CORRELATION BETWEEN THE SIZE OP CANNON 
BONE IN THE OFFSPRING AND THE AGE OF THE 
PARENTS 1 
By Christian Wriedt, 2 
Fellow of the A merican-Scandinavian Foundation 
Jensen (3) 3 and the writer (12, 13) have both found that in the Jut¬ 
land and Gudbrandsdal horses the young and relatively young animals 
have given the best offspring and that old animals have very seldom 
produced high-class stallions. Both of these breeds are selected for 
heavy bones. On the other hand, in the English thoroughbred, which 
is selected for speed, old horses produce high-class animals for that pur¬ 
pose. It is, then, naturally suggested that an investigation be made 
as to whether young parents are producing heavier cannon bones than 
old parents. Von Oettingen (7) noticed this in numerous cases and stated 
that the offspring of the halfbred stallions Halm, Hamish, and Optimus 
(in Gudwallen and Trakehnen, Germany), with relatively heavy bones, 
tended to become slender in the cannon bones when the stallions became 
old. Jensen made a similar statement in a letter to the author about 
the offspring of the famous Jutland stallion Aldrup Munkedal. The 
writer has also had the same experience with Gudbrandsdal stallions. 
In Percheron horses bred in France, where young stallions and mares 
are much used for breeding purposes, it is recognized that the breed 
shows a big increase in cannon-bone size. This can not be substantiated 
by measurement, but it seems to be a fact. Of statements concerning 
other mammals that show a similar tendency, it is worth while to cite 
Stonehenge’s (11) observation concerning dogs: “When, however, the 
produce is desired to be very small, the older both animals are the 
more likely this result is.” 
When these views are considered, although they are not supported 
by any scientific measurements, there seems to be good reason for 
undertaking an investigation of the correlation between the age of the 
parents and the measurements of the cannon bone of the offspring. 
Fortunately the Gudbrandsdal stud book 4 contains material that is suit¬ 
able for such an investigation. The writer selected as material for the 
investigation all mares measured in the “South of Norway” district 
1 Contribution from the laboratory of Genetics, Agricultural Experiment Station of the University of 
Illinois. 
2 The author wishes to express his thanks to Prof. J. A. Detlefsen and Prof. H. L. Rietz, of the Illinois 
Station, for many suggestions and criticisms in connection with this investigation. 
8 Reference is made by number to “Literature cited,” p. 370-371. 
4 Stambog over Heste av gudbranddalsk race. Bd. 3, 1906; Bd. 5, 1909; Bd. 6, 1913. Kristiania. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
gd 
Vol. vn. No 8 
Nov. 20, 1916 
Ill.— S 
64312 0 —16-2 
(361) 
