Ragdoll cat nutrition: weight, urinary stones and HCM

Ragdolls are large, slow-maturing cats, and most feeding decisions for the breed come back to three things: portion size for a big but moderately active cat, water intake for the urinary tract, and awareness of an inherited heart disease that food cannot prevent. According to the Cat Fanciers' Association, Ragdolls reach full coat color at two years and full size and weight at four, and mature males can reach or exceed 20 lb (9 kg), with females usually smaller.

Calories for a large, slow-growing cat

The Merck Veterinary Manual gives a standard way to estimate daily energy. Resting energy requirement (RER), in kcal per day, is 70 multiplied by body weight in kilograms raised to the power 0.75. For adult cats, multiply by 1.2 if neutered, 1.4 if intact, or 1.0 for a cat prone to weight gain. Kittens need about 2.5 times RER. These are starting points, and an individual cat may need 30% more or less.

Figures are kcal per day, rounded to the nearest 5. Because a Ragdoll keeps growing into its fourth year, the right weight for a two-year-old may be lower than for the same cat at four. Feed a complete kitten food in measured meals during the first year, then an adult food, and adjust by body condition rather than trying to speed growth.

Weight management

The CFA describes Ragdolls as moderately active: they appreciate play sessions but do not insist on them. A large cat that eats freely and plays only when invited is well placed to gain weight. Scale weight alone is a poor guide in a breed where a healthy male may weigh far more than a healthy female, so body condition matters more. Ribs should be easy to feel under a thin covering, with a waist visible from above. The silky coat hides a surprising amount, so check with the hands.

• Measure the food. Weigh dry food on a kitchen scale rather than using a scoop, and divide the day's portion into two or more meals.
• Count treats. They come out of the daily calorie total, not on top of it.
• Make food take effort. Puzzle feeders and short play sessions before meals add activity for a cat that will not seek it out.
• Weigh monthly. A baby scale works, or weigh yourself holding the cat and subtract. Record the result so a slow trend shows up.

Extra weight matters for the bladder as well. Cornell lists being overweight and getting little exercise among the features of cats most often affected by lower urinary tract signs, which makes weight control part of urinary care as well.

Heart health and HCM

Hypertrophic cardiomyopathy (HCM) thickens the walls of the heart's main pumping chamber so that it relaxes and fills poorly. The Cornell Feline Health Center names the Ragdoll among the breeds in which HCM is more common. Many affected cats look healthy. Others develop fast or labored breathing, open-mouthed breathing or lethargy as fluid builds up in or around the lungs, and some form blood clots that most often block blood flow to the hind legs, causing sudden pain or paralysis.

In Ragdolls, HCM is linked to the R820W variant in the MYBPC3 gene. Among 2,018 Ragdolls tested by a laboratory serving the British Isles, 27% carried the variant, almost all with one copy. Having two copies matters most. In a survey of genotyped Ragdolls, cats with two copies had a median survival of about 5.7 years and were more likely to die of heart disease, while median survival for cats with one copy or none was over 15 years. Cornell cautions that not every cat carrying a mutation develops HCM, so a result is a reason for monitoring, not a diagnosis.

HCM is diagnosed by echocardiography, after high blood pressure and an overactive thyroid have been ruled out. A Ragdoll that tests positive, or has a heart murmur or abnormal rhythm, should have its heart scanned and followed up on the schedule a vet sets.

No diet or supplement is known to prevent or reverse HCM. Taurine is a different story: its deficiency causes a separate heart disease, dilated cardiomyopathy, and complete and balanced commercial cat foods include it, so a Ragdoll on such a food does not need extra. Fish oil, L-carnitine and coenzyme Q10 are sometimes suggested for cats with HCM, but there is no good evidence that they change its course, and any addition should be agreed with the vet managing the cat. A cat with heart failure may be prescribed a diet with restricted sodium.

Urinary health

Lower urinary tract problems are a common reason for cats to see a vet, and the main causes are idiopathic cystitis (painful bladder inflammation without a clear cause), urinary stones and urethral blockage. Ragdolls have specific risk for stones. In a large North American case-control study, Ragdolls had an increased risk of both calcium oxalate and struvite uroliths. Because the two stone types form under different urine conditions, the right diet depends on which stone a cat actually has, and a stone should be analyzed before a long-term diet is chosen.

Signs of a urinary problem, according to the Cornell Feline Health Center:

• Straining or discomfort when urinating, or crying out
• Frequent trips to the litter box
• Blood in the urine
• Urinating outside the box
• Frequent licking of the genital area

A cat that strains but passes little or no urine may be blocked. That is an emergency. Male cats may be at higher risk.

Cornell's steps for reducing urinary problems include small, frequent meals, weight control, fresh water at all times, one more litter box than the number of cats, boxes kept clean and in quiet places, and as few major changes in routine as possible. It also warns against adding urinary acidifiers to diets that already acidify urine. Wet food raises water intake from meals, and many owners use several water bowls or a fountain placed away from food and litter. For a cat that has had stones or cystitis, the vet will usually recommend a specific diet.

Coat and hairballs

The CFA notes that the Ragdoll coat is mostly guard hair without a significant undercoat, which means less matting and shedding than in many longhaired breeds, though shedding still increases with the seasons. Combing once or twice a week with a steel comb removes loose hair before the cat swallows it. A cat that vomits hairballs often, retches without producing anything, or stops eating should see a vet, because frequent hairballs can sometimes point to a digestive problem.

Sources

1. Ragdoll. Cat Fanciers' Association.
2. Nutritional requirements of small animals. Merck Veterinary Manual.
3. Hypertrophic cardiomyopathy. Cornell Feline Health Center, Cornell University College of Veterinary Medicine.
4. Prevalence and demographics of the MYBPC3-mutations in ragdolls and Maine coons in the British Isles. Journal of Small Animal Practice, 2014.
5. Association of the myosin binding protein C3 mutation (MYBPC3 R820W) with cardiac death in a survey of 236 Ragdoll cats. Journal of Veterinary Cardiology, 2014.
6. Association between patient-related factors and risk of calcium oxalate and magnesium ammonium phosphate urolithiasis in cats. Journal of the American Veterinary Medical Association, 2000.
7. Feline lower urinary tract disease. Cornell Feline Health Center, Cornell University College of Veterinary Medicine.