290 



HEALTH AND DISEASE 



off the injured organ. These will be dealt with iu the articles on sprains 

 to special structures. 



BOG-SPAVIN 



This disease is of an entirely different nature from that referred to 

 in the section on " Diseases of the Organs of Locomotion ". It is presented 

 by a soft fluctuating enlargement at the upper and inner part of the hock- 

 joint, arising out of distension of the capsule (hg. 363) of the true hock- 

 joint with synovia or "joint oil". 



Causes. — It most commonly occurs in young horses between one and 



three years old. The 

 heavy breeds are 

 especially liable to it, 

 and most so animals 

 of lymphatic tempera- 

 ment, with round 

 fleshy legs, coarse 

 hair, thick skin, and 

 feeble energy. 



The predisposition 

 to bog-spavin is essen- 

 tially hereditary. It 

 may also be accjuired 

 by causes which induce 

 poverty and weak- 

 ness. Youne colts of 

 rapid growth when 

 badly nurtured readily 

 contract the disease. 

 The exciting causes are overwork while young, and sprains to the joint; 

 but large numbers of ca.ses are induced by the pernicious system of forcing, 

 which young stock undergo during their show-yard career, and we have 

 known many fine specimens of the heavy breeds to have been ho23elessly 

 ruined in their infancy by this practice. 



Symptoms. — Bog-spavin may arise suddenly, or it may appear in 

 a slow and progressive manner. The former is mostly the case when 

 the result of sprain, and also as a consequence of high feeding and confine- 

 ment. AVork and wear lead to a more gradual and often a more abiding 

 enlargement of the joint. Where the disease is sudden in its onset, it is 

 usually attended with pain and lameness, and the joint is hot, tense, and 

 painful to pressure. 



Fig. 363.— Bog;-Spaviii 

 B, The distended joint with the .skin removed. 



