Behavioral effects of rotation between lactating and nonlactating females.

Rat pups stunted by housing only 8 hr daily with lactating females and 16 hr with nonlactating foster mothers showed a delay in returning to their nest from other parts of the home cage. This delay was not due to changes in activity level or to lack of attraction to the nest, but appeared to be perceptual in nature. Both lactating and nonlactating females caring for stunted litters tended to be more maternal than those caring for control pups. After nutritional rehabilitation, the adult experimental animals showed no deficits in learning a series of visual discrimination problems in a modified version of the Lashley jumping stand procedure with a nonappetitive reinforcement. We compared the results with those obtained when other methods of stunting animals are employed and concluded that different methods of stunting may result in both common and divergent effects on behavior. Although many methods of stunting may produce similar behavioral deficits during the period of food deprivation, after rehabilitation behavioral deficits reported with other techniques of stunting may be due to extranutritional causes rather than to reduced food intake per se.