A prescription iodine-deficient diet (Hill's Prescription Diet y/d) can manage feline hyperthyroidism without medication or radioiodine, but its strict exclusivity requirements raise important welfare questions about feline feeding.
Hill's y/d presents an interesting welfare dilemma: a treatment that avoids the side effects of medication and the isolation of radioiodine, but imposes significant dietary restriction on an animal with strong individual food preferences. Cats that refuse y/d face a choice between remaining hyperthyroid (with its associated welfare costs) or being forced to eat an unpalatable diet. In multi-cat households, the practical impossibility of preventing food sharing means y/d dietary management is rarely successful - creating welfare costs from both dietary frustration and treatment failure. The exclusivity requirement means owners must fundamentally change their cat's feeding environment, which in itself can cause stress in cats attached to specific feeding routines.