8 BULLETIN 800, U. S. DEPARTMENT OF AGRICULTURE. 
Many areas in southern Utah are given up to corn raising by dry- 
land farming and afford another poison-milkweed problem. Some of 
the fields are in the natural habitat of the milkweed ; cultivated soil 
forms a better seed bed than the undisturbed soil ; cultivation breaks 
up the horizontal roots and propagates new plants rapidly. Areas 
of this type may be seen between Kanarraville and New Harmony, 
Utah. 
On some of the overgrazed ranges whorled milkweed has become 
a menace to stock. The range country in Long Valley on the Virgin 
River near Mount Carmel, Utah, appears to be an overgrazed range 
of that sort. Arizona and New Mexico also have the same range 
trouble. 
PART II.— EXPERIMENTAL WORK. 
Although both cattle and horses are killed by the milkweed, the 
greater part of the experimental feeding work was done with sheep, 
since most of the heavy losses are of sheep, and, moreover, it did 
not seem wise to kill cattle and horses unless it was distinctly neces- 
sary. Enough was done with cattle and horses to demonstrate the 
toxicity of the plant for those animals and to show that the results 
obtained from the sheep experiments could be applied to other ani- 
mals. Table 1 gives a summary of the experiments. 
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