There are few things better in life than sitting having a nice leisurely meal surrounded by your loved ones – two legged and four legged. On Sunday mornings at our place, we have a cooked breakfast finished with tea and toast with honey. Both dogs hover around the table when the meal ends because they know they will get a little corner of toast and honey. That is our little ritual and I am OK with it because we keep the dogs lean but…. what if that occurred every day and the little corner of toast became a little more? Very easily, that little bit of “love” we shared with our dog has turned into a weight problem.

We are regularly bombarded with media exclamations about the “obesity crisis”. Regardless of all the hyperbole, we know that being overweight for us and our dogs decreases quality of life and our life expectancy.

Being overweight also has a direct correlation to the occurrence of joint disease, particularly osteoarthritis. It is not clearly understood which comes first – being overweight and joint disease or the other way around. Regardless, the link between weight and joint health has been identified at the biomechanical and biochemical level.

Biomechanics

Being overweight affects dog’s movement in the following ways:

• Firstly, being overweight changes the dog’s gait. Lean dogs have longer strides than their overweight cousins. Overweight dogs take approximately 8% shorter strides. Changes in gait is a compensatory measure and often results in muscular strain from abnormal loading.

• Secondly, overweight dogs apply about 25% more vertical ground force on their forelimbs and 26% more ground force on their hind limbs, than lean dogs. Braking force on joints is also significantly greater in overweight dogs (28% greater force in the forelimbs and 46% in the hind limbs). These increased forces equate to larger stresses on the joint surfaces.

• Thirdly, overweight dogs have greater range of motion in their elbow, shoulder, hip and tarsal joints. It is thought that the greater range of motion may be due to joint laxity (looseness) from reduced muscle “stiffness” around the joint. Greater range of motion combined with greater body mass in obese dogs requires the production of greater muscle torque around the joint during locomotion. Greater torque increases shear and compressive forces on the joints which could be a factor in the progression of osteoarthritis.

Biochemical

The hormone leptin has in recent years been identified as playing a role in obesity and osteoarthritis in human and animal studies. Leptin is a hormone that is produced in white adipose (fatty) tissue.

In lean humans and animals, leptin helps balance the effects of dietary energy intake. When leptin is released it triggers the hypothalamus to decrease appetite and reduce food intake. As the concentration of adipose (fatty) tissue in the body increases so too do leptin concentrations. Increases in leptin concentrations leads the body to become resistant to leptin signals. This interferes with the feedback from the hypothalamus to down regulate food intake which further contributes to the weight problem.

Leptin has also been shown to have an inhibitory effect on the production of chondrocytes which are the cells required for growth and regeneration of articular cartilage in the body’s joints. Osteoarthritis or degenerative joint disease is characterised by the destruction of cartilage and thickening of the bones of the articular surfaces of joints. So high concentrations of leptin in the body does not benefit dogs with degenerative joint diseases.

Combine the effects of greater biomechanical forces on the joints with inhibited articular cartilage growth and the relationship between obesity and osteoarthritis is fairly clear. Studies in dogs show that being overweight not only increases the occurrence of osteoarthritis but also the severity of the disease.

Treatment and management of osteoarthritis in overweight dogs

The extent of disability in overweight dogs with osteoarthritis can be reduced with a combination of nutrition and exercise therapy.

Weight loss

In humans and dogs, there is very strong evidence that weight loss has a significant positive effect on lameness from osteoarthritis. In a study of overweight dogs with osteoarthritis, a moderate weight loss of 6.2% of body weight resulted in improved lameness scores.

Exercise therapy

Myofunctional assessment and treatment including gait training exercises to compensate for force abnormalities in overweight dogs can be beneficial in reducing the clinical signs of lameness associated with osteoarthritis.

Full Stride can formulate a nutrition and myofunctional treatment programme to improve the mobility and quality of life of overweight dogs with osteoarthritis. Full Stride recommends a check with your vet to eliminate diseases such as diabetes, hypothyroidism or other conditions as the cause for weight gain. For more information please contact me to discuss a plan for your dog.

Until next time, enjoy your dogs.

Sources:

Brady, R.B, Sidiropoulos, A.N, Hunter, J.B, Rider, P.M, Marcellin-Little, D,J & DeVita, P. 2013 “Evaluation of gait-related variables in lean and obese dogs at a trot” American Journal of Veterinary Research. Vol 74 (5) May 2013: 757 – 762

Case, L.P, Daristotle, L, Hayek, M & Raasch, M.F, 2011, Canine and feline nutrition (3rd ed), Mosby Elsevier, Missouri.

Sanderson, S.L. 2012 “The epidemic of canine obesity and its role in osteoarthritis” Israel Journal of Veterinary Medicine. Vol 67 (4), December 2012: 195 – 202