Table 2.

Number of studies reporting data sources of active by geographical areas.

	Europe (27)	North America (4)	Asia (3)	Africa (1)	Australia (1)
Farm based survey (14)	11 (Callens et al., 2012, Casal et al., 2007, Dupont et al., 2017, Jensen, Jorsal, Toft, 2017, Moreno, 2012, Sjölund et al., 2016, 2015; Stevens et al., 2007, Timmerman et al., 2006, Visschers et al., 2014, Visschers et al., 2015)	1 (Rajić et al., 2006)	1 (Kim et al., 2013)	1 (Eltayb et al., 2012)	–
National database (consumption/sale/prescription) (7)	5 (Aarestrup et al., 2010, Bondt et al., 2013, Bos et al., 2013, Jensen et al., 2012, Vieira et al., 2011) (Bondt et al., 2013, Bos et al., 2013, de Jong et al., 2014, Jensen et al., 2012)	1 (Apley et al., 2012)	1 (Hosoi et al., 2014)	–	–
Farm based survey and prescription data (5)	4 (Merle et al., 2012, Merle et al., 2013, Merle et al., 2014, Van Rennings et al., 2015)	–	–	–	1 (Jordan et al., 2009)
Prescription data (3)	2 (Arnold et al., 2004, Fertner et al., 2015)	1 (Glass-kaastra et al., 2013)	–	–	–
Antibiotic application records (3)	3 (Trauffler et al., 2014, Trauffler et al., 2014, van der Fels-Klerx et al., 2011)	–	–	–	–
Veterinarian survey (2)	1 (Chauvin et al., 2002)	1 (Rosengren et al., 2008)	–	–	–
Pharmaceutical producer survey (1)	–	–	1 (Van Cuong et al., 2016)	–	–
Farm based survey and national data (1)	1 (Filippitzi et al., 2014)	–	–	–	–