Signs a Testicle Has Not Descended in Stallions

Horse enthusiasts enjoy breeding healthy and strong horses, creating a thriving new foal. However, male horses, or stallions, may acquire a largely genetic defect preventing testicle movement from the body's interior to the scrotum. Many variables influence the cause of undescended testicles. In fact, the stallion may not exhibit any outwardly obvious behavioral signs of the condition.

  1. Testicular Development

    • A stallion's testicles generate sperm cells for reproduction. Both testicles begin development within the horse's abdomen before birth. Located near the kidneys, the testicles drop downward through the inguinal, or groin, canal into the scrotum at birth, or shortly thereafter. Stallions with undescended testicles retain one or both inside the abdomen, or snared within the inguinal canal. The stallion's body heat prevents the testicles from generating sperm if they remain within the abdomen or canal.

    Behavioral Signs

    • Undescended testicles do not affect the outward behavior of the stallion. Though the undescended testicle cannot successfully produce sperm, the male hormones exuded from the testicle are at normal levels, such as testosterone. In fact, if only one testicle is undescended, the remaining testicle within the scrotum will function correctly for reproduction.

    Physical Signs

    • A typical procedure for determining if one or both testicles are undescended is through a rectal exam. A veterinarian tranquilizes the horse and performs a deep rectal examination. Through the rectum, the veterinarian palpates the nearby inguinal canal for the undescended testicle. The veterinarian can also view the stallion's internal abdomen by using ultrasound technology. Both exams will confirm if either one or both testicles are undescended within the stallion.

    Alternative Condition Analysis

    • Veterinarians have the option of using blood tests for verifying an undescended testicle condition, especially if the condition is not visibly apparent. The stallion's blood is taken twice. After the first blood specimen is taken, the veterinarian injects human chorionic gonadotropin (hCG) hormone into the blood stream. The stallion may have undescended testicles if the blood tests show significant increases in testosterone between the first and second blood specimens.

    Treatment Options

    • Commonly, a stallion with either one or two undescended testicles requires removal of both. The surgery takes places with either the horse on its back or standing, both using local anesthesia. The undescended testicle, or testicles, are found first and removed. Afterward, the veterinarian removes the normal testicle from the scrotum.

    Post-Operative Mental Care

    • Removing both testicles affects the normal male hormone production of the stallion. The stallion must be retrained in socialization with other horses, as well as with trainers.