Central to the advancement of Irish dairy is the optimisation of whole colostrum/milk for improved calf health, and adding value to commercial products, such as bringing infant-formula compositionally closer to breast milk. Bovine milk has reduced diversity and yield of health-promoting oligosaccharides (OS), and their valuable effects are largely lost to formula-fed infants. To address this discrepancy, natural optimisation of bovine milk oligosaccharide (BMO) quantity and composition was investigated, by assessing key factors influencing their production. OS profiles revealed colostrum samples, Jersey cows, and 2nd-4th parity cows contained highest OS concentrations and highlighted prolific correlates (3-FL, DSLNT). Furthermore, high inter-cow colostrum variation revealed a wide range of BMO production, with 10 cows producing much higher (> 50% increase compared to mean) total OS concentrations. Three OS traits (LNnH, LSTa, DSLNT) reported heritabilities greater than 0.59 (P < 0.01). However, GWAS analysis reported no significantly associated SNPs after FDR (q < 0.05), with environmental factors significantly contributing to phenotypic variance. This work is the first to report bovine colostral OS hertabilities and paves the way for necessary additional GWAS studies to assess the feasibility of selective breeding initiatives including OS production in the future. Like BMO, specific milk proteins exhibit health-promoting properties. The effect of day post-partum and parity on the global protein profile during early lactation was investigated to expand proteome coverage/characterisation and offer an Irish context to previous analyses. Protein concentration decreased significantly after day 0 before stabilising. Overall, 471 proteins were identified across all samples; 199 protein groups showed altered relative abundance by day of lactation (fold change ≥2, adjusted-P <0.05), but none were altered significantly by parity. Colostrum had the highest levels of immune-related proteins. Subsequently, the association between BMO production and the protein profile of colostrum was explored to improve our holistic understanding of the global milk environment. Comprehensive characterisation of the colostral protein profile from high, mid-range, and low oligosaccharide producing cows (HOP, MOP, LOP) was carried out through analysis of the unfractionated colostrum, extracellular vesicle (EV), and cell fractions. The HOP had significantly higher levels of total protein than LOP. The unfractionated samples of HOP are associated with high levels of gastrointestinal modulatory proteins. In comparison, the EV fraction of the LOP contained higher relative abundances of immune-related proteins. This integrative approach allowed for the characterisation of distinct compositional profiles which may inform selection criteria for naturally enhanced colostrum, potentially targeting immuno-compromised calves and/or for use as a value-added starting material for powder products.