Pig farmers with big farms located in areas with many pigs use more than the average amount of antibiotics. Farms with pigs and other animals also tend to use more antibiotics than specialized pig farms.
Factors which do influence the use of antibiotics are: the type of farm (mixed or specialized), the number of animals on the farm, and the pig density in the region. 'More pigs in an area means more risks from diseases', Van der Fels explains, referring to the results. And yet, these 'technical' factors cannot account for the big differences in antibiotics use among the farms. 'We have come across pig farmers who use almost no antibiotics, and others who use antibiotics every day to keep their pigs disease-free. Social economic factors, including the wish to use less antibiotics, greatly affect the number of daily doses of antibiotics given on the farms.'
Van der Fels advises information workers in their drive to cut down on the use of antibiotics to concentrate on mixed farms in regions with many pig farming concerns, and to take a good look at the social circumstances of the pig farmer.