The placenta is a really vital structure that connects the newly growing foal to the mare. It provides oxygen and nutrients through a variety of blood vessels and interconnections between the foal and the mare.
The placenta attaches to the endometrium of the mare (the inside lining of the mare’s uterus). The endometrium has lots of tiny finger like projections that interconnect with the placenta that increase the surface area for the transfer of oxygen and nutrients for the foal.
The damage of these interconnections is called placentitis (infection or inflammation of the placenta). Placentitis can interfere with the transfer of oxygen and nutrients to the foal, affecting its development and growth, which is a major problem.
Examining The Placenta
When examining the placenta, it is vital that is laid out correctly in an ‘F’ shape, with the horns and the uterine body part laid flat out.
When laid out in this formation, you are presented with a good opportunity to check that there are no abnormalities with the blood vessels. Make sure that you check both sides.
Next turn the placenta inside out to check the inside. Again, lay this out in an ‘F’ shape.
Check the cervical star (the part of the placenta where the foal exited) – there should be a hole present here, where the foal kicked its way out. Check the placenta is the same colour all over, there are no dark regions or areas of a different texture that might suggest placentitis. Ascending infections normally start form the outside and work their way up, so it is important to start at the cervical end and move up.
Next move on to look at the horns. You will notice the horn at the top is much smaller than the lower horn. This is because the lower horn held the foal. When checking the placenta, it is really important to check that the tip of the non-pregnant horn is in tact (this is the most common part to be left inside the mare).
When Is A Placenta Classified As Retained
The placenta must be passed within 3 hours of foaling. If the mare has not passed the placenta after three hours, this would be classified as retained and we would recommend that you obtain veterinary advice.
Your Equine Placenta Examination Checklist?
- Check the placenta from top to tail that both horns are present, and the full tip of the non pregnant horn is in tact.
- Check that the placenta is the same colour all over and there are no areas that are particularly light or particularly dark.
- Turn the placenta over and check both sides, and the inside as well.
- This does not take the place of a new foal check. A vet should still come out and check the foal within the first 36 hours.