Symptoms of Low Thyroid in a Horse

Hypothyroidism is a condition in horses which causes lower thyroid hormone levels. The thyroid is a gland located in the horse's neck and is responsible for helping to maintain temperature, appetite, energy levels and red blood cell production. A low thyroid can cause many symptoms; if you suspect a horse may have hypothyroidism, seek veterinary attention so treatment can begin right away.

  1. Physical Symptoms

    • Physical changes to watch out for include edema (or swelling) in the hind legs, obesity (including a thickening of the crest of the neck), anemia and reduced heart rate or temperature. The horse's coat may become coarser, shed later and be more scaly. Reproductive problems are also possible; mares' cycles can become irregular and their milk production can decrease, while stallions may have a reduced libido and sperm count. Founder, a painful inflammation of the foot, is also common in horses with hypothyroidism.

    Behavioral Changes

    • Changes in a horse's behavior can be symptomatic of a low thyroid problem. Watch for signs of lethargy or a lack of appetite. A horse with hypothryoidism may not perform as well as it used to, and it might exhibit a lack of energy.

    Developmental Problems in Foals

    • A foal with hypothyroidism may have many problems with its limbs and bones. For example, its bones may not be formed properly, its lower jaw may be longer than its upper jaw and its head may have a domed appearance.

    Other Problems in Foals

    • Foals can exhibit other signs of hypothyroidism, some of which are immediate at birth. The foal may be born prematurely, or it may be very weak or even die shortly after birth. Other symptoms include an intolerance to the cold, a longer coat or problems with coordination.