Abstract #M162

# M162
Performance and health of dairy calves fed milk replacers at a conventional or accelerated feeding rate supplemented with different fat sources.
D. Ziegler1, H. Chester-Jones*1, B. Ziegler2, A. Manthey2, E. Dufour2, J. Olson3, 1University of Minnesota, Waseca, MN, 2Hubbard Feeds Inc, Mankato, MN, 3Milk Products Inc, Chilton, WI.

One-hundred (2 to 5 d old) individually fed Holstein heifer calves (39.5 ± 0.63 kg) were randomly assigned to 1 of 4 milk replacers (MR), 24% crude protein (CP):24% fat as-fed, formulated with different fat sources to evaluate calf performance and health through 56 d. The study was conducted between December 2017 and April 2018. All calves were fed ad libitum water and a texturized calf starter, 18% CP as-fed, from d 1 to 56. Calf MR treatments were as follows: 1) MR formulated with 100% animal fat (AF) fed at a low feeding rate (FR) of 0.28 kg MR powder in 2 L of water 2× daily from d 1 to 35, and 1x daily from d 36 to weaning at d 42, (LFNC); 2) MR formulated with 85% AF and 15% coconut oil (CO) fed as for Trt 1, (LFWC); 3) MR formulated with 100% AF fed at a high FR of 0.43 kg MR powder in 3 L water 2× daily from d 1 to 42, and 1× daily from d 43 to weaning at d 49, (HFNC); and 4) formulated with 85% AF and 15% CO MR fed as for Trt 3 (HFWC). Data were analyzed using the PROC mixed procedure of SAS and repeated measures analyses applied where appropriate.There were no interactions between fat source and FR for any parameters. Feeding rate (P < 0.01) and fat source (P < 0.04) improved feed:gain (d 1 to 42) for LFWC and HFWC (0.60 and 0.62, respectively) when compared with LFNC and HFNC (0.57 and 0.61, respectively). Feeding rate (P < 0.01) and fat source (P < 0.07) increased d 56 hip height (HH) with average gains of 10.6, 12.1, 12.7, and 13.1 cm for LFNC, LFWC, HFNC, and HFWC, respectively. Fat source did not affect d 1 to 56 ADG (P > 0.1). Total (d 1 to 56) starter intake was significantly lower (P < 0.01) for HF calves, averaging 44.0 kg compared with 59.9 kg for LF calves. There were no differences (P > 0.15) in overall DM intake from d 1 to 56. Scouring days (days >3, where 1 = normal and 4 = watery) were affected by FS (1.55 vs 0.83 d, P < 0.01) and d 1 to 42 treatment costs ($0.47 vs 0.14, P < 0.001) for LFNC+HFNC vs LFWC+HFWC. Under the conditions of this study, fat source did not affect 56 d ADG, although calves fed a MR with a blend of AF and CO had improved 56 d HH gain, 42 d feed:gain and better health status compared with calves fed MR formulated with AF only.

Key Words: calf performance, milk replacer, fat source