Why Not Cedar Shavings?

By Dr. Bruce Williams, DVM

For years, cedar shavings have been used as bedding for many species of small mammals including ferrets.  Over the last ten years, increasing evidence is cropping up that this may not be a good choice.

Cedar shavings, as well as other aromatic soft woods, such as white and yellow pines, release volatile hydrocarbons which affect those animals living in them.  Plicatic acid, a volatile hydrocarbon, results in asthma in humans and rabbits.  Other hydrocarbons result in changes in the liver, which may impair its ability to detoxify certain drugs, including various anesthetic agents.  Cedar shavings have also been incriminated in increased mortality in rat pups, and various scientists over the years have alluded to possible carcinogenicity.  In chicken litter, cedar shavings harbored more bacteria than other types of litter.

On the more practical side, a 1986 article in Lab Animal evaluated many of the common bedding materials, also including hardwood chips, sawdust, paper chips, newspaper, ground corncob, rabbit pellets, straw, and hay (along with several others) for the following: absorbency, dust, endogenous effects on the animal, cost, use in nesting, and disposability.  In all categories, cedar shavings were not recommended.  Interestingly enough, paper products and heat-treated softwood chips scored highest overall.

In my experience, ferrets are happiest in old sweatshirt or towels, which rarely cause problems.  Beware, however, the bored caged ferret, who may ingest parts of these items for lack of other stimulation, and obtain a gastrointestinal foreign body in the process.

References:

1. Weichbrod RH et al. Selecting bedding material. Lab Anim. Sept 1986, pp.25-29.
2. Kraft LM. The manufacture, shipping, receiving, and quality control of rodent bedding materials. Lab Animal Sci. 1980 pp. 366-372.
3. Weichbrod RH et. al. Effects of Cage Beddings on Microsomal Oxidative Enzymes in Rat Liver. Lab Animal Sci. 38(3): 296-298, 1988.
4. Hessler, JR. Design and Management of Animal Facilities. In Laboratory Animal Medicine, JG Fox, ed. Academic Press Inc, Orlando. 1984.
5. Chan H. et al. A rabbit model of hypersensitivity to plicatic acid, the agent responsible for red cedar asthma. J Allergy Clin Immunol 79(5) : 762-767.

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