254 VETERINARY STATE BOARD 



In chronic corns, the horn is permanently altered, being either 

 soft and moist or dry and crumbled. The inner surface of the horn 

 is covered with horny swellings or nodules and the patient presents 

 well-marked lameness. 



Corns are caused by overparing and thus weakening the horn ; 

 by contracted heels, by improper balancing, and shoeing of the foot ; 

 by neglecting shoeing ; by lack of moisture ; by direct traumatisms 

 as from stones, bruises, etc. Ossification of the lateral cartilages 

 lessens the elasticity and thus increases the effect of concussion when 

 the foot is brought in contact with the ground. Hence corns and 

 side-bones are often associated in the same foot. 



Treatment : Remove the cause ; shorten the toe, lower the quar- 

 ters and remove aU dead horn. Avoid too much paring and expos- 

 ing of the sensitive lamin£e. Apply a bar-shoe with leather sole 

 and pack the foot with tarred oakum. If side-bones are present, 

 and a bar-shoe is not advisable, a three-quarter shoe may be used 

 until the parts are nonnally restored. Suppurating corns should 

 be freely drained and disinfected until the part is covered with 

 horn, when a tar dressing and bar-shoe may be applied. 



Give the causes, sjmiptoms and the treatment of thrush. 



Causes: Standing ia filth (soiled bedding, urine, faeces, etc.), 

 excessive paring of the frog, lack of frog-pressure, and hard work 

 on stony ground are exciting causes of thrush. Among the predis- 

 posing causes are : navicular disease, contracted heels and scratches. 

 Symptoms : Increased moisture of the frog, an ill-smeUing, dark- 

 colored discharge which may entirely loosen the frog. Lameness 

 may be present in severe cases. 



Treatment: Remove the cause; provide clean, dry bedding. 

 Pare away all diseased and ragged portions of the frog. It may be 

 necessary to remove all of the horny frog. Cleanse and dry the parts 

 and keep dry by dusting with calomel. After healing occurs, 

 apply a bar-shoe and tarred oakum, or otherwise provide for frog- 

 pressure to prevent the contraction of the heels which often follows. 



Differentiate thrush and canker. Give prognosis and treatment of 

 each. 



See answer to preceding question. 



Canker is a chronic inflammation of the secreting structures of 

 the foot, due to the presence of an infection (probably specific), 

 which prevents the growth of healthy horn and produces a greasy 

 discharge, exceedingly offensive to the sense of smell. 



Prognosis : In canker, rather unfavorable. Requires long, con- 



