This thesis investigates the effects of increasing fat inclusion in milk replacer (MR) on growth, feed intake, feeding behaviour, and blood metabolites in Holstein calves. It was found that higher fat inclusion reduced MR intake without an evident effect on solid feed intake or growth when MR was offered ad libitum. Nevertheless, greater fat inclusion reduced hunger-related behaviours during the weaning period. When investigating the effects of a high-fat MR on growth, solid feed intake, and blood metabolites in feed restricted calves, no alterations on growth or solid feed intake were observed. However, changes in blood metabolites were detected. Calves consuming the high-fat diet had greater blood NEFA and glucose concentrations than calves consuming a traditional MR. These findings suggest that increasing fat at the expense of lactose provides promising results for enhanced feeding programs such as the reduction of hunger-like behaviours around weaning, and the comparable growth performance.