Equis ISSN 2398-2977

Female: minimal contamination breeding technique

Contributor(s): Annalisa Barrelet, John Dascanio, Graham Munroe, Madeleine L H Campbell


  • Transient endometritis Uterus: endometritis - bacterial is an inevitable sequel to mating, whether by natural or artificial insemination.
  • In natural mating ejaculation occurs through the dilated cervix, contaminating the uterine lumen with micro-organisms and debris.
  • Even semen extended in antibiotic-containing extender may carry some bacteria.
  • Sperm cells themselves provoke an inflammatory reaction in mares' uteri.
  • In the normal healthy mare the induced post-coital endometritis resolves within 24-72 h and the uterus is in a satisfactory state to receive the fertilized ovum when it descends from the oviduct around 5 days after ovulation.
  • Mares which are "susceptible" to uterine infection are not able to clear the post-coital endometritis and inflammatory fluid and debris persists making the uterine environment unsuitable for implanting a fertilized egg.
  • Minimal contamination techniques applied at mating aim at reducing the micro-organism challenge and clearing the inflammatory fluid in the post-coital phase.
  • Timing is critical as the embryo descends from the uterine tube into the uterine lumen about 5 days after ovulation.
  • Physical clearance of uterine fluid is a critical factor in the defense against persistent uterine infection hence the use of oxytocin Oxytocin.
  • Clearance problems may be related to poor uterine contractility (old mare), decreased cervical lumen diameter (cervical adhesion or failure of cervical dilation during estrus), and/or a dependently located uterus (old/pluriparous mares).


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Woodward W M & Troedsson M H (2013) Equine breeding-induced endometritis: A review. J Equine Vet Sci 33 (9), 673-682 VetMedResource.
  • Katila T (2012) Post‐mating Inflammatory responses of the uterus. Repro Dom Anim 47 (Suppl 5), 31-41 PubMed.

Other sources of information

  • Kenney R M, Bergman R V, Cooper W L & Morse G W (1975) Minimal contamination techniques for breeding mares: technique and preliminary findings. In: Proc 21th Am Assoc Equine Pract. pp 327-336.