614 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



turbances are often quite ludicrous. The animal often takes flight 

 apparently at imaginary objects, or at objects which under ordinary 

 circumstances would cause no alarm. Locoed horses are somewhat 

 dangerous for driving purposes on account of their tendency to run 

 away. Such horses are frequently attacked with kicking fits without 

 any apparent cause. The sense of hearing is .often affected, and the 

 response to sounds is irregular and out of proportion to the volume 

 and character of the sound. Irregularities in muscular movements 

 of sheep may assume a variety of forms. The animal may simply 

 carry its head in an extended or otherwise unnatural position. In 

 some cases the back is arched. Trembling is a characteristic symptom. 

 In locoed horses a great difficulty is sometimes experienced in per- 

 suading them to go backward. Locoed sheep are exceedingly diffi- 

 cult to manage. The different members of the band may suddenly 

 take a notion to run away in different directions, with the result that 

 it is almost impossible for the herder to prevent their becoming sep- 

 arated. In cattle the disease appears to be rare, although symptoms, 

 so far as observed, are essentially the same as those in sheep and 

 horses. Occasionally locoed cattle manifest dangerous symptoms, 

 and attack men and other animals. The belief is quite general 

 among sheep raisers that one of the effects of eating loco weeds is 

 an elongation and loosening of the teeth. This symptom is ordinar- 

 ily mentioned as characteristic of the locoed condition. Dr. M. E. 

 Knowles, State veterinarian of Montana, suggested that this was 

 merely the natural process of shedding the teeth, which occurs in 

 sheep at about the age of eighteen months. It hardly seems possible 

 that the loco habit would cause such a peculiar phenomenon. 



In chronic cases of loco the animal gradually becomes more 

 emaciated and crazy. In sheep the fleece may be shed in patches or 

 as a whole. The animal becomes unable to care for itself, and is apt 

 to fall into the water while attempting to drink. Fits of trembling 

 are of frequent occurrence, and the animal finally dies of inadequate 

 nutrition and total exhaustion. In chronic cases of loco disease in 

 horses the animal is usually left to its own resources on the range. 

 During the later stages it may remain for weeks at a time upon a 

 small area of ground without taking water. The writer had the 

 opportunity of observing a number of such cases in horses that were 

 almost unable to walk. Under such circumstances the animals sel- 

 dom or never lie down. One horse which was seen remained for a 

 period of two weeks, in 1897, upon a piece of ground about 150 feet 

 square. During this time the horse had no water. 



Numerous autopsies on locoed sheep and horses revealed con- 

 ditions which, though fairly uniform, do not constitute a well-defined 

 series. A slight congestion of the brain membranes w r as observed in 

 all cases. The lungs and heart were in normal condition. Fatty tis- 

 sue was considerably reduced in quantity, and the muscles were paler 

 in color than under normal conditions. 



The most serious mistake in connection with loco disease is made 

 in allowing locoed sheep to remain with the rest of the band. The 

 loco habit is apparently learned by imitation of locoed animals, and 



