426 Journal of Agriculture, Victoria. [10 July, 1918. 



A CONTRIBUTION TO THE STUDY OF HEREDITARY 



[JNSOUNDNESS IN HORSES. 



By W. A. N. Robertson, B.V.Sc, Chief Veterinary Officer. . 

 (Continued from page 303.) 

 Family 2. 



All the horses in this family are related to one another, being 

 descended from one progenitor, as shown in the following scheme: — 



■ Not examined -Not examined, 2 . 1 



Not eSa mined 



Not examined 



Not examined 



Not examined 



Not examined 

 Not examined 



Not examined 



-Not examined 



-Not examined, 2 . 2 

 -Not examined, 2 . 3 

 -Not examined, 2 . 4 

 ( Not examined, 2 . 5 

 [Not examined, 2 . 6 



.Not examined — -Not examined -Not examined -SidCbone, 2.7 



For convenience, and because of the distant relationship, they are 

 dealt with separately. Only one of the original members (2.7) was 

 examined, and he was found to be unsound; none of his progeny has 

 been seen. His dam was by a stallion which was not examined, 9.5; 

 but unsoundness has been found in 21.5 per cent, of his progeny. This 

 probably accounts for the unsoundness present in 2.7. 



The members of the family show the following percentage of 

 unsoundness : — 



FAMILY 2. 

 Table Showing Percentage op Unsoundness. 



2.1 is a stallion which was not examined. He has the reputation 

 of being a sound horse, and mares by him were eagerly sought by 

 breeders; his male descendants, however, show 18.9 per cent, unsound- 

 ness. 



Whilst 16 of his sons are referred to in the tables, only 4 were 

 examined, and 2 of these were unsound, viz., 2.105 and 2.102. The dam 

 of the former was by a half-brother of 2.7, which was unsound; and the 

 dam of the latter was by 3 — the founder of a most unsound line. It is 



