Ludovica Wiedemann Contacts: ludovica.wiedemann@phd.unipi.itORCID iD: 0009-0007-8518-8020 Thesis supervisors: Prof.ssa Francesca Bonelli Project title: Multi-omic characterisation of colostrum in cattle and impact of colostrum administration as a nutraceutical in the neonatal period on the health of calves and future heifers. Abstract: This study aims to assess how bovine colostrum, administered as a nutraceutical both in colostral and post-colostral phase, affects the health of calves and future heifers. This project will be a prospective cohort study, divided into three research protocols (Tasks) performed throughout the three years of PhD programme. Task I will focus on metabolomic and lipidomic analyses on bovine colostrum and calves’ plasma, during the post-natal (colostral) phase. Data will be used to characterize the composition of both matrices using a multi-omic approach. Furthermore, their interaction and the resulting effect on calves’ health and immunological parameters during the first days of the calves’ lives will be assessed. In Task II, the calves already selected (Task I), will be randomly divided into three study groups (control group, treatment group 1 and 2) (n=6 calf/group). Calves from treatment group 1 and 2 will receive an extrameal of a colostrum replacer containg a different IgG concentration, for 14 days. Data will be alanysed to investigate differences related to the onset, duration and treatment requirements of the most common bovine neonatal diseases (diarrohea and BRD). Furthermore, differences in treated calves’ metabolomic and lipidomic plasma profiles compared to those in the control group, will be investigated. The last year will focus on the analysis of Task III data: three steps clinical follow-up. A larger population will be enrolled (n=60 feamle calves) and it will be housed in a private dairy cows husbandry. Calves will undergo the best nutraceutical treatment among the two tested in Task II, and data will be recorded from their birth to the peak of milk production during the first lactation. Data referred to animals’ health, antimicrobial treatments and heifers’ productive and reproductive performance will be recorded at three key time points: 60 days (weaning), 12 months (sexual maturity), 24 months (peak production at first lactation) of animals’ life. The study aims to investigate, from a multi-omic perspective, the effect of bovine colostrum administered as a nutraceutical, on calves’ plasma composition and an improvement in calves’ health, defined throught a reduction in the incidence of the most common bovine neonatal diseases. Additionally, the study aims to demonstrate an improvement in the health status of future heifers and an optimisation of their productive and reproductive performance. The improvements in animal health are linked to a reduction in the use of antimicrobial drugs, condition that would allow the bovine colostrum administration as a nutraceutical in the post-colostral phase, to be considered a valuable tool in tackling the problem of antimicrobial resistance, thereby contributing the achievement of “One Health” objective. Finally, we hope the new knowledge can lay the foundation to standardize a treatment administration protocol or even to patent a colostrum substitute to be used as an easy-to-use nutraceutical product in livestock field.