Bioenergetics of pregnancy and lactation in European common vole

Abstract

Abstract The food consumption and assimilation were determined in the females of the European common vole Microtus arvalis (Pallas, 1779). The measurements were carried out using 17 pregnant and lactating females as well as 20 non-reproducing females. During the pregnancy the energy requirement of a female with average body weight 28.5 g amounts to the mean value of 13.9 kcal/day and is higher by 32% as compared with the control females. The daily food assimilation of the female (25.2 g body weight) during the lactation is equal to 26.6 kcal/day and exceeds by 133% the corresponding figure for the non-reproducing female. During the whole period of pregnancy and lactation the female assimilates additionally 304 kcal (including 60.5 kcal for gestation and 243.5 kcal for lactation). Hence the metabolism increases in this period by 82.5% on the average. To produce and nurse one young vole the mother requires 75.9 kcal. The losses of energy with faeces are equal to 8.95% and with urine to 3.33%, thus the energy present in the food is utilised in the very high degree (87.72%). The efficiency of net production in the breeding period is also high and equal to 13.9% during the pregnancy and 15.4% during the lactation.