Feeding Miss Lilly: bones (part 2)

On we go with the section of Feeding Miss Lilly about feeding bones to dogs...

why I fed her bones

I gave Miss Lilly raw, meaty bones at least a couple of times a week, sometimes more often. I did this for several reasons:

1. It enabled her to meet her calcium needs in the most species-appropriate way: by eating the bones of her “prey.”

Miss Lilly and other dogs I’ve watched closely got a lot of enjoyment from tearing the soft tissues (skin, muscle, tendons, ligaments, other connective tissues) away from the meaty bones I fed them. It seems to be such a primal thing for a dog. So, too, was eating or gnawing on the bone itself. These are species-appropriate behaviors that I’ll discuss in more detail in a bit.

Fresh bone contains all of the minerals and most of the other nutrients needed to maintain and repair one’s own bones (and teeth). Wild carnivores meet their calcium needs by eating the bones of other animals. Humans do (or have done), too. Even today, most indigenous peoples living ancestral lifestyles meet their calcium needs by eating the bones of small animals (mammals, birds, reptiles, fish).

As for the rest of us, bone meal powder or hydroxyapatite (the form of calcium-phosphate found in bones and teeth) is widely recommended for bone health in people needing supplemental calcium.

So, bone was the principal source of calcium in Miss Lilly’s diet. I fed her fresh bones whenever possible and bone meal powder at other times.

On page 70 is a table that lists the basic calcium requirements for adult dogs, based on body weight. You’ll see that it takes surprisingly little bone to meet a dog’s daily calcium needs. For example, an adult dog Miss Lilly’s size (around 50 pounds, or 23 kilograms) can meet her daily calcium needs with less than 2 level teaspoons of bone meal powder per day.

But what tables such as this don’t tell you is that it’s not necessary to feed exactly that amount every single day in order to meet a body’s calcium needs. Calcium is a nutrient that the body meticulously stores and regulates, so as long as the dog is getting her calcium needs met over the course of, say, a week, then calcium deficiency is unlikely to occur.

A dog Miss Lilly’s size would meet her calcium needs by eating 1.7 ounces (47 grams) of fresh bone per week. (See page 70 for the calculations.) That’s not a lot of bone.

(Pregnant, lactating, growing, and very active dogs need more, but we’re talking about the average pet dog here, for whom the basic or ‘maintenance’ requirements are adequate for good health and activity.)

Another thing these tables don’t tell you is that calcium absorption is quite variable, depending on the body’s calcium balance and what else is in the diet. For example, an excess of phosphorus, which is found in abundance in muscle meat and in cereal grains, increases the need for calcium and inhibits its absorption if calcium is not well supplemented.

So, we can tie ourselves in knots trying to get the numbers just right, but still be way off in meeting that body’s needs at that time. These sorts of nutrition tables can give us a false sense of control.

I used to get all “het up” about how much bone to feed Miss Lilly and whether she was getting enough calcium. But once I noticed how her body self-regulated its calcium intake when given a chance, and I began to take my cues from her, I relaxed and became more adept at reading and meeting her needs.

With regard to her calcium intake, I noticed two key things that I continued to monitor throughout her life.

First, when I didn’t feed her enough bones, she got all “shark eyes” when the bones finally come out. You’ll know what I mean if you’ve ever seen Shark Week on the Discovery Channel. Regardless of how much fresh meat I fed her, Miss Lilly had that same expression when I offered her a fresh bone if I hadn’t been feeding her enough bones.

Second, when I fed her too much bone — which was usually when I got lazy about feeding her a well-rounded and varied diet — her poop got hard, dry, pale, and crumbly. She even got a little constipated. And if the poop lay in the grass for more than a few days, it became white and chalky. That told me I was feeding her too much bone.

I didn’t test her calcium regulation (which involves calculating the urinary excretion of calcium from blood and urine samples collected at the same time). However, she showed no signs of calcium deficiency throughout life, so I assumed she was getting enough calcium and in appropriate proportions to the other minerals and vitamins involved in calcium regulation (primarily phosphorus, magnesium, and vitamin D).

A year after her death, I took the opportunity to examine her skeleton for signs of joint and bone disease.[1] Her bones were remarkably strong and healthy, except for a couple of isolated joints with evidence of osteoarthritis, likely the result of past trauma (e.g., a single small joint in a single toe in a single foot, but not in any of the others).

[1] Yes, I know… But I’m a scientist, and my enquiring mind wanted to know. I still love her dearly and she continues to teach me, even in death. It was important for me to understand the consequences of the choices I’d made during her life, and it was a rare privilege to get to learn from her remains.

Evidently, Miss Lilly really had self-regulated well when I fed her a species-appropriate diet, which included bones at least a couple of times a week.

After all, that’s how bodies are designed to function: we’re born to be self-maintaining and self-repairing, for life.

2.?Chewing on raw, meaty bones helped keep her teeth and gums healthy.

As I mentioned, Miss Lilly had a skewed bite, so she was set up to have dental problems. In fact, I was told by the vet who spayed her that she would probably need a “dental” at least once a year, for life.

A “dental” (routine veterinary dental care) in adult dogs and cats is mostly about removing tartar (mineralized plaques of food debris and bacteria) and addressing the almost-inevitable periodontal disease (inflammation and degeneration of the gums and other soft tissues surrounding the teeth). In addition, diseased teeth are evaluated for possible extraction or for salvage procedures such as root-canal surgery.

Miss Lilly never needed a “dental.” Even when she broke a tooth and I got to have a thorough look at her teeth and gums, she had no signs of the periodontal disease that is so common in dogs in their middle years and beyond, who are fed conventional dog-food diets.

Not only does chewing on raw, meaty bones mechanically clean the teeth and gums, it stimulates saliva flow. Saliva has several functions and contains numerous substances that help keep the teeth and gums healthy. In addition to lubricating the mouth and helping to flush away food debris, chemical components of saliva help keep the teeth mineralized,[2] and chemical and cellular components defend against bacterial invasion of the teeth and gums. Furthermore, saliva has anti-inflammatory properties and growth factors that aid tissue repair and regeneration.

[2] Like bones, teeth are hard because they are primarily composed of mineral deposits, mainly an organized complex of calcium and phosphorus called hydroxyapatite.

Even the anticipation of a meal gets the saliva flowing. Working on a raw, meaty bone to tear away the soft tissues and then gnaw on the bone itself continues the flow of saliva well beyond what occurs when a bowl of dry or canned dog-food, or even a home-made meal, is consumed in seconds.

Food-based dog chews such as rawhide, hooves, and horns also stimulate saliva flow for the time the dog is chewing on them, but they don’t provide the calcium needed to meet the shortfall in a home-made, meat-based diet. That’s why I preferred to feed raw, meaty bones for teeth and gum health.

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3.?The bones seemed to satisfy some primal need to “gnaw on her prey.”

There was a certain enjoyment that Miss Lilly and most of her dog friends got from working on bones, which seemed to have nothing to do with the nutritional content. Most of her dog friends were on conventional dog-food diets which should have contained adequate calcium and other minerals, so those dogs should not have been going to town on bones because they needed calcium. Yet most of them tucked into bones as if they were starving.

But starving for what? It seemed to me it was some sort of basic need to act as nature designed them. I see the same sense of deep satisfaction when stall-confined or dry-lotted horses are let out to graze. It has little, if anything, to do with nutrition — although in a way it does, because food should be nourishing to the whole animal.

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4.?Chewing on a raw, meaty bone kept her busy for hours.

Chewing on a bone could keep Miss Lilly happily occupied for hours. That was no small thing when there was otherwise little for her to do during the day. Like most other dogs, she was an intelligent creature who loved to be fully engaged in life, and to have nothing to do is a kind of slow death. For this reason alone, I’m a fan of feeding dental chews to dogs without jobs.

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5.?She occasionally buried and later unearthed the bone, in the process perhaps cultivating microbes that are important in making full use of animal material.

Why is it that dogs bury bones, digging them up only once they’re green and stinky? Might this be the canine version of sauerkraut or kimchi — microbially altered or “predigested” foods? It certainly seems to give dogs great pleasure. The most prized bones among the dogs I’ve lived with are unearthed bones that are so “ripe” I can’t stand to be near them.

One reason dogs bury their bones might again harken back to the primal food-related behaviors of carnivores: burying the uneaten portion of a carcass can serve to hide it from other predators and scavengers, and thus keep it for later.

My “dogs are omnivores” friend and I would get a good chuckle out of watching her dog hide his bones from the other dogs, then spend the rest of his time checking on his cache, deciding that it’s not safe enough, digging up his freshly buried bone, and then burying it someplace else, only to go through the whole process again. At least it kept him occupied and engaged his considerable mental faculties in a harmless and species-appropriate way.

But still I wonder why dogs often don’t dig up these bones until weeks later, when they’re really quite rotten. My working theory is that this strategy is a useful, not to mention natural, way for dogs to replenish their gut microbes when needed. It might also be a way of making the various components of the bone (especially the mineral deposits and dense connective tissues) more available, just as the aging of meat makes it more tasty and tender — which is to say, more appetizing, digestible, and thus nutritious.

The interactions between bodies and the microbes that live on us and in us, and on/in our food, fascinate me. I think there’s much more to be learned about these relationships, and the simple thing of a dog burying a bone might instruct us as well as any scientific study.

The spectrum of gut microbes is very different between herbivores and carnivores. (Omnivores fall somewhere in between.) That’s because each bacterial species or strain has preferred food sources: substances that the microbe is best equipped or adapted to use as its own source of nutrition, or that provide nutrients which are essential for that particular microbe.

So, the gut microbes of an animal who primarily eats plants will be those that are best suited to breaking down plant material. And the gut microbes of an animal who primarily eats other animals will be those that are best suited to breaking down animal material.

As another neat efficiency of nature, the predominant microbes on or in a presently or formerly living thing are typically the very microbes best equipped to decompose it — or ‘digest’ it, if you like — to break it down into elements that can then be used to compose or recompose something else. This is the process that’s going on in a compost pile, and in the gut.

So, it’s possible that burying a bone and leaving it for days or weeks in the relatively anaerobic (low-oxygen) environment of the soil does two things of physiological value to the dog: (1) it speeds up the microbial breakdown of some otherwise quite indigestible components of the bone, thereby making the bone more digestible, and (2) it cultivates and thus concentrates the very microbes needed to make good use of animal material in the relatively anaerobic environment of the gut. Now, that’s clever.

Another natural and efficient way of obtaining more gut microbes is by eating the feces of another animal. I even toyed with making an entire section titled “Dogs eat poop.”

But between burying bones and eating dog or cat poop, I much preferred that Miss Lilly ate unearthed bones, no matter how stinky they were. Eating the feces of other carnivores might be a natural, albeit occasional, behavior in dogs, but it disgusts me, and I just can’t get past it.

I didn’t mind her eating horse poop or goat poop; in fact, that was probably a useful, not to mention natural, way for her to get the sorts of gut microbes necessary to make good use of the plant material in her diet. (Carnivores will usually eat some or all of the gut contents of their prey, thereby getting both plant nutrients and the microbes needed to break down plant material into a more useable form.) But carnivore poop? Eww!!

I much rather she ate the green, slimy, stinky bones she loved so much, her “dog kimchi.” Not only did her breath not smell of dog poop afterwards, but she was at far less risk of contracting a parasitic, bacterial, or viral infection from the “cultured” bones than from eating dog or cat poop. (Funnily enough, her stinky-bone breath didn’t smell bad for very long after she’d eaten one of those bones.)

It’s interesting to me that Miss Lilly never once showed any signs of digestive upset from having eaten her buried bones. In fact, it seemed to be a self-medication or health-maintenance strategy she used to prevent or treat minor digestive upsets, in much the same way I use probiotics or live-culture foods (raw sauerkraut, yoghurt, kefir, etc.): as-needed, just to set things right.

Miss Lilly buried only some of her bones; most of the time she ate them fresh. But when she did bury and later dig up and eat her stinky bones, I was glad to see it, because it appeared to me that she was practicing a survival strategy which evidently has been used by carnivores with great success for eons.

but aren’t bones unsafe?

[That's tomorrow's topic. Stay tuned...]

? 2022, Christine M. King. All rights reserved.

Feeding Miss Lilly: on feeding dogs a great, nature-inspired diet (revised edition) is available as print and e-book at:

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