LONG-TERM EXPERIMENTS IN RELATION TO TREATMENT EFFECTS: RADIOBIOLOGICAL AND GERONTOLOGICAL PROBLEMS

The care and breeding of dogs, particularly beagles, for use in radiation research are discussed, with emphasis on the pioblems of housing large numbers of animals in outside pens and inside cages. Problems encountered in studying the effects of low levels of radiation on aging are also reviewed. The primary concern in such studies is to distinguish radiation-induced syndromes from normal gerontological phenomena. In such cases, evidence of radiation effect requires statistical methods when adequate numbers of animals are a prerequisite. Furthermore, types of radiations and exposure factors may manifest entirely different syndromes. Thus, radiation can be used as a tool to investigate some of the sequellae that are involved in geriatrices. The consistency of a breed aids considerably in reducing these variances, and the determination of radiation effects dictates that all genetic and environmental factors be maintained at an optimum. The described beagle breeding colonies have whelped almost 750 litters during the past 10 yr, and certain parents consistently produced a sufficient number of progeny of uniform size and conformation and even temperament, relatively free of inherited defects and moderately resistant to common ailments. Parental selection was used to improve breeding-colony production. Dams whelping 4-6 pups per litter havemore » min (17%) puppy losses to the weaning age. Reproduction in the beagle should average 1.45 pups per dam per 100-day breeding period. The most practical means of restraining dogs in a large kennel is with outdoor pens of proper design. Normal beagles can be raised and maintained to maturity in cages that allow companionship and 12 ft/sup 2/ per dog. Inside cages were designed for the safe administration of hazardous radionuclides. (BBB)« less