MENDELISM IN DOMESTIC ANIMALS 475 
hybrids, for hybrids between the Hereford and bison exhibit the typical 
white-face markings. The F, hybrid between the zebu and Hereford, 
however, has a broken colored face, as shown in Fig. 206. The early 
history of the Hereford breed indicates that mottled-faced animals were 
not uncommon in the foundation stock, and today they are met with not, 
infrequently in grade Hereford cattle. The characteristic pattern of 
Dutch belted cattle appears, also, to be a dominant character as con- 
trasted with self-coloration. Another color character, the black of 
Fig. 190.—California Favorite, grand champion steer at 1916 International Livestock * 
Exposition. Out of a red Shorthorn cow by a Hereford bull. The Hereford pattern is 
completely dominant. (Photo from G. H. True.) 
Ayrshire cattle, exhibits sex-limited relations and will, therefore, be dis- 
cussed in another chapter. The polled character in cattle, as we have 
pointed out before, is clearly dominant to the horned condition, but the 
F, may exhibit slight scurs. The breeding of cattle for the polled condi- 
tion is a simple problem in Mendelism involving a difference in a single 
pair of factors. The study of other characters in animals, particularly 
those which are of economic importance from a Mendelian standpoint, 
has just begun. 
Mendelism in Sheep.—As we have already noted the short-eared 
condition in sheep has been shown to be a simple dominant to the long- 
eared character. The factor for black wool in sheep is recessive, as 
Digitized by Microsoft® 
