55 The Humoral Response of Newborn Calves Vaccinated Against Bovine Respiratory Complex and Supplemented with Autolyzed Yeast

Abstract The Bovine Respiratory Complex (BRC) significantly impacts morbidity and mortality in dairy calves between 1 3 months of age, called the immunological gap. receive colostrum milk immunoglobulins; however, these animals are still developing their specific immune system cannot present a robust active humoral response. Vaccines against intranasal BRC recommended for from first week age; although they do not prevent disease, can mitigate condition. yeast-based products have been studied as immunomodulators due to ß-glucans interaction with innate system. Thus, objective this study was evaluate effects autolyzed Saccharomyces cerevisiae yeast supplementation response newborn vaccinated BRC. For this, 20 no respiratory changes who received at adequate immunoglobulin levels were (Inforce 3, Zoets, Brazil) route single dose 30 days age. divided into Control group (n = 10), supplemented [AY] (RumenYeast 10 g/animal/day, ICC Brazil Company). once day 15th 51st Blood samples collected 15, 33, 36, 51 measure serum IgG IgA Serum increased AY compared other moments (P=0.03) both immunoglobulins greater than control (P=0.08 0.007, respectively), shown Figure 1. In conclusion, could potentially improve vaccine calf-dependent on colostral immunity.