You watch your Bernese Mountain Dog play and sometimes wonder if this breed is as robust as it looks.

The scientific answer is no.

The Bernese Mountain Dog is one of the most documented breeds in veterinary medicine, precisely because its health is one of the most complex.

Two major dominant pathologies:

• hereditary joint diseases: hip and elbow dysplasia
• histiocytosis: a breed-specific cancer that remains one of the most frequent causes of death in these dogs.

This article is not intended to discourage owners or future adopters.

It aims to provide them with information that breeders do not always share, so that decisions (medical and practical) can be made at the right time.

Klopfenstein et al., BMC Veterinary Research, 2016: 389 BMDs followed in Switzerland

Life expectancy: why so short?

The median life expectancy of the Bernese Mountain Dog is established at 8.4 years in the Swiss study by Klopfenstein et al. (2016), compared to a median of 10 to 11 years for all breeds. Males die significantly younger (median 7.7 years) than females (8.8 years). These data come from the follow-up of 389 BMDs born in 2001-2002 in Switzerland (a large and representative cohort).

This reduced life expectancy is not solely linked to size. Giant breeds such as the Great Dane or the St. Bernard have similar or shorter life expectancies, but for different cardiovascular and orthopedic reasons. In the Bernese Mountain Dog, the tumor burden is the dominant factor: neoplasia (tumor development) is involved in at least 55% of deaths, according to the Dutch study by Erich et al. (2013) on a large population of BMDs and Flat-Coated Retrievers.

To remember

The Bernese Mountain Dog does not have a short life expectancy because it is "large". It has a short life expectancy because it is genetically predisposed to a specific cancer: histiocytosis (whose rate in the breed exceeds 25% according to studies).

Hip Dysplasia: figures to be nuanced

Hip dysplasia (HD) is a developmental malformation of the hip joint. It is hereditary, multifactorial, and common in large breeds.

In the Bernese Mountain Dog, data vary depending on the country and screening methods. The Swiss study by Ohlerth et al. (2019), covering 8,221 BMDs screened between 1995 and 2016, shows a prevalence that decreased from 21% to 12% thanks to selection programs.

This is a real reduction, but still a significantly higher prevalence than in Retrievers (Golden: 25% → 9%, Labrador: 16% → 3%).

OFA data (United States) report approximately 16% dysplasia in the breed among screened dogs.

Unfortunately, as with the Golden Retriever, dogs with poor hips are less often screened, which underestimates the true prevalence in the general population.

Important: Hip dysplasia is a radiographic spectrum. A dog with mild dysplasia can live a long life if its weight is controlled and its exercise is adapted. A dog with severe untreated dysplasia will develop debilitating arthritis.

Elbow Dysplasia: the least screened pathology

Elbow dysplasia (ED) is perhaps even more widespread in the Bernese Mountain Dog than hip dysplasia, and yet much less often mentioned!

The UFAW (Universities Federation for Animal Welfare) reports prevalence estimates between 20 and 50% in the breed, depending on studies and countries.

One of the most frequent forms is fragmented coronoid process (FCP), whose prevalence is estimated at 36 to 70% according to Lang et al. (1998) (a wide range reflecting the diagnostic difficulties of this pathology).

Males are affected 3 times more often than females according to German screening program evaluation data.

Surgery is effective in 40 to 70% of cases depending on the forms, but does not prevent long-term osteoarthritis.

What you should monitor

Intermittent lameness of the forelimb, especially after exertion or prolonged rest. Reluctance to extend the elbow. Discreet swelling of the joint. These signs can appear as early as 4 to 6 months in severely affected puppies. Radiographic screening between 12 and 18 months is recommended for BMDs.

Histiocytosis: the disease breeders don't mention enough

Disseminated histiocytosis (or histiocytic sarcoma, HS) is a malignant cancer of histiocytes (immune cells normally present in tissues).

In the Bernese Mountain Dog, this disease is both common, genetically transmitted, and rapidly fatal in its disseminated form.

Key figures

The study by Abadie et al. (2009), published in the Journal of Heredity, is the reference on this subject. It collected data on 800 BMDs, 200 of which were affected by histiocytosis. The results are striking:

• Prevalence in the breed: approximately 25% of Bernese Mountain Dogs develop histiocytic sarcoma during their lifetime.

• Average age of onset: 6.5 years (i.e., in full maturity), often without prior indicative signs.

• Survival after diagnosis: estimated at a median of 49 days in the disseminated form. This is one of the bleakest prognoses in veterinary oncology.

• Transmission: oligogenic (involving several genes), which explains why some lineages are more affected than others.

The Dutch study by Erich et al. (2013) confirms that more than 1 in 7 BMDs die directly from histiocytosis (making it the leading cause of non-accidental death in this breed).

Clinical forms

There are three main forms:

• Localized: single mass, often cutaneous or articular. Less bleak prognosis; survival of 1.5 to 3 years possible with surgery and adjuvant chemotherapy.

• Disseminated: multi-organ involvement (spleen, liver, lungs, lymph nodes). Rapid progression, grave prognosis (median survival < 2 months).

• Hemophagocytic: the most aggressive form, affecting the spleen and bone marrow. Survival is less than 2 months in almost all cases.

In the Bernese Mountain Dog population, the disseminated form is significantly more frequent than in the Flat-coated Retriever (60.8% vs 39.4%), which worsens the overall prognosis in this breed (comparative study MDPI Veterinary Sciences, 2022).

Link between orthopedics and histiocytosis

A study by Ruple & Morley (Journal of Veterinary Internal Medicine, 2016) showed that BMDs with prior orthopedic conditions had a 2.5 to 2.8 times higher risk of developing histiocytic sarcoma.

This link between chronic joint inflammation and histiocytic oncogenesis remains to be explored, but it highlights the importance of early joint monitoring.

Warning signs to watch out for

Here are the signs that should lead to an immediate consultation:

What you can do concretely

• Demand hip and elbow scores for both parents before purchase or adoption. We're talking about an OFA or FCI certified score here, not just a verbal assertion.

• Ask the breeder for information on causes of death in the lineage: transparency regarding histiocytosis is a reliable indicator of seriousness.

• Control weight throughout life: every extra pound accelerates the progression of dysplasia and osteoarthritis.

• Avoid high-impact exercises during growth (before 18 months): no repeated jumping, no slippery surfaces, no excessive stair climbing.

• Establish an annual veterinary check-up with abdominal palpation and complete blood count from 5 years of age: histiocytic sarcomas can alter blood work before the first clinical signs.

• Do not downplay unusual fatigue, loss of appetite, or weight loss: in a BMD over 5 years old, these signs should lead to a prompt consultation.

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Sources

1. Ohlerth S. et al. (2019). Prevalence of hip dysplasia in dogs in Switzerland between 1995 and 2016: a retrospective study of 5 common large breeds. Frontiers in Veterinary Science, 6:378. PMC6821640
2. Abadie J. et al. (2009). Epidemiology, pathology, and genetics of histiocytic sarcoma in the Bernese Mountain Dog. Journal of Heredity, 100(Suppl 1): S19–S27. PubMed 19531730
3. Erich SA, Rutteman GR, Teske E. (2013). Causes of death and impact of histiocytic sarcoma on life expectancy in Dutch populations of Bernese Mountain Dogs and Flat-coated Retrievers. Veterinary Journal, 198: 678-683. PubMed 24231621
4. Klopfenstein M. et al. (2016). Life expectancy and causes of mortality in Bernese Mountain Dogs in Switzerland. BMC Veterinary Research, 12: 153. PubMed 27457701
5. Malm S. et al. (2008). Genetic variation and genetic trends of hip and elbow dysplasia in Swedish Rottweilers and Bernese Mountain Dogs. Journal of Animal Breeding and Genetics, 125(6): 403–412. PubMed 19134076
6. Ruple A., Morley PS (2016). Risk factors associated with the development of histiocytic sarcoma in the Bernese Mountain Dog. Journal of Veterinary Internal Medicine, 30(4): 1197–1203. PubMed 27160025
7. UFAW: Bernese Mountain Dog: Elbow Dysplasia HCO and FMCP. ufaw.org.uk