ChessieMom
entry 5 of 63 < previous | next >
Why Test OFA?
Oct 29, 2009 01:43 PM
Casco's coming up on two next month, and so it's time for me to think about her hip X-rays in order to determine her OFA-hip rating.
Hip dysplasia is a relatively common canine problem. Hip dysplasia means that there is a problem -- usually laxity or a malformed joint -- in one or both of the ball-and-socket hip. Dogs with hip dysplasia are significantly more likely to have painful or even debilitating arthritis at some point in their lives. Although dysplasia can be caused by injury, the predominance of dysplasia is passed on genetically.
OFA, or the Orthopedic Foundation for Animals, keeps a registry of dogs whose X-rays have been submitted for rating. There are other reputable registries, most notably PENN-Hips, but OFA is the most common for most AKC breeds. It is vital to the continued health of the breed to ensure that potential breed stock be tested for prevalent genetic diseases. Most larger breeds -- to include Chesapeake Retrievers like Casco -- have the potential for hip dysplasia. Thus, all breeders need to ensure that both sire and dam have acceptable hip ratings before breeding. Although hip X-rays can be submitted for preliminary results before the age of two, OFA will not issue "official" results before the age of two. This is one of a bazillion reasons why responsible breeders would never breed an animal -- sire or dam -- before the age of two.
Because there are multiple causes and types of hip dysplasia, there is no simple genetic test for certain other canine diseases. Likewise, there are varying degrees of acceptable and unacceptable hips, and those degrees are breed, sex and age dependent. For instance, a twenty-six month old b*itch Chesapeake Bay Retriever would only be compared to other Chesapeake Bay Retriever girls of the same age.
Hip X-rays that are submitted to OFA are graded by three radiologists and rated Excellent, Good, Fair, Borderline, or Moderately/Mildly/Severely Dysplastic. In general, Chesapeakes should receive at least an Excellent, Good or Fair rating in order to be considered for a breed program, and it is always a good practice to "breed up." For instance, a breeder with a dam that has a "Fair" rating will typically look for a sire who has a "Good" or "Excellent" rating, in order to reduce the likelihood of dysplasia in future generations.
A breeding of two OFA Fair, Good or Excellent dogs is not a guarantee that the next generation will also have Fair, Good, or Excellent hips. In fact, in retrievers, 20-25% of puppies produced by two OFA sound parents will have some level of dysplasia. That percentage goes up substantially, however, when one or both parents is actually dysplastic.
Testing of unspayed girls is complicated by heat cycles since a b*itch's body will act as though it is pregnant for several weeks after estrus, regardless of whether the bitch is pregnant or not. As with most other mammals (including humans), a hormone called relaxin kicks in order to allow more flexibility of the ribs and pelvis during pregnancy and birth. While it is impossible to make any dog's hips look better than they are on an X-ray, it is definitely to make them look worse, so most breeders believe that X-rays a month before or up to six weeks after a heat cycle are significantly more likely to show some level of laxity that may (rightly or not) be interpreted as dysplasia by the radiographers at OFA.
In addition to breeders, dog fanciers who compete in agility, flyball, field work, advanced obedience or other high impact activities may also want to have their dogs X-rayed since these activities might aggravate dysplastic hip joints and cause premature arthritis or crippling injury.
This is only one of many health certifications that a breeder or purchaser of a Chesapeake Bay Retriever should consider. There are other genetic health tests that are equally important. Moreover, even the healthiest of dogs should not be bred if they exhibit aggression, timidity or lack of intelligence, as these characteristics can also be passed on from generation to generation.
Hip dysplasia is a relatively common canine problem. Hip dysplasia means that there is a problem -- usually laxity or a malformed joint -- in one or both of the ball-and-socket hip. Dogs with hip dysplasia are significantly more likely to have painful or even debilitating arthritis at some point in their lives. Although dysplasia can be caused by injury, the predominance of dysplasia is passed on genetically.
OFA, or the Orthopedic Foundation for Animals, keeps a registry of dogs whose X-rays have been submitted for rating. There are other reputable registries, most notably PENN-Hips, but OFA is the most common for most AKC breeds. It is vital to the continued health of the breed to ensure that potential breed stock be tested for prevalent genetic diseases. Most larger breeds -- to include Chesapeake Retrievers like Casco -- have the potential for hip dysplasia. Thus, all breeders need to ensure that both sire and dam have acceptable hip ratings before breeding. Although hip X-rays can be submitted for preliminary results before the age of two, OFA will not issue "official" results before the age of two. This is one of a bazillion reasons why responsible breeders would never breed an animal -- sire or dam -- before the age of two.
Because there are multiple causes and types of hip dysplasia, there is no simple genetic test for certain other canine diseases. Likewise, there are varying degrees of acceptable and unacceptable hips, and those degrees are breed, sex and age dependent. For instance, a twenty-six month old b*itch Chesapeake Bay Retriever would only be compared to other Chesapeake Bay Retriever girls of the same age.
Hip X-rays that are submitted to OFA are graded by three radiologists and rated Excellent, Good, Fair, Borderline, or Moderately/Mildly/Severely Dysplastic. In general, Chesapeakes should receive at least an Excellent, Good or Fair rating in order to be considered for a breed program, and it is always a good practice to "breed up." For instance, a breeder with a dam that has a "Fair" rating will typically look for a sire who has a "Good" or "Excellent" rating, in order to reduce the likelihood of dysplasia in future generations.
A breeding of two OFA Fair, Good or Excellent dogs is not a guarantee that the next generation will also have Fair, Good, or Excellent hips. In fact, in retrievers, 20-25% of puppies produced by two OFA sound parents will have some level of dysplasia. That percentage goes up substantially, however, when one or both parents is actually dysplastic.
Testing of unspayed girls is complicated by heat cycles since a b*itch's body will act as though it is pregnant for several weeks after estrus, regardless of whether the bitch is pregnant or not. As with most other mammals (including humans), a hormone called relaxin kicks in order to allow more flexibility of the ribs and pelvis during pregnancy and birth. While it is impossible to make any dog's hips look better than they are on an X-ray, it is definitely to make them look worse, so most breeders believe that X-rays a month before or up to six weeks after a heat cycle are significantly more likely to show some level of laxity that may (rightly or not) be interpreted as dysplasia by the radiographers at OFA.
In addition to breeders, dog fanciers who compete in agility, flyball, field work, advanced obedience or other high impact activities may also want to have their dogs X-rayed since these activities might aggravate dysplastic hip joints and cause premature arthritis or crippling injury.
This is only one of many health certifications that a breeder or purchaser of a Chesapeake Bay Retriever should consider. There are other genetic health tests that are equally important. Moreover, even the healthiest of dogs should not be bred if they exhibit aggression, timidity or lack of intelligence, as these characteristics can also be passed on from generation to generation.
entry 5 of 63 < previous | next >
0 Comments: