Mating of a cross breed animal back to one of the pure parent is

Mating of a cross-breed animal back to one of the pure parents is Back crossing.
Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, to achieve offspring with a genetic identity closer to that of the parent. It is used in horticulture, animal breeding, and the production of gene knockout organisms.
Backcrossing may be deliberately employed in animals to transfer a desirable trait in an animal of inferior genetic background to an animal of preferable genetic background.