OTHER NON-COMMUNICABLE DISEASES 339 



Causes. — Poisonous substances in the food appear to be the 

 usual cause of this affection. It is believed that various molds 

 and fungi are the exact cause, but nobody has yet succeeded 

 in producing it by feeding immense quantities of molds to experi- 

 mental animals. Graham has isolated a germ, designated B. 

 botulinus, that has been shown to be the primary agent in certain 

 outbreaks of forage poisoning. The infection is not directly com- 

 municable from animal to animal. 



Symptoms. — Affected patients snow either great mental ex- 

 citement or stupor, depending on the action of the bacterial 

 toxins on the nervous tissue. The animal may become delirious, 

 and rush about in the stall or paw, kick, and in other ways seem 

 blind to its surroundings. In many outbreaks the primary 

 symptoms are a staggering gait, a sleepy attitude, and dizziness. 

 Later the animal falls to the floor, struggles to rise, but is unable 

 to do so, and finally becomes unconscious and dies in two or three 

 days, if not sooner. 



Treatment. — Little or no results follow medical treatment once 

 the disease is well established. Medicines to quiet the animal 

 and eliminate the toxic substances by way of the alimentary 

 canal are indicated. For the latter, subcutaneous administration 

 of arecolin is highly recommended. An immediate change of 

 feed is said to prevent the disease from attacking other ani- 

 mals on the farm. One attack of the disease does not confer 

 immunity. Encouraging results have been obtained from the 

 use of a prophylactic serum produced by hyperimmunizing 

 horses against the B. botulinus. 



GOITER 



Goiter is a disease resulting in enlargement of the thyroid gland 

 of the neck. It is widely prevalent in calves, lambs, foals, and 

 pigs. From the fact that the neck becomes visibly enlarged in 

 all affected animals except fat hogs, it is commonly known as 

 big neck. In pigs, goiter is associated with a condition of hair- 

 lessness, hence in them it is commonly referred to as the hair- 

 less pig malady. 



Cause. — Normally the thyroid gland forms a chemical sub- 

 stance containing iodin which is distributed to the various 

 organs of the body by the blood circulating through the gland. 

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