Tag Archive for: pregnant mare

Mare on pasture with foal at foot

Retained Placenta and Selenium Deficiency

Retained placenta… bad luck? Or is there more to it?

I am going to say there is definitely more to it. And if you look to the cattle industry they agree. And a lot of it comes down to one little mineral… SELENIUM!

I was recently at an Animal Nutrition conference at the University of New England. One of the speakers, Prof Michael Lee (University of Bristol) spoke about selenium. Here are a few photos I snapped of his slides:

Listed at the top of his list of symptoms of selenium deficiency in ruminants was retained placenta. And this is certainly what I see in horses too.

Almost the only time I see retained placenta as a widespread issue is on breeding farms that do not supplement pregnant mares.

The most recent case I dealt with was a farm with more than 100 standardbred broodmares. At the time of my first visit, the mares were not supplemented at all during pregnancy.

And retained placenta was occurring in 25 % of mares! 1 in every 4 mares were experiencing this potentially life threatening complication! Eek!!

I suggested that if they supplement with selenium (as part of an overall balancer pellet) that this shouldn’t be such an issue.

They decided they would experiment. And gave half the mares the balancer pellet. The other half they left unsupplemented.

The results were clear. The supplemented mares had one mare in 60 with retained placenta. That is less than 2%… a big reduction from 25%!

The unsupplemented mares had 2 retained placenta within the first 4 mares that foaled! This was enough to convince the farm that maybe we were onto something… so rather than keep going with the experiment they very quickly put all the mares on to the balancer pellet!

The interesting thing for me was that the incidence of retained placenta dropped almost immediately in this group of mares who were initially unsupplemented.

The nutrition of your pregnant mares is so important. This is just another reason you should pay close attention to mineral nutrition, especially because selenium is a mineral that is often low in forages and is therefore often deficient in diets.

For more about feeding pregnant mares click here to read our post ‘Feeding Pregnant Mares’.



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How to Make Sense of Pasture Analysis Results

Have you ever got the results back from a pasture or hay analysis and been left scratching your head trying to figure out what the numbers mean? Frustrating isn’t it!?

That is unless you have a tool (like FeedXL) to interpret the numbers for you.

Let me show you what I (Nerida) mean. The analysis below shows the analysis result numbers for the bottom pasture at our place, but they are kind of meaningless unless we look at them in terms of how much of that pasture a horse eats and how much nutrient is provided compared to the amount of nutrient the horse actually needs.

Take phosphorus for example, the pasture contains 1.45 g/kg of phosphorus, which is only enough to meet 39% of a late pregnant (month 11) mare’s requirement if she was given full time access to this pasture.

Our pasture is native pasture and our soils are low in phosphorus so the pasture is lower in phosphorus than most pastures. BUT, point is 1.45 g/kg of phosphorus was only a number until we put it in terms of what our late pregnant mare needs each day to meet her requirement (note to my husband, we don’t have a late pregnant mare, this is just an example, in case you are panicking right now! No promises for the future though, it’s all part of my professional development right! )

You will also see from the diet readout from FeedXL below that the pasture only diet (bar graph with the green and red bars) is not meeting requirements for multiple other nutrients for this late pregnant mare, which also would have been difficult to determine just from reading the analysis numbers alone.


So with FeedXL we can see what is not in your pasture that your horse needs. You can then also add other feed ingredients to the diet to meet those requirements.

The second bar graph with the green and blue bars shows a diet I would use for a late pregnant mare on this pasture. The diet uses 2 kg of prime lucerne hay (shown in the darker green) and 3 kg of a commercial broodmare feed (shown in the blue). All requirements are now nicely met!

Pasture analysis made that bit more useful! Using FeedXL to assess your forage analysis also means you will only supplement with the nutrients you need to add, potentially saving yourself a lot of money by not adding unnecessary products and nutrients.

You can upload as many pasture and hay analyses as you like into your FeedXL account, just click the ‘Add my own forage’ link in the Create Forage section of the diet wizard, or directly from the Feeds list (see below). Click here to log in and give it a try!


If you’d like some help finding a forage analysis lab, you can click here to download our free ‘Lab List’ with laboratories in Australia, New Zealand, United States, Canada and the UK.

Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


Horse eating from hand

Feeding Pregnant Mares

Pregnant mares carry your hopes and dreams, be it for the next big champion or just a quiet riding companion. Regardless of what you are breeding, good care of the mare during her various stages of pregnancy has long term impacts on both her and her foal’s long term health and athletic capacity.

Here are some tips for feeding pregnant mares to keep them healthy and breeding sound, strong and athletic foals:

1. Don’t let mares get fat

Mares in their early stages of pregnancy don’t need many, if any additional calories than they needed when they weren’t in foal. All mares are different, so to really know how much feed your pregnant mares need you should condition score regularly. Pregnant mares should ideally be maintained at a condition score of 6 and should not be allowed to exceed a score of 7. Having mares too fat can:

  • Reduce their milk production when they foal.
  • Put unnecessary strain on their hooves and joints, making them heavy and uncomfortable.
  • Lead to difficulty foaling (though this isn’t necessarily proven to occur).
  • Make it difficult to fall pregnant again, particularly if a mare is forced to lose weight just prior to or immediately following foaling.

As mares progress through their pregnancy their requirement for energy and protein does increase, so you may find you need to feed additional feed to maintain their body condition score. For more information on Condition Scoring read our FeedXL Newsletter #1. If you are feeding pregnant mares, get in the habit of running your hands over them every time you feed them. Doing this means you will quickly pick up if they are putting on more condition than they need and will allow you to adjust their feed intake accordingly.

2. Don’t let mares get skinny

A pregnant mare shouldn’t be allowed to drop below a condition score of 5. Mares that are any lighter will fall away quickly after foaling, reducing the body energy and protein reserves for milk production and also switching off the reproductive cycles, making it difficult or impossible to get in foal again. Thin mares may also be more susceptible to disease.

Again, get in the habit of running your hands over your mares to assess whether they need more feed to hold them in the desired body condition. If you notice their ribs becoming easier to feel or their topline and rump starting to fall away, you will need to increase the amount of feed they are getting. Because so much room is taken up in the mare’s abdomen late in the pregnancy you will likely need to feed high energy grains (make sure they are cooked—see FeedXL Newsletter #18) or high energy fibre feeds that use ingredients like sugarbeet pulp or soybean hulls to allow them to increase their energy intake enough to hold their body condition. High fat feeds are also useful for late pregnant mares.

3.­ Make sure mineral and vitamin requirements are met

Meeting the mineral and vitamin requirements of pregnant mares during early and late pregnancy is crucial to:

  • Promote the sound development of their foals.
  • Prevent deficiencies like iodine that can affect the thriftiness and survival of newborn foals.
  • Prevent problems in the mares like retained placenta and the associated laminitis.
  • Maintain a strong immune system in the mare and foal.
  • Maintain the long‐term health and soundness of the mare for future reproduction.

While pregnant mares can often be maintained on good quality pasture with little additional feed, without supplementation of minerals, a pasture‐only diet will almost certainly have quite dramatic deficiencies of copper and zinc and depending on the geographical location may also be very deficient in calcium, phosphorous, magnesium, iodine and selenium.

If the mare doesn’t receive the additional minerals she needs to support herself and her growing foetus she will draw them from her own body reserves. However if she is required to do this for many consecutive breeding seasons it will eventually have implications for both her and her future foals’ long‐term health, soundness and athletic ability. One study has shown that foals born to mares early in her breeding career have less structural problems than foals born later in that mare’s life, which may indicate that over consecutive pregnancies, mares can run out of reserves of minerals that directly impact the sound development of her foals.

FeedXL allows you to quickly and easily determine your mare’s requirements for these critical minerals as well as vitamins and helps you make sure the diet you are feeding is meeting her requirements through all stages of pregnancy.

4. Feed high quality protein

During pregnancy a mare requires high quality protein to meet her own requirements and those of her growing foetus. If the pasture your mare is on is of low quality (for example sub‐tropical C4 Type pastures, or pasture that has matured, gone to seed or browned off), add some high quality alfalfa/lucerne hay to raise the quality of protein in the forage component of her diet.

If you are using supplementary feeds on low quality pasture, select feeds that use legumes and oilseeds with quality protein, including soybean, lupins, faba/field beans and canola meal. Low quality protein sources like cottonseed meal shouldn’t be used for pregnant mares. FeedXL will help you make sure you are feeding enough good quality protein to your mares to produce healthy foals and will also stop you from overfeeding protein which will make your mare’s diet very expensive.

5. Make the most of pasture if you have it

Pasture is an excellent source of energy and protein. Feeding a diet that relies largely on pasture has two main positive effects. The first is it will make for an economical diet, with pasture being one of your cheapest feeds available. Secondly, a high fibre diet will keep your mare’s gastrointestinal tract healthy, reducing the risk of problems like colic (something to be avoided in a pregnant mare).

To really know what is in your pasture and what your mare needs in addition for her diet to be balanced, you should have your pasture tested for energy, protein and minerals levels. Once you have had your pasture tested we can enter the results into your FeedXL account so you can see what is in and what is missing from your specific pasture. Then you only need to add what is missing from the mare’s diet. Equi‐Analytical can run a full analysis starting at $26 USD. It is well worth the investment. If you rely on hay for your mare’s main source of forage this too can be tested and the results put into FeedXL.


Because it is so often said that a pregnant mare needs little more than a horse at maintenance, it is sometimes mistakenly thought that mares and particularly early pregnant mares can be fed diets of forage only with little or no supplementation. However while a pasture or good quality hay diet may be sufficient to maintain your mare’s bodyweight, it will almost certainly be lacking in critical nutrient including minerals that can determine if your foal is born structurally sound or not.

Keeping mares in the correct body condition, making sure you meet mineral and vitamins requirements from day 1 of the pregnancy, feeding high quality protein and using pasture when you can will help you to breed sound foals that are healthy and full of life when born. It will also mean your mares can remain healthy and able to produce strong foals with good structural soundness year in, year out. Being pregnant may not appear to be hard work, but it will take a toll on your mare’s body if she is not properly cared for.

Meet The Author: Dr Nerida McGilchrist

Dr Nerida McGilchrist is FeedXL’s co-founder and equine nutrition specialist. She holds a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group

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