288 The Diseases of Animals 



PULMONARY EMPHYSEMA, HEAVES, OR BROKEN -WIND* 



This is a chronic disease of horses, due to a dilation 

 or rupture of the air-cells of the lungs. It is usually 

 associated with a chronic form of indigestion. 



Heaves is usually the result of improper food or 

 feeding, and is most frequently seen in greedy feeders. 

 Overfeeding, especially with dusty or moldy hay, is a 

 common cause. Fast driving or hard work on a full 

 stomach may induce the disease. There may be an 

 hereditary tendency to the disease. 



In most cases, the disease comes on gradually, but 

 fast work on a full stomach brings it on suddenly. 

 The breathing is labored, the air being taken in (in- 

 spired) with a peculiar outward twist of the ribs. 

 When the air is forced out (expired), there is a double 

 movement of the flank : when expiration begins, 

 the flank falls ; then there is a short pause, followed 

 by a decided contraction of the muscles, which causes 

 a heaving of the flank and belly. All the breathing 

 symptoms are most distinct when the stomach is full 

 of food or water, and the horse is exercised. In most 

 cases of heaves there is a deep, moist, grunting cough, 

 most frequent when the food or the air is dusty. 

 There is considerable gas passed from the bowels, es- 

 pecially when coughing. The nostrils are dilated, and 

 frequently there is a discharge of thick mucus from 

 the nose. Horses badly afflicted with heaves are unable 

 to perform hard or fast work without stopping frequently 

 to breathe. 



*'< Roaring," due to a paralysis of the muscles of the throat, is also called 

 "broken- wind" by horsemen. See pages 288-9. 



