Repeated breeding refers to using the same male rabbit again after the first mating. Repeated breeding can increase fertilization chances, improve pregnancy rates, and prevent false pregnancy, especially for males that have not been mated for a long time, for which repeated breeding is necessary. These males tend to have more dead sperm in their first ejaculation. Double breeding refers to mating with another male after the first breeding. Double breeding is only suitable for commercial rabbit production and should not be used in breeding rabbit production to avoid confusing bloodlines. Double breeding can prevent infertility caused by the male and significantly improve pregnancy rates and litter size. In practice, it is necessary to wait until the scent of the first male disappears before mating with another male; otherwise, the female rabbit carrying the scent of another male may cause fights, which not only prevents successful mating but may also injure the female rabbit.