Fig 2. Isolation of Mannheimia haemolytica from right and left nasal cavities following challenge.

Six pairs of calves were challenged with M. haemolytica B158 and treated with tracheal antimicrobial peptide (TAP) or water at 0.3, 2 and 6 hours after infection. Right and left nasal swabs were taken daily and the number of isolated M. haemolytica colonies was scored as 1, 2, 3 or 4 (maximum score of 8 for each calf). The data show the sums of scores across time for each group. The number of surviving calf pairs on each day are: n = 6 at 1 day post-infection, n = 5 at 2 days, n = 4 at 3 days, n = 3 at 4 days.