Thyroid conditions affect dogs differently than cats, with hypothyroidism being the most common endocrine disorder in dogs and causing significant welfare impacts.
Canine hypothyroidism causes significant welfare impacts through a constellation of effects that reduce the dog's energy, comfort, and quality of life. Affected dogs often gain weight despite reduced appetite, become lethargic and cold-intolerant, and may develop skin problems causing secondary discomfort. The gradual onset means many dogs live with sub-optimal welfare for months before diagnosis, as owners may attribute lethargy to normal ageing. Excellent treatment exists — levothyroxine supplementation typically produces dramatic improvement within weeks — making prompt diagnosis particularly important. Annual wellness check-ups with thyroid screening in predisposed breeds allow early identification. The welfare impact of undiagnosed hypothyroidism is largely avoidable with appropriate veterinary care.