History

The medical history should be directed to the clinical problem. The “herd health” of the stable or farm can be assessed briefly as depicted by the vaccination and parasite control program and visually by the condition of other horses residing on the premises.

The diet (e.g., supplements, grazing environment), stall or housing schedule, and medical problems concerning other animals on the premises, which may coincide with a group incidence of the client's complaint, should be determined. When contagious disease is a concern, travel history of the patient or stablemates, including recent additions to the farm, should also be considered.

When a veterinarian is dealing with neonates, the reproduc­tive and foaling history of the mare may be important in establishing an early diagnosis. Any compromise during a mare's gestational period (e.g., systemic disease, general anesthesia, or administration of certain medications), foaling, or lactation; any placental abnormalities; and any problems that occurred during previous pregnancies should be questioned and con­sidered to be important, pertinent historical data. In some circumstances, the foal's breed should be considered and the possibility of genetic disease transmission by the dam and/or sire should be investigated (e.g., combined immunodeficiency in Arabians).

A description of the types of medication used before hos­pitalization may aid in determining if “masking” agents have inadvertently been administered. Tranquilizers or sedatives, which can cause confounding clinical signs of hypotension, bradycardia, lethargy, weakness, and ataxia, are frequently given for the horse's safety during transport. In many instances a van driver or hauler is unaware of medications used or the patient's medical condition. Sedatives (e.g., xylazine) and analgesics such as flunixin meglumine, administered by owners or farm staff in the hours or days prior, may mask signs of pain or colic and alter interpretation of the severity of the horse's condition on arrival. Failure of such an analgesic to abolish clinical signs may necessitate hospital or clinic admission for further evaluation or surgical consultation. Conversely, the failure of other previous medical treatments can aid in the initial selection of more appropriate therapeutic planning. Knowledge of the quantity and interval of administered drugs is pertinent information as well, particularly in hypovolemic animals given drugs known to be nephrotoxic (e.g., phenylbutazone).