Abstract #156

# 156
Commercial dairy farm evaluation of highly digestible corn grain for calf starters when calves are fed pasteurized waste milk.
David P. Casper*1, Mark Kirk2, 1South Dakota State University, Brookings, SD, 2Masters Choice, Anna, IL.

New corn hybrids have been developed by Masters Choice (MC) that vary in energy density and starch digestibility. These MC hybrids have lower starch densities due to an altered starch structure, which allows for greater ruminal and intestinal starch digestion. Our previous work (Casper et al. 2014) had demonstrated improved nutrient digestibilities, feed efficiency, and reduction in cost of gain when feeding a calf starter (CS) based on MC corn when calves were fed an accelerated milk replacer (28:18 CP:fat). Forty-five (1 to 3 d old) Holstein heifer calves raised on a large commercial Eastern South Dakota Dairy Operation were randomly assigned to 1 of 3 CS to evaluate growth performance of Holstein heifer calves through 7 wk of age from mid-June 15 through mid-August, 2013. Treatments were: 1) Control (C) CS: containing 40% (DM basis) conventional ground shelled corn 24% CP; 2) MC CS: containing (40% DM basis) MC corn and 24% CP; and 3) Standard commercially available CS (S) being fed at the dairy operation containing 16% conventional corn and 16.5% CP. All CS were fed as a pellet. Colostrum was fed the first 3 d of life and then pasteurized waste milk was fed twice daily at a rate of 3.78l L/d for 2–13 d, 5.68 L/d for 14–35 d, and once daily at 2.85 L/d for 35–42 d of age. Feedings were reduce to 1x/d at 35 d to facilitate weaning at 42 d and the study ended at 49 d. Calves were housed in individual poly hutches with ad libitum CS and water. Data were analyzed as a completely random design using the PROC MIXED procedure of SAS Version 9.4. Initial body weights were similar (P > 0.08) for calves fed all CS (38.8, 37.5, and 34.9 kg for C, MC, and S, respectively). Body weight gains (18.0, 16.8 and 13.6 kg) and average daily gains (0.34, 0.32, and 0.28 kg/d) were greater (P < 0.03) for calves fed C and MC compared with calves fed S CS. Calves fed MC CS gained greater (P < 0.03) more body length (4.6, 12.9, and 6.4 cm) than calves fed C or S. Feeding a higher CP CS improved growth rates, but MC CS further increased body length when fed pasteurized waste milk during the summer heat stress.

Key Words: waste milk, corn hybrid, calf starter