Genetic diseases with simple modes of inheritance
Hip dysplasia
Current thoughts on hip dysplasis
Scientists now realize that hip dysplasia is caused by multiple genes and that the severity and progression of the disease is dependent upon a dog’s genetic susceptibility and exposure to certain environmental factors(Runge 2010).
Hip dysplasia has been studied for over 50 years and breeders have been trying to eliminate it in their programs for years yet it still exists and the prevalence has actually increased in later years (Junutta 2008). Some research shows that genetics only account for 15-40% of the variation in hip scores so influence from environmental factors are huge (Lewis 2013).
What is hip dysplasia
Hip dysplasia is a condition where the hip joints are loose. This laxity allows the head of the femur bone to not align properly in the hip socket. Over time this misalignment leads to abnormal wear on cartilage surfaces resulting in inflammation, pain and osteoarthritis.
Current testing and test problems
There is not a genetic test available.
There are 2 organizations that will rate hips on dogs, OFA and Pennhip. Dogs are sedated and x-rays are taken. This needs to be performed by veterinarians who have undergone training on how to properly align hips during the procedure. These x-rays are then sent off to OFA or Pennhip where they are graded by radiologists.
There are several problems with this method. One is that if the dogs legs are not properly aligned during the x-ray, the x-ray may not be accurate. The other is that there may be human error in actually scoring the x-rays.
The OFA classifies hips into 7 categories:
Excellent, Good, and Fair – these are all within normal limit
Borderline – results are not clear
Mild, Moderate and Severe – these all indicate some form of dysplasia
Scores reflect the hip laxity on individuals and does not necessarily reflect the genetics. Remember that there are multiple genes involved and that those genes have not been identified at this time. There have been cases where 2 dogs with excellent hip ratings have produced puppies with poor hips. This may be due to the fact that the environment plays a HUGE role in the development of hip dysplasia.
We still perform OFA test our dogs even though we are aware that research shows that using these values have not led to a reduction in hip dysplasia nor is it a great indicator in determining if a puppy will or will not develop hip dysplasia in the future.
Hedhammar A, F-M Wu, L Krook, HF Schryver, A de Lahunta, FP Whalen, FA Kallfelz, EA Nunez, HF Hintz, BE Sheffy, & GD Ryan. 1975. Overnutrition and skeletal disease: An Experimental Study in Growing Great Dane Dogs. Cornell Vet 64: Supp 5
Janutta V, Hamann H, Distl O. Berl Munch Tierarztl Wochenschr. 2008. Genetic and phenotypic trends in canine hip dysplasia in the German population of German shepherd dogs. 21:102-109.
Hedhammar A, F-M Wu, L Krook, HF Schryver, A de Lahunta, FP Whalen, FA Kallfelz, EA Nunez, HF Hintz, BE Sheffy, & GD Ryan. 1975. Overnutrition and skeletal disease: An Experimental Study in Growing Great Dane Dogs. Cornell Vet 64: Supp 5
Kealy RD, DF Lawler, JM Ballam, SL Mantz, DN Biery, EH Greeley, G Lust, M Segre, GK Smith, & HD Stowe. 2002. Effects of diet restriction on life span and age-related changes in dogs. J. Am. Vet. Med. Assoc. 220: 1315-1320.
Krontveit RI, A Nodtvedt, BK Saevik, E Ropstad, & C Trangerud. 2012. Housing- and exercise-related risk factors associated with the development of hip dysplasia as determined by radiographic evaluation in a prospective cohort of Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds in Norway. Am J Vet Res 73: 838-846.
Lewis, TW, SC Blott, & JA Woolliams. 2013. Comparative analyses of genetic trends and prospects for selection against hip and elbow dysplasia in 15 UK dog breeds. BMC Genetics 14:16.
Runge JJ, Kelly SP, Gregor TP, et al. 2010, Distraction index as a risk factor for osteoarthritis associated with hip dysplasia in four large dog breeds. J Small Anim Pract 51:264-269, 2010.
How does the environment play a role?
Environmental factors play a HUGE role in determining if a dog will develop hip dysplasia. Research shows that all puppies are born with normal hips therefore hip dysplasia in not a congenital defect (Riser 1985) but environmental factors starting in puppyhood may influence their chance of developing hip dysplasia later in life.
What we do to prevent hip dysplasia
Providing excellent footing in the whelping crate
We make sure that babies are raised on a surface with excellent traction to prevent slipping (Krontveit 2012).
Controlling weight in pregnant females
We closely monitor weight in our females to prevent large puppies that will have a hard time moving around (Riser 1985).
Monitoring weight in dogs
We weigh our dogs and evaluate their body condition on a monthly basis. We then adjust the amount of food that they receive to keep their weight in check.
Research shows that dogs kept on a restricted diet are 25% less apt to develop hip dysplasia than dogs that are overweight and they live longer too (Kealy 2002). Obesity may be the single most significant environmental factor.
No stairs for the first 3 months
We do not expose our puppies to stairs before they leave and recommend that new owners prevent their puppies from going up or down stairs until the puppies are 3 months old. (Krontveit 2012)
Hand feeding puppies
Research shows that puppies kept on a restricted diet have a much lower rate of hip dysplasia.(Hedhammar 1975) We do not free feed our puppies.
Feeding a high quality food
We feed all of our adults and puppies a high quality food. Research shows that dogs fed high quality foods have a lower incidence of hip dysplasia than those fed a lower quality food. We feed and recommend Purina ProPlan.
Age appropriate exercise
Our puppies and adults all receive daily exercise based upon their age and stage of development. Research shows that dogs who received appropriate daily exercise have a lower incidence of hip dysplasia. The key is low strenuous exercise and not over exertion. Please note that too much exercise, prolonged periods of exercise, high impact exercise or allowing puppies to tussle and play hard with other dogs or puppies can actually increase the rate of hip dysplasia.
We send home a booklet with every puppy outlining age appropriate exercise based upon age.
What you can do as dog owners
Providing excellent footing
Make sure that your dogs are not living on slippery surfaces.
Monitor your dogs weight
Routinely weigh your dog and evaluate their body condition to make sure that your dog is not overweight.
With puppies, No stairs for the first 3 months
Feed a high quality food
Appropriately exercise your dog
All dogs need daily exercise but it needs to be age appropriate and the right level of exercise. The key is low strenuous exercise and not over exertion. Please note that too much exercise, prolonged periods of exercise, high impact exercise or allowing puppies to play roughly or for long periods of time with other dogs or puppies can actually increase the rate of hip dysplasia.
