40 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. 
range cases, and the conditions under which poisoning may occur 
seem now quite clear. 
It was early recognized that lupme 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 suppled 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 little 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 fall 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 1911, 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- 7 
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 lupime 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 locality are much more 
likely to eat too much of the lupine than those that are accustomed 
to the country. 
An attempt was made in 1912 to demonstrate in an experimental 
way that hungry sheep may be poisoned when they feed upon lupme. 
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 
