April 2021

In this VETgirl online veterinary continuing education sponsored blog sponsored by Purina® Pro Plan® Veterinary Supplements, Maryanne Murphy, DVM, PhD, DACVN, discusses the importance of maintaining healthy hydration in cats. Please note the opinions in this blog are the expressed opinion of the author, and not directly endorsed by VETgirl, LLC.

Maryanne Murphy nutrition Purina blog

Should I lead this cat to water? (And if I do, will they drink?)

It’s no secret that cats often don’t consume an adequate amount of water. Whether or not this is because they evolved from desert-dwelling wildcats, cats appear to have a lower natural inherent thirst drive. They seem to lack that neural prompt that tells them, “Hey, it’s time for you to drink!”

Unfortunately, health issues may occur if cats don’t maintain healthy hydration. A common problem is the onset of lower urinary tract diseases (LUTDs) such as urolithiasis, which is associated with inadequate water consumption and reduced urine volume; and feline idiopathic cystitis (FIC), which is believed to have a stress and environmental component. Along with poor drinking habits, potential risk factors for FIC can include obesity, anxiety, frequent diet changes, living in a confined space, living with other cats and lack of a vantage point.1,2

Cats that don’t consume adequate water have limited excess water reserves to flush out in their urine, resulting in increased urine specific gravity. While we don’t really know the optimal level of water intake for a cat, I believe it’s better for cats to have a lower urine specific gravity than many of them typically create on their own. A mantra you often hear is “dilution is the solution,” and for cats with LUTD, dilution is desirable.

De-stress the cat’s environment
With any LUTD and especially with FIC, stress reduction is important. The key to this may be viewing the home from the patient’s point of view. Questions to ask clients include:

• Does the cat have a “safe zone” in the home to which they can easily escape?

• Does the cat have climbing access to a perch from which they can survey the environment?

• Does the cat have access to sources of visual stimulation (e.g., a fish tank or a window overlooking a bird feeder) or tactile stimulation, such as a scratching post?

Multimodal environmental modification that addresses these needs is recommended as the primary method of preventing recurrence of FIC. I also tell owners that skimping on litter boxes is no place to cut corners. Owners should keep at least one litter box on every level of the home and, in multi-cat households, provide one box for each cat plus an additional box. Keeping litter boxes clean is crucial so cats won’t hold their urine or urinate in inappropriate places.

Boost fluids via food
If cats aren’t consuming enough water by drinking, there are multiple ways to sneak more moisture into their diets.

• Canned food typically contains more than 70% moisture, so offering canned food to cats as the primary diet or as a supplement to dry food can increase liquid intake.

• For finicky cats that refuse to eat wet food, it may be possible to add water to dry food. I tell owners to start with just a drop or two and then increase it, working their way up to the highest volume of water the cat will tolerate. It may not work as well as a canned diet, but we’re always going to be limited to what a cat is willing to accept.

• Feeding a therapeutic diet supplemented with sodium chloride can be a strategy for getting cats to drink more. The result can be increased urine volume.

Coax cats to drink more
While cats may not have a strong thirst drive, there are ways to tempt them to lap up more liquids. Some owners add a bit of tuna juice or clam juice to their pet’s water bowl to make the water tastier. The evidence is anecdotal rather than research-backed, but others swear by the appeal of running water—even if it’s something as simple as letting water drip from a faucet. Of course, it’s essential that water be both fresh and easily accessible.

In keeping with the “dilution is the solution” mindset, a hydration supplement is an appealing option. A hydration supplement may be palatable to cats that don’t drink enough water and may help reduce a patient’s urine specific gravity.

Treat cats as the individuals they are
One of the most important points to remember about cats and hydration is that you may have to try more than one approach. What works for one cat may very well not work for another. While canned food might be a highly effective option for a particular cat, others may refuse to consider wet food, be it minced or paté. As veterinary professionals, we have to be realistic, consider each individual patient and its home environment, and answer the question, “What can I realistically recommend to help this cat better hydrate?”

A resource I recommend for both owners and practitioners is The Ohio State University College of Veterinary Medicine’s Indoor Pet Initiative. This is a great website with ideas on how to increase overall enrichment throughout the life of a cat.

1. Lund HS, Saevik BK, Finstad OW, et al. Risk factors for idiopathic cystitis in Norwegian cats: a matched case-control study. J Feline Med Surg 2016 Jun;18(6):483–91.
2. Kim Y, Kim H, Pfeiffer D, et al. Epidemiological study of feline idiopathic cystitis in Seoul, South Korea. J Feline Med Surg 2018 Oct;20(10):913–21.

Dr. Murphy is a clinical assistant professor of nutrition at the University of Tennessee College of Veterinary Medicine.

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