10 Aug., 1918.] Hereditary Unsoundness in Horses. 



469 



of 21 of his grandsons, 33 per cent, were declared unsound. 

 ing table shows the unsoundness in each generation : — 



The follow- 



It Avill be noticed that, of the stallions examined, 244 were descendants 

 of 3.1, 37.2 per cent, were unsound, representing 75 per cent, unsound 

 sons, 40 per cent, unsound grandsons, 31 per cent, unsound great-grand- 

 sons, and 50 per cent, unsound great-great-grandsons. 



Unsoundness is such a prominent feature in the progeny of Family 3 

 that it may be considered as the dominant factor, and an explanation 

 must be looked for when soundness appears dominant in any branch. 

 It would have been particularly interesting to have had examinations of 

 all the members of this family as aged horses, for among the 153 sound 

 descendants of 3.1, we find 4 were two years, 60 were three years, 29 were 

 four years, 43 were five years, and 16 were six years old or over at the 

 time of examination. As mature horses, there would unquestionably 

 have been many more unsound members in the family than the total 

 now recorded. 



3.1, and many descendants of his not recorded in these tables, are 

 found very frequently on the dams' side of unsound horses which are 

 descendants of stallions known to be sound. 



The first .sound line in this family is noted in 3.141 and his 

 descendants. He was sound when aged, and his six sons examined were 

 also sound — five of them being five years or over at examination. Three 

 grandsons were sound, and two unsound. Evidently, therefore, unsound- 

 ness is not so strongly developed in this line. Can we ascertain why? 



The dam of 3.141 was by 6a.11. jSTine descendants of this horse 

 were examined as mature horses, and only one was unsound. Unfor- 

 tunately, the full pedigree of this unsound horse has not been obtained. 

 We may assume 6a.11 was sound, and his influence is seen through 3.141. 



The breeding of 3.15 on the dam's side cannot be traced, but he also 

 probably introduced soundness, for of his unsound descendants — 



3.156 was from a mare by 3, the founder of this family. 

 3.1541 was from a mare by 3.100014, an unsound horse. 

 3.1514 was from a mare by 1.11, a very unsound sire. 

 The remaining four cannot be traced. 



