Maine Coon nutrition: calories, hip dysplasia and the heart

Feeding a Maine Coon well mostly means keeping a big cat lean. In 20 years of hip screening records from more than 5,000 cats, hip dysplasia affected more than a third of cats and grew more severe with body mass, and the breed is also predisposed to hypertrophic cardiomyopathy. A large frame raises calorie needs less than most owners expect, so portions scaled up from a small cat's tend to overshoot.

Size and slow growth

The Cat Fanciers' Association (CFA) says it is not unusual for males to reach or exceed 20 lb (9 kg), with females usually smaller, and describes a slow-maturing breed that can take up to three years to reach full growth. The same breed standard states that quality should never be sacrificed for size.

Growth is where overfeeding does its quietest damage. Kittens need about 2.5 times their resting energy requirement, and a Maine Coon kitten is heavier than most, but the aim is steady growth with a visible waist rather than the biggest possible cat. There is no good evidence on exactly when a Maine Coon should move from a growth food to an adult one. A food labeled complete for growth suits the first year; after that, the choice matters less than the portion, which should follow body condition and the scale rather than age.

How many calories a large cat needs

The Merck Veterinary Manual estimates a cat's resting energy requirement (RER) as 70 × body weight in kg to the power 0.75. Because of that exponent, energy needs rise more slowly than weight: an 8 kg cat needs roughly 1.7 times the calories of a 4 kg cat, not twice as many. Merck's multipliers are 1.2 × RER for a neutered adult, 1.4 for an intact adult and 1.0 for a cat that gains weight easily.

Use the cat's ideal weight, not its current one, and treat the figures as a starting point. Merck gives the minimum protein for adult cat food as 26% of dry matter. There is no evidence that a large breed needs a higher protein percentage than other cats; a bigger cat simply eats more of the same complete food.

Hip dysplasia and body weight

Hip dysplasia is usually discussed in dogs, but it is relatively common in Maine Coons. A study of 20 years of screening radiographs from 5,038 pedigree Maine Coons found hip dysplasia in 37.4%, with no difference between the sexes. Severity increased with age and with body mass, and was moderately heritable. Where breeders selected against it, the next generations had milder hips and were slightly smaller cats. The authors cautioned against breed standards that encourage very large bodies.

For an individual cat, the practical lever is weight. A lean cat puts less load on a dysplastic hip. Cats rarely limp from chronic joint pain; they jump less, use lower perches, groom their back end less or start missing the litter box. Those changes are worth a vet visit, and X-rays confirm the diagnosis.

On supplements, a 2022 systematic review and meta-analysis of arthritis treatments in dogs and cats found clear pain relief from omega-3-enriched diets and omega-3 supplements, and a marked lack of effect for glucosamine and chondroitin. For a Maine Coon with arthritis, that makes an omega-3-enriched food or fish oil, agreed with the vet, a better bet than a glucosamine product, alongside proper pain medication where needed.

Heart health

Hypertrophic cardiomyopathy (HCM), a thickening of the heart muscle, is the most common heart disease in cats, and the Cornell Feline Health Center lists the Maine Coon among breeds in which it is more prevalent. In Maine Coons it is associated with the A31P variant of the MYBPC3 gene. A 2024 study found moderate to severe HCM in cats carrying two copies, lower penetrance with one copy, and no disease in cats under a year old, with cases concentrated in older cats. The DNA test looks only for this variant, and the CFA lists echocardiograms alongside saliva DNA tests when screening breeding cats.

No diet is known to prevent HCM. Taurine deficiency causes a different heart disease, dilated cardiomyopathy, and Merck notes that cats must get taurine from food; complete commercial cat foods include it, while raw or home-prepared diets need a formulated recipe. Cornell lists the signs of HCM as rapid or labored breathing, open-mouth breathing and lethargy, and, if a clot forms, sudden pain or paralysis in the hind legs. Those are emergencies. For a Maine Coon, ask the vet about a heart check if a murmur or gallop sound is heard at a routine visit.

Kidneys

Polycystic kidney disease is often mentioned for Maine Coons, but the evidence points elsewhere. In ultrasound screening of 187 healthy Maine Coons, renal cysts were found in only 7, mostly single and small, and the cats tested did not carry the PKD1 mutation seen in Persians. The authors concluded that cystic kidney disease is uncommon in the breed and unrelated to Persian PKD. More notably, ultrasound changes compatible with chronic kidney disease were seen in 10 cats (5.3%), and such findings were not uncommon in young Maine Coons.

That is a reason for routine blood and urine tests to include kidney values, especially in older cats, and for making water easy to get. Wet food, several water bowls and a fountain all help a cat drink more. Kidney diets are a treatment for diagnosed disease and should be started by the vet.

Everyday feeding

• Feed measured meals, weighed on a kitchen scale, rather than leaving dry food out.
• Check condition by hand every few weeks. The long coat hides fat, so feel for the ribs and the waist rather than judging by eye.
• Use wide, shallow bowls; a large cat's whiskers touch the sides of small ones.
• Count treats in the daily total, and weigh the cat monthly so a slow gain is caught early.

Sources

1. Maine Coon cat. The Cat Fanciers' Association.
2. Nutritional requirements of small animals. Merck Veterinary Manual.
3. Demography, heritability and genetic correlation of feline hip dysplasia and response to selection in a health screening programme. Scientific Reports, 2019.
4. A 2022 systematic review and meta-analysis of enriched therapeutic diets and nutraceuticals in canine and feline osteoarthritis. International Journal of Molecular Sciences, 2022.
5. Hypertrophic cardiomyopathy. Cornell Feline Health Center, Cornell University College of Veterinary Medicine.
6. Influence of clinical aspects and genetic factors on feline HCM severity and development. Veterinary Sciences, 2024.
7. Maine Coon renal screening: ultrasonographical characterisation and preliminary genetic analysis for common genes in cats with renal cysts. Journal of Feline Medicine and Surgery, 2013.