Companion Animals

Companion Dog Hypothyroidism Management

Canine hypothyroidism is a common endocrine disease causing lethargy and weight gain that responds well to lifelong hormone supplementation.

Key Facts

Hypothyroidism affects 1 in 500 dogs and is most common in middle-aged medium to large breeds
Clinical signs include weight gain, lethargy, skin problems, and cold intolerance
Diagnosis requires measurement of total and free T4 with TSH for most reliable results
Daily levothyroxine supplementation restores normal thyroid function in most cases
Regular monitoring of thyroid levels every 6 months allows dose adjustment

Welfare Considerations

Hypothyroid dogs experience chronic fatigue, weight gain, and reduced quality of life that often develops gradually and is attributed to ageing rather than disease. Diagnosis and treatment transforms welfare - most dogs show marked improvement in energy, weight, and skin condition within weeks. The welfare cost of undiagnosed hypothyroidism is significant given its prevalence and the simplicity of effective treatment.

What You Can Do

Consider thyroid screening for lethargic or overweight middle-aged dogs
Once diagnosed, administer levothyroxine daily at the same time for consistent blood levels
Schedule thyroid monitoring checks every 6 months to maintain optimal dosing