A Simpler Approach to Canine Joint Components & Health
By Jon David Johnson
Many of us dog owners’ deal with some type of joint disease in our pets throughout their life.
Whether it’s our child’s golden retriever that never puts the tennis ball down or our active Labrador retriever that lives for hunting season, we all want to ensure our pets are able to do what they love.
With many products and supplements claiming to provide joint health in our pets, it can be difficult to decide what actually is the best thing for them. To make this decision, we must have the facts about canine joints and their components. Although there are three different categories of joints in the canine body, most of the problems we notice occur in diarthroidial joints. A diarthroidial joint is a joint that consists of synovial fluid and makes up the majority of the joints we commonly think of such as a knee, elbow, hip, etc. Diarthroidial joints consist of a variety of structures, but think about the joint as having three major components: subchondral bone, hyaline cartilage and synovial fluid. Most joint problems occur within one of these three components.
Subchondral bone is an organic matrix that makes up the end of long bones, such as the femur.
During canine development, the subchondral bone must completely ossify (change from cartilage to bone) or our pets will develop osteochondrosis. Osteochondrosis is failure of cartilage to turn to bone in the joint region, which leads to joint incongruence, pain and osteoarthritis later in life. Large breed dogs are predisposed to this disease due to their rapid growth and failure of endochondral ossification.
In order to help prevent this, we must ensure that we are providing the appropriate plane of nutrition to our pet. Too much is not always a good thing in this situation. To calculate your pets resting energy requirement you can use the following formula:
Resting Energy Requirement (k/cal per day) = 70 x Body Weight (kg) 0.75
Growing puppies require 2.40 to 4 times their resting energy requirement depending on their age group. If your puppy is 0-3 months of age then feed 4 times their resting energy requirements, if 3-6 months of age feed 3.20 times their resting energy requirements, and if 6-12 months of age feed 2.40 times their resting energy requirements. To identify the amount of k/cal per cup of your pets’ food, take a look at the food bag itself or the manufactures website and use that number to calculate the volume of feed needed. The goal of providing the appropriate nutrition level is to prevent unnecessary rapid growth and incomplete joint development.
Hyaline cartilage is the avascular, smooth, compressible, resilient surface that covers the articular surface of subchondral bone. This is where the majority of joint disease manifests. Hyaline cartilage consists of a proteoglycan matrix contained in a collagen framework. This proteoglycan matrix consists of several proteins attached to a polysaccharide chain; it helps resist compression, provides turgidity and extrudes water. Joint function is dependent on the health of the cartilage, which is dependent on a healthy proteoglycan matrix. One of the building blocks for this proteoglycan matrix is glucosamine and chondroitin sulfate. To help ensure the health of the joint, providing oral glucosamine and chondroitin sulfate to our pets on a regular basis, and beginning at an early age, may help prevent the many problems that develop in hyaline cartilage.
Most major pet nutrition companies offer dog food with these cartilage building blocks incorporated. Feeding this type of dog food provides an easy, effective and consistent way to ensure cartilage health in our pets.
Synovial fluid is a dialysate of plasma (a liquid filtrate from circulating plasma) and is the medium in which nutrition is provided to the hyaline cartilage. It is the viscous, liquid component of the joint, and fills the space between each bone ends providing frictionless movement of each bone associated with the joint. Since the hyaline cartilage is avascular, the only way that it can be nourished is via the synovial fluid within the joint. When weight is applied across the joint, the hyaline cartilage compresses and extrudes water; when this weight is removed from the joint, the cartilage acts as a sponge to absorb the synovial fluid and its contents.
To ensure our dogs are getting appropriate cartilage nutrition we must ensure our pets spend an appropriate amount of time on their feet to apply weight across the joint. If we just think about the joint as three interconnected components: the subchondral bone, the hyaline cartilage, and the synovial fluid, we can help prevent a majority of joint problems.
Remember that by providing the appropriate plane of nutrition to growing puppies, providing oral cartilage building blocks on a consistent basis, and keeping our dogs active, we can keep each of these components healthy. Let’s do everything we can for our pets, so they will enjoy many years of fetching tennis balls, frisbees, toys and birds.
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G. McCarthy, J. O’Donovan, B. Jones, H. McAllister, M. Seed and C. Mooney. Randomised doubleblind, positive-controlled trial to assess the efficacy of glucosamine/chondroitin sulfate for the treatment of dogs with osteoarthritis. The Veterinary Journal, 174 (2007), pp. 54-61.
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