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This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Cystic ovaries are not uncommon in animals and when they occur they may or may not cause signs

A cyst is a fluid filled swelling, and cysts which form in the ovaries of female animals may occur in the follicles or corpora lutea. Corpora lutea form at the site of the follicles once they have released their eggs. These cysts form spontaneously and can be associated with abnormal amounts of hormone circulating in the blood. Cysts may also form in the remnant tissues following surgical neutering (ovariohysterectomy).

There may be no signs associated with ovarian cysts, but signs that may be seen include :

In dogs :

  • Persistent oestrus - the bitch stays "On heat" - this occurs with some follicular cysts
  • Delayed return to oestrus (delay in the occurrence of next "heat") - this occurs with some corpora luteal cysts - usually high blood concentrations of progesterone concentrations are found in this condition.

In horses and ponies :

  • The mare does not show oestrus (called anoestrus)
  • Continuous , or long and irregular heat periods.

In cattle :

  • Delayed return to oestrus (called anoestrus)
  • Persistent oestrus or returning to oestrus (bulling) every few days - called nymphomania
  • Increased sexual behaviour (called virilism)

In pigs :

  • Irregular heats with increased sexual behaviour (called virilism)
  • Prolonged (but not continuous) heat
  • Some sows behave aggressively

Ovarian cysts are usually identified on ultrasound scans and treatment involves surgical removal of the affected ovary or ovaries  in bitches and mares. Attempts to treat ovarian cysts with hormones have proved unsuccessful in bitches, but in cattle with nymphomania luteinizing hormone with or without progesterone has been used successfully and PRID devices have also been used.  In mares treatment with progesterone may help in some cases.


Updated October 2013