Abstract #T132

# T132
Effects of corn processing and bypass soybean meal in calf starter on growth and digestibility in young dairy calves.
T. S. Dennis*1, F. X. Suarez-Mena1, T. M. Hill1, J. D. Quigley1, W. Hu1, R. L. Schlotterbeck1, 1Provimi, Brookville, OH.

This study evaluated performance and diet digestibility of pre-weaned calves fed starters with 2 types of corn processing and 2 levels of heat-treated soybean meal (SBM). The 4 starters used were whole corn (WC) with conventional SBM (CS; 25% of diet as-fed), WC with a 55:45 blend of CS and SoyPass® (LignoTech USA; SP), flaked corn (FC) with CS, and FC with SP. Starters were texturized (35% corn, 35% protein pellet, 27% whole oats, and 3% molasses) and formulated to be equal in CP (20%), starch (44%), and NDF (17%) on a DM basis. Calves were fed one milk replacer (26% CP, 18% fat on DM basis) at 0.66 kg DM for 39 d then 0.33 kg for 3 d. The trial used 96 male Holstein calves (42.7 kg BW, 3–4 d of age) in 2 separate blocks. Calves were housed in individual pens in a naturally ventilated nursery and bedded with wheat straw. Intake was measured daily, calves were weighed weekly, and hip width (HW) and body condition score (BCS) was measured every 2 wk. In the first block, fecal samples were taken from 5 calves/treatment from d 33–37 and d 54–56 to estimate diet digestibility. Fecal pH was evaluated using a digital pH meter before compositing fecal samples by calf and period. Data were analyzed as a completely randomized design with calf as experimental unit and block as a random variable. Pre-weaning (d 0–42), HW change was greater (3.2 vs. 2.8 cm; P < 0.05) for calves fed WC+CS vs. other treatments. Post-weaning (d 43–56), starter intake was greater (2.08 vs. 1.95 kg/d; P < 0.05) and BCS change was lesser for calves fed WC vs. FC (P < 0.05). No other differences in performance were observed. Digestibility of NDF was less for calves fed FC vs. WC pre-weaning (33 vs. 48%) and post-weaning (46 vs. 51%; P < 0.05). Digestibilities of OM, CP, and fat were greater pre-weaning, whereas NDF and ADF digestibilities were greater post-weaning (P < 0.05). Fecal pH tended to be greater (P < 0.10) for calves fed FC vs. WC (7.51 vs. 7.46) but was not biologically different. In this study, increased corn processing and heat-treated SBM did not improve growth or diet digestibility in calves under 2 mo of age.

Key Words: calf starter, whole corn, steam-flaked corn