Effect of level of milk replacer fed to Holstein calves on performance during the preweaning period and starter digestibility at weaning

Calves following an enhanced-growth feeding program usually show lower starter intakes during the preweaning period compared with conventionally-fed calves. To assess whether this low intake in calves following an enhanced-growth feeding program affects calf capacity to digest starter after weaning, 19 Holstein male calves were used to measure apparent nutrient digestibility at weaning. Calves were divided in two groups: calves on a conventional feeding program (CF) and calves on an enhanced-growth feeding program (EF). After one week of adaptation to milk replacer (25% CP and 19% fat), the CF calves were fed 41/d of milk replacer (MR) at 12.5% DM dilution rate from d 1-28, and 21/d from d 29 to weaning day at d 35, and the EF calves were offered MR at 18% DM dilution rate: 41/d from d 1-6, 61/d from d 7-13, 71/d from d 14-20, 61/d from d 21-28, and 3 1/d from d 29 to 35. Calf starter (20% CP) was offered ad libitum from the beginning to the end of study at d 42, and its consumption was recorded daily. Calves were weighed at d 3, 17, 24, 31, 38 and 42. Daily total faeces collection was conducted for the last 5 d of study. Final BW was numerically greater in EF than in CF calves (88.6 vs 81.2 +/- 3.36 kg, respectively). Starter DMI was greater (P < 0.05) in CF compared with EF calves during the preweaning (0.68 vs 0.36 +/- 0.078 kg/d, respectively) and postweaning (2.52 vs 1.90 +/- 0.102 kg/d, respectively) periods, but there were no differences in total DMI (1.12 and 1.26 +/- 0.078 kg/d, in CF and EF calves, respectively) during the preweaning period. However, apparent DM, OM, NDF, CP, and GE digestibility coefficients were greater (P < 0.05) in CF compared with EF calves (77.4 vs 71.8 +/- 1.23%, 78.7 vs 73.2 +/- 1.18%, 34.7 vs 20.31 +/- 3.79%, 77.1 vs 71.6 +/- 1.29%, and 75.6 vs 69.8 +/- 1.25%, respectively) the week after weaning. It is concluded that calves in the EF treatment presented lower nutrient digestibility coefficients compared with CF calves the week after weaning. (C) 2006 Elsevier B.V. All rights reserved.