Consecutive semen samples of a breeding bull suffering from paratuberculosis were collected over a period of one year and tested for the presence of MAP. Furthermore blood, faecal and after culling organ samples were collected. Semen was tested for MAP by IS900 and F57 Real - Time PCR, ELISA was used for the detection of specific antibodies in blood, faecal and organ samples were tested by culture on Herrold's Egg Yolk Medium and Ziehl-Neelsen staining.

All faecal samples taken during the trial were positive for MAP by culture, blood ELISA also gave a positive result at all times. At necropsy the bull showed typical signs of advanced paratuberculosis. MAP was detectable in multiple organs including the intestine, intestinal lymph nodes and reproductive organs. MAP was detected by IS900 Real-Time PCR in all 9 (100%) semen samples and in 6 of 9 (66.6%) samples using the F57 Real-Time PCR. Semen quality, especially viability of the sperm, was poor in collected samples. The finding that all semen samples were positive for the period of one year in the described case, underlines the potential risk for the spread of MAP by natural or artificial insemination.

The financial support was provided by grants No. MZE0002716201 of the Ministry of Agriculture of the Czech Republic and ParaTBTools (FOOD-SB-023106) from the EU.