Dietary selenium and nutritional plane alter specific aspects of maternal endocrine status during pregnancy and lactation

Abstract Objectives were to examine effects of selenium (Se) supply and maternal nutritional plane during gestation on placental size at term and maternal endocrine profiles throughout gestation and early lactation. Ewe lambs (n = 84) were allocated to treatments that included Se supply of adequate Se (ASe; 11.5 μg/kg BW) or high Se (HSe; 77 μg/kg BW) initiated at breeding and nutritional plane of 60% (RES), 100% (CON), or 140% (EXC) of requirements beginning on day 40 of gestation. At parturition, lambs were removed from their dams, and ewes were transitioned to a common diet that met requirements of lactation. Blood samples were taken from a subset of ewes (n = 42) throughout gestation, during parturition, and throughout lactation to determine hormone concentrations. Cotyledon number was reduced ( P = 0.03) in RES and EXC ewes compared with CON ewes. Placental delivery time tended ( P = 0.08) to be shorter in HSe ewes than in ASe ewes, whereas placental delivery time was longer ( P = 0.02) in RES ewes than in CON and EXC ewes. During gestation, maternal progesterone, estradiol-17β, and GH were increased ( P P P = 0.06) concentrations of estradiol-17β than ASe ewes. Three hours after parturition a surge of GH was observed in ASe-RES ewes that was muted in HSe-RES ewes and not apparent in other ewes. Growth hormone area under the curve during the parturient process was increased ( P P P