Vet. Res. 38 (2007) 481-492
DOI: 10.1051/vetres:2007010

Factors associated with routine mass antimicrobial usage in fattening pig units in a high pig-density area

Jordi Casal^{a, b}, Enric Mateu^{a, b}, William Mejía^b and Marga Martín<sup>a, b

a</sup>  Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
^b  Departament de Sanitat i Anatomia Animals, Edifici V, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain

(Received 10 July 2006; accepted 9 December 2006 ; published online 11 April 2007)

Abstract - One hundred and seven fattening pig units randomly selected in Catalonia (Spain) were surveyed during 2001-2003, in order to determine the frequency of the prophylactic use of antimicrobials and mass treatments against respiratory and enteric disease outbreaks. Logistic regression and regression tree analysis were done to determine the factors associated with the on-farm mass antimicrobial usage. Fifty-eight per cent of the surveyed farms used mass antimicrobial prophylaxis; among them, 39% used two or more antimicrobials. The more frequently administered drugs were colistin, beta-lactams and tetracyclines. Fattening units from strict finishing farms were more likely to use antimicrobials than farrow-to-finish farms (Odds Ratio = 11.7) and farms with changing facilities were less likely to use these compounds (OR = 0.17). In the event of a respiratory disease outbreak, most farms applied mass treatment and 46% used two or more compounds, with tetracyclines, beta-lactams and sulphonamides being the most popular ones. Mass treatment with several compounds in case of respiratory problems was significantly related to the use of growth promoters on the farm (OR = 4.3). If an outbreak of an enteric disease occurred, most farms resorted also to a mass treatment and 48% used two or more drugs. The most frequent antimicrobial agent for the treatment of enteric disease was colistin. Fattening farms (OR = 6.9) and operations that perform routine antimicrobial prophylaxis (OR = 2.0) were more likely to use more than one antimicrobial agent for enteric diseases.

Key words: antimicrobial agents / fattening pig units / prophylactic usage / regression tree

Corresponding author: jordi.casal@uab.es

© INRA, EDP Sciences 2007