Shedding patterns of dairy calves experimentally infected with Mycobacterium avium subspecies paratuberculosis

Table 2 Fecal culture results compared to tissue culture, histology and macroscopy determined at necropsy

Fecal culture¹	Tissue culture²				Histology³				Macroscopy⁴
Fecal culture¹	0	1	2	3	0	1	2	3	0	1	2	3	4
0	8^†	9	1	0	6	11	1	0	10	0	2	8	0
1-4	13	13	1	0	2	24	1	0	9	4	0	12	0
> 4	1	1	1	2*	0	1	2	2*	0	0	0	3	2*

^†Number of calves assigned to each category; 50 in total. Calves in total were experimentally inoculated with MAP.
¹Number of fecal culture-positive samplings starting 2 weeks after inoculation until necropsy.
²0 = no tissue locations culture-positive; 1 = 1–3 tissue locations culture-positive; 2 = 4–6 tissue locations culture-positive; 3 = > 6 tissues culture-positive.
³0 = no lesions; 1 = focal lesions; 2 = multifocal lesions; 3 = diffuse lymphocytic, multibacillary or intermediate lesions.
⁴0 = no macroscopic changes; 1 = one enlarged or edematous lymph node of the small intestine or liver; 2 = multiple enlarged and edematous mesenteric lymph nodes and/or hyperemia of the ileocaecal valve; 3 = enlarged mesenteric lymph node(s) and/or mild to moderate thickening of ileal or jejunal mucosa; 4 = enlarged mesenteric lymph node(s) and severe thickening and corrugation of the ileal, jejunal and colon mucosa.
*These 2 calves had clinical signs of JD and were euthanized at 16 months of age.

ISSN: 1297-9716