THE INFLUENCE OF AGE ON LITTER-SIZE

Authors:
  • DID. L. Ingram
    D. L. Ingram
  • AMAnita M. Mandl
    Anita M. Mandl
  • SZS. Zuckerman
    S. Zuckerman
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Abstract
SUMMARY: In three related strains of rats the numbers of fertile females have been found to fall with age and with the birth of successive litters. In thirty-five rats belonging to these three strains, each of which had a minimum of eight litters, the second litter was generally bigger than the first. From then on, however, litter-size gradually fell until the animals ceased to breed.
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