A case of equine cryptorchidism with undetectable serum anti-Müllerian hormone

J Vet Med Sci. 2020 Feb 18;82(2):209-211. doi: 10.1292/jvms.18-0057. Epub 2019 Dec 26.


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-intact stallion (X/Y). Only one small degenerative testis was present in the abdominal cavity. The reasons of undetectable serum AMH levels and negative response to hCG stimulation might be low numbers of Sertoli and Leydig cells. This study reports a case of serum AMH-undetectable cryptorchid stallion.

Keywords: anti-Müllerian hormone; cryptorchidism; monorchidism; stallion.

Publication types

  • Case Reports

MeSH terms

  • Animals
  • Anti-Mullerian Hormone / blood*
  • Chorionic Gonadotropin / administration & dosage
  • Cryptorchidism / veterinary*
  • Genes, sry
  • Horse Diseases / congenital*
  • Horse Diseases / genetics
  • Horses
  • Male
  • Sex Chromosomes


  • Chorionic Gonadotropin
  • Anti-Mullerian Hormone