DISEASES OF SHEEP 613 



the Judith Basin one prominent stockman was nearly ruined finan- 

 cially by the prevalence for a number of years of the loco habit 

 among his sheep. In another instance the raising of horses was aban- 

 doned over a large tract of country on account of the loco weeds. 

 During the season of 1900 about 650 locoed sheep and 150 locoed 

 horses were seen during the writer's field work. The locoed horses 

 were all in one herd, and of the 650 sheep, 500 were in one band and 

 150 in another. These numbers represent not more than one-fourth 

 of the actual cases. A few locoed sheep and horses were to be seen on 

 nearly every stock range. 



The loco disease occurs under two forms an acute and a 

 chronic. An acute case of loco disease was observed in a 2-year-old 

 ewe with a lamb at her side. The ewe was observed eating large 

 quantities of white loco weed on May 22, 1900. During the after- 

 noon of the same day she became unmanageable, and the lamb was 

 badly affected. An examination of the ewe at this time showed that 

 she was completely blind and was affected with dizziness. She walked 

 around in long circles to the right, and after a short period remained 

 standing for a few moments in a sort of stupor. At the beginning of 

 each attack the head was elevated and drawn to the right; eyelids, 

 lips, and jaws were moved rapidly. Each attack lasted from one to 

 two minutes, and the intervals between the attacks lasted about five 

 minutes. The second day the attacks became more severe and of 

 longer duration, the head being turned more decidedly to the right 

 and the animal sometimes falling upon the ground. Similar symp- 

 toms, accompanied by digestive disturbances, were manifested by the 

 lamb during the second day, and it died during the afternoon. On 

 the morning of the third day it was found that the ewe was pushing 

 against the corral, and had apparently been in that position during 

 the greater portion of the night. The animal then Degan to whirl 

 around to the right. Later she became unable to stand, and the spas- 

 modic movements were largely confined to the legs. On the morning 

 of the fourth day she died. The pupil of the eye was at no time 

 dilated, and the expression was nearly normal. The pulse was at 

 first very irregular, but on the second day became again regular and 

 of normal frequency. The only remedy which was tried was frequent 

 injections of one-quarter grain doses of morphine, but this was with- 

 out effect. Two other ewes ate smaller quantities of loco weed at the 

 same time and were similarly affected, but less severely. In these 

 cases morphine was tried with better success. The lambs, however, 

 died from the poisonous properties contained in the milk of the 

 mother. 



The general symptoms of loco disease are quite familiar to all 

 stock raisers. Perhaps the most characteristic are those of cerebral 

 origin, and are shown in peculiarities of gait and action, which may 

 be compared to a drunken condition. The brain disturbances may 

 consist in impairment of the special senses or in irregular motor 

 impulses, which produce incoherent muscular action. In some cases 

 the animal becomes blind. More frequently the animal makes errors 

 in judgment of the size and distance of objects. These visual dis- 



