Estrus Detection in Swine


Herdsman applying the back pressure test while the boar tries to get closer. A "positive" test occurs when the sow stands still and may press her back into the person's hand. This means she is ready to breed. (The tube behind the herdsman's head is the AI wand which he stuck in his collar to keep his hands free. The cooler holds the sperm tubes.)

Signs of estrus:
  • Standing for mounting
  • Rigidity in response to pressure on the rump (lordosis reflex)
  • Increased vocalization (early)
  • Erect ears
  • Alert attitude
  • Decreased appetite
  • Swollen, reddened vulva (especially gilts)
    		•  Estrus detection is a critical skill for reproductive efficiency. Non-productive sow days accumulate unnecessarily if estrus detection is not effective. Sows show stronger behavioral estrus if brought to the boar's pen rather than vice-versa, but this is not always practical. Estrus females become refractory to the boar's presence after 10-15 minutes because the lordosis reflex is highly exertional and fatiguing.  


    Copyright ©1997 by the University of Pennsylvania School of Veterinary Medicine
    Faculty: Dr. Paul Pitcher
    Student: Sandra Springer,'99