Niamh took Henry on as a pet three months ago, and he’s settled in well. He’s being fed a combination of complete grass-based pellets with plenty of fresh hay. Over a few weeks, he’d begun to nibble less hay than before, so Niamh checked his mouth to see if there was a problem. She was astonished to discover that, hidden behind his lips, his front teeth had become so overgrown that they were forcing his mouth apart, and making it impossible for him to eat properly. She brought him to my clinic for help.
Unlike dogs and cats, rabbits have teeth that grow continually throughout their lives. This is necessary because they do so much chewing and grinding of grass and other vegetation that the teeth need to be continually refreshed and replaced. All herbivores – including cattle, sheep and horses – have teeth like this.
Normally, a rabbit’s upper teeth make direct contact with the lower teeth: this ensures the opposing surfaces rub off each other, and it means that they continually grind each other down, maintaining a level, smooth surface for cutting and breaking-up food. In rabbits like Henry, for unknown reasons, the teeth start to grow crooked, leading to a problem called “malocclusion”. When this happens, the teeth no longer line up with their opposite number, and so there is no hard surface for them to grind against. As a result, the teeth keep growing, and they get longer and longer. Eventually, they grow so long that they stop the rabbit from being able to eat because they get in the way, and they force the mouth to be continually open. If this was left untreated, an affected rabbit would starve to death.
There are two options for treatment. The first way is to simply trim the teeth. This needs to be done under sedation, using a special rotating burr, similar to a dentist’s drill. The only problem with this method is that the teeth soon regrow, so they need to be trimmed every couple of months for the whole life of the rabbit.
The second treatment option offers a permanent cure: under general anaesthesia, the overgrown teeth are completely extracted. This can be a complex procedure, involving digging out their long roots from the rabbit’s jaw. The advantage is that once it has been done, the teeth will never regrow, and the problem will never recur. It does mean that the rabbit can no longer graze on grass, as they have no “cutting” teeth at the front of their mouth, but they still have “grinding” teeth at the back of the mouth, so they are able to use these to grind up hay and pellets.
While I outlined the various treatment options, Niamh had put Henry back into the deep sided cardboard box that she’d brought him in. As I finished talking, there was a loud thump, and Henry shot out of the box vertically, like a jack-in-the-box. He had decided to attempt to escape. He flew into the air, then landed on the floor beside the box with a thump. At first, I was worried that he might have seriously injured himself so I was relieved when he hopped around happily. Then I noticed something on the ground beside him. Astonishingly, three of his four overgrown teeth had broken when his head bounced off the ground as he landed: he had managed to trim his own teeth, and they were now the correct length. I completed the job for him by trimming the one remaining tooth. His teeth will regrow in a few months, and next time we will probably extract the teeth so that this never happens again. But for now, at least, Henry has managed to solve his own problem.