Insight into sickness behavior may be the means to improving identification, management, and welfare of sick animals. The objective of this study was to identify components of sickness behavior in group-housed Holstein dairy calves infected with Mannheimia haemolytica. Calves (aged 3–7 weeks; 58.0 ± 12.0 kg BW) were group-housed based on age and BW in sand-bedded pens (6 calves/pen, 6.6 m²/calf) and provided pasteurized waste milk (8 L/d) 2 × /d. Within group, calves were randomly assigned to treatment. On d 0, treatment calves (MH; n = 12, 3/pen) were inoculated at the tracheal bifurcation with 3 × 10⁹ cfu of MH suspended in 5 mL of phosphate buffered saline (PBS) followed by a 120 mL wash PBS. Control calves (n = 12, 3/pen) were inoculated with 5 mL + 120 mL of PBS. Behavioral and health data were collected for 7 d post-challenge. Each calf was fitted with an accelerometer to record lying time and laterality. Rectal temperatures and respiratory disease scores (based on presence of cough, nasal or ocular discharge, and ear droop; 0 = normal; 5 = treat for illness) were obtained every 12 h. Data were analyzed in a general linear mixed model with day (or hour) treated as a repeated measure. Temperature was subject to a treatment by hour interaction (P = 0.015), peaking for MH calves at 12 h post-inoculation (40.1 vs 39.1°C; SE = 0.14, P < 0.001). Respiratory score was greater overall for MH calves (3.9 vs. 3.2; SE = 0.2; P = 0.024). A treatment by day interaction was evident in lying time (P < 0.001), with MH calves lying down for longer on d 0 (19.9 vs 18.4 h/d; SE = 0.33, P = 0.023). MH calves also spent more time lying on their left side than right in the week following inoculation (9.9 vs. 7.5 h/d; SE = 0.58, P = 0.006), with control calves expressing no lateral preference (P = 0.74). These results show that this challenge model resulted in calves experiencing a mild disease state. Increased lying time and lying laterality may be useful indicators of early stages of disease.