If you know some biology, you may know that although dogs thrive on a vegetarian diet (dog food often has a high cereal content), cats must eat meat to remain healthy (cat food is high in meat protein). This is because cats are “obligate carnivores,” a fancy way of saying: Eat meat or go blind and have heart failure.
Cats lack the ability to construct certain proteins that are vital to good health. One such protein, taurine, is found only in meat, not vegetables. Dogs can manufacture taurine from smaller building blocks, but cats are not able to do this and become deficient on a vegetarian diet.
Therefore, it might seem odd to say, but an all-meat diet can make a cat ill. Too much meat can result in painful joints and a risk of bone fractures, as a couple of my clients found out the hard way.
From Energetic to Withdrawn
When the Unwins adopted 2 ginger kittens, Eric and Ernie, I was delighted to be trusted with their health care. Having nursed an elderly cat for years, the Unwins enjoyed having energetic kittens around the house once again.
They were a real dynamic duo, a pair of delightful fluff balls who loved to rough-and-tumble. But when Eric was 9 months old, he lost his mojo. He developed a limp, slept all the time and got grumpy when disturbed. The lively youngster became a withdrawn, sullen kitty-cat.
When I examined Eric, what I found puzzled me. He walked stiffly, as if on hot coals. When I felt each of his joints, I was rewarded by a stream of hisses because they all hurt.
Something odd was going on. Chatting to the Unwins about Eric’s habits, I found out he was a bit of a chicken addict and rarely ate anything else. A light bulb went on, and I recommended X-raying Eric’s legs.
The X-ray plates confirmed my hunch. Talk about 50 shades of gray!
Instead of dense white bones, Eric’s skeleton was a faint, ghostly shadow — more like paper than concrete. His bones lacked the whiteness associated with healthy calcium deposits. In short, Eric was calcium-deficient.
Another chat with the Unwins, and everything slipped into place. Eric was such a chicken fiend that they’d stopped offering him cat food, and he was fed on a meat-only diet — mainly chicken breasts. The trouble is that meat is pure protein and lacks the vitamins and minerals essential for healthy growth and strong bones.
If you’re scratching your head thinking that cats eat meat in the wild, think again. When a hunter catches a mouse, he eats the whole thing: bones, fur and stomach contents. These provide valuable vitamins and minerals — a balanced diet for cats.
The actual amount of meat on a mouse carcass is relatively low, and the overall nutritional content is very different from dining exclusively on chicken breasts.
Because he lacked calcium, Eric’s bones were the consistency of putty. The resulting pain in his joints was responsible for his bad temper.
Unfortunately, he was also at extreme risk of bone fractures. If we were to avoid disaster, he needed to be wrapped in cotton wool, so he was immediately put on crate rest for 3 weeks.
In the meantime we worked at getting some strength back into his fragile skeleton. As a quick fix, we added a vitamin and mineral supplement to his chicken. The Unwins worked hard at finding a tasty cat food he’d eat and did a great job of transitioning Eric by mixing his favorite chicken with the new food.
To help with the pain in his joints, Eric took a pain-relieving medication from the non-steroidal anti-inflammatory (NSAID) family. Happily, once his body drank in those much needed nutrients, his bone pain eased. He became sweet-tempered again, and we stopped the medication.
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A Balanced Diet
Our story has a happy ending because nature worked miracles, and once Eric was back on a proper diet his bones became strong. He became his robust, playful self again.
The moral of this tale is that, as with so many things in life, balance is important. Too much of a good thing is bad. Always feed a balanced diet that is designed for that species, and all will be well. Go to an extreme, and you risk putting your pet’s health in danger.
Remember: Nature knows best, and when your cat goes hunting, she eats the whole mouse…unpalatable as this may be to us (on so many levels).
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Dec. 17, 2018.