X0 condition in mares

Authors: Walker KS, Bruere AN
Publication: New Zealand Veterinary Journal, Volume 27, Issue 1-2, pp 18-19, Jan 1979
Publisher: Taylor and Francis

Animal type: Horse, Livestock
Subject Terms: Biosecurity, Congenital disease, Genetics, Diagnostic procedures, Disease surveillance, Reproduction, Oestrus/oestrous, Reproduction - female
Article class: Correspondence

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Abstract: In August 1978, we conducted a pilot cytogenetic survey to screen for non-mosaic sex chromosome abnormalities in a horse population. Prior to this survey eight XO mares had been examined by this laboratory in connection with infertility. We have since verified four additional cases. The XO condition in the mare is characterized by either absent, or highly irregular, oestrous cycles, flaccid cervix, small uterus and very small ovaries without follicles. All XO mares so far examined appear normal but, in some cases, may be smaller in stature than other horses of the same breed. The XO condition in mammals has been studied extensively in the mouse and the human, and reported in the cat and pig…

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