Distribution of ELISA OD values for progressors and
non-progressors. ELISA optical density values are shown for MAP progressors and Non-progressors. Progressors (n = 16) were defined as cows with an increasing cfu of MAP shedding over time. Non-progressors (n = 42) were defined as cows with no increase in cfu of MAP shedding and measurement of no shedding in between measurements with MAP shedding.