Virus shedding and clinical responses following BHV-1 infection. (A) Virus shedding in nasal secretions is expressed as plaque forming units (PFU) per ml of nasal secretion collected. Data presented are median values for weaned and maternal separation (WMS) and pre-adapted (PA) calves. (B) Rectal body temperatures of animals presented as mean + 1SD of values for WMS and PA calves. Values were compared between groups for each day post-BHV-1 infection. *p < 0.05. (C) Serum haptoglobin levels were analyzed daily within group following BHV-1 infection and data presented are median values for the WMS and PA groups. *p < 0.05; **p < 0.01. (D) IFN-γ levels in nasal secretions were quantified by capture ELISA and samples were collected prior to BHV-1 infection (Day 0) and 3 and 6 days post-infection. Day 6 was also 2 days after M. haemolytica challenge. Data presented are mean + 1SD for the WMS (open bars) and PA (solid bars) calves (n = 10/group). *p < 0.05.