Nutrient intake in the bovine during early and mid-gestation causes sex-specific changes in progeny plasma IGF-I, liveweight, height and carcass traits

Fetal and postnatal growth are mediated by insulin-like growth factors (IGFs) and their binding proteins (IGFBPs). Maternal nutrient intake during gestation can program the postnatal IGF-axis. This may have significant economic implications for beef cattle production. We investigated the effect of high (H = 240%) and low (L = 70%) levels of recommended daily crude protein (CP) intake for heifers during the first and second trimesters of gestation in a two-by-two factorial design on progeny (n = 68) plasma IGF-I, IGF-II, total IGFBP (tIGFBP), postnatal growth and carcass traits. Calves were heavier at birth following high CP diets during the second trimester (P = 0.03) and this persisted to 29 d. Plasma IGF-I concentrations of males were greater for HL compared to LL (P < 0.01) and HH (P > 0.04) from 29 to 657 d, and for LH compared to LL from 29 until 379 d (P = 0.02). Exposure to low CP diets during the first trimester resulted in heavier males from 191 d onwards (P = 0.04) but a tendency for lighter females from 552 d onwards (P = 0.07) that had lighter carcass weights (P = 0.04). Longissimus dorsi cross-sectional area of all carcasses was greater following exposure to low CP diets during the second trimester (P = 0.04). Heifer nutrient intake during the first and second trimesters causes persistent and sex-specific programming of progeny plasma IGF-I, postnatal liveweight and carcass weight. Refining heifer nutritional programs during early gestation may optimize production objectives in progeny.