42 



BULLETIN 1245, V. S. DEPARTMENT OF AGRICULTURE 





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FIGURE 1' 



«teer poisoned by the 

 A stragalus diph ys us 



blue loco weed, 



loco weed, as large quantities of dried plant have been fed "without 

 injuring the animals in any way. 



Symptoms of Loco Poisoning 



All the loco plants produce similar effects. These symptoms 

 appear only after a somewhat prolonged feeding, and this fact has 



led to the failure of a 

 great many feeding ex- 

 periments with loco. 

 Ordinarily the first 

 symptom in a locoed 

 animal is a loss of con- 

 dition. This is fol- 

 lowed by irregulari- 

 ties of gait and weak- 

 ness, which condition 

 in many cases seems 

 almost to amount to 

 paralysis. The animal 

 shows a lack of co- 

 ordination in its mus- 

 cular movements, due 

 without doubt to the 

 effect of the plant on 

 the central nervous 

 system. Horses form- 

 erly gentle become uncontrollable and shy violently at imaginary 

 objects or leap high over some slight obstruction. Generally speak- 

 ing, a locoed horse can be neither led nor backed, and when put in 

 motion can not easily be stopped or turned, but may continue until it 

 Tuns against a fence 

 or other obstruction. 



Many animals ac- 

 quire a liking for the 

 plants to such an ex- 

 tent that they will eat 

 nothing else. This. 

 however, is not true in 

 all cases. The animal, 

 when affected, shows 

 progressive emaciation 

 and eventually starves 

 to death. It is not at 

 all unusual in a coun- 

 try where there are 

 locoed cattle to see a 

 steer standing by it- 

 self, sometimes re- 

 maining in one position for hours, or even for days, and finally 

 falling and dying without making any attempt to go elsewhere for 

 either feed or water. 



In Figure 17 is shown a steer poisoned by the blue loco weed. Fig- 

 ure 18 is a picture of a steer in the last stages of loco poisoning from 



Figure 18. 



-A steer badly locoed by tbe wbite loco weed, 

 Oxytropis lambertii 



