Antibiotic use and risk factors in Swiss pig fattening farms

The use of antibiotic drugs in food producing animals is considered to be a major risk factor for selection of antimicrobial resistance in humans as well as in animals. All antibiotics used in veterinary medicine are closely related to the antibiotics used in human medicine and may induce cross-resistance. Hence, minimizing antibiotic usage and prudent use of antibiotics are two key points to minimize the development of antibiotic resistance. Antibiotics are used in fattening pigs especially to avoid diarrhea and respiratory diseases. Fear of economic losses and confirmed habit are the main reasons for a prophylactic antibiotic use. Antibiotics are applied mainly orally and in many cases they are underdosed, which promotes antimicrobial resistances.

101 randomly selected fattening farms were visited 3 times during the fattening period to record health status, biosecurity and management measures and indications of antibiotic use. Totally 10,969 pigs were traced from the beginning of the fattening period to the slaughterhouse. Based on farm and slaughterhouse data, the fattening performance data an animal treatment index as well as risk factors for increased antimicrobial use were calculated.

During the fattening period, pigs were treated on average on 4.8 days. On 35 farms, all pigs were prophylactically treated orally at the beginning of the fattening period during 7 – 14 days. These prophylactic antibiotic applications accounted for 79% of the antibiotic treatment days, followed by oral (18%) and parenteral (3%) therapeutic applications. During the fattening period of 10,969 pigs, 7.4% of the animals had to be treated because of diarrhea, followed by lameness (5.4%), cannibalism (3.2%) respiratory diseases (2.1%) and wasting (1.3%). Sulphonamid combinations, tetracycline combinations and tiamulin were the most used antibiotics. Poor biosecurity measures, inadequate water supply, bad hygiene of feeding systems and fear of diseases were figured out as major risk factors for antibiotic use.

A prophylactic use of antibiotics at the beginning of the fattening period had no positive side effect on daily weight gain and did not lead to a decreased number of orally or parenterally treated pigs during the fattening period. A prophylactic antibiotic use was correlated to a higher mortality rate during the two first weeks of the fattening period.

A prophylactic antibiotic use at the beginning of the fattening period had no positive side effect to daily weight gain, treatment incidence or mortality rate. Optimizing biosecurity and management measures are more effective than antibiotics.

Disclosure of Interest: None Declared.