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Poisonous Properties: The toxic principles of the loco weed have 

 not yet been determined, but its poisonous action upon animals has been 

 fully established in Canada and the United States by field observations. 



Animals Affected: Horses, cattle, and sheep may all form what is 

 known as the loco-habit, and succumb sooner or later to its poisonous 

 action. The greatest losses, however, in Western Canada have occurred 

 chiefly among cattle. The world ''loco" meaning ''crazy", is derived from 

 the. Spanish, and is applied in reference to the peculiarities of movement 

 shown by the affected animals. 



Symptoms: The general symptoms of poisoning are awkwardness, 

 trembling, loss of control of muscular movement, impaired eyesight and 

 hearing. In extreme cases the animal becomes blind, loses all power of 

 locomotion, refuses food, except loco weed, and dies usually in convulsive 

 spasms. 



E. A. Watson (Report Veterinary Director General, Ottawa, 1909) 

 describes the effect upon horses as follows: "Mental derangement and 

 inco-ordinate muscular action form the most constant and characteristic 

 symptoms of the disease. The peculiar gait is at once remarked upon, 

 locomotion being performed slowly and with deliberation, accompanied by 

 overflexion and extension of the limbs. The head is carried low, the arm 

 lifted high, so that the knee and chin are nearly horizontal and in close 

 proximity. The animal appears to be walking over invisible obstacles, 

 and if driven fast will frequently stumble and fall, though the ground be 

 perfectly level. When the condition is very severe, it is almost impossible 

 to force him out of a slow walk; if urged he becomes excited, moving the 

 limbs up and down upon the same spot, "marking time" as it were, or 

 moving forward only a few inches at a step. Visual errors are common. 

 The loss of the sense of direction is well marked. When it is attempted to 

 drive an animal in a particular direction he will tread in semi-circles and 

 run into wire fences or gates. An animal is sometimes unable to locate a 

 dish of oats placed before him, the attempts being often ludicrous." 



Remedy and Means of Control: Give laxatives and supply good 

 nutritious food. Strychnine has been recommended for cattle, and Fowler's 

 solution for horses. 



E. A. Watson says in regard to preventive measures :—" Very little 

 can be advised in the way of medicinal treatment. But if the spread of 

 the disease among healthy animals on a range where the grass and fodder 

 conditions appear excellent can be accounted for by the loco habit largely 

 acquired by imitation, it is obvious that affected animals should at once 

 be removed from the healthy to a range or pasture free from the obnoxious 

 weeds. Healthy animals on the range could be placed in charge of a 

 herder and kept separate from locoed animals. Instances are reported 

 where affected cattle, by early removal to a range free from loco plants, 

 or taken and hand-fed, have so far recovered as to be profitably slaughtered, 

 though such animals are always stunted and undersized." 



