Month: July 2020

Cat Care

In Search of the Best Cat Food, Part III: Kitten, Adult, & Senior Diets

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Meredith Hemphill

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Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

The pet food industry offers diets for every stage of a cat’s life, from formula for newborn kittens to senior cat food. The kitten milk-replacement is one thing, but what’s the difference between solid food for kittens, adults, and seniors? And what about the cat food that says it’s for “all life stages”? Today we look at the difference between diets for the various life stages and what really matters for your cat.

Cat and two kittens eating from bowls
Image by mariahuusgaard from Pixabay

Kitten Food

Before doing this research, I knew there was at least one difference between kitten food and any other cat food. I took Joon in when she was about four months old, and I was living with a roommate that already had a cat. Domino is a gorgeous tuxedo cat with spooky yellow eyes, and she was quite pudgy. My roommate had to put her on a diet, and Domino was not a fan. She kept eating Joon’s food, which Joon was too busy playing to care about. My vet told me I should be careful to keep her from doing this, because kitten food is high in calories.

It makes sense, doesn’t it? Kittens are still growing rapidly, and as they get older they use up a lot of energy playing as well. In fact, kittens may need up to three times as many calories as an adult cat each day (1, 2, 3)! And they have higher protein requirements than adults, as well, needing to get about 30% of all that energy from protein (2). Most of the rest of the calories need to come from fat to ensure that they get enough essential fatty acids for proper development (1). Kittens need lots of vitamins and minerals as well. Basically, like all babies, kittens need lots of nutrients in their diet so they can grow up big and strong. So kitten food is made more nutrient-dense than adult food.

The Association of American Feed Control Officials (AAFCO) requires kitten food to be at least 30% protein and 9% fat on a dry matter basis (4). A survey of 212 adult and kitten foods by IdleCat found that kitten foods actually averaged 40.77% protein for kibble and 49.11% protein for canned food (3). The fat content was a little closer to the minimum recommendation, but for both kinds of food was more than 21% higher than the average fat content of the adult foods (3). Carbohydrate and fiber content were lower to compensate (3). Vitamins and minerals weren’t measured in that survey, but in a well-balanced kitten food they should be present in higher amounts as well.

Kitten food is also made to be easier for small mouths with developing teeth to eat. Canned kitten diets are typically softer, and the kibble comes in smaller pieces (1). However, the nutritional differences are what is most likely to impact a cat’s health. Adult cat food is usually not nutrient-dense enough for kittens, although it will do temporarily in a pinch (5). Conversely, as my vet told me, kitten food can cause adult cats to gain too much weight. Depending on the nutrients included, the extra vitamins and minerals could even cause toxicity in an adult cat (1). A few bites here or there is unlikely to cause anybody any harm–Domino is certainly none the worse for it–but kittens need kitten food and adults should be kept away from it as best we can.

Cats are considered kittens up to one year of age, with the exception of some large breeds. Maine Coons do not reach maturity for up to two years. If you are unsure how long to keep feeding your cat a kitten diet, check with your veterinarian.

Tortoiseshell cat eating from bowl
Image by sweetlouise from Pixabay

Adult Cat Food

Adult cat foods are formulated to maintain a grown cat’s weight and health. Growth and development never completely stop. All organisms continue to make new cells, repair damaged tissues, and progress through their life cycle as long as they live. However, an adult cat uses much less energy than a kitten to do these things, so they need far fewer calories and other nutrients relative to their body weight. This is reflected in the nutritive content of adult cat food.

The AAFCO divides their standards for cat food into two categories: “growth and reproduction,” for kittens and pregnant or lactating queens, and “adult maintenance” for the average, older, and sterilized adult cat (6). The minimum protein content for adult maintenance is 4% lower than the recommendation for kittens and queens. The fat minimum is the same, but 5 out of 12 mineral recommendations are lower for adults, as well as Vitamin A (4). These minerals and vitamin can cause toxicity in excess, which is more likely in adult cats who use less of the nutrients than a growing kitten or a queen who is growing kittens.

Cats are typically considered “adults” from the age of one year to seven years, although this varies some by breed and individual cat (7). Those of us with rescue cats often don’t know exactly how old they are, so you and your vet may have to play it by ear to decide when the time seems right to start treating your cat like a senior.

Senior Cat Food

In the United States, the AAFCO is the government body responsible for licensing pet food, and as previously indicated, they don’t issue standards for senior cat food. The consequence of this is that senior cat food is very similar to adult cat food, with some slight modifications that won’t color outside the AAFCO adult cat food guidelines (8). Whether this is a bad thing or not is hard to say. A lot remains unknown about the needs of senior cats. Due to lack of research, many of the decisions made about how to feed senior pets have been made based on what is known about aging humans (9). Even so, there have been improvements in senior cat diets over the years.

But some cats may not need to go on a senior diet at all, or not until much later in life. If an older cat is keeping up their body weight and muscle condition on their adult diet, there’s no need to change them to a senior diet (8). If a senior kitty begins to gain or lose weight or lose muscle mass and no associated health problem is found, a change in diet may be in order (8). However, senior cat diets can be pretty different from one another. Of course, cats with age-related health problems may be put on a diet specific to their needs. If your vet recommends just plain senior cat food, however, the variability in formulations can be overwhelming.

Fat tortoiseshell cat
Cats sometimes gain weight as they get older – Image by Quinn Kampschroer from Pixabay

It used to be the case that senior cat food was low protein, low fat, and high fiber (8), and the myth that senior cats need a diet low in protein still persists. Some health conditions may call for a low-protein diet, but a normal senior cat may suffer greater muscle loss with less protein (9).

Whether or not senior cats need more protein than adult cats is still unclear, however, and may depend upon the individual cat. If they are notably losing muscle mass, then a high-protein senior diet may be the solution (10). There are still senior diets made with low amounts of protein, all the way to those with enhanced protein, so it pays to check the label. Remember that it’s the dry weight of the nutrients that you need to compare, as the amounts on pet food labels are given in minimum and maximum percentages instead of absolute quantities. Check out this page for a rundown of how that math works.

Senior formulas may be low-calorie, hence the traditional wisdom of making them high-fiber, and for some cats this is appropriate. Generally, cats tend to have progressively slower metabolisms up to eleven years of age and are prone to obesity during middle age, around years six to eight (11). Once they get older than that, they often start to lose weight and may need high calorie diets (11).

Sometimes a vet may actually put a senior cat on a kitten diet if weight loss is a major issue, simply to get enough calories into them (8). In milder cases, a more calorie-dense senior food may be the way to go. If your cat has the opposite problem, well, low-calorie is where it’s at. Both obesity and being underweight can cause significant health problems or be symptoms of them, so keep a close eye on the body condition of older cats. If something changes, always have a vet check for disease before trying to treat the problem with diet alone.

There are other variables as well, such as dietary phosphorous and sodium, which sometimes matter for senior cats if they have certain health problems (9). If your cat has any health issues but they don’t require a medical diet, ask your veterinarian if there is anything you should be on the lookout for when choosing their food.

All Life Stages Cat Food

In order for a pet food to claim that it is “complete and balanced” for all life stages, it must meet the standards set by the AAFCO for both the growth and reproduction and adult maintenance stages. Because the minimums for certain nutrients are higher in the growth/reproduction stage, and there are only a few maximums, “all life stages” food may be too nutrient-dense for some adult cats (12). The food has to have enough nutrients for every stage of life, so it makes sense that what you end up with is more like the food intended for kittens and queens. They have higher nutrient requirements.

Opinions are divided, but I found that veterinarians seemed most inclined to think that food for all life stages was really not appropriate for adult or senior cats (12, 13). Pet food companies had the more mixed advice. Personally, I think all life stages food is great for keeping on hand if you find a stray cat or kitten you need to assist, as you never know what age they might be, and the extra nutrients are probably not a bad idea. It’s not what I would feed my cats at home, though.

Works Cited

  1. Paretts, S. (n.d.). What is the difference between kitten and cat food? The Nest. https://pets.thenest.com/difference-between-kitten-cat-food-6832.html
  2. ASPCA. (n.d.). Cat nutrition tips. link here
  3. John, B. (2019, November 19). Kitten food vs. adult cat food: What are the differences? IdleCat. https://theidlecat.com/kitten-food-differences/
  4. Association of American Feed Control Officials. (2014). AAFCO methods for substantiating nutritional adequacy of dog and cat foods: Proposed revisions edited per comments for 2014 official publication. PDF
  5. Syufy, F. (2019, November 4). How to choose the best kitten food. The Spruce Pets. https://www.thesprucepets.com/choosing-best-kitten-food-552267
  6. US Food and Drug Administration. (2020, February 28). “Complete and balanced” pet food. link here
  7. Chewy Pet Central. (2019, November 13). Cat food for all ages: How (and what) to feed your cat during every stage of life. https://petcentral.chewy.com/ages-stages-cat-food/
  8. Chewy Pet Central. (2019, December 10). The best senior cat food: A guide to feeding your older cat. https://petcentral.chewy.com/best-senior-cat-food/
  9. Freeman, L.M., Linder, D.E., and Heinze, C.R. (2016, March 8). When should I switch my pet to a senior diet? Tufts Clinical Nutrition Service. https://vetnutrition.tufts.edu/2016/03/when-should-i-switch-my-pet-to-a-senior-diet/
  10. Pittari, J., et al. (2009). American Association of Feline Practitioners: Senior care guidelines. Journal of Feline Medicine and Surgery, 11(9), 763-778. https://doi.org/10.1016/j.jfms.2009.07.011
  11. PetCoach. (n.d.). Do senior cats have different nutritional needs? https://www.petcoach.co/article/nutritional-needs-of-senior-cats/
  12. Coates, J. (2014, April 25). Are life stage dog foods credible? PetMD. https://www.petmd.com/blogs/nutritionnuggets/dr-coates/2014/april/debate-over-all-life-stage-dog-foods-31604
  13. Rock Veterinary Clinic. (n.d.). Understanding pet food labels. https://www.rockvetclinic.org/post/understanding-pet-food-labels.html

Published July 26th, 2020

Updated November 1st, 2020

Behavior

Why do cats bring home “gifts” of dead animals?

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Meredith Hemphill

mehshadoweye

Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Gray tabby cat holding mouse
“You know who would love this? My human!” – Image by Kurt Bouda from Pixabay

One summer morning when I was in high school, I opened the front door of my parents’ house to go get the mail. Fortunately, I’m in the habit of looking down when I walk, so I managed to avoid planting my bare foot directly into the present that our outdoor cat, Rosenberg, or Rosie, had left on the doormat for us. It was a baby rabbit, or most of one, that is. She had eaten a hole in the side of the head and consumed the brain, but left the rest for us to enjoy. We still call Rosie a zombie cat.

This was not the only time Rosie left us a gift. She’s never brought anything more indoors than the garage, but many people are not so lucky. Sometimes, cats bring gifts that are not so decidedly deceased, either, and cat owners may find themselves chasing rather lively birds, rodents, or reptiles around their homes. We humans generally regard this behavior as disgusting, but our cats seem to think we appreciate it. Why? Just, why?

Humans and cats are obviously very different animals, and we think differently. Cats are hard-wired to hunt, and a lot of their emotional lives revolve around hunting. It’s what they would spend most of their waking hours doing in the wild. Cats simply enjoy hunting. If prey is available, cats will hunt even if they are well-fed. A study found that cats would stop eating in order to kill a rat that was presented to them, only to set the rat beside their food bowl and keep eating what they had been eating before (1).

Cats may have evolved this high prey drive because prey can be scarce and difficult to catch, so stopping whatever they’re doing to hunt available prey, even when not hungry, would have boosted their chances of survival (1). The feline drive to hunt is why cats with access to the outdoors will inevitably at least attempt to. There are a few theories as to why they want to bring some of their prey to their people, however.

One school of thought is that they simply want to bring their prey back to a safe place to consume it, their den as it were, the way they would in the wild (2). But their den is your home or front stoop. Some experts believe that cats may want to show off their good work, but veterinarian Dr. Stephanie Liff points out that pride for their catch may be too human a motivation to ascribe to cats (3).

Tabby kitten playing with plush toy
Kittens have to practice hunting – Image by Ivo Zahradníček from Pixabay

Although cats are usually thought of as solitary and independent animals, they are actually fairly social and often live in colonies or with family members (4). As such, feral cats may bring prey back to the group to ensure the survival of everyone (5, 6). Cats also hunt cooperatively with members of their social group–Elizabeth Marshall Thomas suggests in her book The Tribe of Tiger that a possible explanation for bringing home live prey, at least for some cats, might be the joy of joining in a group hunt with the humans as they frantically chase down the injured animal (4). Domestic cats may be thinking in these terms when they bring prey to us, their family members of another species. Or, they may be thinking of us as family in a filial sense.

Perhaps the greatest consensus for why cats bring their humans prey is that they are treating us like their kittens. Mother cats bring prey to the den to feed their offspring. They also bring home dead, dying, or wounded prey to teach their kittens how to hunt. So our cats may be trying to feed us or teach us, or both. Really, who could blame them? In their world, hunting is everything. But we are clumsy, ungainly things that clearly cannot hunt for ourselves. Who knows where they think we get our food from, but I imagine they pity us sometimes. So perhaps they want to do what they can to help.

Elizabeth Marshall Thomas shares a story about how she and her husband had a she-cat that began to bring home dead mice all the time after she had a kitten (4). She would bring mice for the kitten, even after the kitten became an adult, but she would also bring them to Thomas, her husband, and their dog, the most appreciative of the bunch (4). It was as though motherhood made her suddenly feel responsible for all of these terrible hunters with whom she shared her home. However, even sterilized cats and toms can show this behavior. Maybe they all feel sorry for us.

Even indoor-only cats will bring gifts. They may manage to catch prey that sneaks indoors to present to you, but more often their gifts are inedible. The prey caught by indoor cats is mostly their toys, or whatever other objects they use as a toy, and these are the things they are likely to leave as gifts (5). Joon does this occasionally at night. I’ll wake up in the morning and find one of her toys, most often her beloved plush, pink-and-white sock, lying right beside me on the bed. If I wanted to have someone teach me how to hunt, it wouldn’t be Joon. I think her lifetime achievements are a spider and some flies. But I appreciate the sentiment.

Gray and white cat holding toy mouse
Not all mice are created equal – Image by isaikina13 from Pixabay

If your cat is leaving gifts more like Rosie’s than Joon’s, and you wish they wouldn’t, there are a couple things you can do, but keep in mind that you may not be able to stop this behavior completely. Cats will always find something to hunt, and there’s always a chance that if they catch something, they will bring it to you.

That being said, one thing you can do is engage your cat in interactive play to satisfy their prey drive and diminish some of that need to hunt live animals. The live prey drive will never go away, but you can redirect some of it. Another tactic is to make sure that any cats with access to the outdoors wear a breakaway collar with a bell, so that their hunts are less likely to be successful. That’s good for the local ecosystem and you’ll get much fewer unwanted gifts.

When your cat does bring you a present you didn’t ask for, you may want to scold them, but don’t. They won’t understand. Whatever the reason your cat is doing this, they see it as at least a neutral and probably a beneficial thing that they are doing for you. How would you feel if you did something really nice for somebody, and they yelled at you and called you a bad person for your good deed? It’s usually recommended that you actually praise your cat and then discreetly dispose of their gift, assuming it isn’t still very much alive and you have other things to worry about at the moment. Your cat is, after all, only doing what is natural to them.

By the way, if you have a cat with access to the outdoors, and they don’t bring you gifts, don’t feel insulted or worried. Not all cats have the same prey drive. Yours may just not feel as compelled to hunt when provided with sufficient food. Or they may not be very good at it. (7) Rest assured, they are still finding ways to be a cat, as cats always do.

Works Cited

  1. Adamec, R.E. (1976). The interaction of hunger and preying in the domestic cat (Felis catus): An adaptive hierarchy? Behavioral Biology, 18(2), 263-272. https://doi.org/10.1016/S0091-6773(76)92166-0
  2. Cutolo, M. (2020, March 26). Why do cats bring home dead animals? Reader’s Digest. https://www.rd.com/article/why-do-cats-bring-home-dead-animals/
  3. Puiu, T. (2017, May 5). Why do cats bring dead animals home to you: You should actually be honored. ZME Science. https://www.zmescience.com/ecology/animals-ecology/why-cats-dead-animals-home/
  4. Thomas, E.M. (1994). The tribe of tiger: Cats and their culture. Simon & Schuster.
  5. Shojai, A. (2019, November 19). Why do cats bring ‘gifts’ of dead animals? The Spruce Pets. https://www.thesprucepets.com/cat-hunting-gifts-553946
  6. Primm, K. (n.d.). Ask a vet: Why does my cat bring me dead mice? I Heart Cats. https://iheartcats.com/ask-a-vet-why-does-my-cat-bring-me-dead-mice/
  7. Argos Pet Insurance. (2014, September 10). Why do cats bring their owners dead animals? https://www.argospetinsurance.co.uk/we-talk-pet/are-cats-really-bringing-their-owners-presents-when-they-bring-mice-home/

Published July 19th, 2020

Updated November 10th, 2020

Cat Care

In Search of the Best Cat Food, Part II: Wet or Dry?

mehshadoweye

mehshadoweye

Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

White cat eating dry cat food
Image by Deedee86 from Pixabay

There is a head-spinning variety of cat foods out there, but the most basic distinctions can be drawn based on moisture content. Dry cat food, the familiar dehydrated kibble, contains 6-10% water (1, 2). Semi-moist food is 15-30% water (2). Canned food has a moisture content of at least 75% (1, 2). Generally speaking, the higher the moisture content, the higher the price and the lower the convenience, so dry food is a very popular choice. But is it the best choice for our cats’ health?

Because kibble is already dehydrated, it doesn’t dry out if left in the bowl for long periods of time, so it lends itself to the convenience of free-feeding. Cats usually like to eat lots of small meals, and let’s face it, people like to be lazy, so this arrangement is often mutually agreeable. We’ll discuss in another part of this series why free-feeding may not be ideal, at least for some cats, but regardless it is often what busy people resort to, and dry food makes that easy. Dry food can also be bought in bulk and will last a long time if stored properly in a cool, dry place. And, again, it’s usually cheap.

Human concerns are not the only reason why someone would feed their cat dry food, however. It has long been thought that kibble helps clean cats’ teeth, preventing and/or treating dental disease. Veterinarians sometimes recommend it for this purpose (3). The idea is that chewing the hard bits of kibble mechanically scrapes the teeth clean of plaque buildup (3), and there has been some scientific evidence supporting the idea that dry food does, in fact, prevent periodontal disease (4). More widely, however, the evidence does not support the idea that dry food cleans cats’ teeth, and there is good reason why it wouldn’t (3).

As mentioned in part one, cats are obligate carnivores. They evolved to eat meat exclusively. As such, their teeth are made for biting and tearing, not chewing (3). Plant matter includes tough cell walls that need to be broken down, so animals that are meant to eat plants do a lot of chewing (3). Carnivores just bite off manageable chunks and swallow them whole (3, 5). That is usually what cats do with kibble. They swallow it whole. Sometimes they bite the kibble, but when they do, the hard but brittle kibble shatters on the biting edges of the teeth and doesn’t do anything to scrape the teeth clean (3, 6).

Yawning gray tabby cat
These chompers aren’t for chewing – Image by Martina Misar-Tummelsthammer from Pixabay

As far as the nutrition of dry food goes, it isn’t great news, either. Dry cat food is typically high in carbohydrates, on average 35-50% by calories (6). Cats neither need carbohydrates, nor can they digest them well, due to their biology as obligate carnivores. They need a diet high in animal protein with a moderate amount of fat (see part one).

Not all dry foods are created equal, of course, but even grain-free dry foods can still be high in carbohydrates if they simply replace grains with potatoes or peas (6). It’s also common for much of the protein in dry food to come from plant matter, but plant proteins do not contain all of the amino acids that cats need (6). The missing nutrients are supposed to be added back in, otherwise the food won’t meet required nutrition standards, but pet nutritionists are still learning exactly what cats need.

With all that being said, is dry cat food just the worst? Well, no, trying to make a cat vegan or feeding them a diet of human food would probably be the worst. When I looked up veterinarian opinions on whether dry or wet food was better, there were mixed opinions. Some were adamant that cats should only be fed canned/wet food (i.e. 3, 6). Others said it didn’t matter (i.e. 5), or it depended upon the cat. I didn’t come across anyone who was a staunch defender of dry food, but there were definitely professionals who had no quarrel with it. I’ll touch on semi-moist food at the end, since it is kind of a weird middle ground, but first let’s take a look at wet food.

Wet food, which as far as I know only comes in cans, can vary in quality but is always notable for its high water content, up to 84% (7). Cats should consume about 20-70 ml of water per kg of body weight per day (8). But cats are descended from Felis lybica, a desert wildcat, so they have a low thirst drive. They tend to obtain most of their water from their food. Prey would normally contain 70-75% water (6). Studies have demonstrated that cats can avoid dehydration without drinking any water at all as long as they are given food with at least 67% moisture content (7, 9, 10).

Of course, a cat should never be without fresh water, but it goes to show just how important dietary water is to cats. Canned food replicates the water content of prey well and helps keep cats hydrated. This prevents urinary and kidney problems, which are common in cats and can be very dangerous (3, 5, 6, 11). Cats fed dry food will drink more water, but they don’t drink enough to compensate, resulting in dehydration and possibly health problems (6).

Canned food is usually higher in protein and made with more animal ingredients than dry food, although cheap, low-quality canned food may still be more plant-based. Reading labels is important, even though pet food labels are not as informative as human food labels. When doing so, keep in mind that the amounts of nutrients are listed as percentages, so the more moisture a food has, the less of other nutrients it may seem to have. Some math may be required to determine the comparative dry weight nutrient content.

Calico cat drinking from garden pool
Cats need to get most of their water from their food – Photo by Dorothea OLDANI on Unsplash

Canned food isn’t perfect. A positive correlation has been demonstrated in cats between hyperthyroidism and eating canned food (5, 12). The cause of the correlation is unknown, although there are a number of theories, one of which suggests that the actual cause is a fire-retardant chemical present mostly in indoor fabrics, not the food (13). However, until we know more, all that can be said for sure is that a correlation has been found.

Semi-moist food comes in plastic pouches or trays, which often aren’t recyclable, so I have to say it isn’t my preference just because of the environmental impact of all that plastic. However, semi-moist food provides cats with quite a bit more water than dry food while not going bad in the bowl as quickly as wet food, so it can be a good compromise between a cat’s need for dietary water a human’s busy schedule. Semi-moist food tends to feature animal ingredients as the main event, providing more protein and a more species-appropriate dish than many dry foods (1). Those pouches and trays are pre-portioned and easy to dump in the bowl, but do be careful that the portion it comes in is right for your cat if you choose this option.

Because cats are the domesticated version of a desert animal, dietary water is extremely important. If for this reason and no other, canned food, ideally a high-quality, meat-forward one, would be the best option. Not everyone can afford the most expensive, gourmet canned food, however. Cheap canned food or semi-moist food is still a good option. A 2010 study showed that cats exhibited better urinary health if water was simply added to their dry food (11). We all have to figure out the best plan for ourselves and our cats. If your cat has specific dietary needs, and you aren’t sure how that would affect what form of food would be best for them, it’s always a good idea to ask your veterinarian.

Works Cited

  1. Cornell Feline Health Center. (2017, July). Feeding your cat. Cornell University College of Veterinary Medicine. Retrieved here.
  2. Feuer, D. (2006). Your Cat’s Nutritional Needs. National Research Council.
  3. Kelsey, A. (2014). 6 reasons why dry food does not clean your cat’s teeth. Cat Behaviourist. http://www.catbehaviourist.com/blog/6-reasons-dry-food-clean-cats-teeth/
  4. Watson, A.D. (1994). Diet and periodontal disease in dogs and cats. Australian Veterinary Journal, 71(10), 313-318. DOI: 10.1111/j.1751-0813.1994.tb00905.x
  5. Barchas, E. (2017, July 31). Ask a vet: Would you recommend wet food or dry food for cats? Catster. https://www.catster.com/lifestyle/wet-dry-cat-health-canned-food-kibble-cats-ask-a-vet
  6. Pierson, L.A. (2016, November). Feeding your cat: Know the basics of feline nutrition. CatInfo.org. https://catinfo.org/
  7. Case, L.P., et al (1995). Canine and feline nutrition. Mosby, Inc.
  8. Ackerman, N. (Ed.). (2016) Aspinall’s complete textbook of veterinary nursing, 3rd edition. Elsevier.
  9. Prentiss, P.G., Wolf, A.V., Eddy, H.A. (1959). Hydropenia in cat and dog. Ability of the cat to meet its water requirements solely from a diet of fish or meat. American Journal of Physiology, 196(3), 625-632. https://doi.org/10.1152/ajplegacy.1959.196.3.625
  10. Caldwell, G.T. (1931). Studies in water metabolism of the cat. The influence of dehydration on blood concentration, thermoregulation, respiratory exchange, and metabolic-water production. Physiological Zoology, 4(2), 324-359. Retrieved from https://www.jstor.org/stable/30151145
  11. Waltham Petcare Science Institute. (n.d.) Cats benefit from increased dietary moisture. https://www.waltham.com/news-events/nutrition/cats-benefit-from-increased-dietary-moisture/5548/
  12. Edinboro, C.H., et al. (2004). Epidemiologic study of relationships between consumption of commercial canned food and risk of hyperthyroidism in cats. Journal of the American Veterinary Medical Association, 224(6), 879-886. DOI: 10.2460/javma.2004.224.879
  13. Hofve, J. (n.d.) Feline hyperthyroidism. Jackson Galaxy. https://www.jacksongalaxy.com/blog/feline-hyperthyroidism/

Published July 12th, 2020

Updated November 21st, 2020

Cat Care

In Search of the Best Cat Food, Part I: Feline Nutrition

mehshadoweye

Meredith Hemphill

mehshadoweye

Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Brown tabby eating out of bowl
Photo by Hans Reniers on Unsplash

Today I am trying something new on this blog. Almost anyone with a pet has asked the question, “What is the best food to give them?” Even after asking the advice of my veterinarian what to feed my cat, I still felt pretty lost and confused. I am undertaking a series of articles in which I aim to gather as much information as I can about feline nutrition and what difference the many kinds of cat food really make on a cat’s well-being.

The series will have five parts: feline nutrition, wet vs. dry food, diets for different life stages, specialty diets, and indoor diets. I will be interspersing other articles during this series so that it doesn’t get boring. Feel free to comment with your own questions about cat food, and I will look into them.

Of Carnivores and Calories

To begin with, I thought it would be helpful to go over the basic facts of feline nutrition. The fundamental elements of an animal’s diet, humans included, are very simply broken down into protein, fat, carbohydrates, vitamins, and minerals. Cats of all kinds are obligate carnivores. That means that they have evolved to eat only meat, and they are not well-equipped to derive nutrition from plant sources. This has a major impact on their nutritional needs.

The amount of calories a cat needs per day depends upon their age, activity level, health, and whether or not they have been sterilized. Growing kittens and pregnant or nursing queens need significantly more energy. Intact adults need a bit more than neutered adults. An eight-pound adult cat needs about 240 kcal (kilocalories, or what we usually just call calories) each day [1]. The Animal Medical Center of Chicago has a very helpful chart for getting a good idea of how many calories your cat or kitten is likely to need, which you can download a copy of below [2]. Because cats have evolved to eat only meat, their bodies are designed to obtain these calories primarily, if not exclusively, from proteins and fats.

Calorie Requirements For CatsDownload

Macronutrients in Feline Nutrition

Carbohydrates and Proteins

Obligate carnivores require a high protein, moderate fat, low carbohydrate diet to be their healthiest. Carbohydrates, which are plentiful in plant matter, can be difficult for cats to digest and are not necessary in the feline diet [3]. Instead of deriving most of their energy from carbohydrates, as humans do, cats use protein as their primary source of energy [4, 5]. A nine-pound cat with a 250 kcal-per-day diet is recommended to receive 12.5 grams of protein each day [3]. It isn’t just the amount of protein that matters, however. Proteins are made of molecules called amino acids. There are 23 amino acids. Cats can manufacture some of these themselves, but there are 11 that they must get from their diet [6, 7]. These are known as essential amino acids. The essential amino acids for cats are:

Black and white cat watching mouse
Some cats are fiercer hunters than others, but all are obligate carnivores – Image by Erika Stockenhofen from Pixabay
  • Arginine
  • Histidine
  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Taurine
  • Threonine
  • Tryptophan
  • Valine

Taurine is an unusual requirement particular to cats, but it is very important. A taurine deficiency can lead to blindness, deafness, heart problems, and loss of kittens or congenital defects with pregnant queens [3, 7]. Taurine is only present in animal protein, a callback to the nature of cats as obligate carnivores [7].

Fats

Cats also have rather specific needs when it comes to the fats in their diets. We have a tendency to think of fat as a dirty word, but fats serve very important functions in the body, in appropriate quantities. Fats are an important source of energy, they provide insulation to nerve fibers and protection to internal organs, they aid in absorption of the fat soluble vitamins, and they are critical for cell structure and function [3, 6, 7]. Cats can tolerate fairly high amounts of dietary fat since it is such an important energy source for them [3]. The average cat we used as an example before has a recommended daily allowance of 5.5 grams of fat [3].

Fats are composed of fatty acids, and like amino acids, some of these can be made in the body, and some cannot. Science is still learning which fatty acids are essential for cats, but some things are well-known. Cats are unable to manufacture arachidonic acid, an important precursor molecule with end products that have wide range of functions in the body [6]. Arachidonic acid is found only in animal fat [7]. Linoleic acid is an essential fatty acid for all animals [7]. DHA is a fatty acid that has been shown to be important for the neural development of kittens, so it may be necessary for reproducing queens and young, weaned kittens [6, 7].

Micronutrients in Feline Nutrition

Now, let’s talk micronutrients. Vitamins are organic nutrients, manufactured by a lifeform somewhere in the food chain. Minerals are inorganic nutrients that come from the environment. Cats need Vitamins A, D, E, K, and the B complex [3, 6, 7]. They have no need for dietary Vitamin C, as they are able to make that for themselves [6, 7]. Minerals are a bit trickier, since some of them are needed in very small amounts but are still absolutely critical. The US National Research Council considers twelve minerals essential for cats [3], but I included a thirteenth from another source as well [6].

Vitamins

Five eggs
Photo by 青 晨 on Unsplash

Vitamin A is a big one for cats. Some animals can make Vitamin A from precursors in plants, like beta-carotene, but cats can’t do that [7, 8]. They have to consume Vitamin A in its completed form from animal sources [7, 8]. Vitamin A is important for vision–especially night vision, healthy skin and mucous membranes, and normal bone and tooth growth [6, 7]. Fish oil, liver, eggs, and dairy are natural sources of Vitamin A [6, 7].

Vitamin D is needed for the body to use calcium and phosphorous [6, 7]. Cats can synthesize it in their skin in the presence of UV light, but not very well, so dietary Vitamin D is important [6]. It can be found in marine fish and fish oils, liver, and egg yolks [6, 7]. Vitamin E is an antioxidant synthesized by plants but present in small amounts in animal sources [6]. The amount a cat needs depends upon how much oxidative stress their body is under [6, 7]. Vitamin K is important for blood clotting, but healthy cats are able to synthesize enough of it on their own [6, 7]. If the intestinal bacteria that normally make Vitamin K are decreased, perhaps if the pet is on antibiotics, dietary Vitamin K can become important [6]. In that case, fish meal, egg, and liver can be good sources [6].

There are eight B vitamins, which are necessary for energy metabolism and making healthy tissues [6]. Because they are soluble in water, it is uncommon for a cat to get too much of a B vitamin. The excess just washes out in the urine [7]. Cats usually get enough B vitamins from their food, but while most animals can synthesize niacin, or B3, cats can’t and must get it from their diet [6]. Fortunately, meat is a good source of niacin [6]. The other B vitamins can come from eggs, organ meats, or muscle meat, depending on the B vitamin in question [6].

Minerals

Salmon steak
Salmon is a good, species-appropriate source of potassium – Image by congerdesign from Pixabay

We have a bunch of minerals to get through, and I would feel like I wasn’t providing the most complete information if I left any out. But I don’t think anyone wants this article to go on for twenty pages, so I’m going to summarize the main reasons each mineral is important and where cats get the minerals from in their diet [3, 6, 7].

  • Calcium for skeletal and muscular health: poultry/meat meals, bone
  • Phosphorous for skeletal health and energy metabolism: meat, poultry, fish
  • Magnesium for muscle, nerve, and hormone function: bone meal
  • Sodium for homeostasis and nerve function: fish, poultry meal, eggs
  • Potassium for nerve and enzyme function: fish, especially salmon [9]
  • Chloride for homeostasis: fish, poultry meal, eggs
  • Iron for red blood cells and energy metabolism: meat, organ meat
  • Copper for tissue synthesis: organ meat
  • Zinc for cell growth and wound healing: beef liver, dark poultry meat, egg yolks
  • Manganese for bone growth and neurological health: meat, poultry, fish
  • Selenium for antioxidant activity and immune health: meat, poultry
  • Iodine for thyroid function: meat, poultry
  • Sulfur for protein synthesis: meat, poultry, fish

Moving Forward

What do we do with this information? Out of curiosity, I grabbed one of Joon’s cat food cans to see how much of this information is actually available on the label. What I found was a section giving the crude protein, crude fat, crude fiber, moisture, “ash,” calcium, phosphorous, magnesium, and taurine content in either minimum or maximum percentages. Ash is a term sometimes used to refer to mineral content [6]. Below that, the kcal per can and per kilogram (of this food that comes in 170-gram cans) was given. That gives me the ability to calculate the gram values of the nutrients, although it’s frustrating that I have to. And then there’s the brief feeding instructions, with the ingredients on another panel.

It’s less information than I would have hoped for, and it’s presented much less plainly than on human food labels here in the US. So I tried one of the cans of prescription food we give my parents’ elderly cat. I thought maybe it was just the company I buy Joon’s food from. Nope, Rosie’s food had even less information on it. There were no percentages for minerals at all.

As we continue with this series, I’ll delve into different types of food and what it all means. What looking at the back of this can is telling me right now, however, is that as pet parents we need to be as informed as we can. Evidently, no one is going to hand the information we need about feline nutrition to us. At least, not anybody in the pet food aisle. If I look at the ingredients, I can see that this food has a lot of added nutrients and ingredients that provide them naturally, but a few hours ago I wouldn’t have known that including tuna and fish oil in a chicken-flavored food can provide nutrients that the chicken alone might not. The more we know, the better prepared we are to make the best decisions possible for our cats.

Works Cited

  1. How many calories should your dog or cat eat daily? (2014, April 25). Dunloggin Veterinary Hospital. https://dunlogginvet.com/how-many-calories-should-your-dog-or-cat-eat-daily/
  2. Calorie Requirements for Cats (n.d.). Animal Medical Center of Chicago. https://www.animalmedicalcenterofchicago.com/cat-diet-calorie-requirements-for-cats/
  3. Feuer, D. (2006). Your Cat’s Nutritional Needs. National Research Council.
  4. Optimum feline nutrition: what should you feed your cat? And feline weight loss and prevention plan. (n.d.). Cat Care Center of Baton Rouge. https://www.catcarecenter.com/services/cats/feline-nutrition-cat-food
  5. Llera, R. and Ward, E. (2019). Nutrition: General feeding guidelines for cats. VCA Hospitals. https://vcahospitals.com/know-your-pet/nutrition-feeding-guidelines-for-cats
  6. Case, L.P., et al (1995). Canine and feline nutrition. Mosby, Inc.
  7. Ackerman, N. (Ed.). (2016) Aspinall’s complete textbook of veterinary nursing, 3rd edition. Elsevier.
  8. Schultze, K.R. (2010, February 9). Your cat’s nutritional needs: The basics. Feline Nutrition Foundation. https://feline-nutrition.org/nutrition/your-cats-nutritional-needs-the-basics
  9. Millen, B. et al (2015). Appendix 10: Food sources of potassium. Health.gov. https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/appendix-10/

Published July 5, 2020

Updated June 20, 2022