The genes that cause disability production of spine, legs, and tail. Father of maternal morality are only breeding these animals almost never participate in disease development.
Dominant gene that causes deformity of the spine, back legs and tail ethical breeders to breed these animals and is only rarely associated diseases development.
Dominant gene that causes produce disability of the spine, the hind legs and tail. The breeders will breed on ethics only, and these animals almost never develop the disease.