The food intake of rats during pregnancy and lactation

Quantities of food required by Sprague-Dawley rats during gestation and lactation and in the post-lactation period were examined. Rats allowed to eat ad libitum during pregnancy consumed quantities of food only slightly greater than the amount reported to be the average intake of pregnant Sprague-Dawley rats (20 g/day). Rats delivered their pups on day 22 or day 23 of the gestation period, but regardless of the day of delivery, the food intake of each rat decreased on day 21 of pregnancy and then decreased a second time on the day of parturition. During lactation, food consumption of the rats soon exceeded the amount reported as the average intake of lactating rats (30-35 g/day). Food intake was found to escalate from 12.2 +/- 3.1 g/rat on day 0 of lactation, the lowest intake in the study, to 94.4 +/- 23.7 g on day 21 of lactation. However, in the latter part of the lactation period, the intake represented the combined food intake of dams and pups. Eight days in the post-lactation period were required for food intake of dams to return to a level near that recorded at the beginning of pregnancy.