Page:The Evolution of British Cattle.djvu/107

 its coat is a mixture of red hairs and white—that is, roan. The proportions of the two kinds of hair vary greatly: the white hairs being sometimes so few that the roan is almost a red, and the red sometimes so few that it is almost a white.

When roan crosses are bred together their progeny select their colour determinant one half from each parent, and the chances are one that both halves will be red; two that one will be white and one red; and one that both will be white. It may be a union of these these, or these , or these  Consequently, from a sufficient number of matings, a quarter of the calves must be red, a half roan, and a quarter white.

Again, when red cattle are mated with roan ones, one half their calves are red, the other half roan. Combining the four little diagrams as above, gives two reds, and two roans.

Further, when white cattle are mated with roans, one half their progeny are white, the other half roan. gives two whites and two roans.