Evaluation of Mycobacterium avium subsp paratuberculosis infection of dairy cows attributable to infection status of the dam.
OBJECTIVE
To estimate the extent to which infection with Mycobacterium avium subsp paratuberculosis (MAP) of cows in a large dairy was attributable to the infection status of their dams.


METHODS
Retrospective longitudinal study.


METHODS
625 dam-daughter pairs of Holstein cows.


METHODS
Serologic test results were compared between cows and their dams. Logistic regression was used to assess whether a cow's serologic status was associated with its dam's serologic status. Infection with MAP attributable to being born to a seropositive dam was estimated for individual cows and for the herd.


RESULTS
Cows with seropositive dams were 6.6 times as likely to be seropositive, compared with cows of seronegative dams. For seropositive cows born to seropositive dams, 84.6% of seropositivity was attributable to being born to a seropositive dam and 15.4% to other exposures, including exposure as calves to flush water that contained feces of adult cattle. For the herd as a whole, the seropositive status in 34% of seropositive cows was attributable to being born to a seropositive dam.


CONCLUSIONS
For dairy herds that breed seropositive cows, subsequent transmission of MAP to their daughters, either congenitally or via exposure to feces and colostrum of the dam shortly after birth, can contribute substantially to maintaining prevalence of MAP in a herd. Removal of seropositive, clinically unaffected cows and their daughters would be necessary to reduce infection with MAP attributable to congenital or peri-parturient transmission from dam to daughter.
Aly
Sharif S
SS
Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Thurmond
Mark C
MC
D000818:Animals; D000833:Animals, Suckling; D000907:Antibodies, Bacterial / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000635:transmission*; D003612:Dairying / Q000379:methods; D018562:Disease Transmission, Infectious / Q000517:prevention & control / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005243:Feces / Q000382:microbiology; D005260:Female; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control / Q000662:veterinary*; D008137:Longitudinal Studies; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology; D010283:Paratuberculosis / Q000453:epidemiology / Q000635:transmission*; D011156:Population Density; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D016036:Seroepidemiologic Studies
D000907:Antibodies, Bacterial