400 TTNIVERSITY OF VIRGINIA PUBLICATIONS 



C. FEEDING EXPERIMENTS. 



The campaign of 1903 established the facts that several menacing par- 

 asitic diseases are widely spread among the sheep of Montana; that these 

 diseases, either of themselves, or in combination with insufficient food, are 

 named "loco disease" by the ranchmen, regardless of the type of infection, 

 or its severity; and that whatever symptoms the locoweed may cause can 

 not be recognized accurately in sheep suffering from parasitic infection and 

 underfeeding. If the effects of locoweed poisoning can be determined, it 

 must be done in some other way than by the examination of sheep which 

 the ranchmen call "locoes." 



The Department of Agriculture directed me to continue the study of 

 the loco problem during the summer of 1904, acting with the advice of 

 Professor Chesnut and in cooperation with Mr. Reese of the Montana Agri- 

 cultural College. It was decided to conduct a feeding experiment, and hold 

 sheep in corrals where locoweed abounded, while others fed on alfalfa were 

 kept as controls. Professor Chesnut, whose prolonged studies of the loco- 

 weed from the botanical side particularly fitted him for the purpose, selected 

 Ten Mile Flat as the site of the experiment, for here the locoweed Aragallus 

 spicatus (Hook.) Rydberg was unusually abundant, and other poisonous 

 plants were absent. 



Ten Mile Flat is a stretch of public land east of the Crazy Mountains and 

 north of Big Timber, Montana. It has the reputation of being one of the worst 

 locoed districts in this part of Montana. The soil is very poor and dry ; there 

 is a moderate amount of alkali, and the streams nearby are alkaline. The 

 forage is quite scanty, a small amount of grass, wire grass and other plants 

 occurring together with large patches of locoweed. From June until autumn 

 the flat is very dry, and is exposed to the full effects of the summer sun. 

 There was no shade where the experiment was conducted. In spite of its 

 bad reputation, large bands of sheep are grazed over this flat every year. 

 In the early spring of 1904, there was a moderate amount of grass to be 

 found over the region, but this was quickly removed by two bands of from 

 three to five thousand sheep apiece, which passed over this region before 

 the middle of June. Another band was taken over soon after, leaving very 

 little nutritious forage behind. Inquiries were made, but it could not be 

 ascertained whether these bands suffered particularly from loco poisoning. 



A large area with an abundant growth of locoweed was selected for use 

 during the experiment. The objects of the experiment were: (1) To de- 

 termine whether sheep can be poisoned by the locoweed when it is used as a 

 food. (2) To determine the signs, symptoms and anatomical changes re- 



