Although individual Portuguese Water Dogs can be afflicted with various orthopedic problems, the primary disease condition affecting the breed is CHD, or Canine Hip Dysplasia. CHD is a common canine inherited condition that is not apparent at birth, in which there is irregular development of the hip joint as the dog grows. This results in a poorly fitting ball and socket, which with even normal activity tends to develop degenerative joint disease over time. CHD is a complex disease and it is believed that several genes are probably responsible. None of these have yet been identified and the only way to diagnose the disease is by examining radiographs of the hip joints. Many researchers believe the main contributors to hip dysplasia are joint laxity (or looseness) and a shallow acetabulum (or socket). Environmental influences can affect the expression of the disease. There can be a wide range of outcomes for the dog afflicted with CHD: some diagnosed by routine radiographs live normal lives and never develop clinical symptoms, where others are so uncomfortable or incapacitated that they require surgery. There are a number of things owners can do to help the PWD with CHD live as comfortably as possible. These include keeping weight off, regular moderate exercise, medical management, and in some cases surgery. All cases need to be looked at on an individual basis.
Action taken by the PWDCA:
The Orthopedic Committee monitors issues, studies, and databases relating to the orthopedic health of the PWD and reports to the PWDCA membership. The Orthopedic Committee is also available to provide support and information to all PWD owners with questions or concerns about their dogs.
Why the PWDCA is addressing this:
Portuguese Water Dogs affected with CHD can face a future of discomfort or pain due to the debilitating effects of osteoarthritic changes to their joints. Earlier identification of animals with the disease could allow owners make environmental changes that might reduce the amount of long-term damage. Identification of the genes responsible would allow breeders to make decisions that could reduce the overall incidence of the disease.
How the PWDCA is Addressing This:
Until there are DNA tests available to identify the genes responsible for CHD, the breeder's best means to decrease its incidence is to breed phenotypically normal dogs (i.e. Dogs evaluated as "normal" by OFA certification at 24+ months of age). Although dogs appearing to have normal hips can produce offspring with CHD, they are less likely to than dogs that are themselves afflicted with CHD. According to a recent OFA study, there is a positive and significant relationship between the hip status of the parents and offspring. The PWDCA recommends that all PWD's used for breeding have hip radiographs screened by the OFA. Many responsible breeders also have their breeding animals screened for elbow dysplasia.
An additional method of evaluating hip status with regard to laxity is offered by PennHIP. PennHIP requires a series of 3 radiographs and compares them to identify the laxity present in each hip joint when stressed to approximate normal use. This laxity measurement is provided to the PWD owner both as an absolute value and ranked in relation to all the PWD's in their database. According to their research, tighter-hipped parents tend to produce tighter-hipped offspring who will be less likely to develop CHD.
Other Important References - articles, books, websites:
- Canine Orthopedics, Robert L Rooks, DVM, 1997, Howell Book House
- Hereditary Bone and Joint Diseases in the Dog, Morgan, Wind, and Davidson, 2000, Schlutersche GmbH & Co.
- Genetics of the Dog, Malcolm B. Willis, 1989, Howell Book House
- The Courier, Volume 33, Issue 3; May/June 2005. Comprehensive Health Resource for Portuguese Water Dogs.
- Orthopedic Foundation for Animals (OFA) - www.offa.org (includes a searchable database)
- The University of Pennsylvania Hip Improvement Program - www.pennhip.org