Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081,P.R.China;
Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081,P.R.China;
Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081,P.R.China;
Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081,P.R.China;
Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081,P.R.China;
calves,protein levels,milk replacer,apparent digestibility,biochemical parameters;