Quantification and the effects of secondary colostrum components on neonatal calf physiology and metabolism: A
E V Lopez-Bondarchuk1, J H C Costa1
1Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT 05405.
Abstract:
Bovine colostrum is produced in the weeks leading up to and secreted by the dam after parturition, serving as a complete source of nutrition for neonatal calves. Research has long emphasized the importance of timely colostrum feeding, focusing primarily on IgG transfer and the assessment of passive immunity within 24 to 48 h of intake. However, emerging evidence indicates that "secondary" components-cytokines, oligosaccharides, fatty acids, enzymes, and other nutrients-also play critical roles in metabolism and physiological development. A further examination and understanding of their dynamics could refine colostrum management strategies and support targeted approaches, such as extended colostrum feeding or inclusion of transition milk, to improve neonatal outcomes. Despite their importance, data on these components across successive milkings remain limited, representing a key research gap. In this scoping review, 15 sources published between January 2000 and April 2025 were identified through database searches, with exclusions applied to papers not meeting the inclusion criteria. Collectively, these studies reported measures of secondary colostrum components, describing their kinetics from colostrum to transition milk and mature milk, each serving distinct biological functions in calf development. Unlike mature milk, colostrum and transition milk are uniquely rich in IgG, IgA, and IgM, as well as cytokines and oligosaccharides that promote gut health and protect against pathogens. These metabolites decrease from colostrum to the seventh milking, as shown in the literature. Growth factors like IGF-I and TGF-β are present at significantly higher concentrations in colostrum and decrease exponentially over time; studies have shown that these growth factors enhance GI tract epithelial growth and nutrient absorption. Hormones such as prolactin and cortisol also decrease exponentially after the first milking, and studies have shown that they are related to metabolic regulation. The results of this scoping review suggest that although considerable research has examined IgG, IgA, and IgM levels, as well as cytokines and oligosaccharides and other colostrum bioactive compounds from first to mature milking, few studies have comprehensively quantified other components. Also, most studies have investigated a single component or related components and none have investigated holistically the secondary components in colostrum, transition milk, and mature milk. Also, no study has investigated the effects of management and other factors in the transition milk of dairy cows, underscoring the need for further investigation.
