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Pedigree dogs have distinct and identifiable looks, but these can also lead to them suffering from long-term health problems. While the health issues surrounding dogs are more well known, a new study has found that the same trend of selective breeding for cuteness is also causing serious health issues for our smaller furry friend the rabbit.

Exaggerations of certain features through selective breeding have led to domestic dogs looking distinct, but this beauty can come at a painful cost. The wrinkly skin on the legs of a basset hound can trap bacteria between folds of flesh causing painful skin complaints, while the flat faces of the pug and French bulldog result in them suffering from serious breathing difficulties.

Now research published this week in the journal Vet Record shows that floppy-eared rabbits are also suffering from the traits that make them cute.

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Floppy ears result in reduced ear airflow causing a build-up of earwax, which can lead to pain and deafness. Floppy ears also alter the shape of the skull resulting in dental pain and eating difficulties.

The research looked at rabbits from a rescue centre and studied their medical health. Samples were also taken from each ear to examine for mites, bacteria and yeast. Various breeds of rabbits were studied, with 15 of them being lop-eared and 15 being erect-eared.

The researchers found that the rabbits with floppy ears were 43 times more likely to have narrowed ear canals and were 15 times more likely to be exhibiting pain that the erect-eared rabbits. All but one of the lop-eared rabbits had a build-up of ear wax in their ears and even after a good clean many of them needed repeated ear-cleaning procedures. This compared to only three of the 15 erect-eared rabbits showing ear wax build-up and none of them needing a second ear clean.

The flat faces of the pug could result in them suffering from serious breathing difficulties. Photo / Dean Purcell
The flat faces of the pug could result in them suffering from serious breathing difficulties. Photo / Dean Purcell

The scientists found signs consistent with otitis – more commonly known as an ear infection in the lop-eared rabbits suggesting they were potentially suffering pain, impaired hearing and even deafness.

In addition to their ear issues, the researchers also found that the lop-eared rabbits had malformed skulls. These issues have been known for a long time with detailed records from Charles Darwin, who was fascinated with "half-flop" rabbits dating back to the 19th century. Half-flop rabbits were bred to have one oversized floppy ear and one upright erect ear. In his studies, Darwin observed that the skull morphology on the erect ear side of those rabbits was normal but on the floppy ear side it was deformed. This has now been shown to be due to the erect-ear rabbits having an ear canal scaffold made up of interlocking cartilage, which is not present in the lop-ear breeds, who only have soft tissue around the outer ear so they can fold down.

This altered head shape from having floppy ears affects the teeth and jaw alignment of the rabbit, leading to painful dental issues including overgrowing teeth, tooth pain and eating difficulties.

In the study, half of the lop-eared rabbits had dental abnormalities with most of them needing dental treatment due to diseased incisor or front teeth and they were 12 times more likely to have overgrown molars or back teeth. None of the erect-eared rabbits had any dental issues.

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While the pool of 30 rabbits was small, it agreed with anecdotal reports from the veterinary industry around increased health issues of lop-eared rabbits. Hopefully this new evidence will force us to think more about balancing the health of our furry friends over their looks when we next choose our family pet.