A formulated ration for maintenance or experimental purposes has been developed for moose (Alces alces). It contains 12.7% crude protein and a digestible energy concentration of 2.4 kcal/g. Metabolizable energy concentration is 2.1 kcal/g. Performance was measured over 5 years with data from 11 moose. Daily gain in calves from weaning in August through October and November through April was 0.9 kg ? 0.06 (SE) and 0.4 kg ? 0.03 (SE), respectively, and exceeded those of wild moose. Mean body weights of adult males and females on the diet were greater than those of wild moose. Reproductive performance was also excellent with 83.1% of yearling females breeding and producing a calf at age 2. The ration has been used as the only food of moose for up to 5 years with no apparent adverse affects. It lends itself to constituent alteration for experimental purposes. J. WILDL. MANAGE. 49(1):137-141 Moose management based on sound biological knowledge requires a basic understanding of the animal and its environment. Animal welfare, whether it is measured as growth, reproductive performance, or survival is dependent upon adequate nutrition. The literature is replete with food-habits studies (Peek 1974), and several investigators have evaluated the nutritive quality of moose forage. Considerably less is known or understood about the nutritional requirements of moose. Except for recent studies by Hjeljord et al. (1982), no evaluation of food has been done using in vivo techniques. Of all mammals, ruminants have the most differentiated, specialized, and complex stomach (Hoffman 1973:1). Of the 142 ruminant species (Simpson 1945) living today, we have a poor understanding of the nutritional requirements of all but the three domesticated species (cattle, sheep, goats). Zoos have been successful in maintaining many species of wild animals on formulated diets (Crawford 1968, Rechcigl 1977), but until now, maintenance of moose has been difficult and expensive. Animals were held in enclosures containing enough natural forage to support them (LeResche and Davis 1973), or natural foods were harvested and fed to moose in confinement (Speidel 1965, Miquell and Jordan 1979, Hjeljord et al. 1982, Miquell 1983). Attempts to feed moose diets commonly fed to other cervids have largely failed (Thorne 1979). Because of an apparent difference in dietary physiology, moose do poorly on diets composed f roughage in the form of long hays (Schwartz et al. 1980). This problem has been apparently solved by the inclusion of sawdust in our ration. A major objective of our moose nutrition studies required that captive moose be maintained on a diet that was: (1) readily available; (2) inexpensive; (3) reproducible; (4) suitable to constituent alteration; and (5) able to meet nutritional requirements. This made it necessary to use a formulated ration rather than natural browse. An extensive review of the literature, plus a survey of zoos and wildlife research facilities, revealed that no such ration had been identified. Here we discuss a formulated ration for moose that meets the above criteria. Preliminary discussion and background information were previously presented (Schwartz et al. 1980). We thank M. A. Schwartz, D. Johnson, and D. C. Johnson for help with animal care and digestion experiments and D. E. Ullrey, K. B. Schneider, and S. R. Peterson for early reviews of the manuscript. Funding for these studies was provided in part by the Morris Anim. Found. and from Fed. Aid in Wildl. Restoration, Proj. W-17 and W-21. We thank the Milwaukee Co. Zoo and H. Evans for providing us with Fiberite (American Excelsior Co., Arlington, Tex.) for our earlier studies.