ARE URINARY CALCULI FREQUENT IN CATS? HOW DOES THE URINARY pH VARY?

Here are the up-to-date interesting elements concerning the “ Feline Urologic Syndrom ” that were presented in the last Mondial Veterinary Congress (Sept. 24/26 1999 in Lyon).

Incidence of low urinary tract disease in cats

According to data available in the USA, only 1,5 % cats are presented to a veterinarian because of urinary disorders: painful urination, blood seen in urine… It is understood that the occurence of this disease is even lower, if related to the total feline population.

In 63 % of cats showing signs of lower urinary tract disease, no calculi are found, neither infection, tumors or anatomical defect… Then an “ idiopathic disease ” is diagnosed, that means that the cause is unknown!
Actually, there is probably a nervous origin to this problem: as any stress factor during the cat’s meal is an additional risk factor.
Ex: the cat eats in a room that is available to a dog at any time, the plate is put closed to a dishwashing-machine likely to be noisy…

Only 7 % of cases are attributed to struvite calculi, and 6 % to oxalate calculi.

Study about the variations of the urinary pH in cats

Despite a finally very low incidence of urinary calculi, their prevention stays an actual preoccupation. This can be done only if the variations of urine acidity (measured through pH evolution) are under control.
The influence of the food composition on urinary pH is rather well-known. But so far, we were missing data concerning the influence of the nature of the food (dry or canned), and the feeding rythm.

For this purpose, Royal Canin then initiated a study that was conducted in Nantes National Veterinary School. The results were presented during the Congress.

During the study, 8 spayed cats were successively fed with:

• a dry food (D), fed all day long during 24 h (90 g/day)
• a canned food (C), fed all day long during 24 h (350 g/day)
• a dry food (D), fed only during one hour per day
• a canned food (C), fed only during one hour per day.

After a period of adaptation, urine was sampled in each case during 2 weeks. The urinary pH evolution was analyzed at 3, 6, and 9 hours (T3, T6, T9) after distribution or renewal of the food.

This study clearly shows that:

• a 1 hour restricted time-feeding induces an important rise of the urinary pH in the post-feeding period. This alcalinization is associated with an increased risk of formation of struvite calculi.
• Consumption of a canned food induces a higher urinary pH than a dry food, even if they are both fed according a 24 hours schedule feeding.

The best way to prevent the urinary pH to reach a too high level after food consumption, is to let the cat free to eat a well-formulated dry food all day long.

The distribution can be done only once a day if the cat properly regulates its own consumption. If it has a tendency to wolf down all too quickly, the daily ration will be preferably given in several small quantities spread over the day.

Donated by the Borg Cardona and Co. Ltd. visit Borg Cardona website