Cartilage Is A Nutritional Goldmine

The Importance of Cartilage in the Canine (and Feline) Diet

Cartilage is made up of highly specialized cells and a matrix of proteins. It is more matrix than cells because cartilage does not contain blood vessels to receive oxygen which creates a low-oxygen tissue that is not an ideal environment for cells. The matrix of cartilage is made up of proteins known as collagen and proteoglycans as well as other minor proteins. The wealth of value found in feeding cartilage to pets is in the matrix where we find the collagen, hyaluronic acid, and chondroitin. Because collagen is the most abundant protein in the body, it is vitally important that your pet receives an abundance of collagen from cartilage in their daily meals. As our pets age, their collagen production decreases in the same way as ours. This can lead to an increased risk for tendon and ligament injury and damage, joint injury and destruction, muscle soreness after exercise, and even muscle atrophy. Hyaluronic acid acts as a lubricant and a cushion for the joints and tissues assisting in preventing injury. Couple these with chondroitin, a chemical found primarily within joint cartilage that creates elasticity and the ability to retain water, and you have a cocktail of nutrients that, according to numerous studies, are twice as effective as using glucosamine supplements for joint health. If this is not beneficial enough, cartilage also contains micronutrients that include manganese, copper, and even some vitamin C. Thus it is vital to feed your pet all types of cartilage-rich raw meaty bones (RMB) such as joints, rib cages, and vertebrae as well as cartilage structures such as trachea, ears, and bronchial tubes.

This begs the question, what or how is the best way to feed cartilage to your pet? Since many pet parents follow the popular 80/10/10 meal-formulation guide [80/10/10 is a ratio formula used to create raw meals that translates into 80% muscle meat, 10% secreting organs (5% liver + 5% other), and 10% bone], I am often asked, which category would non-bone cartilage such as trachea or ears fall into; bone or meat? It certainly seems to be a reasonable question, but is applicable only if a pet parent is following a ratio too strictly. In all honesty, it is an irrelevant and futile question in that in the attempt to categorize every tissue and body part ingredient into the 80/10/10 formula, pet parents tend to lose sight of an important fact . All parts of a prey animal’s carcass is simply a part of one WHOLE. Now don’t get me wrong, the 80/10/10 formula is a great guide to reining-in and limiting ingredient amounts to avoid an improperly “balanced” meal. So, let’s consider this more deeply by more closely examining bone and meat.

Cartilage is an integral part of all joints and has a close resemblance to bone in that they both contain a collagen protein matrix. Bone, however, also contains specialized cells and minerals that create the hard outer tissue, soft spongy marrow, the periosteum and endosteum as well as containing a network of nerves and blood vessels. Bone also functions to create blood cells within the bone marrow. Bone is the best and most vital source of macro-minerals in the diet, not to mention also being a great source of trace minerals and vitamin E (which is stored within the marrow). Muscle meat, on the other hand, is made up of excitable cells constituting skeletal, cardiac, and visceral muscle tissues. Muscle cell fibers contain a mere 1% to up to 10% collagen protein which is much lower and very different from cartilage. Muscle is mostly protein filaments known as actin and myosin (which allow for movement) with varying percentages of fat along with facia, nerves, blood vessels, blood, and more. Muscle is a major source of multiple vitamins and minerals that contributes a great deal to nutrient-requirement fulfillment in meals.

Living beings are not merely made up of muscle, organs, and bones as is inferred by the 80/10/10 ratio. Animals, like us, are comprised of four types of tissues: epithelial tissue, connective tissue, muscle tissue, and nervous tissue as well as fluids. Epithelial tissue includes the lining of the intestines (hollow organs) and surface skin. Connective tissue includes bone, tendons, ligaments, cartilage, and fat. Muscle tissue includes skeletal muscles, cardiac muscle, and internal organ muscle (any organ that produces movement). Nervous tissue includes the brain, spinal cord, and nerves. You may note that feeding only muscle, bone, and secreting organs does not create a proper “whole” and leaves out many body structures. Thus following a ratio is unrealistic and can, overtime, create deficiencies and/or toxicities if followed too strictly. This is why it is imperative to feed a species-appropriate diet (following what I call a Frankenprey model) that contains ALL parts of the whole. Whole prey would be ideal, but is not within the grasp of many DIY of raw feeders. Thus for those pet parents who cannot source whole prey, the goal should be to create the likeness or resemblance of whole prey on the plate or in the bowl.

How then do we feed cartilage? ANSWER: As part of the WHOLE. It is not bone and it is not meat. However, cartilage IS connective tissue which is in the same category as bone. Cartilage is easiest to feed as part of raw meaty bones in the daily diet. Adding in cartilage structures such as trachea and ears does not require a category as these types of structures should be fed in smaller amounts to be sure to not decrease the muscle protein being fed. Keep in mind that raw meaty bones contain bone, muscle, and cartilage! Focus on the RMBs in the diet and use the remaining vital ingredients (boneless meat, muscle organs, and secreting organs) to “fill in the blanks.” In fact, if you want to create a truly complete raw meal, feeding the more yucky parts is essential. By this I mean large vessel structures, connective tubes, glands, hide, ears, hoofs, feet with nails, and all the stuff I see most pet parents trimming off of their meal ingredients! Leave it on. Add in blood and myoglobin as well for a truly complete and nutritious meal. Raw feeding isn’t for the squeamish. We are feeding carnivores, after all. 😉

How To Properly Use a Ratio: The Raw Fed Dog

Creating a nutrient balanced meal with a “better” ratio

Let’s talk ratios. Ratios provide a super simple outline or guideline for feeding our dogs species-appropriate foods. The most common ratio is still 80/10/10. What that means is…

  • 80% meat
  • 10% organs (secreting)
  • 10% bone

Simple, right?! The problem with the above ratio is that many pet parents, and especially those new to raw feeding, do not understand that the 80/10/10 ratio is only a guideline and not an absolute set-in-stone plan to follow. Following the ratio too closely almost ALWAYS results in vitally important nutrients coming in consistently too low. This then increases the risk for health concerns down the road and often contributes to the disapproval that raw feeding has within the veterinary community. Feeding variety does help, but when a dog has protein sensitivities and limited proteins are being offered, providing nutrient balanced meals can become quite the challenge.

In my profession, I have the unfortunate job of seeing the bad side of raw feeding on a regular basis. Many pet parents come to me seeking “desperate” help. From my vantage point, raw feeding can look scary! Thus I created this blog and our Facebook group to be a resource and educational platform to help pet parents feed a more balanced (varietal and rotational) nutrition plan. I have mulled over a better ratio that will help pet parents feed a more nutrient balanced diet and still be able to follow a ratio. Let’s take a look…

Standard RatioBetter Ratio
80% meat55% to 65% skeletal muscle +
15% to 25% organ muscle
10% secreting organ3% to 5% liver +
5% to 7% other secreting organ
(Don’t fall for the misconception that you can’t
feed more than 10% secreting organs! Of course
you can!)
10% boneMINIMUM bone 12%
Whole prey has an average bone % of 12%.
10% bone is too low for most dogs and MUCH TOO
LOW for puppies.

Did you notice the percentage variation on the liver? This is important to discuss. Most pet parents feed chicken liver, beef liver, turkey liver, or pork liver. Chicken and beef livers are easiest to source. The problem with liver is that some have a very high amount (saturation) of copper and others have next to none. If you are feeding a full 5% of a high copper liver, then you are likely exposing your dog to too high an amount of the trace mineral copper. Worse yet, if your zinc levels are too low, which is very common in raw meals, then a zinc deficiency is a very real possibility. Zinc and copper need to be in the correct ratio. Let me reemphasize this. Even if you are just hitting your dog’s zinc requirements (at around 90% to 110%), but the copper is coming in at around 200% to even 250% of their copper needs (which can easily be achieved with 5% liver), then the zinc is TOO LOW.

High copper liver includes: beef, calf (veal), lamb, goat (extremely high!)

Low copper liver includes: pork, chicken, turkey

Moderate copper liver: duck liver


1) If you are feeding a high copper liver, 5% liver is going to be too high if you are not adding a zinc supplement, and even then, the copper is still a bit too high to be fed at 5% consistently.

2) If you are feeding a low copper liver, then 5% will not meet copper needs, thus adding oysters or a zinc/copper combination supplement will be necessary. (Oysters are naturally high in zinc and copper!)

3) Rotating with a high copper and low copper liver every other day is also an option as long as you pay attention to zinc in the daily meals.

Some raw feeding “professionals” recommend feeding liver even higher if you do not have another secreting organ to feed a full 10% secreting organs. The recommendation is to feed liver at a dangerous 10%. Please do not ever fall for this ill-advised recommendation. Your dog may be being exposed to copper at a dangerously high level as well as getting far too much vitamin A. The main concern is a nutrient imbalance leading first and foremost to a zinc and vitamin D deficiency as well as a possible forthcoming toxicity condition. Keep liver at 5% maximum or lower.

As for the 80% meat, if you feed only skeletal meat without any organ muscle, you will not hit nutrient requirements unless you are feeding your dog grossly too much food. Of that 80%, a MINIMUM of 15% should come from muscle organs such as heart, lung, gizzard, and tripe. In my opinion, that should be upwards of 20% as often as possible. I feed my dogs a combination total (muscle organs plus secreting organs) of a near 40% organs in most of their daily meals. The remaining is RMBs and a small percentage of boneless meat. This way I am not just barely meeting nutrient requirements, I am exceeding them in a balanced, well-thought out plan.

For bone, the 10% general recommendation is too low for most dogs. Whole prey has an average bone percentage of 12%. You can safely feed your dog 12% to 15% daily even up to 20%. I would not, however, exceed 25% bone. If you have a growing pup then you will need to feed a minimum of 15% up to, but not exceeding, 25%. Bone contains the base of minerals in the diet as well as bone marrow (where white blood cells, red blood cells, and platelets are made) and connective tissues (rich in glucosamine, chondroitin, and minerals) that contain a gold mine of value and nutritional components that are vital if optimal health and maintenance is your plan.  

Ratio Quick view:

Skeletal muscle = 55% up to 65%

Organ muscle = 15% up to 25%

Secreting organs = 10% up to 12%

Bone = 12% to 18%

Work your dog up gradually to a higher overall organ percentage while also increasing bone percentage. Take it slowly and be patient!

©2019 Kimberly Lloyd, PhD, BCHHP, Cert Raw Dog Food Nutritionist