CHAPTER XX. 

 DISEASES OF THE BONES. 



1. Big Head (Osteo-Porosis). 



This disease is more common in some localities than in 

 others. It is not prevalent in Canada or Great Britain, but 

 is quite so in the United States and Mexico. It is a disease 

 which attacks horses from one to four years old, rarely old 

 horses. It develops gradually as the animal grows, without 

 any signs of soreness, the bones of the head and legs becom- 

 ing larger, lighter and very brittle, or easy to break — thus 

 the term "big." It affects the bones of the head more fre- 

 quently than those of any other part of the body. 



Causes. — It is difficult to say what is the real cause of 

 this disease, but it is supposed to be caused by feeding on 

 pasture land deficient in the salts of lime. Some believe it to 

 be wholly caused by grazing on low-lying, swampy land, 

 where the grass grows long and does not contain the full 

 amount of nourishing substances. 



Symptoms. — In the earlier stages the symptoms are not 

 well marked. There is dullness, loss of flesh and softening of 

 the muscles. In from four to six months the true nature of 

 the disease becomes evident. There is a stiffness when 

 traveling and very gaunt appearance accompanied by an 

 enlarging of the head, soon followed by enlargement of the 

 bones of the legs. As the disease progresses these symptoms 

 increase. The animal loses flesh until after a gradual decline 

 he dies. In some cases the bones of the legs become so 

 brittle that they break while traveling. 



Treatment. — The treatment of osteo porosis up to the 

 present has not been attended with but little success, more 

 especially if allowed to go for any length of time before tak- 

 ing the matter in hand. In the earlier stages if he is on low 

 pasture move him to high ground, and give a teaspoonful of 

 sulphate of iron in some oats twice a day to build up the 

 system and counteract the effect of the disease. 



