T^T^6 Journal of Agriculture. [lo May, 1910^ 



Evidence of Hereditary Character of Sidebone. 



Amongst light horses only four (.51 per cent.), and amongst ponies- 

 none have been found to have sidebone ; so that the records as regards 

 these classes are of no positive value in estimating the hereditary character 

 of the unsoundness. As negative evidence, however, the fact of so 

 infinitesimal a proportion of the light breeds being found affected is of 

 the greatest significance ; especially when it is remembered that these horses 

 are, by the nature of their work and paces, subject in a much greater 

 degree than draught horses to one of the alleged principal exciting causes- 

 of ossification of the lateral cartilages, viz., concussion. 



No thoroughbred horse and no pony have been found affected with 

 sidebone. The four light horses in which it has been found have all 

 shown some signs in their type and conformation of admixture of draught 

 blood. One notable instance of this was the imported English hackney 

 " X G " rejected for sidebone. His round nuggety confor- 

 mation, broad flat feet, round bone, fetlock tuft, long curly hair growing; 

 from the coronets, and his high but laboured action all proclaimed the 

 bax sinister of draught horse blood to such an extent as to belie his- 



published pedigree. Another of these sidebone light horses, " M 



G ," although having " light " characteristics at the time of examina- 

 tion, has been found, according to his bi^eeding, to l>e actuallv a draught 

 horse. 



By the time the first hundred or so of draught horses had been 

 examined, it appeared evident that valuable information concerning the 

 transmission from sire to son of a predisposition to the formation of side- 

 bone could l)e obtained. To that end, I determined that the pedigrees 

 and relationship of the different horses examined should be ascertained 

 at the time of examination. This has been done, and as a result I am 

 able to present a series of tables of family groups of horses examined — 

 some families in which there is a great preponderance of sidebone in the 

 progeny, and some, the members of which are virtually all sound. 



In perusing the tables of sideboned families, attention should be given 

 to the ratio of sideboned to sound progenv. Such ratio in each case, 

 when compared with the general percentage (20.17) of sideboned horse.s — - 

 as shown in the previous tables, will be found to be greatly in excess- 

 Similarl)-, in the case of the sound families, only those have been tabulated 

 in w'hich the percentage of sound animals greatlv exceeds the general 

 percentage. 



For the reason alreadv mentioned, viz. — -that the influence of the dam 

 in any given case cannot be calculated — the deductions to be drawn from 

 these tables are not as exact as is desirable, but there is one family {See 

 Table IX., Family " A ") in which it would appear that when the horse 

 was mated with mares belonging to a sidebone sire family, the offspring 

 developed sidebones, but when mated with outside mares the offspring 



remained sound. Seven .sons of this sire " T 1 "' have been 



examined. Three of these, viz. : — " C M ," " I 



M ," and "I Q ," were ex. "Q of B— " 



mares, and all of them were rejected for sidebone. The other four were 

 ex. mares of sound sire blood, and were found sound. 



[Note. — (i) In the tables following, for obvious reasons, the actual 

 names of the horses are not given. The names are indicated by the use 

 of a cipher consisting of initial letters bearing a similar relationship in 

 all cases to the actual names of the horses concerned. A duplicate series 



