DISEASES OF SHEEP 599 



avoided by the others. The habits of sheep vary not only individually, 

 but in the same band as a whole from season to season, and an equally 

 striking variation is noted in the different parts of the State and in 

 different States. An illustration of this variation may be of interest 

 in this connection. The feeding habits of a band of sheep on a foot- 

 hill range, at an altitude of 4,600 feet, were observed. Some of the 

 sheep ate considerable quantities of wild sunflower, a few ate false 

 lupine, some fed largely upon the wild geranium, while others grazed 

 almost exclusively upon sand vetches. Two were seen eating the 

 leaves of lupine, and about 50 ate a few specimens of death camas. 

 The majority of the sheep in this band fed exclusively upon the na- 

 tive grasses. On one range a band of sheep was kept for two months 

 during the spring of 1900 on a range which abounded in death camas 

 without any cases of poisoning occurring. Another band on the same 

 range passed over a conspicuous area of purple larkspur twice daily 

 in going from and coming to the corral, and no evidence was to be 

 obtained that they had touched this plant. The same band, however, 

 on being moved to a locality where they found the death camas, be- 

 came poisoned, and a number of them died. Nearly all of the band 

 had been affected, showing that the plant was generally and greedily 

 eaten. The arbitrariness of the appetite of sheep exercises a great 

 influence on the occurence and extent of poisoning. Obviouly, poi- 

 sonous plants do no harm until eaten, and the chief factor in deter- 

 mining the amount of poisoning which is likely to occur on a given 

 range is the extent to which the plant will be eaten by the sheep. 

 This factor can not be estimated with any certainty. It can not be 

 determined by feeding experiments, since it is impossible to repro- 

 duce the natural conditions which prevail upon the range. It is man- 

 ifestly unsafe to assume that an animal is fond of a certain plant be- 

 cause it is eaten in confinement when no other fodder is to be had. 



REMEDIAL AND PREVENTIVE MEASURES. 



A number of remedial and preventive measures may be sug- 

 gested from observation and experience. Experiments have been 

 tried on a small scale in various parts of the State in displacing poison- 

 ous plants upon the range by the use of aggressive forage plants, such 

 as smooth brome grass and blue joint (Agropyrum occidentale) . 

 These grasses grow vigorously upon the ranges of the plains and 

 mountains. Naturally the brome grass attains a much greater size 

 and covers the ground more completely in moist than in dry situa- 

 tions. Judging from the present outlook in Montana, it will require 

 several years for the brome grass to form a sod sufficiently thick to 

 displace death camas, larkspur, or loco weeds. The brome grass starts 

 early in the spring and is much sought for by sheep. A native species 

 of brome grass (Bromus marginatus) is rapidly spreading in some 

 parts of the State, especially near Augusta and in the Judith Basin, 

 and in the former locality has killed out a few timothy meadows and 

 entirely replaced the timothy. Although it can not be said that ex- 

 periments have so far demonstrated the possibility of driving out 

 poisonous plants by this method, the habit of starting early in the 

 spring, which is characteristic of brome grass, is very useful, since 



