| dc.description.abstract | Nutritional management during gestation as well as postnatally is critical to optimize efficiency and profitability of cow-calf systems. Two experiments were performed to evaluate the effects of trace mineral supplementation during gestation and supplementation with calcium salts of soybean oil (CSSO) to nursing beef steers on performance and physiological responses. In experiment one, the impact of inorganic or organic Co, Cu, Mn, and Zn supplementation to beef cows during gestation were evaluated on parameters associated with offspring performance and physiological responses. One hundred and ninety non lactating pregnant beef cows were assigned to the experiment at 117 ± 2.2 days of gestation (d 0) and received diets containing either 1) sulfate sources of Cu, Co, Mn, and Zn (INR), or 2) organic complexed source of Cu, Co, Mn, and Zn (AAC). No treatment differences were detected (P ≥ 0.19) for calf body weight at birth or at weaning. Heifers born to INR cows had delayed puberty attainment (treatment ×day interaction; P < 0.01), whereas no treatment differences were detected (P ≥ 0.24) for carcass traits when male offspring were reared as feeder cattle. In experiment two, the impacts of supplementing CSSO at 2 months of age via creep-feeding and/or postweaning via preconditioning were evaluated on parameters associated carcass quality and development. Steers receiving CSSO at 2 mo of age had greater (P ≤ 0.01) mRNA expression of genes associated with lipid metabolism in the longissimus muscle later in life, although this did not translate into improved carcass characteristics. Outcomes of these experiments may be used to develop nutritional strategies to enhance reproductive efficiency in female offspring and upregulate genes associated with lipogenesis during the finishing period. Research is still warranted to examine the effects of such supplementation during these periods of developmental plasticity on cattle productivity. | en |
