Question
Over the past two years, we have had three adult horses in our stable nibble on their manure. Is this a mineral deficiency? If not, what causes this? All three horses originated from the same feeding program. Could this be a possible factor?
Answer
Horses and ponies are extremely inquisitive, even as youngsters. Coprophagy, the fifty-cent word for manure-eating, is common among foals and other young horses, which is one reason veterinarians suggest a deworming program begin before weaning. Coprophagy is a form of pica, which is a term that describes an unusual appetite for objects with little or no nutritional value, such as tree bark or dirt.
Aside from sheer boredom, mature horses will sometimes engage in coprophagy when they are not offered enough forage to satisfy their nutritional requirements. Although you don’t mention the breed or weight of these horses, you can follow a simple guideline to ensure adequate forage and feed consumption: for most horses, 1.5-2% of body weight daily in forage and concentrate should be offered.
If an idle, 1,100-lb (500-kg) horse is to be fed a diet composed entirely of hay, for example, offering 22 lb (10 kg) of hay should meet energy requirements for weight maintenance. Offering more than this will encourage weight gain; offering less will cause weight loss. Like humans, horses have individual metabolic rates, so this guideline should be considered a starting point in terms of what is right for your horses.
Some horses on fast-growing spring pastures, which are primarily water, will engage in pica-like behavior if they’re not consuming forages with some structural components or rigidity to them. These horses often turn to wood-chewing, rather than manure-eating, as the consistency of the manure would likely be too wet.
In addition to sufficient quantities of feed, horses should be offered appropriate vitamin and mineral fortification. For those on all-forage diets, like the example above, vitamins and minerals can be added through a well-fortified supplement, such as Micro-Max (in the U.S.) or Gold Pellet (in Australia). Some horsemen believe that unusual appetites are caused by nutritional deficiencies. By supplying horses with adequate quantities of vitamins and minerals, this would no longer be a concern.
Horses can also derive sufficient vitamins and minerals from a commercial feed, assuming it is a good-quality product and fed according to the manufacturer’s recommendations.
Thank you for including the point that all of the horses mentioned in your query came from the same feeding program. Though this is interesting, it is impossible for me to determine if this historical common denominator has anything at all to do with the current behavior.
