Excrement eating (coprophagy) occurs in both stabled and open yard horses, in all breeds, and all age groups.
In foals, the behavior is still normal. By eating their mother’s excrement, they absorb important microorganisms, which settle in the foal’s large intestine and build up their microbiome (intestinal flora) This means that the foal is only able to build up a healthy intestinal flora if the mother has a healthy intestinal microbiome.
The microorganisms that are ingested during the first 4-5 months of life settle between the intestinal villi and in the superficial layers of the intestinal mucosa. The immune system recognises them as a friend, not foe, and therefore does not fight them off.
This intestinal flora, absorbed at an early age, then remains with the horse throughout its life, whereas in the intestinal lumen, aka the food bolus, major changes can happen depending on the feeding. Foals usually stop eating faeces between the fourth and sixth month of life, as this is when the intestinal flora stabilises and multiplies, thus forming a stable microbiome.
However, there are also adult horses you can observe eating feces. You can sometimes watch that behaviour directly or you may find a half-eaten pile of droppings that are all churned up (and not by birds, which they like to do!).
Feces eating has serious reasons
Whilst birds merely spread the faeces around to access any excreted oat grains, the actual amount of manure left is reduced when it comes to coprophagy cases. Therefore, you end up mucking out a lot less than usual (assuming if, on average, one horse normally fills half a wheelbarrow per day in an open yard – in stables, the amount changes depending on the bedding used). In some cases, you can even observe horses purposefully walking up to another horse’s manure pile and starting to eat it, or turning around to eat their own fresh faeces.
Eating excrement is not something to shrug your shoulders at; the behaviour usually has a solid reason for happening. A healthy, adult horse would not do this on their own any more than a human would.
Alongside eating sand (risk of sand colic), eating excrement increases worm infestations for coprophagous horses. Therefore, one should always try to stop or at least greatly reduce the behavior.
To find out a cause, it is worthwhile to observe the behaviour more closely, if necessary with cameras in the stable. There are a few things to ask yourself when you observe: is it only one horse that is eating droppings, or is it several or even all horses in the yard? Is it only the faeces of a specific horse, or a few, or is it randomly selected?
Because feces eating can have various reasons:
Hunger
The horses are hungry because too little roughage is being provided or there is too long a gap between (roughage) feedings. In this case, many or all horses are coprophagous and the manure of all horses is eaten at random. In addition to poo, soil is sometimes eaten, wood is gnawed (like fence posts or wooden hay racks), other horses’ manes are chewed off, or the horses lie down on the carpal joints in an attempt to get the very last stalk of grass or weed from under the fence. If the horses are not eating anything, they usually stand around apathetically and pain-faced, due to the painful stomach ulcers caused by long feeding breaks.
The behavior can easily be stopped by offering the horses hay around the clock, for example in suspended nets or as a net-covered rack on the dry lot.
Be mindful that all horses should be able to reach the food without problems. Hanging up a 3kg net for 10 horses is not an adequate solution, but only causes more stress and aggression. For herds, several feeding stations are a good solution. A second hay rack or additional slow feeders should be offered.
Disturbed intestinal flora
The affected horse(s) have a disturbed intestinal flora. If this is the case, it is only one or a few horses that eat the faeces of a few selected horses. Horses with constant intestinal problems (flatulence, faecal water, mild colic, diarrhoea, etc) are mostly affected and usually the excrements of the most intestinally healthy horses in the stable are eaten.
This behavior usually occurs if the horse did not have the opportunity to develop a healthy intestinal environment as a foal because their mother suffered from dysbiosis (faulty fermentation in the large intestine). These horses often do not discontinue the coprophagic behavior because they realise that it makes them feel better. They often show the coprophagous behavior in times when the intestine is particularly stressed, e.g. after worming, when moving yards, when a new horse is integrated into the group or while they’re transitioning onto the grass fields.
It is beneficial to regularly support these horses with intestinal rehabilitation measures, especially during stressful periods. Often, it is not possible to completely put a stop to the behaviour because, due to incorrect colonisation during foaling, the wrong microbiome has settled in the intestinal mucosa and therefore will never be completely stable in their microenvironment.
But through supportive intestinal rehabilitation measures, at least more severe derailments can often be intercepted and faeces eating reduced to a minimum.
Mineral deficiency
Deficiency in minerals, trace elements and/or microelements. Again, only individual or specific horses are affected and predominantly only the faeces of specific horses are eaten.
Most minerals found in the feed in inorganic ionic form. The natural “sorting mechanism” in the intestinal wall ensures that unneeded minerals remain mostly in the food bolus and are then excreted with the feces. This ensures that there is no oversupply, and thus avoids metabolic stress.
If the natural fluctuations or mineral deficiencies in basic feed, which are partly caused by soil or vegetation, are not regularly compensated – by providing a mineral feed – then deficiency symptoms can occur. By eating the manure of horses that are well supplied with minerals, they often try to get what their metabolism lacks.
In this case, the behavior can easily be stopped by regularly giving the affected horse a proper mineral feed (e.g. Pure Minerals G from OKAPI) and also offering seaweed from time to time. Mineral feeds only contain (and allow) the usual minerals and trace elements. However, if there is a deficiency of so-called microelements, i.e. minerals that the body needs only in minute amounts, the horse cannot absorb them from the mineral feed and is dependent on another source. Seaweed is a good alternative.
For therapy, it is therefore always important to find the cause. Nobody is at fault for a disturbed intestinal flora due to a dam with dysbiosis (except, perhaps, the breeder). However, feed and mineral deficiencies can, and should, be corrected immediately.
