Physical, behavioral, endocrinologic, and cytogenetic evaluation of two Standardbred racehorses competing as mares with an intersex condition and high postrace serum testosterone concentrations

Journal of the American Veterinary Medical Association
Marc G KnobbeSue M McDonnell

Abstract

2 Standardbred racehorses that had been winning races while competing as mares underwent postrace drug testing and had serum testosterone concentrations above the acceptable limit for female racehorses. Initial physical examinations by the referring veterinarian revealed ambiguous external genitalia and suspected intra-abdominally located testes leading to a preliminary diagnosis of male pseudohermaphroditism. Horses were referred for further evaluation of sex. Physical examination of the external genitalia confirmed the findings of the referring veterinarian. Transrectal palpation and ultrasonography revealed gonads with an ultrasonographic appearance of testes. On cytogenetic analysis, both horses were determined to have a 64,XY karyotype and 8 intact Y chromosome markers and 5 SRY gene markers, which were indicative of a genetic male and confirmed an intersex condition. Additionally, both horses had some male-type behavior and endocrinologic findings consistent with those of sexually intact males. Taken together, these findings confirmed that both horses were male pseudohermaphrodites. Both horses returned to racing competition as males. As of October 1, 2008, the Pennsylvania Horse and Harness Racing Commissions implemented...Continue Reading

References

Oct 1, 1976·Equine Veterinary Journal·C W McIlwraithP K Basrur
May 1, 1990·Equine Veterinary Journal·M M Power, D P Leadon
Sep 1, 1988·Journal of Endocrinological Investigation·M G KentS S Wachtel
Jun 16, 1999·Molecular Reproduction and Development·V N Meyers-WallenA Keyzner
Jun 8, 2001·Human Reproduction Update·C SultanJ C Nicolas
Jan 5, 2002·Animal Reproduction Science·M SwitonskiK Urbaniak
May 2, 2002·Developmental Dynamics : an Official Publication of the American Association of Anatomists·E PailhouxC Cotinot
Jun 16, 2004·Proceedings of the National Academy of Sciences of the United States of America·T RaudseppB P Chowdhary
Jan 24, 2007·Physiological Reviews·Dagmar WilhelmPeter Koopman
May 10, 2008·Cytogenetic and Genome Research·Monika BugnoEwa Słota

Citations

Nov 19, 2011·Sexual Development : Genetics, Molecular Biology, Evolution, Endocrinology, Embryology, and Pathology of Sex Determination and Differentiation·T RévayW A King
Feb 20, 2014·Proceedings of the National Academy of Sciences of the United States of America·Elizabeth L ScholtzA J Conley
Jul 29, 2016·The Journal of Endocrinology·C J CorbinA J Conley
Apr 4, 2021·Animals : an Open Access Journal From MDPI·Monika Bugno-Poniewierska, T Raudsepp

Related Concepts

Behavior, Animal
Karyotype Determination Procedure
Sports
Sterotate
46, XY Sex Reversal 3
Biological Markers
Genitalia
Equus caballus
Palpation
Racial Group

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