FROM THE WILD DESERT TO YOUR COUCH: CATS HAVE RETAINED THE ABILITY TO CONSERVE WATER
That little furball curled up and purring contentedly on your couch traces his origins back to wild ancestors who were among the first carnivores that evolved over 35 million years ago. The African wild cat (Felis sylvestris lybica, abbreviated as F. lybica), also called Near Eastern wild cat, is generally accepted as the ancestor of most of today’s domestic cats.
Felis sylvestris lybica lived in Northern Africa, the Near East and around the periphery of the Arabian Peninsula. Their descendants still roam the deserts of Israel, Saudi Arabia and other countries in the Middle East today. Living in a desert environment where water sources are few, the body physiology of these wild cats have adapted to the demands of their environment. They have developed kidneys that are very efficient in conserving water and they are able to obtain most of the water they need from the food that they eat. They did not need a lot of water to survive. African wild cats are hunters with their main prey being rodents. Their natural diet also consisted of hares, rabbits, insects, birds, fish, and occasionally poultry and small livestock. The fresh meat of these animals is made of around 75% water and this is where wild cats get most of their water requirement from.
From their origins in the desert, our domestic feline companions have retained some of the physiology characteristics of their ancestors. Their kidneys still concentrate urine to conserve body water. Today’s cats still have a low thirst drive making them bad drinkers even when there is ample water in their bowls and their bodies are still adapted to getting most of the water they need from their food.
COMMERCIAL CAT FOOD: WET VERSUS DRY
These characteristics inherited by our cats should pose no problem at all if they were allowed to go out and hunt for their natural food. But majority of cats being kept as pets today live purely indoors for safety reasons and are being fed with commercial food. In recent years, the growth of the pet food industry has skyrocketed and we have seen a deluge of commercial cat food, both wet canned and dry, in the market. Wet canned food is approximately 78% water and is closer in approximating fresh meat in terms of amounts of protein and water content. Dry food is at most only 10% water while having more carbohydrates than protein.
Because of this very low water content of dry cat food, it has been called as “unnatural” but its use has become widely popular among pet owners because of its inherent advantages: (1) they can be kept longer after the pack is opened as long as they are placed in airtight containers, (2) they are easy and not messy to feed, (3) there is minimal waste, (4) they can be left longer in the bowl so the cat can have access to food even when the owner is away during the day, an advantage for busy cat parents, and (5) they are cheaper than canned wet food for pet parents on a tight budget.
Many believe that dry food of superior quality, grain-free and having a specific meat in the ingredient, not just animal by-products, is not really bad for cats but they would need to drink more water to make up for the very low water content of these dry food. Therefore cats on dry food should have access to fresh water at all times and drink a sufficient amount of it. But even cats who are on a canned wet food diet need and can greatly benefit from drinking extra water.
THE DIFFICULTY OF GETTING CATS TO DRINK WATER
Water makes up about 80% of a cat’s body. It is essential for good health and vital to almost all body processes that maintain life. Cats need to drink more water, especially those who are on a dry food diet. Just keep kitty’s water bowl filled with water at all times and he will drink from it. Sounds fairly simple, right? But in reality pet parents know that if a cat doesn’t drink water then it is more complicated than that.
As mentioned earlier, our domestic cats today have inherited the low thirst drive of their desert-dwelling ancestors so they are by nature not inclined to drink much water even when it is available. A compounding factor is the cat’s instinctive dislike for stagnant water making a still water bowl not good enough to provide for their daily water requirement.
A number of theories have been proposed as to why this is so. Foremost factor is the evolutionary process. In the wild, the moving water of rivers is generally less polluted than the stagnant water of ponds and puddles. Therefore, cats that instinctively preferred to drink only from running water got sick less and had better odds at surviving and passing on their genes.
Cats have also learned that running water is fresher, cooler and taste better than standing water. Cats, being predators, have more superior peripheral than forward vision so they can detect movement better. Cats cannot see still water very well so they will have difficulty determining the water level and be hesitant to drink from still water sources.
PROBLEMS THAT ARISE WHEN A CAT DOESN’T DRINK WATER
When your cat does not care for the water in his bowl, it is difficult to force it to drink from it. This will result to your cat having long-term low-level dehydration especially when he is on dry food. Dehydration, a condition wherein there is a harmful reduction in the amount of water in the body, increases the risk for developing a host of problems primarily related to the urinary system and affecting other body systems as well.
The urinary system is composed of the kidneys, ureters, urinary bladder and urethra. The kidneys filter waste products and toxins from the blood; they regulate the volume of body fluids; and they control the blood levels of certain chemicals and hormones. The other organs, collectively called the “lower urinary tract”, act as the passageway for urine carrying the body’s waste products to be excreted from the body. According to Dr. Lisa Pierson, a veterinarian and expert on feline health and nutrition, “Water flowing through the urinary tract system is the most important factor in keeping it healthy.”
The following is a simplified picture of what happens in the cat’s body, particularly the urinary system, when there is persistent low water intake and dehydration:
Urine Becomes More Concentrated
When the body senses that the amount of water in the bloodstream is lacking, it compensates for this by reabsorbing water from the urine resulting to a urine that has increased specific gravity. This means that because water was reabsorbed, the urine becomes more concentrated. The risk for the formation and growth of urinary crystals and stones is increased with concentrated urine.
Elevation of the BUN and Kidney Damage
BUN stands for Blood Urea Nitrogen. Urea is a chemical waste product from the breakdown of protein in the body. Normally urea is brought to the kidneys via the bloodstream. The kidney filters the urea and other waste products from the blood and the waste leaves the body through the urine.
If the cat is dehydrated, the blood volume will decrease and the blood will become thicker resulting to slower blood flow from the organs back to the heart. When this happens, the amount of blood that the heart can pump per minute is reduced and this affects the efficiency of the heart in sending blood to the other organs of the body. This results to lowered blood flow to the kidneys, thus blood is not filtered effectively resulting to an increase in the amount of urea waste products remaining in the blood, hence elevation of the BUN.
Persistently increased levels of BUN can make the cat feel tired and sluggish. It can also result to vomiting and ulcers on the lining of the stomach and gums. Accumulated toxins in the blood and low blood flow can damage the organs including the kidneys. When kidney function declines they become unable to properly filter the toxic substances in the blood hence increasing the BUN even more. When waste products remain in the blood, it recirculates back to the different organs where it may cause organ damage that can be lethal to the cat.
Increased Risk of Formation and Growth of Urinary Crystals and Stones
According to Dr. Richard Goldstein, a veterinarian at the Animal Medical Center in New York, USA and former faculty member of the College of Veterinary Medicine at Cornell University, it was observed that crystal and stone formation tends to occur in domesticated cats who don’t take enough fluids and don’t urinate enough. Urine is made up of water with suspended minerals, cells, proteins and other debris. If cats are not getting adequate amounts of water and are chronically dehydrated, they produce urine that is more highly concentrated in these minerals particularly either struvites or calcium oxalate. When a concentration threshold is reached, the minerals precipitate out as microscopic crystals. Later these crystals combine to form sand like material which may accumulate more minerals on their surface to form uroliths or urinary stones.
In a study published in Veterinary Clinics of North America: Small Animal Practice, an examination of obstructed cats found that 60.4% presented with urethral plug made of crystals, proteins and other debris in the urine, and 11.3% with uroliths. Also, recently, at the 2016 World Small Animal Veterinary Association Congress, a study showed the prevalence of urolithiasis has undergone considerable change over the last 20 years and is associated with the use of commercial dry diets with its very low water content.
Urinary crystals are sand-like and they irritate the bladder causing inflammation. They may plug the urethra (the tube that carries urine from the bladder, through the penis, to the outside of the body) causing an obstruction to the flow of urine. This condition presents a bigger problem in male cats whose urethra are narrower than the female’s.
Urinary stones also irritate the wall of the bladder and block the passageway of urine flow from the bladder to the urethra. Urine becomes trapped in the bladder and backs up into the kidneys resulting to scarring and kidney damage. When kidney function is impaired, this leads to increased BUN and Creatinine (another waste product from the muscles) together with the associated clinical signs mentioned earlier. When the obstruction to urination goes unchecked, it could ultimately become life threatening and many cats die from this.
Feline Lower Urinary Tract Disease (FLUTD) and Cystitis
FLUTD is a term used to describe a group of disorders that affect the lower urinary tract (bladder or urethra) in cats due to various predisposing factors. According to claims data published by the Veterinary Pet Insurance Company in Veterinary Economics, FLUTD is the most common reason owners took their cat to the veterinary office.
In the article “Epidemiologic Study of the Risk Factors for Lower Urinary Tract Disease in Cats” published in the Journal of the American Veterinary Medical Association, uroliths account for 15-23% of FLUTD cases and bacterial urinary tract infections up to 22%. Other factors predisposing cats to FLUTD are stress, decreased moisture content of food and not consuming enough water to flush out and clean the urinary bladder.
The most common disorder under the FLUTD group is Cystitis which is the inflammation of the urinary bladder. Stress is a significant risk factor in the development of cystitis but according to Walker, et.al. in a study titled “Epidemiological Survey of Feline Urological Syndrome” published in the Journal of Small Animal Practice, the risk is increased with decreased moisture content of food and decreased water intake. The concentrated urine irritates the lining of the bladder wall predisposing the cat to cystitis. An inflammed urinary bladder makes it difficult and painful for a cat to urinate. Urine retained in the bladder backs up to the kidneys and cause damage.
Other Problems Caused By Chronic Low Water Intake and Dehydration
Aside from causing problems in the urinary system, not drinking enough water can also cause a chronic imbalance of water and electrolytes in the body which is detrimental in the long term. A lack of water also affects negatively blood circulation and compromises the effective delivery of oxygen and other nutrients to the different organs and the collection of waste products. Chronic dehydration affects digestion too. When the body senses that it lacks water, the large intestines reabsorb most of the water from food resulting to chronic constipation.
CATS NEED TO DRINK MORE WATER
The importance of water to the overall well-being of your cat cannot be overemphasized. It is needed in almost all body processes essential to life. Increasing water intake results in dilution of urine which is beneficial for the prevention diseases of the kidneys and the lower urinary tract. It helps reduce the risk for the formation of crystals in the urine, urethral plugs and urinary stones. Stress reduction is key in the prevention of FLUTD and cystitis but increasing water intake is also vital. Water makes the urine more dilute and it increases the frequency of urination which is nature’s way of “flushing” of cleaning the urinary system and warding off infections. The dilute urine also lessen the ability of minerals to form into crystals, plugs, and stones. Dr. Richard Goldstein of the Animal Medical Center in New York recommends that to reduce the risk of kidney and bladder stones make sure the cat always has access to fresh water and is drinking it.
Drinking water can not only prevent disease but also help manage existing ones. Cats already sick with Chronic Kidney Disease (CKD) and having loss of kidney function over time can be stabilized by minimizing the accumulation of toxic body waste products in the blood through adequate hydration. Additional intake of water in cats who have had urinary crystals, urethral plugs and urinary stones can likewise help in preventing its recurrence.
GETTING YOUR CAT TO DRINK MORE WATER: A WATER FOUNTAIN WORKS!
All that being said about the importance of water, we go back to the problem of how to get cats to drink more water. Cats are one of the most discriminating creatures to ever walk on this planet and for most of them a still water bowl is just not good enough. One way to encourage a cat to drink more water is providing him a source of clean and fresh moving water. Whether your cat is on a dry or wet food diet, he will benefit greatly from the extra water. One of the best things you can do for your cat is to get him a water fountain to entice him to drink more. It is a worthy investment toward your cat’s well-being.