Representative samples of feed were taken every 14 d for analysis. evaluated, sand was scored to be the dirtiest, while pens bedded with rice hulls, long wheat straw, and solid wood shavings scored cleaner. Long wheat straw experienced the warmest surface temperature, and rice hulls and solid wood shavings were warmer than granite fines and sand. Serum cortisol, Antibody; Jorgensen Laboratories, Inc., Loveland, CO) one time only within 6?h of birth by plastic esophageal feeder. Calves were reweighed at 1 d of age to establish an average initial BW. At 1 d of age, calves were randomly assigned to individual pens on 1 of 5 types of bed linens materials (12 calves per treatment). Calves began the study over a 4-wk period (3 calves per treatment per week). The week that calves started was used as a block in the statistical models. Calves were offered 2?L of medicated milk replacer (Vigortone Ag Products, Inc., Cedar Rapids, IA) mixed with Optimil concentrate calf supplement-MR type B medicated feed (Manna Pro Corp, St. Louis, MO) twice daily at 0700 Nuclear yellow and 1530?h with nipple bottles throughout this study. Medicated milk replacer was formulated to contain oxytetracycline at 220?mg and neomycin sulfate at 440?mg/kg of milk replacer powder. Optimil concentrate was formulated to contain oxytetracycline-HCl at 7.04?g and neomycin at 14.08?g/kg of Optimil powder. After 760?g of Optimil was mixed with 22.7?kg of the milk replacer, 227?g of this combination was used the make the 2 2?L offered. Commercial calf starter (Caldwell Milling Co; Rosebud, AR) was offered once daily in the morning in an open plastic bucket beginning on d 3. Calves were offered 0.12?kg/d of starter in wk 1, 0.24?kg/d in wk 2, and were increased to ad libitum in wk 3 until the weaning date after wk 6. Each morning any orts Nuclear yellow were removed, weighed, and discarded, and new starter was offered. Starter contained a coccidiostat (49.5?mg/ kg as fed; Deccox; Alpharma Animal Health Nuclear yellow Division, Lowell, AR). Representative samples of feed were taken every 14 d for analysis. Commercial medicated milk replacer and calf starter were analyzed for DM (AOAC, 1990), CP (nitrogen by combustion; Elemental Analyzers for the determination of nitrogen; Elementar Americas, Inc., Mt. Laurel, NJ), and excess fat (AOAC 920.39C, 1990). Calf starter and milk replacer samples were digested in duplicate by wet ash methodology using concentrated trace metal grade nitric acid in 50-mL conical, trace metal free, polypropylene centrifuge tubes with a heated digestion block (ModBlock, CPI International, Santa Rosa, CA). After digestion, samples were brought to 50?mL volume with a 0.1% cesium chloride answer. Concentrations of Ca were determined by atomic absorption spectroscopy (Perkin-Elmer, model 5000, Norwalk, CT). Concentrations of P were determined with a spectrophotometric process (AOAC, 1990) altered for use in microtiter plates. Starter and milk replacer intakes were recorded daily. Calf starter refusals were measured daily in the morning. Milk refusal was measured twice daily. Water was available at all occasions in an Nuclear yellow open plastic bucket. Calves were weighed in the beginning and at 1, 2, 4, and 6 wk of age (an average of weights on 2 consecutive d was utilized for the final BW). Calves were housed until weaning at 6 wk without removing any bedding materials from your pens. However, at 2-wk intervals, a bed linens score was decided for each pen, then bedding materials that had been forced out round the pen were removed and placed back into that Nuclear yellow pen before adding new bedding FLJ14936 material, if required by bedding score. The bedding score was rated on a scale of 1 1 to 5 as follows: 1?=?dry and clean, 2?=?20 to 40% of surface dirty or wet, 3?=?40 to 60% of surface dirty or wet, 4?=?60 to 80% surface dirty or wet, and 5?=? 80% of surface dirty or wet. Approximately 1.3?cm (depth) of additional bed linens was added over the previous bed linens when the bed linens score was 3, or if less than 50% of bed linens material remained in the pen, or if the bed linens material became packed and a large hole developed in the surface. Fresh bedding material was added into the middle of pens or into any hole, and the excess weight.