This study aimed to determine the effects of age at first gestation on offspring growth performance, glucose metabolism, and IGF1 concentration.Heifers impregnated by AI from a single Door Handle bull at 15 months of age (15 M, n = 20), or 27 months of age (27 M, n = 20), and multiparous cows (adult, n = 20) were used.Dams from all groups were managed in a single group during gestation and lactation.Gestational length was longer in the 15 M and 27 M than in adult dams (p = 0.
009).Bodyweight at birth, at weaning and ADG during lactation were higher in calves from adult dams than in LIP BRUSH those from 27 M dams, and higher in calves from the latter than in 15 M calves (p p = 0.005).Body mass index was greater in calves from adults than in those from 15 M and 27 M dams (p = 0.
002).Milk production from 15 M and 27 M dams was similar but lower than that from adults (p = 0.03).Calves born from adult dams had greater blood glucose concentrations than those from 15 M and 27 M dams (p p = 0.
01).This study showed that age at first gestation affects offspring postnatal growth performance, glucose metabolism and IGF1 concentration.