Why Pets Need Vitamin A (and How Much)
📝 Summary
Vitamin A supports vision, skin, reproduction, bones, and immunity in cats and dogs. Dogs can convert beta-carotene; cats cannot and must get it from animal sources like liver and fish oil.
1 The Essential Vitamin A for Pets
Today we discuss the vitamin A that cats and dogs cannot lack.
Vitamin A’s nutrition acts on epithelial tissue, vision, reproduction, and nerve function. These are maintained by retinol and retinal in the diet, which convert into each other in the body.
Roles of vitamin A:
① Vision
Maintains low-light vision; vitamin A is the light-sensing substance in visual cells — rhodopsin.
② Epithelial tissue
Keeps epithelium healthy; tied to mucus-secreting glycoprotein synthesis. Deficiency dries and over-keratinizes tissue, inviting infection.
③ Reproduction
Takes part in sex-hormone formation, maintaining fertility.
④ Bones
Linked to osteoblast activity, keeping bones developing normally.
⑤ Immunity
Many deficiencies relate to weakened immunity or slow responses to antigens.
So how much vitamin A do our pets need daily?
Dogs’ requirement
Growing puppies: 303 RE/1000 kcal recommended; no guaranteed value set for adults.
That diet concentration equals 40 RE·(kg BW^0.75·d) for adult maintenance, 80 RE·(kg BW^0.75·d) for growth.
No public data on pregnant/nursing dogs; same concentration as growing puppies (303 RE/1000 kcal) is recommended.
Cats’ requirement
NRC (1986) suggests 1 mg/kg (5 kcal/g) retinol, or 200 μg/1000 kcal, for growing cats.
For pregnancy and lactation, 400 μg/1000 kcal. At 200 μg/1000 kcal, a maintained adult cat takes 20 μg/kg BW^0.67 — twice the growing cat’s need on the same basis.
Data show liver vitamin A rises with age in cats on commercial food. Even when supplementing, without knowing liver levels, stay cautious and don’t far exceed the RA.
Where to get vitamin A?
Meat / plant sources
Meat is a good source; plants have none, but have beta-carotene. Dogs convert it to vitamin A; cats lack this and must get it from food.
Animal sources
Cod liver oil, liver, milk, egg yolk, fish meal are rich in vitamin A.
Plant sources
Leafy greens, red/yellow sweet potato, pumpkin, yellow corn, and most of all carrots.
Want to learn more about pet health?
Explore our pet health channel for more science-based care guides
Read More Articles →