Effects of nutrient restriction of bovine dams during early gestation on postnatal growth and regulation of plasma glucose.

Angus x Hereford heifers (15 mo and AI to a single sire) were used to evaluate the effect of prenatal nutritional restriction on postnatal growth and regulation of glucose in plasma. Dams (d 32 of gestation) were stratified by BW and BCS and allotted to low [LN, 55% of NRC (1996) requirements, n = 7] or moderate nutrition [MN, 100% of NRC (1996) requirements, n = 7]. After 83 d of feeding, dams were commingled and received a diet in excess of requirements. Dams were allowed to calve naturally, and bull calves were castrated at birth. Dams and calves were maintained as a group until weaning, and calves were maintained as a group after weaning. Calves (15 mo of age) were adapted to a similar diet during 2 wk; catheters were placed in both jugular veins; and calves were confined in stalls. Two days later, calves were subjected to an intravenous glucose challenge and the next day to an insulin challenge. Dams had similar (P = 0.31) BW at the beginning of the experiment. At the end of restriction, LN dams weighed less (P ≤ 0.01) and had less BCS (P < 0.001) compared with MN dams. Length of gestation was not affected by prenatal nutritional treatment. Nutrient restriction during gestation did not influence birth weight or postnatal growth. Concentrations of glucose (P = 0.49) and insulin (P = 0.29) were not different in plasma of LN and MN calves before glucose infusion. Plasma concentrations of glucose, after intravenous administration of glucose, decreased more rapidly (P = 0.05) in LN compared with MN calves. Concentrations of glucose (P = 0.68) and insulin (P = 0.55) in plasma of LN and MN calves were similar after infusion of insulin. Nutritional restriction of dams during early gestation did not influence postnatal growth, but altered clearance of glucose after a bolus infusion of glucose.