91 Early Life Management and Long-Term Productivity of Dairy Calves M. E. Van Amburgh 1 , E. Raffrenato, F. Soberon and R. W. Everett Department of Animal Science Cornell University, Ithaca, NY Introduction The topic of calves and calf management traditionally involves discussions about dry cow management, colostrum, scours, rumen development and weaning. In more recent times the topic of “intensified feeding or accelerated growth” has become a focus of discussion and some debate and the concept has been applied in both research and on farm in various ways. Much of this discussion involves differences in perspectives about how to best manage the nutrition and nutrient intake and weaning of the calf. There are teleological arguments for providing a greater supply of nutrients from milk or milk replacer, e.g. what would the dam provide, and there are also arguments for improving welfare status by following the same concept (Jasper and Weary, 2002; de Paula Vieira et al., 2008). At the recently held 15 th American Dairy Science Association Discover Conference on Calves (Roanoke, VA) the overwhelming consensus of the participants was that we need to feed calves for a specific rate of daily gain, much higher than currently considered, and that is significant change in industry perspective. The calf has a requirement for maintenance and once maintenance requirements are met, growth can be achieved if enough nutrients and the proper balance of nutrients are provided to the calf. The nutrient requirements of the calf have been described in the current nutrient requirements of dairy cattle 7 th edition (NRC, 2001) publication. The requirements can be easily actualized and are very useful for diagnosing the impact of temperature on the maintenance requirements of the calf through the computer program that accompanies the publication. Just prior to and since the release of the dairy cattle NRC (2001), new data were being developed and are now available that help us refine those predictions (Bartlett, 2001, Diaz et al., 2001, Tikofsky et al., 2001; Bascom et al., 2007; Blome et al., 2003; Brown et al, 2005; Meyer, 2004; Mills, 2005). Table 1 summarizes the current knowledge about the requirements for growth of the calf based on the body composition data derived since the 2001 NRC (NRC, 2001) was published. These values are consistent with the current publication (NRC, 2001), but have slightly lower energy requirements per unit of gain because the original equations were based on heavier veal type calves fed higher fat diets and depositing more fat per unit of weight gain. These predictions for energy requirements are consistent with dairy replacement calves being fed diets more typical of our system. The protein requirement 1 Contact at: Morrison Hall, Room 272, Ithaca, NY 14850-2488; Work Phone: (607) 254-4910; Fax: (607) 255-1335; Email: mev1@cornell.edu