DR. LE(TEAR'S STOCK BOOK. 165 



BIG -HEAD. 



This disease is properly termed "Osteo-porosis," as it is a 

 porous condition of the bones. It is commonly known as big- 

 head, as the disease is more noticeable about the head by the 

 bones of the face and lower jaw becoming enlarged. The bones 

 become enlarged, but are lighter, more porous, and more easily 

 broken than in health. Not only the bones of the head are 

 affected, but every bone in the body becomes more or less 

 changed. It is a disease of young horses, as it is never seen in 

 an old horse. Big-head is rather rare in Texas, but we have seen 

 a few cases in our practice during the last three years. We are 

 often called upon to examine and prescribe for horses said to 

 have the big-head, when it is nothing but an enlargement on the 

 face caused by a bad jaw tooth. 



Causes. The causes of big-head are rather obscure. Some 

 authors claim it is due to a deficiency of lime, while others claim 

 it is due to eating certain grasses and foods, and drinking certain 

 kinds of water. 



Symptoms. Perhaps the first symptom noticed is the enlarg- 

 ing of the face. One or both sides may enlarge, and usually both 

 sides of the face and each side of the lower jaw bulge out. The 

 animal may appear somewhat stiff and dull in its movements. 

 In many cases when the animal lays down it is difficult for it to 

 get up. Also as the bones are so very porous and brittle, fracture 

 may take place very easily. 



Treatment. Treatment is almost useless. A complete change 

 of food, water, and climate is about all that can be done. 

 A change of climate has been known to cure big-head, but as a 

 general thing, when a horse becomes affected with the disease it 

 is a hopeless case. 



