94 STOCK-POISONING PLANTS OF MONTANA. 



assume a variety of forms. The animal may simpl}" carr}- its head in 

 an extended or otherwise unnatural position. In some cases the arched 

 carriage of the back is to be noticed with awkward movements of the 

 legs. Trembling is a frequently noticed characteristic of the locoed 

 animal. This may be confined to the legs, especially to the knees, or 

 may involve all the voluntary muscles, and occurs in a most pronounced 

 manner after any fright which the animal may have experienced. It 

 is often observed of locoed horses that even when they are able to 

 move forward with considerable precision they experience difficulty in 

 backing. 



It is the universal experience of sheep raisers that locoed sheep are 

 exceedingly difficult to herd. The sheep may, without a moment's 

 warning, stray away from the band, each one in a diflFerent direction, 

 and it is easy to understand how nearlj^ impossible it is to prevent 

 such a band of sheep from becoming separated. Besides giving the 

 herder much trouble in directing the course of the band on the range, 

 locoed sheep often refuse to enter the corral at night, and under any 

 and all circumstances may suddenly manifest perplexing stubbornness. 



Few cases of locoed cattle have come under our observation. The 

 symptoms, however, in cattle are essentiall}^ the same as in sheep and 

 horses. Occasionally locoed cattle manifest dangerous symptoms and 

 attack man or animals. It is difficult to understand why the loco habit 

 is apparently so rare in cattle as compared with sheep and horses. In 

 their ordinary feeding habits cattle can hardly be said to be as fastidi- 

 ous in selecting forage plants as horses. The fact remains, however, 

 that cattle do not acquire the habit of eating loco weeds to any great 

 extent. 



Man}^ sheep raisers believe that in sheep one of the effects of eating 

 the loco weeds is an elongation and loosening of the teeth. As this 

 condition is almost invariabl}" noticed in sheep from a jear and a half 

 to two years old it would appear to be quite possible that this is 

 merel}" the natural phenomenon of shedding the teeth, which occurs 

 at the age just mentioned. The symptom in question is one which is 

 almost alwaj^s mentioned by sheep raisers as characteristic of the 

 locoed condition. No careful and continued observations have been 

 made which would enable one to come to any definite conclusion in 

 regard to the matter. The suggestion that the loosening of the teeth 

 is merely a natural process of shedding the teeth was made by Dr. 

 M. E. Knowles, State veterinarian of Montana, and seems, according 

 to available observations on the subject, far more reasonable than the 

 other theory. As this loosening of the teeth occurs at the age when 

 the loco habit is most apt to l)e acquired, in the frequent examinations 

 made by stockmen it might easily be mistaken for an effect of eating 

 loco weed. 



In chronic cases of the loco habit in sheep the animal, as already 



