PennHIP
The information provided on this page, was gathered from antechimagingservices.com/antechweb/pennhip
What is PennHip?
PennHIP is a technique used to assess the quality of canine hips and measure the laxity within the hip joint. Passive hip laxity refers to the degree of "looseness" of the hip ball in the hip socket when the dog's muscles are completely relaxed. Research has shown that the degree of passive hip laxity is an important factor in determining susceptibility to osteoarthritis.
Participation in PennHIP evaluation requires the practicing veterinarian be certified and trained specifically to properly perform the PennHIP process.
The PennHIP method consists of three separate radiographs; the distraction view, the compression view and the hip-extended view.
- The distraction view is used to obtain accurate and precise measurements of joint laxity.
- The compression view is used to determine the hip joint congruity (i.e. looking closer at the fit of the femoral heads into the acetabula).
- The hip-extended view is used to evaluate the existence of osteoarthritis (OA) of the hip joint.
Overall, the objective of screening for hip dysplasia in canines is to be able to identify those with tighter hips, vs those with looser hips inevitably making them more susceptible to hip dysplasia later in life. The PennHIP method allows breeders to confidently identify the members of their breeding stock with the tightest hips and the best breeding potential.
In summary, the looser the joint as determined by the PennHIP method, the greater is the chance that the hip will develop OA, ultimately resulting in hip dysplasia.
PennHIP evaluations are expressed as a number between 0-1. Evaluations closer to 0 indicate minimal laxity/tighter hips, than those graded closer to a 1.
Participation in PennHIP evaluation requires the practicing veterinarian be certified and trained specifically to properly perform the PennHIP process.
The PennHIP method consists of three separate radiographs; the distraction view, the compression view and the hip-extended view.
- The distraction view is used to obtain accurate and precise measurements of joint laxity.
- The compression view is used to determine the hip joint congruity (i.e. looking closer at the fit of the femoral heads into the acetabula).
- The hip-extended view is used to evaluate the existence of osteoarthritis (OA) of the hip joint.
Overall, the objective of screening for hip dysplasia in canines is to be able to identify those with tighter hips, vs those with looser hips inevitably making them more susceptible to hip dysplasia later in life. The PennHIP method allows breeders to confidently identify the members of their breeding stock with the tightest hips and the best breeding potential.
In summary, the looser the joint as determined by the PennHIP method, the greater is the chance that the hip will develop OA, ultimately resulting in hip dysplasia.
PennHIP evaluations are expressed as a number between 0-1. Evaluations closer to 0 indicate minimal laxity/tighter hips, than those graded closer to a 1.
Selective Breeding
"For the most rapid genetic change, the breeder can decide to mate only the tightest-hipped dogs within the breed (those with the lowest DI) and then continue to inbreed for tight hips from there. This approach, however, will create increased inbreeding which may have adverse effects. Founding a breeding program on only a few dogs, and inbreeding on these dogs, would reduce the overall genetic diversity in the gene pool and could contribute to the loss of some desirable traits or lead to the expression of some undesirable traits. This reality affects some breeds more than others.
For example, less than 2% of Golden Retrievers have hip laxity in the ‘tight-hipped’ range, meaning a DI below 0.30. If one were to require that breeding candidates conform to this standard, 98% of the Golden Retrievers would be excluded from breeding, resulting in a serious reduction in genetic diversity. This breeding strategy would neither be practical nor acceptable to breeders and it is certainly not recommended by PennHIP.
To avoid the potential problems accompanying ‘extreme’ selection, PennHIP suggests a more ‘moderate’ approach which goes hand in hand with PennHIP testing. Particularly in breeds with few or no members having tight (OA-unsusceptible) hips, this moderate approach is preferable. In such breeds it is recommended that breeders choose breeding stock from the tightest half of the breed, thereby maintaining an acceptable level of genetic diversity while still applying meaningful selection pressure.
By breeding only dogs having hips better than the breed average (or the breed median) the overall breed average will move toward better (tighter) hips from one generation to the next. Clearly the more selection pressure applied (i.e., the tighter the parental DI's), the more rapid the genetic change."
For example, less than 2% of Golden Retrievers have hip laxity in the ‘tight-hipped’ range, meaning a DI below 0.30. If one were to require that breeding candidates conform to this standard, 98% of the Golden Retrievers would be excluded from breeding, resulting in a serious reduction in genetic diversity. This breeding strategy would neither be practical nor acceptable to breeders and it is certainly not recommended by PennHIP.
To avoid the potential problems accompanying ‘extreme’ selection, PennHIP suggests a more ‘moderate’ approach which goes hand in hand with PennHIP testing. Particularly in breeds with few or no members having tight (OA-unsusceptible) hips, this moderate approach is preferable. In such breeds it is recommended that breeders choose breeding stock from the tightest half of the breed, thereby maintaining an acceptable level of genetic diversity while still applying meaningful selection pressure.
By breeding only dogs having hips better than the breed average (or the breed median) the overall breed average will move toward better (tighter) hips from one generation to the next. Clearly the more selection pressure applied (i.e., the tighter the parental DI's), the more rapid the genetic change."
To Summarize
At Farmstead, we look at a combination of both PennHIP and OFA ratings for the adults being considered for our breeding program and only consider breeding those that score above the breed average, in most cases the adults within our breeding program have scored significantly better.
The Golden Retriever breed average is 0.53
The Pembroke Welsh Corgi breed average is 0.65
The Golden Retriever breed average is 0.53
The Pembroke Welsh Corgi breed average is 0.65
