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![Why is My Horse Eating Soil? – [Geophagia Causes & Prevention]](/wp-content/uploads/2022/09/How-to-Stop-Horse-Eating-Soil.jpg)
Has your horse started eating or licking the soil? The ingestion of soil in animals is referred to as geophagia.
The reason some horses eat dirt is not fully understood, but the behavior is thought to serve a nutritional purpose by providing minerals and other nutrients that might be lacking in the diet. [1][2][3]
Geophagia may also be linked to boredom or stress. [1] Horses may nibble on the soil to pass the time, relieve anxiety, or alleviate stomach pain.
Geophagia can be harmful because the soil may contain parasites and other pathogens that cause illness. [2] Excessive ingestion of dirt can also damage the intestines and lead to impaction colic.
You can help to prevent your horse from practicing geophagy by providing them with a healthy forage-based diet that meets their nutritional needs.
If your horse is ingesting dirt, consult with your veterinarian to rule out any underlying medical causes and to develop a management plan to help redirect this behavior.
Why is My Horse Eating Soil?
Geophagy, also referred to as geophagia, is a sub-type of pica. Pica refers to eating non-food material or objects, and geophagy is a specific form that involves eating dirt. [1][2][3] The condition has been observed in domesticated and wild horses and in other species including camels, buffalo, and sheep. [2]
This condition is a form of pica, the craving for and consumption of non-food items. [1] Horses may also be seen eating tree bark, wood (lignophagia), bedding, hair and manure (coprophagy).
Some expressions of geophagy may be an example of stereotypic behaviors, which are repetitive behaviours expressed to alleviate stress or boredom.
However, in some horses, the licking or eating of dirt does appear to serve a purpose. Horses may engage in geophagy because they are seeking one or more nutrients in the soil that are missing in their daily diet. [2][3]
In other species, pica is associated with amino acid deficiencies, vitamins and trace mineral deficiencies, a lack of alkaline substances, or imbalances in minerals such as the calcium to phosphorus ratio. [2]
Seeking Nutrients in Soil
Wild horses have been seen visiting the same sites repeatedly to ingest soil from specific areas. Domesticated horses have been observed performing the same behavior in paddocks and yards. [3]
The sites that horses visit when engaging in geophagia are typically small in area and returned to on multiple occasions. [3] Their return to the same sites suggests the locations are associated with a resource that may provide a physiological benefit. [3]
Research also shows that areas in which horses engage in geophagia tend to contain higher levels of iron and copper in the soil compared to control sites. [3]
Mineral deficiencies could explain why some horses eat soil, including diets that are lacking in the following minerals: [2]
What's your top priority with your horse's health?
What's your top priority with your horse's health?
Signs of Geophagy
Many horse owners become aware of geophagy by observing their horse repeatedly eating soil when turned out. But even if you don’t see your horse eating soil, a few key signs indicate a horse is engaging in geophagy.
Abnormal Particles in Manure
The presence of dirt or other foreign material in the manure provides evidence that your horse is ingesting substances other than their regular feed.
Behavioral Changes
If your horse is observed licking or biting the ground, it may indicate that they are ingesting soil.
According to a study on the feeding habits of 35 horses across 13 sites, owners reported that 30 horses (86%) licked at the soil, 24 (69%) pawed at it, and 23 (66%) used their teeth on the soil. [3]
Changes in Eating Habits
Pay attention to any changes in your horse’s eating habits. Horses with geophagy may consume less hay and grain than normal if they are eating soil.
Complications
Geophagia is a relatively common behavior in horses, but if left unchecked it can lead to complications in the digestive tract including parasites, blockages and nutritional deficiencies.
Parasites
Soil can contain harmful bacteria and parasites that can cause intestinal illness and infection. [2]
Some of the most common internal parasites include large strongyles, small strongyles, roundworms, tapeworms, and pinworms. These parasites can cause weight loss, diarrhea, anemia, hair loss, and colic.
Intestinal Blockages
Ingesting large amounts of soil, stones and debris can lead to blockages in the gut. In severe cases, surgery may be required to remove the blockage.
Complications can include constipation, cramping, colic, loss of appetite, pain, obstruction, diarrhea, weight loss, and perforation from sharp objects such as rocks or gravel. [4]
Nutrient Deficiencies
Geophagy may lead to lower levels of important nutrients and minerals, leading to poor health and decreased performance. [2]
Ingesting excessive amounts of soil and clay may result in secondary nutrient deficiencies by inhibiting the absorption of dietary iron. Soil binds to iron complexes and decreases the uptake of this macromineral from the intestines. [2]
Sand Colic
Ingesting soil in a sandy area presents a health hazard due to sand colic. [4] This condition occurs when ingested sand accumulates in the horse’s intestines forming a hard, compacted mass.
If left untreated, sand colic can be fatal.
Causes
You may be unsure why your horse is ingesting soil, but it is important to determine the cause of geophagy to prevent the behaviour from continuing.
The causes of geophagia are often difficult to identify but may involve:
1) Nutritional Deficiencies
Horses may lick, bite or eat soil in response to a dietary deficiency. The location where horses eat soil and the timing of when horses engage in geophagy may reflect their need for certain nutrients.
Anecdotally, geophagy is said to occur primarily in horses returning to pasture in the spring. These horses are transitioning from consuming hay to spring grass after not having access to pasture or being stabled for the winter. [3]
Low Sodium
Sodium deficiency is believed to be a primary cause of soil ingestion in horses. [3] Sodium is an important electrolyte and plays a role in thirst regulation, fluid balance, muscle contractions and nerve signal transmissions.
Horses appear to have nutritional wisdom regarding their need for salt (NaCl or sodium chloride). When levels are low in the diet, they naturally seek out and voluntarily consume higher amounts of salt. [3]
Low Iron
A study comparing blood nutrient levels between 15 healthy horses and 15 horses with geophagy found that the serum concentrations of iron were lower in horses with the condition than in healthy animals. [2]
In this study, the iron-containing oxygen-transport protein, hemoglobin, was also lower in horses with geophagy but still within a normal physiological range compared to healthy horses. Low hemoglobin can be caused by iron deficiency. [2]
Geophagy is thought to contribute to iron deficiency because soil and clay can bind dietary iron complexes and decrease the absorption of iron through the intestinal wall. [2]
Research shows an association between geophagy and iron deficiency in humans. In many cases, geophagy can be treated effectively by correcting depleted iron levels. [2]
Low Copper
Low copper intake is also associated with geophagia. [2][3] In the study previously mentioned, blood concentrations of copper were lower in horses with geophagy compared to those without the condition. [2]
This study also noted that the copper to zinc ratio was lower in horses with geophagy compared to those without the condition. [2]
Copper plays an important role in transporting iron across membranes and into circulation. Copper is also important for equine hoof health, skin and coat quality, immune function, joint health and more.
In one study, soil samples taken from areas where horses perform geophagia have higher iron and copper content than soil where horses do not engage in this behaviour. [3]
Other Potential Nutrient Deficiencies
Research is required to determine whether there is an association between geophagy in horses and nutrient deficiencies in amino acids, phosphorus, calcium, and cobalt.
However, studies involving other animal species suggest an association between these nutrient deficiencies and the condition. [2]
2) Stress and Boredom
Stress and boredom may contribute to geophagy in horses. [1][2] Your horse may eat soil or dirt to pass idle time or displace anxious energy.
Your horse may experience boredom if they do not get adequate turnout or exercise, are housed alone or cannot express natural behaviors. Boredom is also associated with other stereotypic behaviours and health problems.
Insufficient forage and diets primarily consisting of grain-based complete feeds can also contribute to geophagy because the horse does not spend enough time during the day eating.
You can help to prevent boredom by giving your horse more turnout in an appropriate social group, extending feeding time, providing a stimulating environment, and providing enrichment activities.
3) Stomach Discomfort
Anecdotal reports indicate that horses with stomach pain due to ulcers may eat substances such as wood and soil. Geophagy may be an attempt to soothe stomach discomfort by buffering gastric acid.
Further research is needed to confirm an association between stomach pain and wood and/or soil consumption.
Diagnosis
If you suspect your horse is engaging in geophagy, have your veterinarian perform an exam to rule out any underlying medical conditions and develop a plan to address the behavior. Testing for parasite infestation or other health issues could also be warranted.
You can also work with an equine nutritionist to evaluate your horse’s diet. A nutritionist can assess your horse’s feeding plan to determine whether there are any nutrient deficiencies or imbalances that could be contributing to the problem.
A nutritionist will also assess management factors including forage availability, access to water, activity level and the general environment for potential causes of the behavior.
If your horse is healthy, has an adequate diet, and has no other causative factors for geophagy, the condition may be related to curiosity or boredom.
Treatment
Treatment for chronic soil ingestion depends on the underlying cause of the behavior. Most horses can overcome geophagia and live healthy lives with proper treatment.
Treatment will focus on eliminating the behaviour and mitigating complications, such as intestinal blockages or parasites.
Nutritional supplements may be necessary to correct mineral imbalances that are causing your horse to ingest dirt. Your horse may require supplemental sodium, copper, zinc, iron, cobalt, calcium, or phosphorus to restore normal mineral levels. [2][3]
It is recommended to have your horse’s hay analyzed and feed a balanced vitamin and mineral supplement to correct for common deficiencies.
Access to forage, adequate turnout time with a social group, and enriching activities can help to reduce stress, anxiety, and boredom-related geophagy.
To reduce complications from geophagy, ensure your horse has constant access to clean water and feed salt to promote water intake.
Consumption of water promotes the transit of feed and other particles through the gastrointestinal tract, reducing the risk of sand colic or intestinal blockages.
Prevention
Occasional episodes of eating soil are normal and should not cause concern for horse owners. However, you can implement the following strategies to help support natural behaviours and potentially prevent geophagia from becoming chronic and more problematic:
Provide a Forage-Based Diet
Provide sufficient long-stem forage to support gut health, help prevent ulcers, and reduce boredom. This requires choosing hay that meets your horse’s needs, allowing them to have constant access to forage.
Consult with your vet if you notice your horse is not consuming forages properly. This is common in senior horses or those with dental issues.
Encourage Natural Feeding Behavior
In the case of hay shortages or rationing the hay, use a slow-feeder hay net to extend the amount of time forage is available.
This can help to minimize gut health issues, boredom and stress related to low-forage intake. [5]
Feed a Balanced Diet
Consult an equine nutritionist to ensure your horse’s diet is properly balanced and provides adequate levels of essential vitamins and minerals.
Supplement your horse’s diet with a balanced vitamin and mineral supplement, such as Mad Barn’s Omneity® or AminoTrace+.
Ensure Sufficient Exercise and Socialization
Provide plenty of turnout time to encourage exercise and socialization. Allowing positive social interactions can lower their stress and reduce the risk of stereotypies. [6][7]
In contrast, social disruption can increase stress and contribute to gastric discomfort. [8]
Give Your Horse Enough Salt
Ensure your horse’s diet contains enough salt. Most horses benefit from being fed 1 – 2 ounces of loose salt per day. They should also have loose, free-choice salt available at all times to voluntarily increase their salt intake as needed. Access to a salt block may not provide enough of this mineral. [9]
Address Stomach Pain
Help prevent gastric ulcers by ensuring a forage-first diet that maximizes forage intake and limits high-grain meals. Gastric pain may be contributing to geophagia in your horse.
If you notice common signs of gastric ulcers such as girthiness, aggression or changes in appetite, consider consulting with an equine nutritionist to adjust their diet in support of gastric health.
Feeding a nutritional supplement such as Mad Barn’s Visceral+ can also support a healthy gastric environment.
Support Digestive Health
Maximize your horse’s nutrient absorption by feeding gut health-promoting ingredients including probiotics and yeast. These are included in Mad Barn’s Visceral+, Optimum Digestive Health, and Optimum Probiotic.
Frequently Asked Questions
Here are answers to common questions horse owners ask when a horse is eating or licking dirt:
Horses eat dirt for several possible reasons, including mineral deficiencies, boredom, stress, or stomach discomfort. Some horses appear to seek nutrients such as sodium, copper, or iron from soil when their diet is unbalanced. Limited forage intake, low turnout, and gastric irritation may also increase dirt licking or soil ingestion in some horses.
Occasional soil licking can be normal and does not always indicate a serious problem. Many horses briefly investigate or taste dirt without developing health complications. Frequent or compulsive dirt eating is more concerning, especially when paired with weight loss, reduced appetite, colic signs, or repeated licking and pawing at specific areas in the paddock or pasture.
Low sodium intake is strongly associated with dirt eating in horses, particularly during spring turnout or periods of heavy sweating. Horses naturally seek salt when dietary intake is inadequate, and some may lick or consume soil in response. Many horses benefit from 1 to 2 ounces, or approximately 30 to 60 grams, of loose salt daily alongside free-choice salt access.
Mineral deficiencies are one possible cause of geophagia in horses, especially when diets lack sodium, copper, zinc, phosphorus, or iron. Research shows horses engaging in soil ingestion often have lower blood concentrations of certain minerals compared to unaffected horses. Repeated visits to specific soil sites may also suggest horses are seeking nutrients unavailable in their regular feeding program.
Boredom and stress can contribute to dirt eating, particularly in horses with limited turnout, low forage intake, or restricted social interaction. Some horses use geophagia as a repetitive coping behavior when they cannot express normal grazing and movement patterns. Increasing forage access, turnout time, exercise, and enrichment activities may reduce stress-related soil ingestion in affected horses.
Stomach discomfort may contribute to dirt eating in some horses, although more research is needed to confirm the connection. Anecdotal reports suggest horses with gastric ulcers sometimes consume soil, wood, or other non-food materials while attempting to relieve irritation from stomach acid. Horses with ulcers may also show girthiness, appetite changes, irritability, or reduced performance during work.
Signs of geophagia include repeated licking, biting, or pawing at soil, along with visible dirt or sand in manure. Some horses spend time focused on small areas of ground and repeatedly return to those locations. Changes in appetite, reduced hay intake, weight loss, or compulsive behaviors around dirt may also indicate ongoing soil ingestion.
Dirt ingestion can increase the risk of colic when soil, sand, or debris accumulates inside the intestines. Horses living on sandy ground are particularly vulnerable to sand colic, which occurs when ingested sand forms a compacted mass in the digestive tract. Severe intestinal blockages may lead to pain, appetite loss, diarrhea, obstruction, or surgery in advanced cases.
Soil can expose horses to parasites and harmful bacteria that contribute to digestive illness and poor health. Horses ingesting dirt may consume parasite eggs or larvae associated with strongyles, roundworms, tapeworms, and pinworms. Parasite burdens can contribute to diarrhea, weight loss, dull coat quality, anemia, and recurrent colic when infections become significant.
Stopping dirt eating starts with identifying causes related to diet, management, stress, or health problems. Horses benefit from constant forage access, balanced vitamin and mineral intake, daily loose salt, turnout, and social interaction. Veterinary evaluation and nutritional assessment can help determine whether ulcers, parasites, nutrient deficiencies, or environmental stressors are contributing to geophagia.
Poor forage intake can increase dirt eating when horses spend too little time chewing and grazing throughout the day. Horses consuming inadequate hay may experience boredom, stomach irritation, or unmet nutritional needs that encourage geophagia. Feeding sufficient long-stem forage and using slow feeders during hay rationing may reduce stress and support healthier feeding behavior.
Manure eating, also called coprophagy, occurs for different reasons depending on the horse’s age and environment. Foals commonly eat manure while developing their gut microbiome, while adult horses are more likely to engage in the behavior due to boredom, limited forage, stress, or dietary imbalances. Persistent manure eating may warrant evaluation for digestive issues, parasites, or management problems.
Veterinary evaluation is recommended when dirt eating becomes frequent, compulsive, or associated with colic, diarrhea, weight loss, or appetite changes. A veterinarian can assess for ulcers, parasites, digestive problems, and other medical causes contributing to geophagia. Nutritional review with an equine nutritionist may also identify mineral deficiencies or feeding imbalances linked to the behavior.
Summary
Geophagia is a form of pica in which horses lick or ingest soil and other non-food materials. While the behavior is relatively common, persistent soil ingestion may indicate underlying nutritional, behavioral, or gastrointestinal factors and can pose health risks if left unaddressed.
- Geophagia involves the voluntary consumption of soil and has been observed in both domesticated and wild horses
- The behavior may be associated with mineral imbalances, particularly involving sodium, iron, copper, zinc, or phosphorus
- Stress, boredom, limited forage intake, or restricted ability to express natural behaviors may also contribute to horses licking or eating dirt
- Ingesting dirt or mud can increase the risk of parasite exposure, intestinal irritation, impaction, and sand colic
- Diagnosis involves veterinary assessment and evaluation of the horse’s diet, environment, and management practices
- Management focuses on correcting nutritional imbalances, ensuring adequate forage and salt intake, reducing stress, and addressing any underlying gastrointestinal discomfort
References
- Ralston, SL. Feeding behavior. Vet Clin North Am Equine Pract. 1986. View Summary
- Aytekin, I. et al. Changes in serum mineral concentrations, biochemical and hematological parameters in horses with pica. Biol Trace Elem Res. 2011. View Summary
- McGreevy, PD. et al. Geophagia in horses: a short note on 13 cases. Appl Anim Behav Sci. 2001. View Summary
- Jurjanz, S. et al. Ingestion of Soil by Grazing Sport Horses. Animals. 2021. View Summary
- Rochais, C. et al. “Hay-bags” and “Slow feeders”: Testing their impact on horse behaviour and welfare. Appl Anim Behav Sci. 2018.
- Sauveroche, M. et al. Hair cortisol in horses (Equus caballus) in relation to management regimes, personality, and breed. J Vet Behav. 2020.
- Hepburn, R. Gastric Ulceration in Horses. Equine Pract. 2011.
- York, C.A. and Schulte, B.A. The relationship of dominance, reproductive state and stress in female horses (Equus caballus). Behav Processes. 2014. View Summary
- Jansson, A. and Dahlborn, K. Effects of feeding frequency and voluntary salt intake on fluid and electrolyte regulation in athletic horses. J Appl Physiol. 1999. View Summary
