Anyone who has ever had to look after a horse for any length of time knows that they produce a lot of manure. In fact, a 500kg horse defecates about 4-13 times a day, producing 15.5 to 22.5kg of faeces and urine daily, which adds up to 8 metric tons a year! While those unfamiliar to horses might think finding no poop in the stall in the morning would be a Godsend, for those of us with horses, such an occurrence is a nightmare we hope to never experience.
The ideal poo
While many of us scoop the poop and throw it away giving it little consideration, your horse’s manure can tell you quite a few things about their overall health. To begin, there is the consistency. Horse manure should be moist, with clearly formed balls and it should slightly break apart when it hits the ground.
Faeces that pass as defined individual balls is too dry. There will be noticeable stems from the forage portion of the diet, although pieces should not be more than a couple of centimetres long.
Sometimes, horses pass very moist manure that is more like the consistency of a cow pie. Often, healthy horses pass such manure when they are excited or nervous, such as while being loaded into a trailer or during exercise. In these situations, loose manure is not a concern. Passing a small amount of liquid with, or shortly before or after faeces is also generally not considered a concern. However, true diarrhoea may indicate something more serious is going on and should be explored. Diarrhoea may be inflammatory, infectious, cancerous or related to management.
Inflammation in the large colon may lead to a reduction in water absorption and loose manure. The cause of the inflammation may be hard to pinpoint, but may be due to damage from internal parasites or as a result of irritation from the large intestinal contents becoming too acidic.
This can result when starch (high grain meals) escapes small intestinal digestion, resulting in rapid fermentation in the hindgut and lactate formation. Grains should be fed in small amounts in multiple meals, rather than few large meals to help avoid this scenario. Such fermentation of starch in the hindgut along with other rapid changes in diet will also lead to sudden changes in the hindgut microbial population, which may cause diarrhoea due to microbial die-off.
Further, diets containing excessive levels of fat will also result in diarrhoea. When adding oil to a ration, diarrhoea is a sign that you have added too much or introduced it too quickly.
For horses that develop diarrhoea on diets with higher starch intakes, but that need additional calories, using a high fibre supplementm such as HYGAIN® FIBRESSENTIAL®, that utilises super fibres (beet pulp, soybean hulls and lupin hulls) or HYGAIN® MICRBEET® as sources of calories, rather than high levels of starch is often beneficial.
Bacterial infections such as E. coli and Salmonella will also result in diarrhoea. Exact infections can be hard to diagnose as a negative faecal culture does not necessarily mean the infection does not exist and multiple cultures may be necessary, along with antibiotics.
While loose manure may not be cause for major concern, it can damage the skin on the horse’s hindlegs and projectile diarrhea can result in dehydration. Dehydration is of particular concern in foals, so veterinary assistance should be sought promptly for foals showing signs of loose manure and for any horse displaying projectile diarrhoea.
The other end of the moisture scale is equally concerning. Faeces that are too dry indicate a risk of impaction. Overly dry faeces are the result of inadequate water consumption. This may be due to inadequate access to water, a lack of desire to drink, due to electrolyte imbalances, or the available water not being to the liking of the horse. Horses do not like drinking water that is overly cold or that tastes different to the water they are used to.
Transport stress and pain may also reduce water intake. One of the easiest things you can do to encourage your horse to drink and reduce the risk of impaction is to supply adequate daily salt, and to use a well formulated electrolyte supplement like, HYGAIN® REGAIN®, to replace electrolytes lost in sweat.
When horses are provided water in automatic waterers, it is often impossible to determine how much water is being consumed. Paying attention to faeces can help determine whether water intake is adequate. Horses consume about 50mg of water per kilogram of bodyweight per day or 25 litres for a 500kg horse at rest. This amount will go up and down, depending on work level and how dry the diet is.
Horses on fresh pasture will drink less water than horses fed dry hay. It is important to know your horse’s normal daily water consumption. Similarly, know what normal faecal production looks like for your horse.
The next manure variable is colour. Manure should have a fairly uniform colour that will depend on what your horse is eating. Horses consuming large amounts of fresh pasture will have manure that is bright green in colour, while those consuming dry forages may range from green to the colour of straw. Large amounts of beet pulp may result in manure turning to a brownish, reddish colour and diets containing a lot of oil may have a grey hue. If excessive oil is fed, an oily film may develop.
Equine faeces typically do not have a mucus covering and the appearance of mucus in faeces may indicate passage through the digestive tract has been delayed due to impaction. Rarely will you find evidence of blood in faeces, but if you do, it indicates bleeding is occurring in the digestive tract. Blood from the lower tract will show up as red in faeces; blood from the upper tract will appear black. If you believe you are seeing evidence of blood in your horse’s manure, you should contact your veterinarian.
Faecal odour is generally due to microbial metabolism of amino acids in the hindgut. Dietary amino acids should be digested and absorbed in the horse’s small intestine. However, some will make it to the hindgut where they are metabolised by microbes. Smell is typically mild, especially compared to carnivores; although sometimes horse faeces can omit a strong odour.
Faecal smells arise from microbial fermentation in the colon, and when protein levels entering the colon are high and microbial growth is inefficient. Therefore, strong smelling faeces may be an indicator there is too much protein in the diet and/or the microbial population in the hindgut is not functioning optimally. Interestingly, one of the end products from the microbial breakdown of the amino acid tryptophan results in a smell that may attract flies.
Composition of faeces
While it is tempting to only look at faeces from a distance, you can learn even more if you get up close and personal. Take a closer look at the composition of faeces. Are the contents well chewed? Appearance of overly long pieces of forage and whole pieces of grain suggests your horse is not chewing their feed adequately and indicates your horse’s teeth may require a visit from your veterinarian or equine dentist. Should you find whole pieces of grain in the manure, be sure to investigate whether this is just the indigestible hull or whether it also contains the internal contents of the grain. Finding undigested hulls is not a concern.
Your horse’s manure may harbor unwanted guests in the form of eggs from internal parasites. Having your veterinarian perform a faecal egg count on your horse’s manure can tell you whether your de-worming program is effective and may allow you to cut back on de-worming, depending on the findings. Horse manure can also contain sand the horse has consumed. It is wise to evaluate your horse’s manure for sand on a regular basis as sand in the gastrointestinal tract can cause colic.
This is easily done by taking a few freshly produced pieces of manure that have not touched the ground and placing them in a clear plastic bag. An exam glove used for rectal exams works particularly well. Next, put water into the bag or glove, and break apart the faecal balls. Then hang the bag and allow the content to settle. Forage material will float and the sand will sink to the bottom in the glove - collecting in the glove’s fingers. If you find sand in your horse’s manure, discuss with your veterinarian what management steps you should take to reduce the sand in the digestive tract and reduce the consumption of further sand.
While on face value your horse’s manure is just waste to get rid of, on further investigation it is so much more. Paying careful attention to your horse’s manure can give you vital information - not only about gastrointestinal health, but your horse’s overall wellbeing. Next time you scoop the poop, take the time to give it a really good look. You may be surprised what it has to tell you.