DISEASES OF ANIMALS 



167 



tering laudanum and linseed oil. In 

 some cases hypodermic injections of 

 morphine may be given. 



Poisoned pastures — I n smelter re- 

 gions it has been observed that the 

 continual use of forage on wnich sul- 

 phurous or sulphuric acid is precipitated 

 may lead to a weakness and softening of 

 the bone, accompanied with other 

 troubles, particularly an inflammation 

 of the respiratory passages. Under 

 such circumstances the only treatment 

 which can be recommended is to re- 

 move animals beyond the influence of 

 these poisons. 



Poisonous plants — A large number of 

 wild plants have been shown to be poi- 

 sonous to a greater or less extent to 

 domestic animals and man. Naturally 

 the most serious cases of plant poison- 

 ing in stock occur on the western 

 ranges, where for all or a greater por- 

 tion of the year, stock are allowed to 

 graze on the native vegetation. In 

 cultivated pastures, particularly where 

 a system of rotation is followed, such 

 weeds do not secure a foothold and losses 

 from poisonous plants are therefore 

 much less serious in the thickly settled 

 regions. It has been observed in the 

 study of poisonous plants during recent 

 years that the losses are most severe 

 at times and under conditions where the 

 range is over pastured, so that grass 

 and more palatable plants are not to be 

 obtained in sufficient quantities. Farm 

 animals do not voluntarily choose to 

 eat poisonous weeds in preference to 

 grass, but may be driven to eat such 

 plants under stress of hunger. The 

 losses from poisonous plants in the 

 western states are annually a very se- 

 rious matter, but this problem as a 

 whole may be looked at as a part of the 

 problem of range management and range 

 improvement. Where the ranges are so 

 managed that the animals are able to 

 secure good grass in sufficient quanti- 

 ties, little danger need be apprehended 

 from stock being poisoned by harmful 

 plants. Briefs notes follow on the more 

 important plants which are concerned 

 in poisoning farm animals. 



Loco — Throughout the western range 

 country there are a number of wild le- 

 guminous plants which have been sus- 

 pected of causing the loco disease and 

 are commonly known as loco weeds. The 

 most abundant, species in Colorado and 

 Kansas is Astragalus moUissimus; 

 while in Montana the plant most fre- 



quently concerned in causing loco dis- 

 ease is Aragallus spicatus* Contro- 

 versy has prevailed regarding the loco 

 disease. It has been supposed by va- 

 rious investigators to be due to eating 

 alkali, to tapeworms, stomach worms, 

 insect parasites contained in the loco 

 weed and to the poisonous or injurious 

 effects of various loco weeds. In in- 

 vestigations which were carried on in 

 Montana it appeared that, in some 

 parts of the state, horses and sheep 

 were badly affected as the result of 

 eating the common loco weed of those 

 sections. In the southern Rocky moun- 

 tain states the disease is more preva- 



Fig. 122 — purple 



LOCO WEED 



lent among cattle. The symptoms are 

 those of extreme emaciation, malnutri- 

 tion and weakness accompanied with va- 

 rious cerebral symptoms such as perver- 

 seness and stupidity on the part of the 

 animal. In fact, affected animals are 

 commonly crazy or foolish, as is indi- 

 cated by the Spanish word 'loco." There 

 is no medical treatment for loco disease, 

 but affected animals may be removed 

 from pastures where the loco weed grows 

 and fed on a nutritious diet. When this 

 is done they soon recover, to all intents 

 and purposes. Locoed sheep may be 

 readily fattened and make good mut- 

 ton. Similarly with locoed cattle, the 

 disease does not interfere with their sub- 

 sequent use for beef purposes. Locoed 

 horses may be restored to a serviceable 



