Inbreeding depression is:

Inbreeding refers to the mating of closely related animals within the same breed for about $4 - 6$ generations. Inbreeding helps in the development of animals of genetic purity. It promotes homozygosity and expression of recessive genes is observed. Continuous inbreeding leads to inbreeding depression, which affects the productivity and quality of animal products as well as health. The inbreeding depression can be eliminated by crossing animals to the same breed's superior animal but having no common ancestors on both sides.