very little opportu- 

 nity to eat. About 5 p. m. they were brought to a thick lupine patch 

 and allowed to graze. They fed until about 8.30 p. m., when they 



