Pica

By Horse & Hound Veterinary Services | Oct 12, 2009

Owls Head — As the cold and often inclement weather returns to Maine, our horses and ponies may resort to pica. This term refers to the voluntary consumption of nonfood items. Cool fall temperatures bring an end to nutritious pasture grazing resulting in more time spent in dirt paddocks and stall confinement. Indigestible pasture weeds and stall boredom may cause a horse to chew on tree bark, fallen limbs, wooden fencing, dried weeds and leaves, stall boards, manure and even the tails of pasture mates. Horse owners may notice large, scallops missing from the top rails of paddock fencing or stall boards, the disappearence of wooden door frames, the enlargement of holes originally made by kicking, stripping the bark from trees, and ingestion of tree trunks or stumps. Most apt to occur during winter months, pica has been known to occur at any time that a horse or pony is confined in a grass-less, muddy, or snow-covered field or paddock and has restricted exposure or intake of nutritious hay. Lack of quality exercise and boredom can also lead to wood chewing. The consumption of poisonous woody plants (yew bush) or wilted leaves (red maple tree) can even lead to death. Horses can also ingest stall or paddock manure when their diet is either deficient or lacking long fiber for proper large intestine fermentation. The observation of herd mates with shortened tails especially when the hair is missing from the bottom of the tail often means that one or more animals are tail chewing in their quest for roughage. Tails can be treated with unpleasant-flavored "paints" such as hot sauces or bitter citrus gels to discourage chewing. Eating soil, rocks, and other objects without nutritional value occurs less commonly but is much more dangerous because of the chance of causing intestinal obstruction, severe colic, and death. Sand colic can result from inadvertent ingestion of sand with feed, especially grain. Horses can separate hay from sand quite easily with their prehensile lips but they are more likely to ingest sand when small pieces of grain are gathered from the ground. Such ingestion is accidental and should be considered a management problem rather than true pica. Most horse owners have dealt with wood chewing at some time, resorting to painting surfaces with noxious substances, applying hand or laundry soap to boards, or electrifying the top of wooden surfaces. This may discourage the horse from chewing a particular surface but it does not address why the horse is chewing. It also does not change a horse's motivation, so chewing may continue elsewhere. True treatment of pica almost always is dietary. Increasing good quality forage helps prevent wood chewing. Increasing the protein level, vitamin content, or roughage level reduces coprophagia (eating of manure). Tail chewing has been dealt with by spreading pungent tasting substances on the tails, but a better approach is to provide a palatable dietary supplement or even access to a mineral salt block. Good observation, good horse husbandry, and management go hand-in-hand with eliminating pica from our equine companions.

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