Interpretive Summary: Supplementing organic-complexed or inorganic Co, Cu, Mn, and Zn to beef cows during gestation: physiological and productive response of cows and their offspring until weaning

By Caitlin Vanderohe

The bovine fetus relies on the cow for all of the trace minerals necessary for growth and metabolism, making fetal calves sensitive to maternal nutrition. Previous work in this area has demonstrated that supplementation of organic Co, Cu, Mn, and Zn complexes to pregnant cows improved calf growth and reduced the incidence of bovine respiratory disease. Additional work has also shown that trance minerals have a profound impact on reproductive development. A recent work published in the Journal of Animal Science by Harvey et al. evaluated the effects of supplementation of organic complexed and inorganic Co, Cu, Mn, and Zn to beef gestation diets on growth and reproductive performance of calves.

The authors hypothesized that prolonged maternal supplementation of organic complexed trace minerals during gestation will improve calf performance.  To test this hypothesis 190 nonlactating, pregnant beef cows were fed a supplement containing either sulfate sourced  or organic complexed forms of Cu, Co, Mn, and Zn in the final two trimesters of gestation. After caving and weaning, cows and calves were managed and fed similarly; heifer calves were housed together until reproductive maturity, and steers were appropriately managed during backgrounding and subsequently moved to a feedlot until harvest.

Calves from cows fed the organic premix had greater rna expression of enzymes involved in reducing reactive oxygen species, demonstrating the potential utility of organic complexed trace minerals supplementation to metabolize metabolic manifestations of stress during weaning. Additionally, heifers from cows fed the organic complexed trace minerals attained puberty sooner, despite similar growth rates than their inorganic-conditioned cohorts. There were no statistical differences observed in growth or carcass characteristics between steers from cows fed organic-complexed or inorganic sources of trace minerals. Overall, the data suggest that supplementation of organic-complexed trace minerals to gestation diets can enhance the reproductive development of offspring.

The full paper can be found on the Journal of Animal Science webpage.