BUREAU OF ANIMAL INDUSTRY. Ill 



BLACKLEG VACCINE. 



Tho preparation and free distribution to stock owners of vaccine 

 for the prevention of blackleg in cattle has been continued, 6,050,195 

 doses having been sent out during the fiscal year, an increase of more 

 than half a million doses. 



INVESTIGATIONS OF PLANT POISONING OF STOCK. 



The work in the investigation of plant poisoning of live stock in- 

 volves (1) the collection and collation of information in regard to 

 poisonous plants and the conduct of correspondence relating to this 

 subject, (2) the investigation of cases of poisoning with reference to 

 determining the plants producing the disease and of giving advice in 

 regard to methods of treatment of affected animals and of prevention 

 of losses, and (3) the experimental investigation of the effects of 

 poisonous plants. The research work is carried on in part in the 

 laboratories in Washington and in part in field stations. The princi- 

 pal field station at present is on the Fish Lake National Forest, about 

 16 miles from Salina, Utah. This station was erected by the Forest 

 Service and comprises pastures, feeding corrals, and necessary build- 

 ings. Laboratory facilities are provided and detailed experimental 

 work is carried on with animals suffering from poisonous plants upon 

 the range. 



The general plan of the experimental work includes tests to prove 

 whether suspected plants are actually poisonous, experimental feed- 

 ing to determine the symptoms and pathology of poisonous animals, 

 and the study of possible remedies and of the methods by which 

 poisoning can be prevented. With the feeding experiments is con- 

 ducted a chemical study of the plants, in order that there may be a 

 scientific basis for possible remedies. Some of the studies are made 

 difficult by the fact that many of the so-called poisonous plants are 

 not acute poisons and cause trouble only as the}^ are eaten in some- 

 what large quantities and under certain peculiar conditions. In some 

 cases the plants are poisonous only at certain seasons, while in others 

 they affect one kind of domestic animals but are harmless when eaten 

 by others. 



The plants which have been the subject of special investigation 

 during the past season are the western sneezeweed {Dugaldia 

 hoopesH), which occasions heavy losses of sheep on the national 

 forests of Utah, and oak brush, which is reputed to kill cattle in 

 many sections of the West. In connection with the oak-brush study 

 a station was maintained at Monahans, Tex., for two months for a 

 study of the so-called shinnery oak poisoning. Experimental work 

 has been conducted also on pingue (Hy7nenoxf/s floribunda)^ yellow 

 weed {Gutierrezia diversifolia), aconite, the larkspurs, and on As- 

 tragalus diphysus^ the loco plant particularly destructive to horses 

 and cattle in New Mexico, Arizona, and southern Utah. Milk sick- 

 ness, a disease destructive to cattle in the mountains of North Caro- 

 lina and common in many other States as far as New Mexico, also 

 has been a subject of investigation. 



Some of these investigations are incomplete, and final results can 

 be published only after further prolonged study. Others, like the 

 oak brush, may be considered as practically finished, while in other 

 cases the material at hand is sufficient for preliminary reports which 

 will aid in reducing the losses. 



