Use of antibiotics in livestock farming

Antibiotics are medicines used to fight bacterial infections. The pathogens causing such infections can enter a livestock population in various ways. Because many animals live close together in such herds, pathogens that have entered the herd can spread rapidly and lead to significant losses. Veterinarians use antibiotics in livestock animals to cure the animals of such infections and protect them from the consequences of the infection (illness, suffering, death). In the case of animals kept in groups, often all animals in the group are treated to prevent the infection from spreading from sick animals to those still healthy in the group and to prevent the onset of the disease in animals already infected with the bacteria.

The use of antibiotics as growth promoters has been banned in the European Union (EU) since 2006.

Many antibiotics are used in both veterinary and human medicine. However, there are also a number of classes of antibiotics that may only be used in human medicine.

The European Medicines Agency has External Link:categorised antibiotics according to their importance for human medicine. The categories range from antibiotics that should not be used at all for the treatment of animals and are reserved for human medicine under an EU regulation in force since 2023 (Regulation (EU) No 2022/1255), to those that may only be used in rare exceptional cases in companion animals (Category A), and finally to Category D, which should be used as a matter of preference when antibiotic treatment is necessaryFootnote1Show.

The quantity of antibiotics supplied to veterinarians and veterinary pharmacies in Germany decreased from 1,706 tonnes (t) in 2011, the first year of recording, to around 562 t in 2024, External Link:a decrease of 67 % (link leads to a press information in German).

It can be assumed that the majority of these substances are used in livestock farming. The decrease affects all groups of antibiotics.

The German Federal Institute for Risk Assessment (BfRshort forGerman Federal Institute for Risk Assessment) conducts assessments of treatment frequencies and antibiotic consumption quantities in cattle, pigs, chickens and turkeys. To this end, the BfRshort forGerman Federal Institute for Risk Assessment publishes annual reports in which it examines the different animal groups in detail (in German, see the ‘Wissenschaftsberichte’ tab).

The use of antibiotics varies greatly between the different domains of livestock farming. In 2023 and 2024, antibiotics were used particularly frequently in broiler chickens, fattening turkeys and suckling piglets. The quantities used also depend heavily on the size and number of animals. Thus, the largest quantities of antibiotics in Germany are used on pigs, although pigs are treated with antibiotics less frequently than broiler chickens and turkeys raised for meat production. Antibiotics are used relatively rarely on laying hens, dairy cows and cattle raised for meat production over one year old. A blanket statement about ‘livestock farming’ is therefore not appropriate.

The decision on the use of veterinary medicines lies in each individual case with the veterinarian who looks after the livestock or who is commissioned by the livestock owner to treat sick animals. The German Federal Chamber of Veterinarians last published updated “External Link:Guidelines for the prudent use of antibacterial veterinary medicinal products” in 2015 (in German).

Veterinarians and farmers work closely together when treating animals to ensure, on the one hand, that the correct medicines are used in the correct dosage and, on the other hand, that no food is obtained from treated animals immediately after treatment. Those involved must document the treatment of animals used for food production and retain the documentation for several years.

Bacteria can become insensitive to certain antibiotics; this is referred to as antibiotic resistance. This means that such bacteria are no longer affected, or are only insufficiently affected, in their growth by substances that previously inhibited or killed them. Bacteria have developed a variety of mechanisms to become resistant to antibiotics.

Infections caused by resistant bacteria are more difficult to treat. As a result, the infections can last longer and take a more severe course.

In general, the prevalence of resistant germs is high in or on a wide variety of food products. Resistant bacteria are particularly common on raw chicken and turkey meat, as many bacteria are transferred from the animal to the animal carcass during slaughter, and broiler chickens and turkeys are often treated with antibiotics. This generally applies to organically produced food as well, although the rates of bacterial resistance to antibiotics are usually lower here than in conventional production. Heat treatment (boiling, baking, frying or pasteurisation) kills the bacteria.

When handling raw meat, it is particularly important to ensure that bacteria are not transferred to other foods before cooking or frying. This can happen, for example, during the processing of the meat using the same kitchen utensils (knives, chopping boards, plates) or if hands are not washed thoroughly with soap and water after handling the meat before touching other foods that may not be heated.

Many foods are not heated before consumption (fruit, salads, some vegetables). If these foods become contaminated with germs, the germs are taken up when the food is consumed.

A large proportion of the bacteria ingested with food are killed in the stomach by the highly acidic conditions. However, this does not offer 100% protection, as some bacteria always manage to pass through the stomach alive.

If bacteria are taken up with food, what happens to a person depends on the bacterial species. Pathogenic bacteria such as Salmonella, Campylobacter or EHECshort forenterohemorrhagic Escherichia coli can cause gastrointestinal illnesses. This happens very frequently. In Germany, approximately 40,000 to 50,000 cases of Campylobacter infection and 12,000 cases of Salmonella infection are reported each year, most of which are caused by contaminated food.

In the case of bacteria that do not immediately cause illness in humans, they may transfer their antibiotic resistance properties to other bacteria in the intestine. These bacteria, now resistant, may then be involved in subsequent infections.

In principle, the measures consumers can take to protect themselves against resistant bacteria in food are no different from those taken against other bacteria, such as pathogens like Salmonella or Campylobacter. Hygiene measures during the transport, storage and preparation of food also offer protection against bacteria that are resistant to antibiotics. For example, raw meat should be heated to 70 degrees Celsius throughout for at least two minutes before consumption. When handling raw meat, care should be taken to ensure that bacteria are not transferred via the hands or utensils (e.g. knives, chopping boards) to other foods that are not heated before consumption, such as salad or fruit. Before and after preparing meat, consumers should wash their hands thoroughly with soap to remove bacteria from their hands.

The BfRshort forGerman Federal Institute for Risk Assessment FAQ “External Link:Foodborne infections in private households – identifying sources and avoiding risks” summarises the most important hygiene rules for handling food. The guidelines apply equally to both resistant and sensitive bacteria.

In addition, the BfRshort forGerman Federal Institute for Risk Assessment has published the video clip “External Link:Don’t touch raw chicken” on the topic of kitchen hygiene.

Occupational contact with livestock is a significant risk factor for colonisation with certain antibiotic-resistant bacteria, such as MRSAshort forMethicillin-resistant Staphylococcus aureus. Bacteria can also be transmitted from these animals to humans through occasional non-occupational contact. The extent to which this occurs depends on the intensity and duration of the contact, as well as the species of bacteria involved. It is therefore important to wash your hands thoroughly after contact with the animals. Generally, the transmission of bacteria from animals does not lead to illness. However, there are also bacteria that are directly pathogenic to humans, such as Salmonella, Campylobacter and Shiga toxin-producing E. coli (STECshort forShiga toxin-producing Escherichia coli).

In general, the use of antibiotics in humans or animals undergoing treatment benefits bacteria that are resistant to these antibiotics. It can therefore be assumed that the use of antibiotics in animal facilities contributes to the development of resistance and the spread of resistant bacteria, particularly among the treated animals.

Resistant bacteria from animals can be carried along the food chain and enter private households via meat contaminated with them. The consequences of this depend on various factors. If the bacteria in question are pathogenic to humans, such as Salmonella, Campylobacter or Shiga toxin-producing E. coli (STECshort forShiga toxin-producing Escherichia coli), people can fall ill as a result of the intake of these bacteria. The antibiotics to which these bacteria have become resistant in animals will then be ineffective if used for treatment.

Often, however, the bacteria themselves are not pathogenic. In such cases, the only risk is that they pass on their resistance properties to bacteria in the human intestine, which can then indirectly lead to infections being more difficult to treat. The strongest influence on bacterial resistance in humans, however, is the use of antibiotics in humans themselves.

Good kitchen hygiene can largely prevent foodborne infections by killing the bacteria present on meat through heating and preventing their transfer to other foods in the kitchen.

However, there are currently no reliable studies indicating to whatextent the use of antibiotics in livestock farming contributes to the spread of resistance in humans.

To prevent a further increase in resistance, the BfRshort forGerman Federal Institute for Risk Assessment is of the opinion that the use of antibiotics should be limited to what is strictly necessary for therapeutic purposes. Efforts to keep animals healthy so that treatment is not required in the first place should be a priority in this regard.

Awareness that the use of antibiotics in livestock farming should be reduced has improved significantly in recent years. As a result, many livestock farmers and veterinarians have made efforts to reduce use within their areas of responsibility, which has contributed to a 67% reduction in the dispensing of antimicrobial substances to veterinarians.

In 2014, the Antibiotic Minimisation Concept was introduced for livestock farming. Since then, owners of animals raised for meat production and their veterinarians have been required to report details of antibiotic use in a herd to a central database if the number of animals raised exceeds a certain threshold. Farms that use antibiotics significantly more frequently than comparable farms must take measures to reduce their use. The aim of the minimisation scheme is to achieve a lasting reduction in the use of antibiotics in livestock farming. In 2023, the group of livestock owners required to undergo this comparison with other farms was further expanded to include additional animal groups. In addition to animals raised for meat production, the minimisation scheme now also covers dairy cows, laying hens, broiler chickens, sows for reproduction and suckling piglets.

Bacteria originating from animals are also found in manure and slurry from livestock farming and are released into the environment from there. The implications of this for humans remain unclear. The bacteria are heavily diluted in the environment and face competition from bacteria that are better adapted to the respective habitat. However, fertilisation, for example, can lead to contamination of the crops, which is why the application of slurry in horticulture is also strictly regulated.

Wastewater in sewage treatment plants mainly contains (resistant) bacteria originating from humans. Although the number of these bacteria is reduced in the treatment plants, they are also released into the environment via the plants, primarily into surface waters. Here, too, it is unclear to what extent these bacteria contribute to the problem of antibiotic resistance in humans. The BfRshort forGerman Federal Institute for Risk Assessment does not conduct its own research into antibiotic-resistant bacteria in wastewater, as there is no direct link to food production. The German Federal Environment Agency (UBAshort forGerman Environment Agency) and the relevant regional authorities are responsible for this issue. The issue becomes relevant to the BfRshort forGerman Federal Institute for Risk Assessment when treated wastewater is to be used for the irrigation of food or feed crops.

In principle, antibiotic residues may be present in all foodstuffs derived from animals. These include, amongst others, meat, eggs and milk. If an animal has been administered veterinary medicinal products, no foodstuffs may be obtained from that animal within a specified waiting period. When veterinary medicines are used as intended in livestock farming, no amounts of residues posing a health risk are to be expected in food products once the waiting period has elapsed.

It is conceivable that, in exceptional cases, plant-based food may contain small amounts of antibiotic residues if, for example, the field has been fertilised with organic fertiliser containing antibiotics (e.g., slurry) and the substances have been taken up by the plants via the roots. However, the concentrations reached here are unlikely to exceed the residue limits in food of animal origin.

The health risk to consumers from eating food is low with regard to veterinary medicine residues, including antibiotics, as the use of veterinary medicines is regulated by law and compliance with the rules is monitored in Europe. The establishment of a maximum residue limit in food is a prerequisite for the authorisation of a veterinary medicinal product for use in food-producing animals. The maximum residue limits for veterinary drugs in food are established through a procedure at the European Medicines Agency. As part of the authorisation process, the time period is also determined after which the concentration of the veterinary drug in the treated animals is so low that the maximum residue limits in food are no longer exceeded.

Compliance with the maximum residue limits for veterinary medicines in food of animal origin is monitored by the food monitoring authorities in the German federal states. The German Federal Office of Consumer Protection and Food Safety (BVLshort forGerman Federal Office of Consumer Protection and Food Safety) provides an External Link:overview of the results of residue tests (in German) carried out by the regional authorities in accordance with the National Residue Control Plan (NRKP).

A maximum residue level is the quantity of a substance which may be contained in a food product. This quantity may not pose a health risk to consumers. In Germany, the food monitoring authorities of the federal states ("Laender") check for compliance with maximum residue levels.

In principle, livestock reared on organic farms may also be treated with antibiotics. However, further-reaching regulations apply here as defined by an EU Regulation, as well as several regulations issued by the various organic agriculture associations. There are currently no reliable statistics on the use of antibiotics in organic livestock farming.

In general, food intended for consumption must not contain any residues that could be harmful to consumers’ health. Heating does not necessarily inactivate the substances used or their degradation products. The degree of inactivation depends heavily on the type of substance and the heating process; therefore, it is not possible to make general statements on this matter.