Abstract #T122

# T122
Effect of feeding milk replacer at moderate rates with and without Neo-Terramycin and at high rates on calf performance and digestion immediately post-weaning.
F. X. Suarez-Mena*1, T. S. Dennis1, T. M. Hill1, W. Hu1, J. D. Quigley1, R. Schlotterbeck1, 1Provimi-NA, Brookville, OH.

This study looked into the effects of milk replacer (MR) feeding rate and Neo-Terramycin (NT) feeding in MR on calf performance and digestion. Neonatal Holstein male calves (n = 48; 45 ± 1.4 kg) were randomly assigned to 3 treatments, a moderate rate of MR (MOD), a moderate rate containing NT (Neomycin-Oxytetracycline, 1300 each g/ton; NTMOD), and a high rate of MR (HIGH). The MR rate for MOD and NTMOD was 0.66 kg/d for 39 d, then 0.33 kg/d for 3 d, and for HIGH was 0.85 kg/d for 5 d, 1.07 kg/d for 30 d, and 0.53 kg/d for 7 d (DM basis). The MR with NT was fed for 14 d, non-med for 1 d, NT for 14 d again, non-med for 1 d, then NT for the last 12 d. All MR had 25% CP and 18% fat (DM). Textured starter (40% starch, 20% CP; DM) and water were fed ad libitum through d 56. Calves were individually housed and bedded with straw. Medical treatments were recorded daily. Calves were weighed initially and weekly thereafter. Body condition score (BCS) and hip widths were measured initially and every 2 weeks thereafter. During d 47 to 51 of the trial, feces were collected from 5 calves per treatment to estimate digestibility using acid insoluble ash as marker. Data were analyzed as a completely randomized design with repeated measures when appropriate. Pre-planned contrast statements of MOD vs. NTMOD and MOD vs. HIGH were used to separate the means. Pre-weaning starter intake was less (P < 0.05), ADG tended to be greater (P = 0.06) and BCS change was greater (P < 0.05) for calves fed HI vs. MOD. Pre-weaning medical treatment days were less (P < 0.05) for calves fed NTMOD vs. MOD. Post-weaning ADG was less (P < 0.05) for calves fed NTMOD vs MOD. Digestibility of DM, OM, ADF, and NDF were greater (P < 0.05) for calves fed MOD vs. NTMOD and HIGH. Digestibility of NDF was 28, 17, and 18% for MOD, NTMOD, and HIGH respectively. Fat digestibility (P < 0.05) was greater for calves fed MOD vs. HIGH. In this study, the reduction of starter intake by feeding more MR and the prolonged feeding of NT in MR reduced digestion immediately post-weaning.

Key Words: antibiotics, medication, growth