Lymphatic fluid for the detection of Mycobacterium avium subsp. paratuberculosis in cows by PCR, compared to fecal sampling and detection of antibodies in blood and milk.

•Lymphatic fluid from 122 animals was collected and tested for MAP by nested PCR.•MAP was detected in 27.1% of the lymph samples; agreement with other tests was poor.•Resampling revealed 20.0%, 5.5% and 27.8% lymph-positive cows, respectively.•Lymph-positive cows had a 7.2 times greater likelihood of being culled.•Lymphatic fluid might be promising for the detection of early MAP-infection in cows.