PennHIP vs OFA: Understanding Hip Testing in Small Munsterlanders

Why Hip Health Matters and Why “OFA Excellent” Isn’t the Whole Story

Anyone researching a responsible Small Munsterlander breeder will eventually encounter discussions about hip dysplasia and hip testing. Puppy buyers frequently ask breeders whether their dogs have “good hips,” often assuming that a simple test determines whether a dog is safe to breed.

In reality, hip health is more complicated.

Hip dysplasia is influenced by both genetics and environment, and the tools breeders use to evaluate hips measure different aspects of joint structure. The two most common evaluation systems used in North America are:

• Orthopedic Foundation for Animals

• PennHIP

Both systems provide valuable information, but they evaluate the hip joint differently. Understanding those differences helps puppy buyers and breeders interpret hip scores more accurately.

Just as importantly, hip health should always be considered alongside other essential breeding priorities such as temperament, performance ability, and long-term breed stewardship.

What Is Hip Dysplasia in Dogs?

Hip dysplasia is a developmental orthopedic condition affecting the hip joint.

In a healthy hip:

• the femoral head fits tightly into the acetabulum (socket)

• the joint remains stable during movement

• surrounding muscles provide additional support

When the joint is loose (a condition called hip laxity), abnormal movement can occur. Over time this instability may cause inflammation, cartilage wear, and eventually arthritis.

However, hip dysplasia is not caused by a single gene.

Instead, it is considered a polygenic and multifactorial condition, meaning many factors influence the final outcome.

These include:

• genetic predisposition

• growth rate during puppyhood

• body condition and nutrition

• exercise and muscle development

• environmental influences during development

Because of this complexity, hip testing should be viewed as a risk assessment tool rather than a guarantee.

Hip Health in the Small Munsterlander

Compared with many sporting breeds, the Small Munsterlander has historically demonstrated a relatively low incidence of hip dysplasia.

Several factors likely contribute to this:

• moderate body size

• strong emphasis on functional hunting performance

• careful breeding practices within the breed community

Working breeds that rely on athletic performance tend to naturally favor dogs with sound structure and efficient movement, because dogs with significant structural weaknesses often cannot maintain demanding hunting workloads.

Even so, responsible breeders continue to evaluate hips to ensure the breed maintains this strength over time.

OFA Hip Testing Explained

Orthopedic Foundation for Animals

The OFA hip evaluation system has been used for decades and remains the most widely recognized registry in North America.

Radiographs are reviewed by veterinary radiologists who assign dogs to categories:

• Excellent

• Good

• Fair

• Borderline

• Mild, Moderate, or Severe Dysplasia

Certification typically occurs at 24 months of age when skeletal maturity is reached.

Strengths of OFA Hip Testing

OFA offers several advantages:

• extensive public database of results

• decades of historical breed data

• widely recognized by puppy buyers and breeders

• simple categorical grading system

These features have made OFA a valuable tool for tracking hip health trends across many breeds.

Limitations of OFA Hip Evaluations

OFA scoring is based on radiographic interpretation, which means results depend heavily on the image quality and positioning.

Several factors can influence how hips appear on an X-ray:

• pelvic positioning

• femur rotation

• muscle tension during imaging

• overall radiograph quality

Additionally, OFA grades are broad categories rather than precise measurements, meaning dogs within the same category may still have meaningful variation in hip structure.

PennHIP Hip Testing Explained

PennHIP evaluates hips differently by measuring joint laxity directly.

The test uses three radiographs including a specialized distraction view that measures how far the femoral head can move within the socket.

The result is expressed as a Distraction Index (DI).

Lower DI values indicate tighter hips.

Strengths of PennHIP

PennHIP provides several advantages:

• objective numerical measurement

• direct evaluation of hip laxity

• can be performed as early as 16 weeks of age

• strong research correlation with arthritis risk

Because joint laxity is believed to be a major driver of hip dysplasia, many breeders appreciate the additional information PennHIP provides.

Limitations of PennHIP

PennHIP also has some practical limitations:

• fewer veterinarians are certified to perform the test

• higher cost than standard radiographs

• results may be less familiar to puppy buyers

Both PennHIP and OFA provide useful insights, but they measure different aspects of hip structure.

PennHIP vs OFA: Key Differences

Feature	OFA	PennHIP
Result type	Category	Numerical index
Age tested	24 months	16 weeks or older
Measures laxity	Indirectly	Directly
Interpretation	Radiologist grading	Objective measurement
Database familiarity	Very high	Moderate

Many responsible breeders now use both methods or rely primarily on PennHIP for additional structural insight.

Why Breeding Only OFA Excellent Hips May Slow Genetic Progress

A common belief is that breeders should only breed dogs with OFA Excellent hips.

While selecting for strong hips is important, categories alone do not always represent the full genetic picture.

For example:

Two dogs graded “Excellent” may still differ significantly in:

• actual joint laxity

• family hip history

• genetic diversity contributions

At the same time, a dog graded “Good” may come from multiple generations of consistently strong hips.

If breeders eliminate all dogs outside the highest category, they may unintentionally:

• reduce genetic diversity

• discard valuable bloodlines

• slow overall improvement in the population

For this reason, responsible breeding programs evaluate the whole dog and the broader pedigree, not a single label.

Hip Health Is Only One Part of Responsible Breeding

Hip evaluations are important, but they should never be considered in isolation.

Responsible Small Munsterlander breeding must also prioritize:

• stable temperament

• cooperative trainability

• hunting performance

• structural balance

• long-term genetic diversity

In fact, temperament is often considered the foundation trait that determines whether a dog thrives as both a hunting partner and family companion.

(See our related article: “Breeding for Temperament in Small Munsterlanders.”)

Prospective puppy buyers should also evaluate breeders holistically when selecting a puppy.

(See: “How to Choose a Responsible Small Munsterlander Breeder.”)

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Frequently Asked Questions

Is PennHIP more accurate than OFA?

PennHIP provides a numerical measurement of hip laxity, while OFA evaluates overall joint conformation through radiographic interpretation. Both provide useful information but measure different aspects of hip structure.

Can dogs with good hip scores still produce dysplasia?

Yes. Because hip dysplasia is polygenic, dogs with normal hips may still carry genes that contribute to laxity.

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Should breeders only breed OFA Excellent dogs?

Not necessarily. Responsible breeders consider hip scores along with pedigree history, overall structure, temperament, and genetic diversity within the breed.

Is hip dysplasia common in Small Munsterlanders?

Compared with many breeds, the Small Munsterlander historically shows a relatively low incidence of hip dysplasia, likely due to strong performance selection.

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Can environmental factors affect hip development?

Yes. Nutrition, body weight, growth rate, and exercise during puppyhood can influence how hips develop.

Conclusion

Hip testing is an important tool in responsible dog breeding, but it should always be interpreted within the larger context of breed stewardship.

The most thoughtful Small Munsterlander breeders balance:

• structural soundness

• temperament stability

• hunting performance

• genetic diversity

When these elements are considered together, breeders can preserve the qualities that make the Small Munsterlander an exceptional hunting companion and family dog.

References

• Smith GK, Mayhew PD, Kapatkin AS, McKelvie PJ, Shofer FS, Gregor TP. Evaluation of risk factors for degenerative joint disease associated with hip dysplasia in dogs. Journal of the American Veterinary Medical Association.

• Orthopedic Foundation for Animals. Hip Dysplasia Information.https://www.ofa.org

• PennHIP Program. University of Pennsylvania School of Veterinary Medicine.https://www.pennhip.org

• Willis MB. Genetics of the Dog. CAB International.

• American College of Veterinary Surgeons. Canine Hip Dysplasia Overview.

• International Small Munsterlander Breeding Guidelines and Breed Health Data.

Author Bio

Jeffery Mizenko is a breeder and steward of the Small Munsterlander focused on

preserving the breed’s versatility, temperament, and structural soundness. His breeding program integrates pedigree analysis, health testing, and performance evaluation to support responsible breeding decisions and maintain long-term genetic diversity within the breed