Why does my horse eat mud?

Lack of dietary fibre

In general, we recommend a daily dietary intake of at least 1.5-2% bodyweight of dry matter or forage. Youngsters on high concentrate diets, stabled for long periods of time are at an increased risk of coprophagia (eating droppings). Fibre is critically important in the diet to maintain digestive health. Diets that are higher in starch rich concentrates are linked to an increased risk of stereotypical behaviours. 

Age

Coprophagia in foals is extremely common during the first few months of life. This behaviour rapidly disappears by five months of age. They usually eat the faeces of their own mother, rarely that of others; leading to the theory that a maternal pheromone may drive this behaviour. It may serve to populate the foal’s digestive tract with “good” bacteria that will help with digestion of forage as the diet adapts. Care should be taken to ensure that the mare has been treated with appropriate wormers, though. This is because coprophagia can lead to parasitic infestation in the foal.

What are the risks of pica in horses?

Geophagia may be associated with an increased risk of sand colic; when large volumes of sand accumulate in the digestive tract leading to diarrhoea or intestinal impactions. Sand is most commonly involved. But any large quantities of rough soil may irritate the mucosal lining of the digestive tract. It is not unusual for horses to ingest small quantities of soil when grazing or when eating forage in the field; this can be reduced by moving sites where hay is given or by putting mats down. Dietary supplements such as Psyllium may help to reduce the risks of sand colic in some horses, but this is not a cure all. In horses that are known to eat mud or sand, other changes may be needed to reduce the risk of colic. 

Intestinal parasitism is also a risk for any horse on pasture or in group housing. But those who engage in coprophagia may be in greater danger as they may have higher worm burdens due to ingestion of faecal material. As with all horses, regular faecal worm egg counts and tapeworm tests are recommended to check for infestations that may warrant treatment. 

Treatment or prevention

It may not be possible to prevent pica in horses completely, however, there are some things that may help to reduce the frequency of this. 

Provide adequate forage 

Evidence suggests a strong direct correlation between low forge intake and pica. Ensuring that your horse has an adequate intake may help to reduce this behaviour. Forage is also critically important in the maintenance of gastrointestinal health. In general, horses need to consume 1.5-2% of their bodyweight in dry forage per day. This figure may change depending on energy needs; but diets containing below 1% bodyweight of forage can lead to an increase in stereotypical behaviours and medical problems. 

Environmental enrichment

As there is strong evidence to suggest that boredom may play a role in the development of pica, there are ways in which we can improve the horse’s environment to reduce this risk. Companionship with others, increased turnout or the provision of a window or mirror in their stable may help. Even spending more time with your horse, increasing ridden work or teaching them something new will all help to reduce boredom.