Daily calcium (Ca) intake is critical for bone health and energy metabolism, but less is known about its metabolic role at young ages. We used targeted electrospray ionization liquid chromatography-mass spectrometry-based metabolomics and candidate gene expression to compare the effect of dietary Ca level (high vs. adequate intake), as influenced by dietary cereal composition (wheat-barley vs. corn grains), on postprandial serum metabolome profiles and hepatic expression of genes related to glucose, lipid and amino acid metabolism in juvenile pigs (n = 32; 7-weeks of age). Explorative analysis of 132 metabolites demonstrated that postprandial serum of pigs fed high Ca contained greater (p < 0.05) concentrations of hexoses, 13 amino acids, 3 polyamines and 33 phosphatidylcholines compared to pigs fed adequate Ca. Partial-least-squares-discriminant analysis and cereal-Ca interactions indicated that the dietary cereal source may modulate the metabolic Ca response to a meal. Hepatic responses showed trends for upregulation of PPARG and SRBEF1 expression with high versus adequate Ca diets. Present data are consistent with the concept that dietary Ca modifies systemic metabolic processes in young animals. Targeted metabolomics provided greater insight into the complex metabolic responses related to dietary Ca than previously reported.