Reference | Santman.Berends_2017_JoofDaSc (10326)

For this cross-sectional study, all 400 Dutch organic dairy farms that are officially registered in the SKAL database (control organization for organic farming, Zwolle, the Netherlands) were put in a random sequence and were contacted in that order by phone. All milking cows of the first 90 organic farmers that agreed to participate were included in the study and are described as herds in the remainder of this paper. These herds represent organic herds and have a low AMU compared with conventional herds. According to European Union regulation (EC, 2007, 2008), these herds are obliged to apply a very restrictive AMU policy. In the period between December 2011 and February 2012, all participating farmers were contacted by phone and a questionnaire was administered to obtain information on management factors such as housing facilities, hygiene, feeding regimen, milking procedures, udder health, and treatment regimens. The items included in the questionnaire are summarized by category of management practices (Table 1).

All herds were sampled between September 1 and December 31, 2011. During the visits, a transport swab with Amies medium (Beldico, Duiven, the Netherlands) was used to swab the scraper at different places. When no scraper was present, slurry samples from 5 randomly selected places on the slatted floor were thoroughly mixed and sampled by using the transport swab. The slurry samples were cooled and transported to GD Animal Health (Deventer, the Netherlands) for laboratory analysis. Because the slurry may not be sensitive enough to detect a low ESBL/AmpC prevalence within the herd, herds with ESBL/AmpC-negative slurry samples were described as unsuspected herds. Herds that tested positive for ESBL/AmpC in the slurry sample were described as positive herds.

AST Method: Unclear

Reference explicitly reports AST breakpoints: False

Reference reports using a MIC table: False