Looper M L, Edrington T S, Rosenkrans C F
USDA-ARS, Dale Bumpers Small Farms Research Center, Booneville, AR, USA.
Lett Appl Microbiol. 2009 Sep;49(3):361-5. doi: 10.1111/j.1472-765X.2009.02669.x. Epub 2009 Jun 8.
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.
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 2.6% and 2.0% for Salmonella. Percentage of cows positive for both E. coli O157:H7 and Salmonella on at least one occasion was 6.1%. BC, forage type or the interaction did not influence the prevalence of E. coli O157:H7 or Salmonella in the faeces of cows.
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.
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.
确定体况（BC）和饲草类型对肉牛粪便中大肠杆菌O157:H7和沙门氏菌排泄率的影响。
将体况瘦或中等的奶牛（n = 115头）随机分配到普通百慕大草（n = 3个牧场）或感染了有毒内生菌的高羊茅（n = 3个牧场）上放牧62天。在第0、30和62天采集粪便样本。粪便样本中大肠杆菌O157:H7呈阳性的总体百分比为2.6%，沙门氏菌为2.0%。至少有一次大肠杆菌O157:H7和沙门氏菌均呈阳性的奶牛百分比为6.1%。体况、饲草类型或二者的交互作用均未影响奶牛粪便中大肠杆菌O157:H7或沙门氏菌的排泄率。
放牧期开始时的体况或中等体况的奶牛在放牧期内体况的下降均未影响大肠杆菌O157:H7或沙门氏菌的粪便排泄。食用这两种饲草类型均未影响瘦或中等体况的肉牛粪便中大肠杆菌O157:H7或沙门氏菌的排泄。
放牧奶牛正常生产周期中通常出现的体况变化不影响病原菌的粪便排泄，与饲草类型无关。
