351 Awardee Talk: Effects of vitamin and mineral supplementation to beef cattle during gestation on programming outcomes in the offspring
Authors: Hurlbert Jennifer L , Dahlen Carl R 
Published: September 2024

Abstract
Vitamins and minerals are essential elements in beef cattle diets, and are critical for reproduction, immune function, and overall health, and trace elements provided to the gestating dam during gestation are important factors for the establishment and recognition of pregnancy, placental development, embryogenesis, and organogenesis in the conceptus. During pregnancy, the fetus relies on the transfer of trace elements across the fetal-maternal interface for growth, development, and the establishment of a postnatal mineral reserve. However, there is significant variation in vitamin and mineral supplementation strategies in cow-calf production systems, and little is understood regarding the impacts of providing vitamin and mineral supplements to pregnant beef cattle on developmental outcomes in the offspring. Our current work investigated the effects of providing (or not providing) a vitamin and mineral supplement to gestating beef cattle during early gestation grazing native range (Exp. 1) and to beef heifers from breeding to calving (Exp. 2 and 3). Analysis of liver mineral concentrations in gestating beef cows in Exp. 1 indicated increased concentrations of Cu, Se, and Co in cows and suckling calves with free-choice access to the vitamin and mineral supplement on pasture. However, birth and weaning weights of calves in utero at the time of supplementation, weaning weights of suckling calves, and overall cow pregnancy rates were not affected by supplement access. In Exp. 2, we evaluated female neonatal calves born to vitamin and mineral supplemented (VTM) or nonsupplemented dams (CON) at harvest 30 h after birth. We observed no effect of maternal supplementation on calf birth weight, calf organ weights, or ovarian follicle counts in the neonate. However, concentrations of Se, Co, and vitamin D in serum and Se in liver were increased in VTM calves. In Exp. 3, we observed greater liver concentrations of Se, Cu, Zn, and Co at birth in female calves born to VTM dams, along with altered feeding behavior and physical activity in VTM offspring from weaning to puberty. Despite observing no differences in morphometric characteristics in the calf at birth in Exp. 2 or 3, later postnatal evaluations of the offspring in Exp. 3 revealed that calves from VTM dams had increased body measurements and carcass composition characteristics after weaning, and were nearly 17.5 kg heavier from weaning to 15 mo of age compared with offspring from the nonsupplemented cohort. Herein, these physiological alterations in VTM offspring during post-weaning development suggests that vitamin and mineral supplementation in utero modulated postnatal growth and may also impact whole-body physiology, epigenetic profiles, and organ development later in postnatal life. Assessing F1 offspring after puberty and through the subsequent gestational period with the F2 conceptus would allow us to determine if developmental programming effects originating from F0 dietary treatments extend multigenerationally.