Hyperthyroidism is the most common endocrine disorder in senior cats and highly treatable — early recognition prevents significant welfare harm from untreated disease.
Feline hyperthyroidism is a highly impactful welfare problem that is often missed because initial signs — increased appetite, apparent energy — may seem positive to owners. As the disease progresses, the welfare cost increases substantially: weight loss despite eating, hypertension causing blindness or neurological signs, heart disease, and kidney damage impose significant suffering. The good news is that multiple effective treatment options exist, and treated cats typically return to excellent quality of life. Early diagnosis through routine blood testing in cats over 8 years is the most effective welfare intervention. The availability of a dietary treatment option that requires no medication administration is particularly valuable for cats where pilling is difficult and owner compliance is a challenge.