Mammary hypoplasia (underdeveloped udders)

This disease affects sows. The key clinical sign is an underdeveloped udder.
calendar icon 15 November 2018
clock icon 7 minute read

Background and history

This term defines failure of udder development and is relatively uncommon.

Clinical signs

An underdeveloped udder.


Following clinical signs.


  • It can occasionally be seen in gilts because the hormones that are responsible for the development of the udder have not been produced in sufficient quantity.
  • Occasionally herd problems are seen where poor nutrition, heavy worm burdens, chronic disease or mycotoxins may be implicated.
  • The most likely mycotoxin to cause it is from ERGOT poisoning in pregnant gilts running in grass paddocks.
  • Shortage of water is a common cause.
  • Rarely, hypoplasia may be due to a genetic mutation in the affected gilts ancestors.


  • Ensure a good supply of water.
  • Do not breed from affected sows.


Affected animals should be culled.

Emily Houghton

Editor, The Pig Site

Emily Houghton is a Zoology graduate from Cardiff University and was the editor of The Pig Site from October 2017 to May 2020. Emily has worked in livestock husbandry, and has written, conducted and assisted with research projects regarding the synthesis of welfare and productivity of free-range food species.

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