Types and Market Classes of Live Stock 



525 



outside and just behind the hock. It is caused by a weakness in the 

 synovia] sacs of the joint, accompanied by a hyper-secretion of synovial 

 fluid or joint oil. Bog spavins are more often blemishes, rather than 

 unsoundnesses. They are classed as the latter only when they are 

 well developed or cause lameness. Slight cases are described as merely 

 "a little full in the hocks." Treatment consists of rest, blistering, 

 cauterization, and the use of pressure pads and peculiar bandages. 



Bone spavin is a bony growth of variable size in the hock, which 

 may or may not make itself visible on the exterior. It most often 

 occurs at the inner and lower border of the hock, but may arise on the 

 upper part, or on the outside of the hock. In some cases, no outward 

 signs of spavin are perceptible; these are called "occult" spavins. Care 

 should be taken not to mistake a prominent development of the inner 

 and lower border of the hock, natural in some animals, for a spavin. 

 Hocks that are narrow or tied in below are subject to bone spavin, as 

 are also those of coarse structure. 



Fig. 210. — Bone spavin. A, Bone spavin; B, sound hock. 



Bone spavins affect one or more of the six bones of the hock. 

 The spavin usually represents an effort on the part of nature to repair 

 the joint. Spavins are caused by sprains, by violent efforts in jump- 

 ing, galloping, trotting, or pulling, by slipping or sliding, and other 

 similar causes. This is classed as an hereditary unsoundness. It is 

 one of the most serious unsoundnesses of horses; it causes lameness and 

 stiffens the joint. As with sidebones and ringbones, the size of the 

 spavin is not a safe index of its seriousness. An excellent test for 

 spavin lameness consists in lifting the affected leg off the ground for 

 one or two minutes, holding the foot high so as to flex all the joints. 

 Then start the animal off in a trot, when the lameness will be greatly 

 intensified if it is caused by spavin. Treatment consists of complete 

 rest for a month or more, blistering, the use of proper medicaments, 

 firing, and special operations on the joint. Firing produces a small 

 scar, and when this is present the spavin is called a "jack." 



