Evaluation of the risk of paratuberculosis in adult cows fed Mycobacterium avium subsp paratuberculosis DNA-positive or -negative colostrum as calves.
OBJECTIVE
To estimate the risk of subclinical Mycobacterium avium subsp paratuberculosis (MAP) infection in cows that ingested MAP DNA-positive raw colostrum as calves, compared with risk in cows that ingested MAP DNA-negative raw colostrum as calves.


METHODS
205 calves born in 12 commercial dairy herds.


METHODS
Each calf was separated from its dam within 30 to 60 minutes after birth and fed raw colostrum. For each calf, samples of the colostrum fed were collected and tested for the presence of MAP DNA by use of a nested PCR assay for the target gene ISMAP02. Calves fed colostrum positive or negative for MAP DNA were classified into exposed (n = 69) and unexposed (136) groups, respectively. Each calf was tested for MAP infection at 30, 42, and 54 months of age by use of a serum ELISA and bacterial culture of feces. Weibull hazard regression models were used to evaluate the association between exposure to MAP DNA-positive colostrum and time to testing positive for MAP infection.


RESULTS
Hazard of MAP infection was not different between groups (exposed vs unexposed) when serum ELISA, bacterial culture of feces, or both diagnostic tests (parallel interpretation) were positive.


CONCLUSIONS
Heifer calves fed MAP DNA-positive colostrum were at no greater risk of MAP infection, compared with heifer calves fed MAP DNA-negative colostrum. This result contradicts findings from other studies and should be interpreted with caution.
Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA. pithuap@missouri.edu
Patrick
P
Pithua
Sandra M
SM
Godden
Scott J
SJ
Wells
Judith R
JR
Stabel
D000818:Animals; D000831:Animals, Newborn; D000907:Antibodies, Bacterial / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D003126:Colostrum / Q000382:microbiology*; D003612:Dairying; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005243:Feces / Q000382:microbiology; D005260:Female; D015994:Incidence; D008910:Minnesota / Q000453:epidemiology; D015999:Multivariate Analysis; D016927:Mycobacterium avium subsp. paratuberculosis; D010283:Paratuberculosis / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology / Q000635:transmission*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012044:Regression Analysis; D018570:Risk Assessment; D011795:Surveys and Questionnaires; D014922:Wisconsin / Q000453:epidemiology
D000907:Antibodies, Bacterial