Hypervitaminosis A is a serious and irreversible bone disease caused by chronic excess vitamin A in cat diets, most commonly from feeding excessive amounts of liver.
Hypervitaminosis A causes progressive, painful bone disease that significantly impairs cats' quality of life and their ability to perform normal behaviours including self-grooming. The neck stiffness and pain are chronic and irreversible once established. Because the condition develops over months of dietary excess, cats may be significantly affected before owners notice the progressive postural change and reluctance to move. Prevention is straightforward — limiting liver to a small proportion of the total diet — but many owners feeding raw diets are unaware of the risk. Veterinary nutritional guidance is essential for owners choosing to feed raw diets to ensure appropriate balance of all nutrients including vitamins A and D.