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Determination of the Prevalence and Level of Multi-drug Resistant (MDR) Salmonella in Rectal-anal Swab and Hide Samples Obtained from Calf-fed Holstein Steers


Higher levels of multi-drug resistant (MDR) Salmonella have commonly been associated with
dairy production. This trend has been notable in beef packing plants that process mature cows
and bulls. Past research has found higher levels of MDR Salmonella in these facilities, compared
to fed beef processing facilities and the higher incident rates of MDR Salmonella are often
connected with cull dairy cows. <P>

The researchers involved in this project have done an extensive amount of sampling for MDR
Salmonella in beef primarily from native or beef breeds of cattle. Based on an apparent
association between dairy production systems and MDR Salmonella, the researchers
hypothesized that Holstein steers might be exposed to MDR Salmonella during the neonatal
period (i.e. while at the dairy) or during the growing phase (i.e. while at a calf ranch) and may
pose a risk for introducing MDR Salmonella into the fed beef supply. The objective of this
project was to evaluate the prevalence and level of MDR Salmonella in Holstein steers, which
has never been specifically documented.

More information

Findings: Preliminary data demonstrate that
Holstein steers do not carry Salmonella at a higher rate than other fed cattle. Further analyses
will be conducted to determine if there is a difference in the proportion of MDR Salmonella
between the two groups.

<P> For complete projects details, view the <a href="…; target="_blank">Project Summary. </a>

Arthur, Terrance
USDA - Agricultural Research Service
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