Proliferation and cytokine production in bovine proliferative blood cells as biomarkers of immune memory in OmniGen-AF fed heifers

The impact of an immunostimulant, OmniGen-AF, on BRD vaccine response in Holstein heifers was tested. They were fed a standard diet (12 heifers) or also supplemented with OmniGen-AF (13 heifers) for 170 days. All were vaccinated at the beginning of the trial (day -110), and again on study day 0. Lymphocyte proliferation and cytokine production in response to BHV-1 and BVDV viruses were measured in vitro. Neutralizing antibody titers were determined for the same viruses. Initial vaccination induced increased antibody titers against the viruses, and booster vaccination greatly increased titers to BVDV virus; though, no differences were seen between diets. Feeding OmniGen-AF significantly enhanced proliferation responses to the viruses measured 42 and 60 days following booster vaccination. Significant differences in cytokine production were also observed relative to the diet treatments, but did not show a useful pattern of response relative to booster vaccination.