Influence of sprinklers, used to alleviate heat stress, on faecal shedding of E. coli O157:H7 and Salmonella and antimicrobial susceptibility of Salmonella and Enterococcus in lactating dairy cattle.
OBJECTIVE
To determine the effect of sprinklers on faecal shedding of Escherichia coli (E. coli) O157:H7 and Salmonella in lactating dairy cattle.


RESULTS
Sprinklers were applied to lactating dairy cattle on two farms at either the feedbunk or in the holding pen prior to milking. Faecal samples were collected approx. 1 and 4 weeks following initiation of sprinkler treatments for culture of E. coli O157:H7, Salmonella and Enterococcus. No treatment differences were observed for E. coli O157:H7. Salmonella was higher (P = 0.11) in the control treatment on day-7 whereas on day-28, the bunk sprinklers increased the number of Salmonella positive cows. Salmonella prevalence decreased (P = 0.0001) on day-5 and when examined across days in cows exposed to sprinklers prior to milking. Antimicrobial susceptibility screening found very few isolates that were multi-drug resistant. All Enterococcus isolates were susceptible to vancomycin.


CONCLUSIONS
This study demonstrated a significant decrease in faecal prevalence of Salmonella in lactating cattle following exposure to sprinklers administered prior to milking.


CONCLUSIONS
Identification of current dairy management techniques that are also effective in reducing on-farm prevalence of pathogenic bacteria could have significant food safety and environmental implications.
US Department of Agriculture, Agricultural Research Service, Food and Feed Safety Research Unit, TX, USA. edrington@ffsru.tamu.edu
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Edrington
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Carter
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Friend
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Hagevoort
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Poole
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Callaway
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Anderson
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Nisbet
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle / Q000382:microbiology / Q000502:physiology*; D003612:Dairying / Q000379:methods*; D016983:Enterococcus / Q000187:drug effects* / Q000302:isolation & purification; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D005260:Female; D006358:Hot Temperature; D007774:Lactation; D008826:Microbial Sensitivity Tests; D012475:Salmonella / Q000187:drug effects / Q000302:isolation & purification*; D013312:Stress, Physiological
D000900:Anti-Bacterial Agents