Colostrum, also known as beestings or colostrum, is the first mammary secretion produced by dairy cows after parturition. It plays a fundamental role in the transfer of passive immunity, regulation of neonatal metabolic responses, and improvement of calf survival and future performance. The process of colostrum production (colostrogenesis) occurs mainly during the final weeks of gestation and around the onset of calving, and it is influenced by complex hormonal and physiological changes. A decline in progesterone concentration, concurrent with an increase in prolactin and glucocorticoids near parturition, initiates the secretory differentiation of mammary epithelial cells and the selective accumulation of immune components, particularly immunoglobulin G (IgG), within the alveolar lumen. Regulation of the permeability of the blood–milk barrier and structural modifications in mammary epithelial tight junctions are considered key mechanisms in this process. In this context, the neonatal Fc receptor (FcRn) plays an important role in the active and selective transport of IgG from the bloodstream into mammary secretions, thereby determining the immunological quality of colostrum. In addition to internal physiological regulation, the nutritional and metabolic status of the cow during the prepartum close-up period has a significant impact on both the quantity and quality of colostrum. Adequate supply of metabolizable protein, maintenance of energy balance, and control of metabolic stress have been reported to be associated with increased IgG concentration and improved colostrum composition. Furthermore, inflammatory and oxidative stress markers during late gestation may affect colostrum volume and its immunoglobulin profile. Management-related factors, including the length of the dry period, timing of the first milking after calving, use of oxytocin, and environmental or seasonal conditions, can also lead to considerable variation in colostrum production and quality. Overall, colostrum production in dairy cows is a multifactorial phenomenon involving interactions among hormonal regulation, mammary barrier function, immune status, and nutritional management. A comprehensive understanding of these mechanisms provides the scientific basis for developing effective strategies to optimize colostrum quality and enhance calf health and performance.