Cystic Ovaries

This disease primarily affects breeding age sows. The key clinical signs include: sow continually on heat; pigs show discomfort; repeat matings.

Background and history

This is a common condition, particularly in old sows. Large cysts develop in the ovaries which often produce high levels of oestrogen.

The carcass is safe for human consumption.

Clinical signs

  • Abnormal heat.
  • Not accept the boar at mating.
  • Continually on heat.
  • Infertility.
  • Repeat matings.
  • Pigs show pain/discomfort.
  • May grind teeth.


Made on clinical grounds and normally only involves individual animals. Carry out a post-mortem examination of the ovaries.

Post-mortem lesions

  • Abnormally sized ovaries – 25mm in diameter.
  • Cysts 2–3cm in diameter in the ovaries, filled with clear fluid.
  • Occasionally regressing corpora lutea in ovary.


  • Age.
  • Hereditary.
  • Stress.
  • Mycotoxins.
  • Breeding.
  • Hormonal malfunctions.
  • Hormone misuse.
  • Mouldy bedding or food.
  • Badly stored grains.


  • Reduce causes of stress on sows.
  • Consider delayed weaning.


  • Culling of affected sows is most common.
  • Synthetic hormone treatment:
    • Progestogen by mouth
    • Gonadotrophic hormones by injection.