Prevalence of Salmonella spp on conventional and organic dairy farms

Abstract

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.

Changes in Tetracycline Susceptibility of Enteric Bacteria following Switching to Nonmedicated Milk Replacer for Dairy Calves

“…The recovery rates for Salmonella in this study were in agreement with findings from other field studies of dairy cattle (36). The sporadic nature of Salmonella shedding by cattle, which unfortunately made inferences about changes in resistance in Salmonella over time difficult, has also been found in other studies (15,42).…”

“…Because the objective of the current study was to determine how removing oxytetracycline from preweaned-calf diets affects antimicrobial susceptibility, conventionally managed (not certified organic) dairy herds infected with laboratory-confirmed Salmonella, E. coli, or Campylobacter with low Tet susceptibility that were feeding on milk replacer containing oxytetracycline were solicited for participation. The herds included in this study were either enrolled in an earlier project designed to describe the prevalence and the antimicrobial susceptibility of Campylobacter and Salmonella isolates obtained from organic and conventional dairy farms across key animal management groups (15,16) or were identified based on veterinary diagnostic laboratory submissions. A total of eight herds were enrolled for the study: four from Michigan, and four from New York.…”

Within-Farm Changes in Dairy Farm-Associated Salmonella Subtypes and Comparison to Human Clinical Isolates in Michigan, 2000-2001 and 2009

“…Retrospective data were retrieved from a 2000-2001 multicenter, longitudinal study of Salmonella shedding on randomly selected dairy farms in Michigan, New York, Wisconsin, and Minnesota (10 (9). Briefly, in 2000-2001, farms were sampled every other month, resulting in five sampling events (10). Two farms (101 and 102) were initially sampled weekly for 8 consecutive weeks in the spring/ summer of 2000 and then subsequently sampled every 2 months for five consecutive visits.…”

“…This study used a retro-prospective study design, and the data consisted of two components: retrospective data collected from Michigan dairy farms in 2000-2001 and prospective data collected 10 years later from the same farms. Retrospective data were retrieved from a 2000-2001 multicenter, longitudinal study of Salmonella shedding on randomly selected dairy farms in Michigan, New York, Wisconsin, and Minnesota (10 (9). Briefly, in 2000-2001, farms were sampled every other month, resulting in five sampling events (10).…”

Changes in Multidrug Resistance of Enteric Bacteria following an Intervention To Reduce Antimicrobial Resistance in Dairy Calves

“…Four dairy herds from Michigan and four from New York were enrolled from an earlier project (3,5). Two large and two small herds from each state were selected, and each pair was divided into the intervention and control groups.…”