544 IOWA DEPARTMENT OF AGRICULTURE. 



using sires and dams that show a congenital tendency to this defect. Pur- 

 chasers of horses usually look with considerable disfavor on a hcrse that 

 is at all knee-sprung. Personally I would rather buy a horse for my own 

 use that is a little forward in the knees, than one that stands back in the 

 knees or is what is called calf-kneed. A horse with the former defect 

 is almost sure to be much more elastic in his step than one with the latter 

 and consequently will not suffer to the same extent from the ill effects 

 of concussion. A calf-kneed horse is also much more likely to suffer from 

 strains. Knee-sprung, unlike the other unsoundnessses given in the list 

 of hereditary trouble, is not very infrequently congenital. 



Swan-necked horses and those with thick coarse throttles are consid- 

 ered to be of the formation most liable to develop the defect of the wind 

 called roaring. In Great Britain and Ireland and on the continent of 

 Europe breeders are usually very particular about avoiding roarers for 

 breeding purposes. The climatic conditions there seem very favorable to 

 its developement, but in this country it is not nearly so much to be feared 

 and I would not hold aloof from an otherwise desirable sire on account of 

 his being a roarer, though I admit the predisposition to the trouble may 

 be transmitted. 



The predisposition to periodic ophthalmia or moon-blindness is handed 

 down from parent to offspring, but it is not nearly so common in this 

 country as it once was when the sanitary conditions were not so good; 

 and it may be that some care has been exercised in breeding so as to avoid 

 its propagation. The only appreciable evidence of a predisposition to this 

 unsoundness outside of the existence of the disease is the small or what 

 is called the "pig eye." I knew a sire well that had "pig eyes," but sound 

 ones, and that remained sound throughout his long life. Certainly ten 

 per cent, of his progeny developed mooa-blindness. 



The tendency to stringhalt is undoubtedly transmissible from parent 

 to offspring. Horses with snappy hock action are most likely to develop 

 it. Nowadays it is not feared nearly so much as it formerly was for, if it 

 should develope, a very large percentage of cases are curable by not a very 

 difficult and my no means dangerous operation which consists in the cut- 

 ting of a tendon and the removal of a small portion of it. A change has 

 taken place in the generally accepted view as to the nature of stringhalt. 

 It was considered a purely nervous malady until it was found that the cut- 

 ting of a tendon would cure it. 



Curb, although not as I remember it included in the list of hereditary 

 unsoundness is decidedly hereditary as well as the predifposition 

 to it. It is not an infrequent occurrence to find foals dropped with 

 curbs, which frequently disappear in a large measure, but there is 

 always some trace of them remining. It is the rarest possible 

 occurrence to find a broad hock and one with the tendon standing 

 well out behind with any sign of curb. Narrow hocks and those 

 with the point dipped forward towards the body of the joint; a leg with 

 small circumference immediately below the hock, or what is commonly 

 called, tied-in; those with the back tendon not standing out posterior to the 



