SHINING SOME (UV) LIGHT ON RABBIT HUSBANDRY
DR. MARK A. MITCHELL DVM, MS, PHD, DECZM (HERPETOLOGY)
Rabbits are popular pets, with 3.2 million in U.S. households, according to a 2012 AVMA survey. Veterinarians should be prepared to help educate their clients about best practices for rabbit husbandry.
Rabbits’ lighting needs have not been explored in depth. Rabbits evolved to be crepuscular (active at dawn-dusk) to diurnal (daytime); therefore, they spend a fair amount of their day exposed to natural sunlight, which provides three important spectrums of light:
- ultraviolet light, associated with the photobiochemical synthesis of vitamin D in some vertebrates;
- visible light, which allows vertebrates to see in a certain range of colors; and
- infrared light, associated with the heat provided by the sun.
The importance of ultraviolet radiation for captive animals is only now being investigated, primarily in reptiles. Because rabbits, much like diurnal reptiles, can synthesize vitamin D when exposed to natural ultraviolet B radiation, we recently studied the impact of artificial ultraviolet B radiation on the vitamin D levels of captive rabbits. We found vitamin D levels significantly higher in rabbits exposed to artificial ultraviolet B radiation than in their cohorts not exposed to ultraviolet B radiation.1
Given the importance of vitamin D as an essential hormone that regulates many biological functions, a further study was completed by Dr. Megan Watson to evaluate the long-term (6 months) effects of exposing rabbits to ultraviolet B radiation. The findings reinforced the pilot study and showed that rabbits exposed to ultraviolet B radiation maintained significantly higher vitamin D levels over the course of the study. No side effects were found to be associated with regular exposure to ultraviolet B radiation. The research suggests that pet rabbits housed indoors would benefit from exposure to ultraviolet B radiation.
It should be noted that housing indoor rabbits near windows will not provide exposure to ultraviolet B radiation because glass removes these short ultraviolet B wavelengths. However, commercial ultraviolet B light bulbs are available at many pet retailers. Current recommendations are that the lights should be placed within 9 inches of the animal’s cage and changed every 9 months, as the ultraviolet B radiation decays over time in these bulbs.
Studies in chinchillas and guinea pigs found similar results, suggesting that these animals may also benefit from exposure to ultraviolet B radiation. We are planning further research into the role of lighting in the long-term health of pet rodents.
1 Emerson JA, Whittington JK, Allender MC, Mitchell MA. Effects of ultraviolet radiation produced from artificial lights on serum 25-hydroxyvitamin D concentration in captive domestic rabbits (Oryctolagus cuniculi). Am J Vet Res. April 2014, Vol. 75, No. 4 , 380-384.
NON-OBSTRUCTIVE GASTROINTESTINAL MOTILITY DISORDERS OF RABBITS
DR. JULIA WHITTINGTON, DVM
Because of the unique anatomical and physiological characteristics of rabbits’ digestive process, a high-fiber diet is essential for their normal motility and GI health. It’s important for owners to provide grass hay ad libitum and to watch for signs of GI disorders (decreased appetite, diarrhea, decreased stool production, lethargy, abnormal stance, and tooth grinding), any of which indicate veterinary intervention is necessary.
Any change in the normal microflora of the GI tract may lead to ileus or enteritis in rabbits. Stress, whether physiologic or environmental (such as a change in diet), has a direct effect on gastrointestinal motility and may result in GI ileus.
Decreased motility and delayed or arrested gastric emptying may be brought about by gastric impaction of ingesta secondary to dehydration, foreign body ingestion, and mass effects as well as by stress, anorexia, lack of exercise, and ingestion of high-carbohydrate/low-fiber diets.
Palpation in the cranial abdomen of a firm doughy stomach that extends beyond the border of the rib cage, with or without gas, is suggestive of gastric stasis. Abdominal radiography showing a distended stomach with fluid, gas, or consolidated ingesta with a gas halo is indicative of gastric stasis. Gas accumulation throughout the GI tract is seen with generalized ileus. Accumulation of fluid in the stomach or intestines in a critically ill rabbit may indicate an obstructive lesion. Prolonged gastric stasis may lead to potentially severe hepatic lipidosis and gastric ulceration. Aggressive therapy is generally indicated.
The hallmarks of treatment for non-obstructive GI motility disorders in rabbits are hydration therapy, analgesia, and the promotion of GI motility. Antibiotic therapy may be implemented as needed for bacterial infections. Providing analgesia is important when managing motility disorders in rabbits as pain will further reduce GI motility. Buprenorphine is an effective option. Non-steroidal anti-inflammatory medications may be implemented after the patient is rehydrated.
Rehydration therapy may be given by intravenous or intraosseous route in severely debilitated animals or by oral and subcutaneous routes in stable rabbits. Oral administration of a high-fiber gruel diet for herbivores will also help hydrate the stomach contents. Canned pumpkin, rabbit pellets mixed with water, and vegetable baby food may be substituted for commercial diets.
Prokinetic drugs used to restore motility in rabbits include cisapride and metoclopramide. Some antacids, such as ranitidine, also have prokinetic properties. With prompt intervention and aggressive supportive care, most rabbits suffering from non-obstructive GI motility disorders recover completely.
For more details about rabbits’ unique digestive system and how to treat motility disorders, see go.illinois.edu/rabbitgi.