Persistent XXXX shedding in five dairy herds.

@entity291 @entity5746 @entity4092
OBJECTIVE: To monitor patterns of @entity5746 fecal shedding in naturally infected dairy herds, determine the association between fecal shedding and individual animal production measures, and evaluate potential risk factors for shedding of @entity5746 organisms among @entity291 in dairy herds. DESIGN: Longitudinal study. SAMPLE POPULATION: 5 Ohio dairy herds. PROCEDURE: For 3 herds, fecal samples were collected from all mature @entity291 and unweaned @entity291 7 times during an 18-month period. For the remaining 2 herds, fecal samples were collected from 50 lactating @entity291 6 times during a 12-month period. Individual animal production records for 3 herds were used to examine associations between individual @entity5746 shedding status and 305-day mature-equivalent milk production, somatic cell count, milk fat content, and milk protein content. Multivariable logistic regression was used to test for associations between fecal shedding status and breed, lactation status, lactation number, and duration of lactation. RESULTS: None of the adult animals had clinical signs of @entity5746 , but prevalence of @entity5746 shedding at individual collection times ranged from 0 to 99% for @entity291 and from 0 to 67% for unweaned @entity291 . Mature @entity291 were more likely to be shedding @entity5746 organisms than were unweaned @entity291 . Within herds, lactation status and duration of lactation for individual animals were associated with @entity5746 shedding status. @entity5746 fecal shedding status was not associated with individual @entity291 production measures. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that @entity4092 shedding can persist in dairy herds for up to 18 months with no measurable effects on health or production of individual @entity291 .
