Prevalence of Salmonella spp on conventional and organic dairy farms

Department of Clinical and Population Science, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA.
Journal of the American Veterinary Medical Association (Impact Factor: 1.56). 08/2004; 225(4):567-73. DOI: 10.2460/javma.2004.225.567
Source: PubMed


To describe the occurrence of fecal shedding, persistence of shedding over time, and serogroup classification of Salmonella spp on a large number of dairy farms of various sizes.
Longitudinal study.
22,417 fecal samples from cattle and 4,570 samples from the farm environment on 110 organic and conventional dairy farms in Minnesota, Wisconsin, Michigan, and NewYork.
5 visits were made to each farm at 2-month intervals from August 2000 to October 2001. Fecal samples from healthy cows, calves, and other targeted cattle groups and samples from bulk tank milk, milk line filters, water, feed sources, and pen floors were collected at each visit. Bacterial culture was performed at 1 laboratory.
Salmonella spp were isolated from 4.8% of fecal samples and 5.9% of environmental samples; 92.7% of farms had at least 1 Salmonella-positive sample. The 75th percentile for median within-herd prevalence of Salmonella spp in cattle for 5 sampling visits to a given farm was 2.0% and for maximum within-herd prevalence of Salmonella spp was 13.6%. Farms with a median within-herd prevalence of Salmonella spp of > or = 2.0% accounted for 76.3% of Salmonella-positive samples. There was no significant difference in the prevalence of Salmonella spp between conventional and organic farms. Seasonal differences in Salmonella shedding were observed. More farms had at least 1 serogroup B isolate than any other serogroup, whereas serogroup E1 was the most common among all Salmonella-positive samples. More than 1 serogroup was isolated on 76.4% of Salmonella-positive farms.
Salmonella spp were isolated from > 90% of dairy farms; however, 25% of farms accounted for > 75% of Salmonella-positive samples. This information is critical for the direction of intervention strategies to decrease the prevalence of Salmonella spp on dairy farms.

1 Follower
14 Reads
  • Source
    • "These results demonstrate the importance of diarrhea in calves within the first 2 weeks of age and that improved management practices during this time are necessary to reduce calf scours and its consequences. In Brazil, there is no longitudinal study for Salmonella infection in calves, and there are only few studies worldwide (Huston et al. 2002; Warnick et al. 2003; Fossler et al. 2004; Cummings et al. 2009a, b). Cummings et al. (2009a) found that 17 % (16/93) of positive herds were responsible for over 70 % of clinical cases of Salmonella which means most farms do not experience any clinical illness due to Salmonella infection and a subset of the positive properties had a very high incidence of salmonellosis. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This prospective longitudinal study investigated the epidemiology of enteric disease associated with infections in calves aging up to 70 days. A total of 850 fecal samples were collected from 67 calves. Seventeen isolates of Salmonella spp. were recovered from feces of 11 calves (16.4 %), and statistical analysis revealed no association between the presence of Salmonella spp. and clinical signs of diarrhea or age. Virulence factors of Escherichia coli were identified in 103 strains: eae (7), K99/STa (7), Stx1 (7), Stx1/eae (36), Stx1/Stx2/eae (2), Stx2 (43), and Stx2/eae (1). There was statistical association between diarrheic animals carrying E. coli Stx1/eae + in their feces at 2 and 4 weeks of age (P = 0.003) and E. coli Stx2 + at 5 weeks of age (P = 0.03). Rotavirus was detected in 49 (5.76 %) fecal samples collected from 33 calves (49.2 %). The presence of rotavirus was correlated with diarrheic feces (P < 0.0001) rather than feces with normal consistency. There was a significant relationship between age group and diarrhea (P = 0.001). Bovine coronavirus (BCoV) was detected in 93 fecal samples collected from 46 calves (68.6 %). There was an association (P < 0.0001) between diarrheic animals positive for BCoV and age groups. The results demonstrate the importance of the pathogens studied in the etiology of diarrhea in calves.
    Tropical Animal Health and Production 09/2014; 47(1). DOI:10.1007/s11250-014-0675-5 · 0.82 Impact Factor
  • Source
    • "The finding of cows excreting foodborne pathogens, such as Campylobacter sp., E. coli O157 and Salmonella sp. is not infrequent in Italy (Conedera et al., 1997; Bonardi et al., 1999; Bonardi et al., 2001; Ricci et al., 2006) as well as in other countries (Huston et al., 2002; Rugbjerg et al., 2003; Fossler et al., 2004; Hakkinen and Hanninen, 2009; Anon, 2010). According to the current European legislation (Reg. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A pilot study was implemented in the Veneto Region of Italy, aimed at classifying dairy farms which produce milk to be commercialised unpasteurised on the basis of their risk of faecal contamination of milk, which is directly correlated to the probability of a foodborne pathogen, if present in the herd and eliminated through faecal excretion, to contaminate the raw product. Factors considered to be relevant in the definition of the risk of pathogens potentially present in animal faeces to be transmitted to milk, were hierarchically structured, weighted through the application of experts elicitation methods (Analytic Hierarchy Process, Delphi) and used to categorise farms through the application of a herd questionnaire. The probability of faecal contamination of milk, and thus the risk of pathogens transfer appears to be modulated more by farm management than by the structure of the farm or the health status of the herd. Such a method, combined with the microbiological evaluation of the prevalence of faecal excretion of such pathogens, can be used to implement a risk-based surveillance programme and to apply targeted control measures.
    Research in Veterinary Science 02/2013; 95(1). DOI:10.1016/j.rvsc.2013.02.007 · 1.41 Impact Factor
  • Source
    • "We believe the temporal distribution pattern is representative of the prevalence of serotypes in enteric disease investigations. Subclinical infections with Salmonella Cerro and other Salmonella have been reported on a dairy farm previously (Huston et al., 2002; Fossler et al., 2004; Van Kessel et al., 2007). In a longitudinal study that focused on Salmonella serotypes on a dairy farm, Van Kessel et al. (2007) reported that Salmonella Cerro replaced other prevalent Salmonella serotypes that were responsible for causing clinical disease. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Abstract The aim of this study was to identify Salmonella serotypes infecting cattle in Pennsylvania, to compare infection rates for the predominant serotype, Salmonella enterica serotype Cerro, with the infection rates for the same serotype in humans, and to study the clonal diversity and antimicrobial resistance for this serotype in cattle from 2005 to 2010. Clonal diversity among the selected isolates was studied using pulsed-field gel electrophoresis (PFGE) and repetitive (rep)-polymerase chain reaction (PCR). Salmonella Cerro showed the single largest increase as a cause of cattle infections over the study period. The proportional distribution of Salmonella Cerro serotype among laboratory-submitted Salmonella positive cases in cattle was 36.1% in the year 2010 compared to 14.3% in 2005. A simultaneous decrease in serotype Newport infections was also observed in cattle (25% in 2005, to 10.1% in 2010). Studies of clonal diversity for cattle and human isolates revealed a predominant PFGE type but showed some variability. All tested isolates (n=60) were susceptible to sulfamethoxazole-trimethoprim, but 2% of cattle isolates (n=1/50) and 20% of human isolates (n=2/10) showed resistance to tetracycline and sulfisoxazole. One human isolate showed additional resistance to ampicillin and gentamicin. This study suggests an increase in Salmonella Cerro infections in the cattle population and a decrease in Salmonella Newport infections. The increase in Cerro infections appears to be restricted to the cattle population, but occasional human infections occur.
    Foodborne Pathogens and Disease 09/2012; 9(10):928-33. DOI:10.1089/fpd.2012.1142 · 1.91 Impact Factor
Show more