Cryptorchidism in horses refers to the condition where one or both testicles fail to descend into the scrotum. This condition is a developmental anomaly that can affect a horse's reproductive capabilities and behavior. Cryptorchidism can be unilateral, involving one undescended testicle, or bilateral, involving both. The undescended testicle(s) may be located in the abdominal cavity or the inguinal canal. Diagnosis typically involves physical examination, ultrasound imaging, and hormonal testing. Treatment often requires surgical intervention, commonly known as cryptorchidectomy, to remove the retained testicle(s). This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, diagnosis, management, and implications of cryptorchidism in equine health and reproduction.
Serum anti-Müllerian hormone (AMH), a marker of equine cryptorchidism, is detectable in intact and cryptorchid stallions but not in geldings because it is secreted from Sertoli cells. A 4-year-old uncastrated Thoroughbred racehorse had no visible testes; therefore, the horse was considered a bilateral cryptorchidism. However, the serum AMH was undetectable (<0.08 ng/ml). Human chorionic gonadotrophin (hCG) stimulating test result indicated that the horse was a gelding. The results of sex chromosomal analysis and sequence analysis of SRY gene suggested that the horse was a genetically-intac...
Omyla K, Conley A, Varner D, Dini P.Persistent stallion-like behavior is a common sign of cryptorchidism in supposed geldings. The presence of testicular tissue can be evaluated by analyzing hormones such as testosterone and anti-Müllerian hormone (AMH). Here, we used hormonal analysis to investigate relationships between the likely presence of testicular tissue and stallion-like behavior in samples submitted from presumptive geldings (n = 1,202), retrospectively. Most geldings with stallion-like behaviors had serum concentrations of testosterone (851/1,056; 80.6 %) and AMH (682/877; 77.8 %) below the laboratory reference range...