Proceedings of the 10th International Colloquium on Paratuberculosis

#239 Mycobacterium avium subsp. paratuberculosis (MAP) infection in cull dairy cows
Robert H Whitlock, T Fyock, Y Schukken, J Van Kessel, J Karns, E Hovingh, J Smith
University <strong>of</strong> Pennsylvania, USA; Cornell University, USA; USDA-ARS, Beltsville, MD, USA; Penn State University,
PA, USA; University <strong>of</strong> Vermont, Burlington, VT, USA
Objective: To correlate fecal shedding to MAP tissue bio-burden and to determine what proportion <strong>of</strong> fecal
culture negative cows would have culture positive fecals and tissues at slaughter.
Materials and Methods: Tissues and fecal samples were harvested from 230 cows culled from 3 dairy
herds over four years. Five samples were collected from each animal; 2 intestinal lnn, ileum, IC valve and a
fecal sample. Samples were cultured on HEYM.
Results: Of <strong>the</strong> 230 cattle with harvested tissues, 17 (9.8%) were previously fecal culture positive for
MAP. Fourteen <strong>of</strong> 17 animals were positive at slaughter (82%) and 3/17 (18%) cattle had all 5 samples culture
negative. Of <strong>the</strong> 20 fecal culture positive cattle at <strong>the</strong> time <strong>of</strong> slaughter, 9 were heavy shedders each massively
infected in <strong>the</strong> four tissues examined (>300 cfu MAP/tube). No o<strong>the</strong>r fecal culture positive or negative cows
had such massive tissue infection with MAP. Interestingly 5/20 (25%) fecal culture positive cows at slaughter
had negative cultures on all four tissues. Three positive fecal culture cows (very low shedders) had only one
colony on <strong>the</strong> four tissues cultured, suggesting infections as adults.
Of <strong>the</strong> 156 cattle with all negative fecal cultures prior to culling, 58/156 (37%) had at least one positive
sample at slaughter. The lnn was positive most frequently, followed closely by ileum and IC valve. 26/58 (45%)
cattle had less than 10 total cfu <strong>of</strong> MAP on 20 tubes <strong>of</strong> HEYM for <strong>the</strong> five samples suggests a more recent
infection.
Conclusions: 35% <strong>of</strong> fecal culture negative cattle had positive tissues at slaughter. Cattle shedding more
than a few colonies <strong>of</strong> MAP or with multiple positive fecal cultures had multiple tissues positive at high MAP
concentrations.
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