From Cow

Cryptorchidism (Rig) is a relatively common genetic disease of bulls worldwide.

Cryptorchidism is a failure of one or both testicles to descend into the scrotum due to testicular hypoplasia, estrogen exposure in pregnancy, breech labor compromising blood supply to the testes, and delayed closure of the umbilicus resulting in an inability to increase abdominal pressure[1]. Bulls with bilateral cryptorchidism are usually infertile. Testicular hypoplasia of the undescended testicle is common.

Clinically, affected bulls are overtly aggressive compared with other bulls due to elevated testosterone.

Diagnosis is based upon visual evidence of either or both testicles within the scrotum. Additional evidence of location of undescended testis can be ascertained by external palpation of the superficial inguinal rings and by palpation per rectum.

Unilateral cryptorchidism appears to be more common than bilateral cryptorchidism. The left testis appears to be more predisposed to not descending than the right. Many retained testes are located in the inguinal canal[2].

Treatment usually involves surgical removal of the abdominal or inguinal testicle. A cryptorchidectomy can be performed through an inguinal, paramedian or flank approach.

Fibrolipomas[3], sertoliomas, seminomas, and interstitial cell tumors[4] tend to develop within cryptorchid testicles.

Due to the hereditary nature of this disease, breeding with affected bulls is not recommended.


  1. Merck Vet Manual
  2. St Jean G et al (1992) Cryptorchidism in North American cattle: breed predisposition and clinical findings. Theriogenology 38(5):951-958
  3. Osawa T et al (2011) Fibrolipoma of a cryptorchid testis in a young bull. J Vet Med Sci 73(9):1253-1255
  4. López A et al (1994) Unilateral interstitial (Leydig) cell tumor in a neonatal cryptorchid calf. J Vet Diagn Invest 6(1):133-135