By Dr. Becker
Researchers have discovered that rabbits who live entirely indoors probably suffer from vitamin D deficiency. This includes both pets and laboratory animals. A lack of vitamin D in rabbits is thought to contribute to dental disease, cardiovascular problems, and a weakened immune system.
The study, which was published recently in the American Journal of Veterinary Research, showed that regular exposure to artificial ultraviolet B light over a two-week period doubled the rabbits' serum vitamin D levels.1 These results cannot be achieved using artificial light that lacks UVB radiation.
Vitamin D Deficiency in Rabbits Can Cause Dental Disease and Other Health Problems
According to Mark Mitchell, a University of Illinois veterinary clinical medicine professor who led the research:
"We know that vitamin D is important to vertebrates in that it helps with calcium absorption, but it has also been shown to benefit cardiovascular health and immune function. We know of several types of diseases that can develop with vitamin D deficiency. Some of the problems we see are tooth-related."
Also according to Mitchell, managing dental disease and performing tooth trims in rabbits, guinea pigs, and chinchillas is done routinely across the country and internationally – an indication that these animals may be vitamin D deficient on a large scale.
Small Animals Living Indoors Should Have Routine Monitoring of Serum Vitamin D Levels
Most laboratory animals and lots of pet rabbits and other small pets don't go outdoors for safety reasons, and windows block most UVB radiation. If the animals don't get enough vitamin D from their diet and are never exposed to ultraviolet light, chances are they're deficient.
"As a clinician," Mitchell said, "I want to better manage these animals, give them a longer, higher quality of life." He believes animals used in research or kept indoors should have their vitamin D levels measured as part of routine veterinary exams.
Future studies will hopefully establish optimal levels of UVB exposure and vitamin D levels in rabbits, guinea pigs, chinchillas and other animals (NOT including cats, who don't require sunlight to synthesize the vitamin D hormone).
If you own a rabbit, I strongly encourage you to find a way to safely allow your bunny to have access to direct, outdoor sunlight on a daily basis, if possible. If your rabbit is harness-trained, you can sit with her on unsprayed grass and allow her to exercise and enjoy direct sunlight. Or you can move her indoor wire cage outdoors for a few hours every day (assuring it's not above 80 degrees and she has access to a shady spot in the cage). If taking your rabbit outdoors isn't feasible or it's too cold (below 65 degrees), then consider asking your exotic vet about what full spectrum light is appropriate for your pet's habitat.
I don't recommend giving rabbits vitamin D supplements unless advised by your exotic vet; vitamin D is a fat-soluble vitamin and can reach toxic levels in small mammals very quickly.