Some Interesting Notes on Rabbit Teeth
Here is an Etherbun post from a few years ago from Mary Cotter who summarizes
a vet dentists observations on rabbit teeth:
Last week at NAVC David Crossley (who is a renowned veterinary dentist,
working on his Ph.D. right now) gave a very informative talk on rabbit
teeth. A lot of the points he made are worth summarizing here. Some of
this will be brief quotes from his paper in the proceedings of the conference
anyone interested can order the entire proceedings (covering all
species) for around $45 from NAVC.
1) Because rabbits upper and lower molars do not "match"
(there are different numbers of upper and lower molars, and the upper
and lower molars are different sizes), "abnormalities of a tooth
in one jaw may affect up to three teeth [!] in the opposite jaw."
2) It is largely the silicate content of grass that helps to abrade down
molar length, and rabbits should chew primarily grass for several hours
per day. Chewing less abrasive foodstuffs can result in molar overgrowth.
Even some wild rabbits who have access to more lush vegetation (higher
in energy and lower in silicate content typical of most vegetables
as far as I know) can start to show a minor degree of molar overgrowth.
3) Side-to-side chewing motion is required for a rabbit to chew grass,
but mostly up-and-down motion to chew pellets, grains, etc. It is the
side to side motion that prevents molar spurs from forming. Because the
lower dental arcade is somewhat narrower than the upper, up-and-down motion
will permit the formation of molar spurs fairly readily.
4) Teeth in the lower jaw grow faster than teeth in the upper jaw, so
spurs and other abnormalities are seen more readily in the lower teeth.
5) "Once any dental problem progresses to a stage which affects the
efficiency of chewing, affected rabbits tend to alter their eating habits,
increasingly searching out higher energy foods. Owners frequently notice
the change and increase the supply of this type of food. Unfortunately
this further reduces tooth wear and may result in serious dietary imbalances
and caries development. Any reduction in jaw function has a dramatic effect
on the bone, particularly around areas of stress such as muscle insertions."
6) Because of their blunted head shape, dwarf rabbits incisors often
do not function normally, which can result in not only overgrown incisors,
but also problems with molars. In larger breeds, incisor malocclusion
is more often the **result** of overgrown (over-long) molars.
7) "Any rabbit that does not wear its teeth sufficiently will end
up with its mouth held open by elongated cheek and/or incisor teeth. This
interferes with chewing, and once established the problem tends to self
perpetuate." Crossley made the point that the chewing of fresh grass
probably tends to abrade the teeth even better than the chewing of hay.
Needless to say, however, in many areas of the USA, chewing grass outdoors
will expose the rabbit to life-threatening diseases such as Baylisascaris,
West Nile virus, etc. etc. so hay may be the overall best choice
for those who dont have protected "grazing land" for their
house rabbits. In any case, the overall thrust of his lecture was this:
Feed your rabbit low-energy, high-silicate vegetation that will require
hours (literally) of chewing. The way to keep your bunny's GI tract healthy
turns out also to be the way to keep his teeth healthy.