Abstract #153

# 153
Influences of SmartCare in milk replacer and XPC in calf starter on the performance and health of preweaning Holstein calves challenged with Salmonella enterica serotype Typhimurium.
Tyler L. Harris*1, Yu Liang1, Matt D. Sellers1, Jeff A. Carroll2, Ilkyu Yoon3, Mark F. Scott3, Michael A. Ballou1, 1Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX, 2USDA-ARS, Lubbock, TX, 3Diamond V, Cedar Rapids, IA.

This study investigated how supplementing milk replacer with SmartCare(SC) and calf starter with original XPC(XPC) would affect performance and health following an oral challenge with Salmonella enterica serotype Typhimurium. The study was performed in 2 35 d periods with 30 Holstein bull calves per period. In each period, calves were blocked by location in the barn and randomly assigned to treatments that included: CON: base milk replacer and calf starter with no added products, SC: milk replacer with 1 g SC/calf/d and base calf starter, and SC+XPC: milk replacer with 1 g SC/calf/d and calf starter with 0.5% XPC. Calves were fed 350 g of milk replacer at 0700 and 1700. Calf starter and water were offered ad libitum and recorded daily. Calves were challenged with 108 cfu of sulfamethazine-resistant Salmonella enterica orally on d 14 of the study. Fecal Salmonella shedding was determined on d 14 to 21, and d 24, 28, and 35 using selective media. Blood samples were collected on d 0, 7, 14, 16, 18, 21, 24, 28, and 35 and analyzed for hematology. Contrasts were analyzed to determine SC and XPC effects. All data were reported as CON, SC, and SC+XPC, respectively. The LSMeans with various superscripts differ (P ≤ 0.05). Calf starter intake (0.178a, 0.218ab, 0.254b ± 0.022 kg) was improved in both SC and SC+XPC (SC contrast P = 0.029; XPC contrast P = 0.035). Average daily gain (0.48a, 0.48a, 0.58b ± 0.028 kg) was greater among SC+XPC calves vs. the other treatments (XPC contrast, P = 0.001). Post challenge, the SC+XPC calves had a lower neutrophil to lymphocyte ratio (0.81a, 0.83a, 0.69b ± 0.051) vs. CON and SC calves (XPC contrast, P = 0.005). The SC+XPC calves also had lower hematocrits (35.1a, 35.3a, 33.4b ± 0.54%) and hemoglobin concentrations (10.8a, 10.6a, 10.1b ± 0.16 mg/dL) after the challenge. Fecal Salmonella shedding tended to be reduced by both SC and SC+XPC (3.21, 2.84, 2.42 ± 0.279 d shedding; SC and XPC contrasts P ≤ 0.071). Calves fed both SC in milk replacer and XPC in calf starter had improved performance and enteric health.

Key Words: calf, health, yeast culture