During the first 2/3 of pregnancy, energy requirements are not different from those of young adult dogs (Gesellshaft, 1989a; Ontko and Phillips, 1958). At 35 days, only 2% of fetal mass has been developed compared to 5.5% of fetal mass at 40 days. After 40 days, fetal tissue grows exponentially (Gesellshaft, 1989a; Leibetseder, 1989). Thus, energy needs increase during Week 5 and peak between Weeks 6 and 9 of gestation.

Energy needs can peak at 30% to 60% above mating weight, depending on litter size. Even though energy requirements are highest during Weeks 6 to 8 of pregnancy, food intake is limited by abdominal fullness as a result of the gravid uterus. Giant breeds may not be able to eat enough food to maintain body weight before the last week of pregnancy. Food intake may drop dramatically just before whelping, with some bitches completely lacking appetite. Enough energy should be provided during the early weeks of pregnancy to help maintain body condition and milk production after whelping.

Food should be high in energy density throughout gestation.

Adapted from Small Animal Clinical Nutrition, 5th Edition