Abstract #M136

# M136
Prebiotic supplementation influences feed intake, body weight gain, and adaptive immunity in Holstein heifer calves during commingling.
Caleigh E. Payne*1, Luis G. D. Mendonça1, Sonia J. Moisá1, Sophia C. Trombetta1, Lucas D. S. Rocha1, Suzy Q. Fowler1, Juan C. Gordienko1, Lindsey E. Hulbert1, 1Kansas State University, Manhattan, KS.

After weaning, the transition from individual housing to group housing (commingling) is stressful for calves and increases the risk of respiratory disease during this period. Prebiotics can include mannan-oligosaccharide (MOS) and β-glucan (BG) which may help improve calf health and performance. Therefore, the objectives of this study were to determine if a daily bolus dose of oral prebiotics (20% MOS; 10% BG) influence feed intake, body weight gain, or adaptive immunity in Holstein heifer calves (n = 60) during the transition from individual hutches to pens of 3. One week before commingling, calves (age 52 ± 4.0 SD d; body weight 83 ± 14.92 SD kg) were randomly assigned to daily treatments of either 4 g of prebiotic (Preb) dissolved in 15 mL of molasses or control (Con; 15 mL of molasses only) for 7 weeks. Calves were fed ad libitum TMR top-dressed with 9 pounds of 18% CP calf starter once per day with refusals collected and measured daily. Calves were weighed and measured weekly. All calves were administered an innocuous protein injection, ovalbumin (OVA; subQ; 0.5 mg/mL), at commingling and 4 weeks after commingling. Blood was collected 2 weeks after OVA to measure primary and secondary OVA-specific IgG and IgA responses. Prebiotic-fed calves ate more than control-fed calves 2 weeks after commingling (3.18 vs. 3.06 ± 0.034 kg/d; P = 0.015). Prebiotic calves also gained more weight 3 weeks (ADG 0.90 vs. 0.86 ± 0.060 kg/d; P = 0.037) and 6 weeks post-commingling (ADG 1.08 vs. 0.96 ± 0.060 kg/d; P = 0.025). In addition, the interaction between treatment and week affected F:G (P = 0.044) with preb-calves having lower F:G 1, 3, and 6 weeks post-commingling. The Preb-calves had a greater primary IgA response to OVA than Con-calves (P = 0.0315), but no differences were observed for IgG (P = 0.8289). Prebiotic supplementation may improve calf performance and adaptive immunity in the transition to group-housing situations post weaning.

Key Words: prebiotic, bovine, performance