Exploring the impacts of colostrum on systemic immune development in dairy calves

Colostrum provides essential immune components, but its role in shaping neonatal immune development is not fully understood. Twenty-four Holstein calves were randomly assigned to 1 of 3 treatments: fresh colostrum (n = 8), frozen colostrum (n = 8), or colostrum deprived (n = 8). Animals were raised in a biosafety level 2 facility to avoid pathogen exposure and keep colostrum-deprived calves healthy. Blood samples were collected from the jugular vein for immune phenotyping at different time points during the first month of life. Data were analyzed using R 4.4.1 with a linear mixed-effects model with repeated measures. Gamma delta T cells expanded markedly within the first 2 d in all groups, but their maintenance was impaired in colostrum-deprived calves, accompanied by a compensatory increase in CD4⁺ and CD8⁺ T cells. Moreover, neutrophils from colostrum-deprived calves exhibited a heightened proinflammatory state. Additionally, colostrum deprivation altered T and B cell profiles as well as monocyte profiles. Memory development was also affected: calves fed fresh colostrum showed lower proportions of CD45RO⁺ γδ T cells compared with those receiving frozen colostrum. Overall, these findings highlight the critical role of colostrum in supporting the balanced development and regulation of both innate and adaptive immune cells in early life. Although both fresh and frozen colostrum supported IgG transfer, frozen colostrum altered γδ T cell memory maturation, suggesting that processing methods might shift developmental trajectories.