Role of bovine colostrum in programming early immune responses in calves 3699

Abstract Description This study investigated the effect of colostrum on the development of the main T cell subsets during the first month of life. Twenty-four Holstein calves were randomly assigned to one of three treatments: fresh colostrum (FSH, n = 8), frozen colostrum (FRZ, n = 8), and colostrum-deprived (DPR, n = 8). FSH and FRZ calves received colostrum equivalent to 8% of body weight (BW) within the first 3 hours of life and 6% BW at 8–12 hours after birth, while DPR calves were fed milk replacer at the same % of BW as the colostrum-fed calves. Blood samples were collected at birth and on days (d) 2, 7, 14, and 28. Flow cytometry was used to assess the proportions of CD4+, CD8+, and γδ T cells, as well as the memory marker CD45RO. In this study, no significant differences were observed between treatments on d 0 and 2 (P > 0.89). However, DPR calves had significantly lower proportions of γδ T cells on d 7 and 14 (P < 0.01) and showed a compensatory increase in CD4+ and CD8+ T cells on d 7 (P ≤ 0.07). Additionally, FSH calves had lower expression of the memory marker CD45RO in γδ T cells on d 28 compared to FRZ (P = 0.05). In neonatal calves, γδ T cells are the predominant lymphocyte subset in systemic circulation during the preweaning period, and its reduction in DPR calves might suggest that colostrum plays a crucial role in programming early immune development, promoting γδ T cell function to provide non-specific cell mediated protection and protect against environmental pathogens. Topic Categories Veterinary and Comparative Immunology (VET)