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Basics ⬇

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BASICS

Overview!!navigator!!

In human medicine pica is defined as an abnormal craving and compulsive eating of substances not normally deemed as food. In horses, the assessment of cravings is subjective; therefore, pica is a sign suggestive of nutritional, mental health, or behavioral imbalances.

Although the pathophysiology of pica is not understood, it is likely a conserved mechanism of adaptation to nutritional deficiencies. Clinically, pica can occur with obesity, parasitism, malnutrition, and deficiencies in fiber, electrolytes (sodium, chloride, or phosphorus), protein, or trace minerals (iron, copper, zinc). In stabled horses, pica might occur owing to lack of external motivation for masticatory muscle exercise or possibly “boredom.” Decreased dietary roughage has been associated with wood chewing, although it is questionable as horses kept on pastures may ingest trees and shrubs. Behavior-altering diseases, such as rabies, or repetitive stereotypies may result in pica.

Signalment!!navigator!!

  • Miniature horses and foals are more prone; no associations with a particular signalment have been documented
  • Pica may be seen in stabled horses with reduced pasture time and low-roughage/high-concentrate diets
  • Coprophagia in foals and adults is normal

Signs!!navigator!!

  • History of eating nonfood items
  • Colic, choke, or diarrhea may be secondary to consumption of inappropriate substances
  • Animals with pica exhibit no differences in body weight, or changes in external appearance
  • Excessive or abnormal wearing of teeth might be observed

Causes and Risk Factors!!navigator!!

Pica may be nutritional or mental in nature. Among the minerals, studies in horses indicate that iron and copper deficiencies may correlate with pica. Inadequate housing, exercise, stimulus, or nutrition can lead to pica.

Diagnosis ⬆ ⬇

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DIAGNOSIS

Differential Diagnosis!!navigator!!

  • Dietary deficiencies should be investigated before determining if pica is behavioral
  • Behavioral stereotypies may also be secondary to neurologic disorders (e.g. rabies) or malnutrition
  • Pica could also occur in horses as a drug side-effect behavior

CBC/Biochemistry/Urinalysis!!navigator!!

  • Urinalysis may be normal, but fractional excretion of relevant electrolytes may aid in diagnosing specific mineral deficiencies
  • Hematologic and biochemistry blood parameters are uninformative
  • Low serum iron and copper concentrations and low copper/zinc ratios may be important treatable deficiencies in horses with pica. However, as nutritional factors in feedstuff and pastures oscillate with weather impacting nutrient availability in feed, serum test abnormalities may be interpreted with caution. In addition to iron and copper mild deficiencies, mild deficiencies in cobalt, magnesium, selenium, zinc, and marked deficiencies in phosphorus need to be assessed

Other Laboratory Tests!!navigator!!

  • If complete neurologic examination is normal, pica is likely behavioral
  • Fecal examination for parasites and any other tests indicated by prior testing; feed evaluations, especially for trace minerals such as copper, cobalt, phosphorus, and zinc, are not conclusive or diagnostic, unless consistently deficient diets are documented

Imaging!!navigator!!

N/A

Other Diagnostic Procedures!!navigator!!

N/A

Treatment ⬆ ⬇

TREATMENT

  • Treatment of pica will depend on the suspected underlying disease or risk factor and type of material ingested
  • Redirecting the behavior, providing appropriate feedstuff substitute, increasing roughage, altering the environment causing the stereotypy (see chapter Oral stereotypic behaviors), altering the desirability of nonfood item by using unpalatable repellents, and increasing exercise
  • Consider potential complications from ingesting aberrant materials and monitor, prevent, or treat clinical complications, e.g. toxicity from toxic materials, or intestinal impaction or perforations

Medications ⬆ ⬇

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MEDICATIONS

Drug(s) of Choice!!navigator!!

N/A

Contraindications/Possible Interactions!!navigator!!

N/A

Follow-up ⬆ ⬇

FOLLOW-UP

  • The extent of follow-up required depends on the primary disease. Assess owner compliance and response to treatment. Repeated serum mineral analysis in plasma, and testing other animals is desirable
  • Monitor potential complications, i.e. intestinal obstruction, teeth wear

Miscellaneous ⬆ ⬇

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MISCELLANEOUS

Associated Conditions!!navigator!!

N/A

Age-Related Factors!!navigator!!

N/A

Zoonotic Potential!!navigator!!

N/A

Suggested Reading ⬆ ⬇

Aytekin I, Onmaz AC, Aypak SU, et al. Changes in serum mineral concentrations, biochemical and hematological parameters in horses with pica. Biol Trace Elem Res 2011;139(3):301–307.

Husted L, Andersen MS, Borggaard OK, et al. Risk factors for faecal sand excretion in Icelandic horses. Equine Vet J 2005;37:351–355.

McGreevy P. Ingestive behavior. In: McGreevy P, ed. Equine Behavior. A Guide for Veterinarians and Equine Scientists. Philadelphia, PA: WB Saunders, 2004:200–206.

McGreevy PD, Hawson LA, Habermann TC, Cattle SR. Geophagia in horses: a short note on 13 cases. Appl Anim Behav Sci 2001;71:119–215.

Author(s) ⬆

Author: Alexander Rodriguez-Palacios

Consulting Editors: Henry Stämpfli and Olimpo Oliver-Espinosa

Acknowledgement: The author and editors acknowledge the prior contribution of Debora A. Parsons.