Effect of Milk Replacer Feeding Level and Concentration on Feed Utilization, Growth Performance, and Blood Parameters of Hanwoo Calves

This study aims to determine appropriate milk replacer feeding amounts and concentrations for artificial suckling of Hanwoo calves by analyzing growth and blood parameters in response to varying feeding levels and concentrations. A total of 90 Hanwoo calves (45 females; 45 males) (Mean weight 30.84 (3.61) kg; females 29.22 (3.47) kg; males 32.46 (2.99) kg) were allocated in the experiment. The treatment design consisted of a 3 × 3 factorial arrangement, resulting in 9 treatment groups based on milk replacer feeding levels and concentrations. Milk replacer feeding levels were set at 10, 20, and 30% of calf body weight, while concentrations were 15, 20, and 25%. The blood parameters, average daily gain, feed efficiency, diarrhea incidence, feed intake, and water intake were measured. Optimal feed intake was observed at milk replacer levels above 4.0% DM of BW (20% of body weight × 20% concentration) (<i>p</i> < 0.05). Maximum average daily gain was achieved with 4.5% DM of BW (30% of body weight × 15% concentration). The 25% milk replacer concentration showed reduced growth performance and increased diarrhea incidence compared with lower concentrations. Blood parameters remained unaffected across treatments. For 30-day-old Hanwoo calves, the ideal feeding regimen appears to be 4.5% DM of BW (30% of body weight × 15% concentration) divided into four daily feedings. However, for younger calves or when digestive issues are a concern, a two-phase approach is recommended: 3.0% DM of BW (20% of body weight × 15% concentration) for the first 10 days, followed by an increase to 4.5% DM of BW (30% of body weight × 15% concentration) thereafter. This feeding strategy aims to optimize growth performance while minimizing potential digestive disturbances during the critical early development stage of Hanwoo calves.