Feeding more milk replacer (MR) in the summer may improve calf growth by increasing energy availability for maintenance and growth. Therefore, the objective of the first experiment was to evaluate the effect of different MR feeding programs on calf performance and metabolism during summer. Feeding 0.66 kg/d dry matter (DM) of a MR containing 26% crude protein and 17% fat (26:17) improved calf growth compared with feeding 0.55 kg/d DM of a MR containing 20% crude protein and 20% fat (20:20), but feeding 0.77 kg/d DM did not support further improvements in calf performance. Feeding MR more frequently when large amounts of MR are fed may improve energy utilization and alleviate heat stress. Consequently, the objective of the second experiment was to evaluate the effect of MR feeding rate (FR) and frequency (FF) on performance, health, abomasal emptying, nutrient digestibility and glucose metabolism during the summer and winter. Increasing feeding frequency in the summer, lowered respiration rate and rectal temperature, however no effect was detected on average daily gain (ADG), and nutrient digestibility. Feeding more frequently accelerated abomasal emptying and feeding more MR delayed abomasum emptying in the summer only. Increasing feeding frequency improved insulin action at the peripheral tissue level.