Urinary tract disease is a common issue in the feline patient. Problems such as urinating outside of the litter box, pain and straining during urination, blood in the urine and increased frequency of urination can all be indicators of urinary tract disease. These symptoms can occur in both male and female cats of any age, however male cats are at an increased risk of urethral blockage, which is a life threatening emergency.
Urethral blockage occurs when there is an obstruction to the outflow of urine from the bladder. Males are more at risk of urethral obstruction than females, because their urethra is much longer and more narrow than females. The most common cause of urethral blockage is the formation of a urethral plug which is composed of crystals that have formed in the urine. Prevention of urethral blockage hinges on prevention of formation of these crystals.
Risk factors for formation of crystals include feeding an exclusively dry food diet, feeding a diet that does not help to control urine acidity (pH), feeding a diet that does not help to control the mineral concentration (relative super saturation or RSS), and dehydration. Risk factors for the occurrence of a urethral blockage include obesity, stress, inadequate number of litter boxes or unclean litter boxes, and being a male cat under 7 years of age.
Due to pet food industry requirements, most commercial pet foods only measure ash content. Ash is the inorganic mineral content of the food, and includes any combination of magnesium, potassium, calcium, phosphorus, sodium, silicon, sulfur and other trace minerals. “Low ash” cat foods are misleading for cat owners as they create a false perception that these foods will help prevent urinary tract disease and urine crystal formation. The ash content in the diet has no correlation with the RSS value of the urine, and is therefore irrelevant with regards to urinary tract health.
Through scientific research and proven feeding trials, we know that it is the RSS factor and the urine pH that are the most important factors that determine the formation of urine crystals within the bladder. Ask your veterinarian about which diets have been formulated to control these important properties and prevent the formation of urine crystals. This may save you and your cat a trip to your local emergency hospital. An ounce of prevention is worth a pound of cure!
Written by Tiffany Lennox, DVM
