PRINCIPLES OF LIVESTOCK BREEDING. 
61 
sistent grading to one pure breed are perhaps rather in obtaining 
uniformity of color and type than in efficiency of pork production. 
In many parts of the country, however, there is still much room for 
improvement in the fundamental qualities. 
Sheep breeding is complicated by the simultaneous selection for 
wool and mutton. Each of the breeds produces its own characteristic 
kind of wool. Any desired fineness or length of fiber which is found 
in a pure breed can easily be fixed in common stock by grading up. 
As regards mutton, the same principles apply as in beef production. 
The same qualities have been fixed in the middle and long- wool 
breeds of sheep as in the beef breeds of cattle. 
Fig. 21.— The same Piney- Woods ewe as in 
figure 19, showing the lack of wool on the 
abdomen. Total wool clip, 3 pounds. 
Fig. 22.— First cross between Piney-Woods 
ewe and a purebred ram, showing wool on ab- 
domen. Total clip, 8 pounds. 
BREEDING AND SOUNDNESS IN HORSES. 
The hereditary differences among the breeds of horses are more 
conspicuous than in any other kind of livestock. Differences in 
weight, speed, and conformation are fairly well fixed in the pure breeds, 
but, of course, unfixed in scrubs. The effect of a cross with a given 
pure breed can be predicted, at least in a rough way, but no predictions 
are of value in case the stallion is a scrub. Of the greatest importance 
for any kind of horse are good feet and legs. Scrub stallions, even 
if apparently sound themselves, are more likely to transmit unsound- 
ness than stallions of the pure breeds, especially if the latter are 
known to come from sound stock. There is, perhaps, less excuse 
