Himalayan cat nutrition: PKD, hairballs and tear staining

A Himalayan is a Persian with the pointed coat pattern, and the Cat Fanciers' Association shows it as the Himalayan division of the Persian breed. It therefore shares the Persian's health profile: an inherited kidney disease, a flat face that makes eating and tear drainage harder, and a long coat that ends up in the stomach. Feeding decisions for a Himalayan follow from those three.

Polycystic kidney disease

In polycystic kidney disease (PKD), fluid-filled cysts form in the kidneys and enlarge over years, gradually replacing working tissue. When the mutation was identified in 2004, the researchers estimated that PKD affected about 38% of Persian cats worldwide. It is caused by a single change in the PKD1 gene and is dominant. There are no healthy carriers: a cat with one copy has the disease, even if it shows no signs yet. No cat with two copies has been found, which suggests that combination is lethal before birth. That 38% figure dates from before DNA testing became routine in breeding programs, so it is not a current prevalence.

A DNA test identifies affected cats long before kidney function declines, and ultrasound shows the cysts. Every Himalayan kitten's parents should have a negative PKD1 result. An untested adult can be tested at any age.

What diet can and cannot do

No diet prevents the cysts. Diet matters once the kidneys start to fail. In a randomized, double-masked trial of cats with stage 2 or 3 chronic kidney disease, cats fed a renal diet had no uremic episodes over two years, against 26% of cats fed a maintenance diet, and fewer kidney-related deaths. That renal diet was modified in protein, phosphorus, sodium and fat.

The trial involved cats that already had kidney disease. Evidence is lacking that switching a PKD-positive cat with normal blood and urine results to a renal diet delays anything, and restricting protein too early may cost muscle. The practical plan for a positive cat is regular monitoring (blood pressure, blood tests and urine tests, at intervals the vet sets) and a change to a renal diet when results show the kidneys are failing.

• Water. Wet food provides much of a cat's water in its meals. Several water bowls, or a fountain, away from the food bowl, encourage drinking.
• Signs to report. Drinking or urinating more, weight loss, a poor or fussy appetite, vomiting or bad breath can all mean declining kidney function.
• Supplements. Phosphate binders, potassium or fish oil are decisions for the stage of disease, made with the vet, not additions for a cat with normal results.

Eating with a flat face

The degree of flattening varies a lot between Himalayans, and so does the difficulty of eating. Cats with very short faces tend to push food around the bowl, drop pieces, and struggle to pick kibble up off a flat surface or out of a deep dish.

• Use a wide, shallow dish or a plate with a low rim so the face does not press against the sides.
• A slightly raised bowl can make it easier to reach food without bending the neck far down.
• Try different kibble shapes and sizes. Some flat-faced cats manage flat or almond-shaped pieces better than small round ones. Wet food in a smooth pâté texture is often easiest of all.
• Allow extra time for meals and do not take food away early.
• Noisy breathing, open-mouth breathing or struggling for breath during meals is a reason for a veterinary check.

Hairballs

Long-haired cats swallow a lot of hair while grooming, and many owners of Persian-type cats accept regular hairballs as normal. A review in the Journal of Feline Medicine and Surgery says it is unclear whether they are ever normal. In most shorthaired cats, it notes, frequent hairballs signal an underlying problem, and it names itchy skin disease, fleas and dietary intolerance as common contributors that should not be overlooked. The same review found no objective public data on how well commercial hairball-control diets work, and no studies of the other common preventive measures.

• Grooming first. Daily combing removes hair before it is swallowed. The CFA's Persian profile describes regular grooming as a serious commitment and recommends a steel or Teflon-coated comb with coarse and fine teeth.
• Hairball diets. Higher-fiber hairball formulas are a reasonable thing to try, with the understanding that their benefit has not been shown objectively.
• When to see a vet. Hairballs more than occasionally, retching without producing anything, vomiting food, constipation, loss of appetite or weight loss. A hairball can occasionally block the gut.

Tear staining

Tears normally drain from the corner of each eye through a duct into the nose. In brachycephalic cats that route is distorted. A CT and anatomical study found that the flatter the face, the more steeply the drainage duct runs, and in severe brachycephaly the duct is forced below the canine tooth and seems to drain poorly. Tears spill onto the face and stain the fur, especially on pale-coated cats.

That is a structural problem, and no evidence shows that food additives, filtered water, probiotics or avoiding particular proteins reduce it. The CFA advises cleaning the eyes with a soft, damp cloth. Staining that suddenly gets worse, thick or colored discharge, squinting, or a red or cloudy eye needs a vet.

Weight and teeth

A long coat hides both fat and weight loss, so check by hand: ribs easy to feel under a thin covering, a waist behind them, and no heavy belly pad. Weigh the cat every month. Weight loss in a PKD-positive cat is an early warning worth acting on.

The Merck Veterinary Manual gives resting energy requirement as 70 × (body weight in kg) raised to the power 0.75. A neutered adult cat needs about 1.2 times that, an intact adult about 1.4 times, and an obesity-prone cat about 1.0 times. For a Himalayan of 3 to 5 kg, that is roughly 190 to 280 kcal a day if neutered, 220 to 330 if intact, and 160 to 230 if it gains weight easily. Short play sessions with a wand toy add activity for a cat that would otherwise mostly rest.

In the same CT study, the more brachycephalic cats had upper canine teeth rotated to an almost horizontal position. Crowded, misaligned teeth trap plaque more easily. Tooth brushing, if the cat accepts it, and regular dental checks are the useful steps. Bad breath, drooling, pawing at the mouth or dropping food needs a dental exam.

Sources

1. Persian breed profile and standard. The Cat Fanciers' Association.
2. Feline polycystic kidney disease mutation identified in PKD1. Journal of the American Society of Nephrology, 2004.
3. Clinical evaluation of dietary modification for treatment of spontaneous chronic kidney disease in cats. Journal of the American Veterinary Medical Association, 2006.
4. Hair balls in cats: a normal nuisance or a sign that something is wrong? Journal of Feline Medicine and Surgery, 2013.
5. Brachycephalic feline noses: CT and anatomical study of the relationship between head conformation and the nasolacrimal drainage system. Journal of Feline Medicine and Surgery, 2009.
6. Nutritional requirements of small animals. Merck Veterinary Manual.