NASA/TM-- 208145 Laboratory Animal Science Copyright' 1980 . by the American Association for Laboratory Animal Science The Manufacture, Shipping and Receiving and Quality Control of Rodent Bedding Materials I Lisbeth M Kraft Summary [ The criteria for rodent bedding and nesting materials are discussed. The literature is reviewed regarding sources of bedding materials, manufacturing methods, quality control procedures (microbiological, physical and chemical), storagemethods, shipment, methods of use and disposal, current knowledge concerning bedding effects on animals as related to research and testing and legal aspects. Future needs, especially with respect to the promulgation of standards, also are addressed. Key Words ] Animal bedding -- Microbiological safety -- Rodentia In 1974, a journal published for the For the most part, contact bedding laboratory animal field cited 11 commercial will be discussed, although materials placed sources of contact bedding for laboratory ani- under suspended wire cages, as well as no bed- mals in the form of wood shavings or chips and ding at all, also will be mentioned. Most of the six for pelleted products (1). In 1979, the same data will center about mice and rats. publication again listed 11 sources of shavings or wood chips, however, seven of those men- tioned in 1974 were no longer listed 12L Thus seven new vendors had entered the market in Specifications and Requirements: Types of the interim, and, whereas six suppliers offered Contact Bedding pelleted bedding in 1974, there were only four The specifications and requirements in 1979. Of these, three were new vendors. What are we to conclude from this? for rodent contact bedding vary depending on whether one wishes only adequate or optimal, Do bedding vendors tend to be an evanescent lot? Or is the fault to be found in the nature of that is, ideal, conditions for the animals. In our view, adequate conditions are those that will the products? (We assume, of course, that the permit an animal to reproduce and survive in journal personnel were equally industrious in reasonable health. Food and pet animals fall soliciting vendors for listing in both issues). into this category. Optimal conditions, then, While it might be more interesting to are those which follow when all variables, discourse on the vendors themselves, the pur- other than those imposed by experimentation, pose of this presentation is to examine their are known in detail and then are controlled. A products, and even if we cannot reach a conclu- propos of this comment is the fact that the ICLA sion as to the precise reasons for the changes (International Committee on Laboratory between 1974 and 1979, we should be able to Animals) Governing Board (3) strongly urged infer from our discussion if the products them- in 1978 that bedding {type, changing schedule, selves are to blame or tic,perchance, the labora- sterilization status) always be described when tory animal field might be found wanting. the results of experiments using animals are reported. Table 1 indicates a number of desir- 1From the Ames Research Center, National Aeronautics and Space Administration, Moffett Field, CA 94035. able characteristics for contact bedding that 366 Rodent Bedding Vol30,No 2 PartIIofTwo Parts Printedin USA Table 1 Table 2 particular product, Desirable criteriaforrodent contact bedding Additional desirable criteria for rodent contact polyethylene gran bedding stances and theref, Moisture absorbent Nondesiccating to the animal variability and at Dust free Uncontaminated Remains chemically stable during use Unable to support microbial Non-nutritious Manifests batch to batch uniformity which one is chose growth Nonpalatable Optimizes normal animal behavior "continues to be a Inedible Unlikely to be chewed or Nondeleterioua to cage washers ence" (11). Nonstaining mouthed Noninjurious and nonhazardous to personnel Nontraumatic Nontoxic Ammonia binding Nonma]odorous Even re_ Sterilizable Nestab]e results in a cost responsible fashion. Whether very specific con Deleterious products not Disposable by incineration guidelines. The Go_ formed as a result of Readily available or not we now have all the data necessary to (GLP), for example. sterilization Relatively inexpensive formulate such standards is, as we shall see, Easily stored Fire resistant bedding, indicating somewhat in question. rated from areas hc A number of authors (4-111 have tected against inf mentioned the types of contact bedding and (14); it also states are thought to provide optimal conditions (4 - bedding supplements (as for nesting) that have cages or pens shall 13), while Table 2 shows some personal addi- been utilized in the past or are still in use: pose or conduct c tions. While composing these lists, the author white, ponderosa, sugar and lodgepole pine changed as often a_ was reminded of the "little list" of the Lord shavings; redwood, aspen or other types of pop- mals dry and clear High Executioner in Gilbert and Sullivan's lar, basswood, cedar and maple shavings; white "Mikado" as well as of their patter songs. In- pine sawdust and flakewood; flax stems; shred- The Ani: spiration then brought into being the following ded newspaper, both used and unused; chopped reference to beddin doggerel: and ground corncobs; wood wool, excelsior, Cancer Institute, c I bet you any money that you cannot find a shreds or filaments of aspen; peat moss; paper that its bioassay bedding sheets; pine or hardwood chips; cotton batting; treated hardwood, That will give a mousie comfort from attapulgite (hydrated magnesium aluminum The Gui unmitigated wetting, silicate); clays, such as bentonite; filter paper, Laboratory Anima That will be both hygroscopic but yet dry paper towels; peanut hulls; hay ffor guinea "In general, beddix the critter not, pigs); bagasse (crushed sugar beet or sugar bent and free of s_ That will burn just when you want it to, cane pulp}; cellulose fibers; alfalfa stems; dry animals or persom but not burn very hot, sand; shredded computer printouts; nonabsor- eaten by the anirr That contains no toxins, viruses, no fast bent cotton; and polyethylene granules (pre- cage to keep anima fermenting bug, pared from ethylene polymerized with organic •.. should not com That is stored with ease in cubbyholes or peroxides), it may be safe to say that, of these, tubes. Some bedd underneath your rug, white pine shavings are the most widely used. substances that af_ That smells good both to man and beast Hardwood or pine chips and aspen shreds prob- animals to some ex before it's messed upon ably follow some distance behind. Without an It states further t_ As well as after usage when its wasted extensive survey, however, the precise usage contain substance._ youth is gone, cannot be stated with certainty. on an animal's bic That will do the universal task of cutting A few bedding types mentioned have cedar, for example. variation fallen out of favor for a variety of reasons. in hepatic micros, To give test results with only zero Cedar, and in some instances pine, shavings rats: therefore, th_ standard deviation. i may not be used in pharmacological studies. In the r With aims so high Hay is edible. Peat moss, used newsprint and Long-term Holdin_ And motives so deep, alfalfa stain the animals' coat, although peat bedding criteria I wonder why moss does have the apparent advantage of ment: "The type of ft should also be cheap. relatively high acidity and therefore may con- ability for the dl In any event, fulfilling the criteria trol ammonia. Attapulgite is too hygroscopic should be known.' (some of which seem antithetical as they stand} for some animals, and, together with sand, it is Is it pos_ should provide the basis for standards for the not combustible and thus difficult to dispose of. general nature oft] specific use of a bedding material, with the Pelleted peanut hulls are relatively new on the given above is thai ultimate aim of removing bedding from the list market. Comparative studies with these have contact bedding t} of environmental variables that beset the in- not, to our knowledge, been reported. Regard- therefore, it is not vestigator who attempts to obtain reproducible less of the advantages or disadvantages of a ic? On the other h 367 368 Vo130, No 2 Part II of Two Parts Printed in USA particular product, it is true that, except for the still afloat in a sea of relative ignorance, and polyethylene granules, all are natural sub- 'therefore, it is prudent not to be too specific? stances and therefore subject to considerable Requirements of the animal: To this variability and at least some contamination. point, we have been almost entirely anthro- Which one is chosen in a particular instance pocentric in dealing with requirements for bed- "continues to be a matter of personal prefer- ding. But what does the animal require? Few ence" (11). studies in which mice or rats have been given Even regulatory agencies are not free choice of bedding for parturition and lacta- very specific concerning requirements or tion or for extended holding periods have been guidelines. The Good Laboratory Practices Act conducted (15-17). Even in these studies, it (GLP), for example, addresses storage areas for must be recognized that the test bedding mate- bedding, indicating that they are to be sepa- rials were first selected by the investigator. Of rated from areas housing test systems and pro- those provided, wood products were preferred tected against infestation or contamination in all cases by the animals, with aspen in the (14); it also states "bedding used in animal form of shreds (excelsior, wood wool) chosen by cages or pens shall not interfere with the pur- all the animals. Of more than passing interest pose or conduct of the study and shall be is the fact that combinations were chosen. Thus changed as often as necessary to keep the ani- all pregnant mice in one study chose aspen mals dry and clean." bedding, 75% added cedar shavings to this, 45% The Animal Welfare Act makes no added pine shavings, 5% added hardwood chips reference to bedding specifically.