There is a saying in medicine: if the gut works, use it. Obviously this is
particularly true of maintaining hydration, where it is a lot easier and
less stressful for everyone if a cat takes in sufficient fluids orally and
thus avoids the need for more proactive fluid management such as
intravenous or
subcutaneous fluids. This is also the most natural way for cats to take in fluids.
When we talk about oral fluid intake, we are not only referring to
drinking. Cats obtain quite a lot of their fluid needs from the food they eat. Canned food contains about 80% water,
so it is a good choice for a CKD cat.
Oral Fluid
Requirements
In order to maintain
hydration, a cat generally needs around 24-30ml of water per pound
bodyweight per day (though this amount will be affected by activity levels
and climate). This means that a 10lb (4.5kg) cat would require 240-300ml
of water a day (a cat in congestive heart failure may need less).
Daily water requirements and needs for cats
(2011) Peterson ME Animal Endocrine Clinic Blog says "A normal cat’s daily water requirement
ranges from 5 to 10 fluid ounces per day (or an average of 60 ml/kg/day)."
The water requirements and drinking habits of cats
(2018) Fritz J & Handl S Veterinary Focus 28(3)
states that cats need about 50ml/kg per day, or 200-250ml a day for a
4-5kg cat.
The cat does not need to obtain this by drinking alone.
If you are feeding canned food, which contains a lot of water, that will
make a sizeable contribution to total intake.
Unfortunately, in older cats generally there can be a reduced thirst
response, as mentioned in
Senior cat care: special considerations for cats (2008). This may be
the case even though CKD cats tend to need more fluids because they lose
fluids through the
increased urination caused by CKD.
Never restrict a CKD cat's access to water (unless your vet has advised
you to do so for a brief period prior to surgery).
Fluid Choices
Some people give their cat bottled water.
The taste of chlorine in normal tap water doesn't taste too good to cats,
so this is worth considering but not essential.
Some people like to use distilled water, though I can't say I'm a fan. Some types of distilled
water have a low pH level, and the extra acidity in these products is not
appropriate for CKD cats, who tend towards acidity anyway. Distilled water
may also cause potassium imbalances.
My cats' favourite water is rain water. Normally though we give them filtered water, at room temperature, and
when we were using a bowl, we changed it
several times a day (such frequent changes are not necessary
with water fountains).
I would not recommend syringing the bags of fluid used for sub-Qs into
your cat's mouth. Your cat is unlikely to accept these fluids orally
because they taste salty and apparently rather oily. It is also far more
expensive than giving ordinary water.
You should never try to inject ordinary water into your cat if you are
giving sub-Qs because it is
not the correct composition for injection; you should only use fluids
approved for this purpose and prescribed by your vet.
Tips on
Increasing Oral Fluid Intake
Cats generally are not known for drinking a lot, a legacy of their desert
heritage. Therefore the more you can do to encourage them to increase their oral
fluid intake, the better.
Cats in the wild do not eat and drink in the same place. Therefore it is
better not to put the water bowl next to the food bowl. Some cats don't
like a narrow bowl where their whiskers touch the side, so experiment, and
also consider using a
water fountain.
Some people find placing ice cubes made from low sodium
tuna water in their cat's water bowl encourages their cat to drink more.
You may also wish to give your cat homemade
chicken broth to drink.
With a CKD cat, it makes a lot of sense to have more than one water
source. We used to just have one bowl of water out but once Thomas was
diagnosed we switched to three, including one placed upstairs so Thomas
didn't have to go too far for a drink in the night.
You can also add water to your cat's food. One teaspoon of water is 5 ml,
so if you can add 10 tsp a day to your cat's food, you are increasing
fluid intake nicely. However, you do not want to overdo it, because if
your cat takes in a lot of water, s/he could end up feeling quite full so
calorie and nutrient intake reduce. Therefore aim to start slowly and make sure your
cat still eats sufficient food.
If your cat is in mid-stage CKD and needs help with hydration but your vet refuses to allow you to give
sub-Qs, you could consider syringing water into your cat's mouth instead.
Discuss this possibility with your vet. You have to be careful because cats can
only swallow a tiny amount at a time, and you should always syringe from
the side of the mouth, never from the front - see
syringe feeding for more information. Some people also use a water
dropper. Don't give too much because if
you do, your cat may feel full and then not eat enough.
Effects of feeding frequency on water intake in cats
(2005) Kirschvink N, Lhoest E., Leemans J. Delvaux F, Istasse L, Gustin P,
Diez M Journal of Veterinary Internal Medicine 19 p476 found
that cats fed more frequently increased their fluid intake. Frequent
feeding can also help with
excess stomach acid.
Hill's explains why cats may prefer running water and gives tips on
increasing your cat's water intake.
PetCoach has some tips on how to get
your cat to drink more.
About Cats Online has tips on how to get your cat to drink.
Water Fountains
Many people find water fountains increase their cat's
water intake.
Effect of water source on intake and urine
concentration in healthy cats
(2010) Grant DC Journal of Feline Medicine and Surgery 12(6)
pp431-4 found that cats drank a bit more from a water fountain but there
was not a massive difference. This was a short study though.
Quantified water intake in laboratory cats from
still, free-falling and circulating water bowls, and its effects on
selected urinary parameters (2019)
Robbins MT, Cline MG, Bartges JW, Felty E, Saker KE, Bastian R & Witzel AL
Journal of Feline Medicine and Surgery 21(8) pp682-690 found
that water intake did not differ significantly between the three methods,
but three of the cats in the study (of fourteen cats) had a significant
preference (one for still water, one for circulating and one for
free-falling).
The water requirements and drinking habits of cats
(2018) Fritz J & Handl S Veterinary Focus 28(3)
states that cats need about 50ml/kg per day, or 200-250ml a day for a
4-5kg cat found that many cats seemed to prefer bowls, but concludes that
offering cats a variety of drinking options may be helpful.
I found my cats needed time to get used to the fountain, but that they do
like it and my personal scientific studies indicate that if you are a cat
who lives with me, you do drink more if you have a free-falling water fountain. In fact, when the water fountain is in the
dishwasher, we get indignant complaints until it is returned to its
rightful place.
My cats have used the Fresh Flow
brand for more than fifteen years and they love it (see photo left; I have no
idea why Karma clambered over the tapestry frame rather than approaching
it from the front or left, but hey, she's a cat and she has her reasons). Some
people find the Catit easier to clean. Any of them should be fine for most
cats.
When you first get a fountain, leave it out without
water in for a few days to allow your cats to get used to it. Then add
water, but don't turn it on. Once your cats are drinking from it, turn it
on. Be sure to leave other water sources available until you know your
cats are willing to use the fountain.
Instructables
tells you how to build your own water fountain.
Sixerdoodle Electronics has instructions
on using a sensor to turn a tap on when your cat approaches it:
There are several brands of water fountain available:
Water
Fountains Sources
USA
Amazon sells the Pioneer stainless steel
model for US$53.99.
Glacier Point sells a variety of ceramic
fountains.
UK
Pet Planet
sells a variety of water fountains.
Amazon UK
sells a variety of water fountains.
Canada
Real Canadian Superstore sells the Petmate Freshflow
Water Fountain in Western Canada for CAN$29.98.
Dino Direct sells freestanding water
bottle holders, similar to the water supplies designed for hamsters etc.
Some cats like this sort of fountain.
Oral
Products for Rehydration
Normally a cat relying on oral fluid intake simply needs water. However,
if a cat is clinically dehydrated, perhaps from vomiting or diarrhoea,
s/he needs electrolytes
(body salts) in addition to water. In such cases your vet may recommend oral rehydration sachets.
My vet gave me some of these for use when my cat was recovering from
dental surgery.
Some of these products contain additional zinc, so do not use without your
vet's approval.