I’ve always been aware that lop eared rabbits can suffer more from health issues with regards to their teeth than ‘up eared’ rabbits but I wasn’t prepared for my vet explaining how lops were basically the ‘Pug’ of the rabbit world.
Pugs are small dogs which sadly are plagued by health issues. They have eye problems, issues with their knee caps slipping, neurological problems and like dwarf rabbits and lops they have smaller skulls and flatter faces (brachiocephalic) resulting in breathing problems. The Pug’s teeth end up overcrowded because they have the same number of teeth as other breeds but they have to fit into a smaller area. This results in plaque build-up, gum disease and infections.
Like Pugs, Dwarf rabbit breeds and lop breeds have been bred to have a smaller rounder skull (possibly because this makes them cuter). When the skull size is reduced the upper and lower jaws do not always scale down by the same ratio. This can result in malocclusion where the teeth do not align properly, causing uneven wear and overgrown teeth.
The smaller rounder skull of the lop rabbit also means that the face is flatter and there is a shortening of the nasal passages – as seen in the Pug. Even when healthy these rabbits may make snorting or snuffling sounds, however this is not currently thought to be risk factor for respiratory problems.
Lop eared breeds have a much higher incidence of a painful condition known as otitis media (infection of the middle ear). The fold in their ear stops air flowing freely, dirt can accumulate and infections are more likely to occur. If left untreated, ear infections can then spread to the upper respiratory tract. Ear mites are also more commonly seen in lop eared rabbits.
As lop eared rabbits become older they also appear to suffer from a condition called stenosis; a narrowing of the ear canal. This can cause the canal to become clogged with detritus leading to infection and possible hearing loss.
After the diagnosis that my own lop had a bilateral ear infection I was advised by our exotics vet that myself and all owners of lop eared rabbits should be routinely cleaning their ears at least once a fortnight. Ear cleaning is quite easy once your vet has shown you how to do this.
To conclude, if you are looking at getting (or already have) a lop eared rabbit be prepared for possible health issues relating to the teeth, ears and nose. Controversially, we should be asking whether it is ethically right to breed from lop eared rabbits at all.
CT scan right ear
 Richardson, V (2000) Rabbits. Health, Husbandry & Diseases, Oxford: Blackwell Science Ltd.
 Eatwell, K. (2012). Approach to Ear and Nose Diseases in Rabbits. [PDF] Webinar Club, p.Exotics Club recordings 2012. Available at http://veterinarywebinars.com/assets/Study_Notes_Ear_Nose_Rabbits.pdf [Accessed 30 Dec. 2014].
 Lennox, A.M (January 2010) ‘Care of the Geriatric Rabbit’, Veterinary Clinics of North America: Exotic Animal Practice,, 13(1), pp. 123-133.