A tubal ligation, whether in veterinary or human medicine, only affects the oviducts. These small structures are isolated during surgery and then cut and tied off with suture material. This prevents the ova from coming in contact with sperm cells or passing into the horns of the uterus. The procedure is fairly easy. The hormones that are normally produced by the ovaries and other parts of the reproductive tract continue to be released to the rest of the body. This is fairly important in humans. However, in dogs it may be a disadvantage.