After sterilization, the testicles and attached reproductive organs of male cats no longer play their original functions of producing sperm, stimulating sexual desire and producing hormones. Therefore, the metabolism and tissue structure of testis have changed, which may lead to the deepening of testicular color and the appearance of black spots or irregular spots.
Usually, the appearance of these blacks has no effect on the health of male cats, and they usually do not cause any pain or discomfort to the organs of male cats. If you have any questions about male cat sterilization, it is recommended that you consult a veterinarian or a professional pet caregiver for more information and help.