Hip Dysplasia

in

the Retriever Breeds

by

Keith Stroyan

Why this article?

...knowing the scientifically proven facts can help to improve the retriever breeds and prevent suffering...

I own a dysplastic dog. A talented, energetic, strong, animal with years of intensive training and hunting. She is also a family friend. The bad condition of her hips came as a total surprise with the X-rays taken shortly after her second birthday. I have since learned that a lack of symptoms at this age is common. Two year old dysplastic dogs are between the most destructive phases of the disease. She was somewhat worse at 3, but has remained fairly active until her present age of almost 8, hunting some, earning a Grand Master Hunting Retriever title and qualifying for 4 NAHRA Invitational Field Tests. There are various treatments to help her when they are needed, for now, buffered asprin (Ascriptin) given before and after strenuous exercise (or when she seems to be having a bad day) is enough. She won't be destroyed unless the pain can't be controlled and she's done better than we expected at 3 and 4. With treatment, she may do well to an old age.

The breeder did the best I could ask for under the circumstances and refunded my purchase money on proof of spaying. Dysplasia is a very wide-spread problem and no matter how conscientious, every breeder will eventually be called upon to honor a genetic defect guarantee. It's a guarantee no one wants to collect, but reputable breeders will honor when needed. (Most want the dog returned or destroyed.) I have learned that guarantees are sometimes abused by buyers who neglect or mistreat a dog and I am sure there are also breeders who don't honor legitimate claims. My experience is "good," but would be better if I hadn't had to collect. I wanted to help avoid the problem.

My first reaction to the bad news was to ask all the old-time dog people I know what to do. The advice I received was so contradictory that I decided to track down the actual scientific literature as well as to talk to every breeder I could. I have no medical training, but I have access to good libraries. I have since read a great deal about hip dysplasia and eye problems (and come across various other genetic defects) from up-to-date sources. (Most recent: Seminars in Veterinary Medicine and Surgery (Small Animal), Vol.II, nr.2, May 1987 subtitled, Hip Dysplasia: Perspectives of the Eighties.) This article is to give a practical summary of what I have learned about hip dysplasia. I believe that knowing the scientifically proven facts can help to improve the retriever breeds and prevent suffering animals and disappointed owners. Some of the "common knowledge" on hip dysplasia is destructively wrong, but veterinary science does not have all the answers, either (as they freely admit).

What is Hip Dysplasia?

Hip dysplasia starts as a combination of loose ligaments and shallow socket on the hip joints. This poor fit causes injury to the bones and results in varying amounts of arthritis (remodeling). A rough ill-fitting joint can cause crippling pain, but there is a spectrum of responses depending on many factors. Some fairly badly dysplastic dogs will not show outward signs (but usually should not be bred).

What Causes Hip Dysplasia?

Without doubt hip dysplasia is primarily an inherited disorder. Moreover, the inherited component is where we have the best chance of improvement. However, it is a complicated recessive inheritance involving several genes, and more confusing yet, is also highly influenced by "environment." For example, two identical pups with genes for bad hips may develop quite differently. If one is kept lean, exercised and fed a balanced diet, he may develop normal hips, while if the other is overfed, and worst of all, given calcium and vitamin D supplements, he will develop bad hips. Both have the same bad genes that they will pass on to their offspring. Reducing hip dysplasia is a long term part of breeding better retrievers.

One thing science knows for sure is this:

Don't overfeed your pup. And don't supplement his diet with calcium and vitamin D. Feed a high quality fresh dog food, give him plenty of exercise and keep him lean (not starving). Take him off puppy food at four months, changing to high quality adult dog food. There is currently a popular "quick fix" theory that feeding massive doses of vitamin C will "cure" dysplasia. It simply doesn't work in controlled experiments and high doses present other dangers. The only current prospect for "cure" is a long term breeding program that includes careful attention to hips (along with the rest of the dog).

You can't tell by looking.

... my guess is that over half of the living retrievers are dysplastic...

The evidence for inheritability of hip dysplasia is most convincingly presented in a study of 401 litters of German Shepherd dogs that was done at the Swedish Armed Forces Training Center from 1965 to 1975. Hip dysplasia in shepherds is similar to that in the large retrievers as far as I can tell. They X-rayed 2,404 dogs and kept complete breeding records of every pup. Records like that are not easy to get. When dogs that 'looked good' were bred, they got 50% dysplastic pups (and my guess is that over half of the living retrievers are dysplastic to some extent), but when X-rays of parents and maternal grandparents as well as progeny testing was instituted, in two years this was lowered to 28% with only 15% worse than "grade I" (mild) dysplasia. Contrary to one recent popular article, long term breeding programs are reported to produce 10% or less dysplastic pups, so progress is possible.

What should we do?

...dogs without OFA numbers are like dogs without registration papers...

First, don't breed dogs that do not have OFA certificates (or good Wind Morgan or PennHip evaluations) from X-rays your vet submits to the Orthopedic Foundation for Animals [2300 Nifong Road, Columbia, MO 62501, phone (314)-442-0418]. OFA has three unbiased experts read the X-rays and agree on a rating. Your dog must be two years or older to receive an OFA number, because younger dogs often change. To me, dogs without OFA numbers are like dogs without registration papers. If they don't have 'em, they ain't. It is possible to use a dysplastic dog in a successful program, but it should only be done with great caution, careful selection of the mate and follow-up on the pups.

A dog identified only as "Champ" in the literature, but listed as two time national amateur champ, three time Canadian national champ and all time high point retriever was dysplastic, but produced 50% sound pups when bred to a good dam. The good pups in turn produced 80% sound pups. If your dog is dysplastic and beats River Oaks Corky's all-time record, think about breeding him, otherwise train him, hunt him, love him, and get your pups out of another good retriever with OFA hips. If you do breed him, expect a lot of bad hips and breed the second generation accordingly.

Second, ask to see the OFA numbers of the parents and grandparents of a pup you're thinking of buying. Here is the rating system recommended in the book by Fred L. Lanting (Canine Hip Dysplasia, Alpine Publications, Loveland, CO, 1981) to use as a further guide in rating prospective parents of your pup.

Acceptable: Dog has OFA certificate of "fair."

Good: Dog has OFA "good" or "excellent."

Better: Dog has OFA "good" or "excellent" plus both parents have OFA numbers.

Best: Dog has OFA "good" or "excellent" and both parents have OFA, plus has produced 70% OFA progeny when bred twice to an OFA "good" or "excellent" partner or 80% OFA progeny when bred twice to a "good" or "excellent" partner with OFA parents, or 90% when bred to a "Best" dog.

There just don't seem to be adequate records to produce many "Best" ratings - you need to X-ray every pup you produce for at least two breedings. The breeders who have done this reduce dysplasia to under 10%. The moral of this rating system is simple: hip dysplasia is recessive, reducing it takes generations. Each dysplastic breeding sets retrievers back to square one in the hip department. On the other hand, even non-environmentally influenced polygenic recessive traits could be hard to eliminate and dysplasia isn't that nice. One of the top breeders in the country told me she produced a litter of dysplastic dogs from two OFA "excellent" parents with OFA grandparents. Progress will take steady effort thru generations, so look for those GMHRs, MHRs, WRs, FCs, AFCs and OFAs - and now PennHips and Wind Morgans.