QThe mare’s placenta is an important part of foaling – they feed the foal and grow it – but how do we deal with them once they’re out after foaling?

In the last few weeks I’ve had quite a few questions in the FoalEd community so I thought we’d tackle the topic.

Here are five things every breeder should (but may not) know about equine placentas

1. The Shape

The shape of the mare’s uterus (and placenta) is not one big uterus like a human – it’s actually ‘Y’ shaped. A mare’s uterus has two ‘horns’. In a dry (non-pregnant) mare they are referred to as the left and right uterine horn. When a mare is bred the pregnancy will embed in one of these horns. The horn where it embeds becomes the pregnant horn and the other one (no surprises) is the non-pregnant horn.

Interestingly when a mare becomes pregnant with twins they can be in either the same uterine horn or separate horns, depending on which horn the follicles that have ovulated in were in.

The shape of a mare’s horn is important to know when checking the mare’s placenta after foaling (more on that later).

2. Placentas can get infected – and cause abortion

Sometimes during pregnancy bacteria makes its way in through the vulva. Depending on the angle and seal of the vulva faeces and other bacteria can make their way into the reproductive tract (which is supposed to be sterile) and cause an infection in the placenta.

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A mare’s discharge during placentitis

If the mare’s placenta gets infected this can lead to abortion of the foal. If the mare’s placenta does get infected you will likely see significant vaginal discharge in the mare’s tail, on her vulva, and potentially on the muscles either side of her vulva and the legs. If you notice vaginal discharges in your mare it’s important to call a vet as soon as possible. With the right veterinary care and support mares with placentitis can hold their foals long enough for them to be viable when they’re born. The foal may also require additional supportive care once it arrives, especially if it ends up being premature.

If a mare has vulval conformation which makes her prone to infection you can talk to your vet about performing a caslick operation to create an artificial seal (it’s important that this is opened before foaling).

3. Placentas burst when the mare’s water breaks – but sometimes they don’t burst

The majority of the mare’s placenta is very thick – too thick to be broken with your fingers. There is a tiny part of the placenta that is thinner and slightly discoloured – this is called the cervical star. This is the piece of the placenta that gives way and bursts open when a mare transitions from Stage 1 to Stage 2 Labour. The fluid that sits between the placenta and the white bag (amniotic sac) comes out and this is what we refer to as the ‘water’ or breaking water.

Sometimes the mare’s placenta begins to separate from the mare’s uterus before the foal is delivered. On this occasion instead of a white bag we see a red one at the vulva. This is a foaling emergency as the foal is no longer getting oxygen from the mare, but it also can’t breathe. Using a scalpel to carefully cut the placenta open, you then need to get the foal out as quick as possible and get it breathing. We cover this foaling issue (and many others) in our online foaling course.

4. Placentas should be passed within 8 hours of the mare foaling

Some mares will pass their placenta immediately after foaling (these mares are dreams to have). Others will take a bit longer. The hormone oxytocin has a number of purposes – it causes milk let down, it causes uterine contractions and it is the ‘love hormone’ – responsible for the bonding between the mare and foal.

When a foal starts nursing from a mare this stimulates the production of oxytocin which then helps the mare’s uterus to contract and assists in the passing of the placenta.

To assist with the passing of the mare’s placenta it helps to ensure that the white amniotic sac remains attached to the main placenta. We then tie this up into a knot a couple of times. This provides additional weight that naturally assists in passing the placenta, and also keeps it off the mare’s legs and out of the way of the foal while it’s trying to find the udder to nurse.

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The mare’s placenta immediately after being passed

NEVER under ANY circumstances pull on a placenta.

If your mare has not passed her placenta within 2-3 hours she may require oxytocin (a vet drug – speak to your vet about this prior to Foaling for usage and dosage info) to help her do so. This drug causes uterine contractions and can assist in passing the placenta.  If she has still not passed her placenta by eight hours you’re going to need a vet. They can, if the situation requires it, manually remove them (they’re trained to do this – please don’t try it at home).

5. Placentas need to be checked after foaling for missing pieces that can be retained in the mare.

Once a mare passes her placenta it’s important to check it over. When the placenta comes out of the mare it turns inside out, so the smooth, pale purple surface is the surface that was up against the foal. When we check the placenta we’re checking a number of things.

We check that there is no large tears or missing pieces. The only part of the red velvety surface that can be seen should be the cervical star, where the placenta burst open. To ensure all the pieces are there the placenta should be laid out in an ‘F’ shape (see below). You will have to go digging for the two horns. The large horn (at the top in the picture) will be smoother and flatter – this is the pregnant horn. The non-pregnant horn (second one down) is darker purple, smaller and less smooth (it looks like a brain – that’s a good description).

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The mare’s placenta in the ‘F’ formation for checking tears, missing pieces. The red portion at the bottom is the cervical star where you can see the other red, velvety surface.

We also check over the red surface of the mare’s placenta for any discolouration. Any brown/yellow discolouration may be an indicator of an infection in the placenta that could have been transferred to the foal.

It’s a good idea to keep your mare’s placenta after it has passed and showing it to the vet for inspection. Any bits of retained placenta can quickly lead to an infection and the mare going septic. If she does retain placenta you will see yellowy/sticky/pussy discharge in the days after foaling. If you see this you will need to contact a vet who will clean the mare’s uterus with a wash and give her some antibiotics.

That wraps up our overview of the equine placentas. Remember these five things and you’ll be on your way to a successful foaling with no post-foaling complications.

If you want more information on placentas, foaling, (including a lot of what is contained in The Horse Midwife posts in more detail and with more information and images etc.) you can check out our Online Intro to Foaling Course which is now live! Until 21st October 2017 you can save up to $99USD so get over to www.onlinetraining.foaled.co.nz now and check it out!

Until next time,

Happy foaling all!

The Horse Midwife

P.S. As always please feel free to check out our Website (www.FoalEd.co.nz) or Facebook Support Group (www.facebook.com/groups/foaledsupportgroup), or download our free Foaling Roadmap at www.foaled.co.nz/getfoalingroadmap

Please don’t use any images without permission.

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