Hypothyroidism is the most common endocrine disorder in dogs, causing metabolic slowing, weight gain, lethargy, and skin problems. It is highly treatable but frequently goes undiagnosed for months or years.
Hypothyroidism causes chronic, progressive welfare impairment that is frequently attributed to normal ageing rather than identified as a treatable medical condition. Affected dogs experience persistent fatigue, cold discomfort, and the physical consequences of weight gain and skin deterioration. Neurological signs in severe cases including weakness and cognitive changes add to the welfare burden. The gradual onset means owners may not recognise how much their dog's quality of life has diminished until successful treatment reveals the improvement — many owners describe their treated dog as returning to their personality of years earlier. The condition is both common and highly amenable to inexpensive treatment, making diagnostic delay an avoidable welfare harm. Regular thyroid screening in middle-aged dogs of susceptible breeds is a straightforward welfare intervention.