Abstract
SUMMARY: Changes in body weight and food consumption during lactation in rats nursing various sizes of litters were studied. The rate of increase in body weight of the mother rats during the experimental period (day 3–14 of lactation) was very similar in mothers with different numbers (2, 4, 8 and 12) of suckling pups/litter. It is suggested that the weight increase of adult female rats during lactation is related more closely to the alteration of ovarian function caused by the suckling stimulus than to the enhanced food intake during this period. Both the food intake of mother rats and the daily gain in weight of litters increased as the number of suckling pups/litter increased and as lactation advanced. Linear relationships were observed between the logarithm of the litter size and both the food intake of the mother rats and the weight gain of the litters. The presence of a close correlation between the food intake of mother rats and the quantity of milk produced by them is suggested.