102 DOMESTIC ANIMALS, DAIRYING, ETC. 



OTHER UNSOUNDNESSES. 



Chorea, Shivering, or St. Vitus' Dance. This is considered 

 a hereditary disease and also constitutes unsoundness in work horses. 

 It is commonest in nervous, tall, narrow animals. The disease is 

 most readily detected when moving the horse from one side to the 

 other, or in backing out of the stall. The leg is jerked up once or 

 twice at these times and the tail and muscles quiver momentarily. 

 The symptoms disappear when the horse is exercised. Stringhalt 

 (akin to chorea) is the term applied to the exaggerated jerking up 

 action of the hind leg seen in some horses. The trouble in some in- 

 stances is remediable by operation (peroneal tenotomy). 



Roaring. (Laryngeal hemiplegia) is characterized by noisy 

 breathing when the horse is exercised. It constitutes unsoundness 

 in both work and breeding horses. 



Heaves. (Emphysema of the lungs), is indicated by double 

 bellowslike action of the abdominal muscles as the horse breathes; 

 cough also is present. Like roaring it is an unsoundness of the 

 breeding animal and work horse. 



Vices. They are such as cribbing, windsucking and weaving 

 and are best discovered when the horse is in the stall and although 

 not certainly hereditary are highly objectionable and detrimental 

 unsoundnesses. (Wis. Circ. 17.) 



HORSESHOEING. 



Bad and indifferent shoeing frequently leads to diseases of the 

 feet and to irregularities of gait which may render a horse unservice- 

 able. It is important, therefore, to consider the principles involved 

 in shoeing healthy hoofs. In this discussion of the subject it is in- 

 tended to give the intelligent horse owner sufficient information, 

 based on experience and upon the anatomy and physiology of the 

 foot and leg, to enable him to avoid the more serious consequences of 

 improper shoeing. 



The Foot. Let us first examine the mechanism of the foot and 

 learn something of its structure and of the natural movements of its 

 component parts, that we may be prepared to recognize deviations 

 from the normal and to apply the proper corrective. 



Gross Anatomy of the Foot. The bones of the foot are four 

 in number, three of which the long pastern, short pastern, and cof- 

 finbone placed end to end, form a continuous straight column pass- 

 ing downward and forward from the fetlock joint to the ground. A 

 small accessory bone, the navicular, or "shuttle," bone, lies cross- 

 wise in the foot between the wings of the coffinbone and forms part 

 of the joint surface of the latter. The short pastern projects about 

 1% inches above the hoof and extends about an equal distance 

 into it. 



Hinge Joints. The pasterns and the coffinbone are held to- 

 gether by strong fibrous cords passing between each two bones and 

 placed at the sides so as not to interfere with the forward and^back- 

 ward movement of the bones. The joints are therefore hinge joints ; 

 though imperfect, because, while the chief movements are those ov 



