Influence of body condition and forage type on prevalence of Escherichia coli O157:H7 and Salmonella in grazing beef cows

Aim: To determine the influence of body condition (BC) and forage type on the prevalence of faecal shedding of Escherichia coli O157:H7 and Salmonella from beef cows. Methods and Results: Thin or moderately conditioned cows (n = 115) were randomly assigned to graze either common bermudagrass (n = 3 pastures) or toxic endophyte-infected tall fescue (n = 3 pastures) for 62 days. Faecal samples were collected on day 0, 30 and 62. Overall percentage of faecal samples positive for E. coli O157:H7 was 2 center dot 6% and 2 center dot 0% for Salmonella. Percentage of cows positive for both E. coli O157:H7 and Salmonella on at least one occasion was 6 center dot 1%. BC, forage type or the interaction did not influence the prevalence of E. coli O157:H7 or Salmonella in the faeces of cows. Conclusions: BC at initiation of the grazing period or loss of BC in moderate conditioned cows during the grazing period did not influence faecal shedding of E. coli O157:H7 or Salmonella. Consumption of either forage type did not influence faecal shedding of either E. coli O157:H7 or Salmonella in beef cows of thin or moderate BC. Significance and Impact of the Study: Change in BC that typically occurs during the normal production cycle in grazing cows did not influence faecal shedding of pathogenic bacteria regardless of forage type.