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 Citrobacter freundii. The study was performed over a 54 d period with 30 Holstein bull calves. Calves were randomly assigned to treatments that included: CON: 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% of DM as XPC. Calves were fed 350 g of milk replacer at 0700 and 1700 from d 0 to 42. Calf starter and water were offered ad libitum and recorded daily. Calves were challenged with 10⁸ cfu of Citrobacter freundii orally on d 16 of the study. Blood samples were collected on d 0, 7, 14, 16, 18, 21, 24, 28, and 35 and analyzed for hematology. All data were reported as CON, SC, and SC+XPC, respectively. LSMeans with various superscripts differ (P ≤ 0.05). Calf starter intake and ADG did not differ overall (P ≥ 0.127); however, the SC+XPC calves consumed more calf starter from d 36 to 54 (0.865^a, 0.840^a, 0.981^b ± 0.053 kg/d; P = 0.054) and had increased ADG from d 15 to 21 (0.677^a, 0.696^a, 0.840^b ± 0.046 kg/d; P = 0.006). There was treatment x time interaction in neutrophil to lymphocyte ratio (N:L; P = 0.043), whereas CON calves had greater (P ≤ 0.019) N:L than SC and SC+XPC on d 7 (1.21^a, 0.83^b, 0.72^b ± 0.15) and d 16 (1.43^a, 0.93^b, 0.99^b ± 0.15). Additionally, the SC+XPC calves had lower hemoglobin throughout the study (10.9^a, 11.2^a, 10.3^b ± 0.19 mg/dL; P = 0.006). Average fecal scores by period were greatest among CON calves after the challenge on d 17 to 21 (2.7^a, 2.1^b, 1.9^b ± 0.003; P ≤ 0.010) and CON was also greater than SC+XPC calves on d 22 to 28 (2.8^a, 2.4^ab, 2.1^b ± 0.15; P ≤ 0.002). The Citrobacter challenge increased scours, but did not result in systemic disease. Feeding SC in milk replacer and XPC in calf starter improved calf performance, health, and reduced the risk of scours during neonatal life.