The use of antibiotics in Dutch livestock farms has gone down by 51 percent in the last three years. This is shown in the MARAN study released by LEI.
Each year, the research institute LEI determines the quantity of antibiotics used by conducting a random survey of 300 animal farmers who together keep about two million cows, calves, pigs and chickens. The quantity of active substances needed to combat animal diseases has dropped from 495 tonnes in 2009 to 244 in 2012, according to the figures from the first half of 2012.
In all the sectors, antibiotic use has been reduced, with the biggest reductions in the pig and the chicken sectors.
LEI expresses usage in dosage days: the number of days per year that an animal is given antibiotics. In sow farms, the number of dosage days has dropped, for example, from 25 in 2009 to 10 in 2012. The differences among the farms are, however, big: 60 percent of them have reached the targeted level, while 15 percent of the sow farmers are still big users. Since registration has now been made compulsory, farmers with a high use can be addressed and asked to set up a plan of improvement.
Based on the first semester, the average use in sows/piglets is estimated to be 10 daily dosages per year in 2012 (95% Confidence Interval: 8-13 dd/ay). In 2009 the use was 25 daily dosages per year (95% CI: 21-30 dd/ay). The large confidence intervals are mainly caused by the large variation in use that exists between different farms. Seventy-five per cent of the antibiotics were orally administered, probably predominantly in piglets. In 2012 31% of the total antibiotic use in sows/piglets consisted of tetracyclines, 36% of penicillins and another 17% of trimethoprim/sulfonamides. An important finding is that since 2009 the use of macrolides decreased substantially, and that in 2012 both the use of third- and fourth-generation cephalosporins and the use of fluoroquinolones in sows/piglets has dropped to zero. Within the sample, about 57% of the farms had an antibiotic use within the target level ('streefniveau') for 2012 of the Animal Drug Authority (SDa, 2012), 29% within the signalling level ('signaleringsniveau'), and 14% within the action level ('actieniveau').
Based on the first semester, the average use in fattening pigs is estimated to be less than 6 daily dosages per year in 2012, of which 90% are orally administered (95% Confidence Interval: 4-7 dd/ay). In 2009 the average use was 16 daily dosages per year (CI: 11-20 dd/ay). In 2012, 74% of the total antibiotic use in fattening pigs originated from the administration of tetracyclines and 10% from macrolides/lincosamides. An important finding is that since 2009 the use of macrolides dropped substantially, and that in 2012 both third- and fourth-generation cephalosporins and fluoroquinolones were no longer applied.
Assuming a production period of 117 days, 2 daily dosages (= 6 x (117/365) are administered to each fattening pig during its production period from 25 kg to slaughter weight. This fattening pig has also received antibiotics at the breeding farm (during a maximum of 10 days), which brings the total exposure to antibiotics per fattening pig to approximately 12 days during its whole life from birth to slaughter at the age of 191 days. If it is assumed that the average treatment weight of fattening pigs will be 30% lower than their average live weight - since younger animals are more likely to receive antibiotics than older animals - the estimation of the true exposure during the total lifetime increases from 12 days to a total of 13 days. Compared with 2009 this is a decrease of the total exposure of approximately 60%.
Friday November 9, 2012/ MARAN-Wageningen University/ Netherlands.