Abstract At birth, the calf has a naïve immune system and is reliant upon maternal antibodies until it begins to produce its own. Gut absorption of these antibodies may be facilitated by the consumption of colostrum soon after birth, a process described as the “transfer of passive immunity”. Additional components found within colostrum, such as maternal leucocytes, microRNAs, hormones and oligosaccharides also contribute to calf health and development. These compounds stimulate intestinal epithelial cell development and the establishment of a healthy gut microbiome, which may enhance antibody absorption, inhibit pathogens and modulate immune responses. Different methods of colostrum collection, storage, handling and feeding will influence how colostrum is consumed and absorbed, and an appreciation of these factors is essential. Information © The Author 2024