Grading up.. Add blood strain to another strain and replace it gradually generation after generation to replace the other strain

Grading up:
Is the addition of blood strain to another strain and gradually replaced generation after generation to replace the other strain and gradually be either animals of the same strain or animals of another strain and resort to this system to fill the resulting deficiency in the females of a strain. The males of the breed are to be married to females of the same strain or another strain for several generations