730 
DISEASES OF THE HOCK. 
slight. For a similar reason, marked muscular atrophy is not a hopeful 
symptom. Severe lameness points to extensive change in the joint, and 
is also unfavourable, but slight lameness does not prevent the animal 
being used for certain purposes, even though it cannot be completely 
cured. 
(o) The animal s conformation. The worse the conformation of the 
limb, and especially of the hock, the less the chance of recovery. In 
badly-foimed hocks even moderate work produces fresh strain and 
prevents the bones uniting. 
(4) The position of the disease. It has long been known that 
exostoses on the flexor surface of the joint are particularly troublesome, 
and that the chance of recovery is greater if the spavin lie towards the 
back of the joint, and be confined to the cuneiform bones. This may 
Partly be explained by the fact that new growths of bone in front of the 
joint aie moie likely to mechanically interfere with movement, even 
after obliteration of the joint; while disease of the joint in this situation 
is less likely to be followed by anchylosis, because the amount of 
unavoidable movement is here greatest. As indicated by Havemann, 
the size of the exostosis is of less importance; horses with marked 
spavins may often be seen going sound, whilst those with a small growth 
may prove useless for every kind of work. 
(o) The animal s age. The occurrence of spavin in young animals 
which have not done much work points to a strong hereditary predisposi¬ 
tion, and naturally gives an unfavourable cast to the prognosis. In such 
animals the lameness may disappear for a time, but returns immediately 
woik is resumed. On the other hand, spavin lameness first developed 
at an advanced age is not likely to disappear, as reparative processes are 
then sluggish. 
Piognosis, though to some extent guided by the facts given, is always 
uncertain. It is never possible to say confidently that lameness will 
disappear, even when the diagnosis is beyond doubt. The varying 
formation of the hock-joint and of the limb in the different breeds, the 
uses to. which horses are put, and other factors (including errors in 
diagnosis), lead to the percentage of recoveries being very varyingly 
estimated by different experts. Taken altogether, they may number 
about 50 per cent. 
As already stated, eight to ten weeks’ rest and suitable treatment are 
generally necessary for the disappearance of lameness. Although 
recovery is not impossible, even during continued work, yet a great many 
of such reported cases must be referred to errors in diagnosis. 
Treatment. Spavin lameness is seldom followed by spontaneous 
recovery, and the first essential of treatment is sufficiently prolonged 
rest. Havemann, Strauss, and others consider all treatment useless, but 
