The Role of Feed and Water in On-Farm Infection
A current study funded by an FDA grant traces the path of
E. coli O157
Fecal, feed and water samples will be taken from 24 dairies over a 2-year period.
These samples will be cultured for both E. coli O157
species. The prevalence of pathogens in the feed and water will be compared to the
prevalence of pathogens in the cattle feces to help answer questions about how cattle are
exposed to infection.
The study encompasses the following goals:
Determine if total dietary
E. coli exposures are correlated with the prevalence
of E. coli O157 and Salmonella sp. infection in exposed cattle.
Determine the frequency of contamination of cattle foodstuffs and water sources with
coli O157 and Salmonella sp..
Determine the ability of cattle feeds and water sources to support the replication of
the enteropathogenic bacteria E. coli O157 and Salmonella sp..
Determine whether feed and water contamination frequency and the ability of feed and
water sources to support the proliferation of E. coli O157 or
sp. are significantly associated with the prevalence of bovine infection with
O157 or Salmonella sp. in the herds consuming that feed and water.
Results as of June 30, 1999 (Preliminary
E. coli exposures in feed and water seem stable over time.
E. coli O157 and Salmonella have been found in bunk feeds, water
troughs, and component (purchased) feeds.
We have successfully completed growth assays for generic
E. coli and Salmonella
typhimurium DT104 in total mixed rations from all farms, and none were found to support
growth of these organisms.
There seems to be a relatively high degree of natural variability among the herds in
terms of bacterial counts and prevalences of E. coli O157 and