Food animals

Here you find guidance, methods and tools to generate data on antibiotic consumption in food animals.

At present, national data on antibiotic consumption in the animal sector is lacking in many countries. However, the OIE has initiated a global data collection and an increasing number of countries are able to report, though quality and completeness may differ. To achieve this, OIE has developed standards and guidelines to provide methodologies to monitor the use of antibiotics in the animal sector. These are presented in the Terrestrial and the Aquatic Animal Health Codes.

The quantitative reports from OIE shows that there are great differences between different regions. This can only partly be explained by different animal species and different production systems and may reflect differences in data recording, government policies and their implementation.

Also, within countries, antibiotic use varies between different animal species and different production systems. Furthermore, there is a variation between individual farms and individual veterinarians.

Measure antibiotic consumption in animals

Antibiotic use data in the food animal sector can be obtained from farm animal records, veterinary prescriptions/records, pharmacies, distributors or the pharmaceutical industry. If such sophisticated systems are not yet available, data can also be gathered through point prevalence or longitudinal studies on consumption at the farm level, which has been described by both AGISAR and European Surveillance of Veterinary Antimicrobial Consumption (ESVAC). In most countries, information on antibiotic consumption is obtained from sales data. In the European Union, ESVAC collects veterinary antibiotic sales data from member countries using a harmonized protocol, which is available at the ESVAC website. Similar programs and methods are often lacking in many low- and middle-income countries but the methods used by ESVAC can be applied globally.

Harmonization of data

In order to ensure uniformity of comparison, the sales data need to be linked to the animal demographics in each country. A population correction unit (PCU) was initially developed for this purpose. The PCU is used as a proxy for the total live weight of food producing animals within the country (Number of livestock × estimated weight at treatment). In the EU, it only includes the main production animals in that region. OIE has recently developed a more global PCU, where animal species of relevance more globally are included.

However, this denominator does not take into account that the antibiotic use differs between different animal species, and that different antibiotics (the numerator) have differences in potency and hence differences in dosage in different species. There is therefore at present ongoing work to establish systems for the collection of standardized data, which includes data on antibiotic consumption per animal species, and sometimes weight group and production type.

Standardized units

In human medicine the defined daily dose (DDD) was established in the mid-1970s for the purpose of drug consumption studies, mainly in order to follow therapeutic trends. Similarly, ESVAC has proposed that defined daily dose for animals (DDDvet) and defined course dose for animals (DCDvet) for antimicrobial veterinary medicinal products should be established. By this, standardized fixed units of measurement for the reporting of data on consumption by species that take into account differences in dosing is provided. DDDvet and DCDvet are technical units of measurement solely intended for the purpose of drug consumption studies.

• The DDDvet is the assumed average dose per kg animal per species per day;
• The DCDvet is the assumed average dose per kg animal per species per treatment course.

The units were developed on basis of average dose and duration of treatment in a number of EU countries. For national purposes, units based on national conditions may also be applicable. Standaridized units such as DDDvet however are difficult to interpret in settings where antibiotics are used for other reasons than treatment.

At farm level

At farm level, the treatment frequency and the number of treatment days, and the antibiotic compound used are relevant measures of antibiotic use in farm health programs and quality assurances schemes. In its simplest form, the number of treated animals per day during an observation period (preferably a production cycle) can be recorded. For more refined studies, a treatment unit (UDD, Used Daily Doses) has been defined as the administration of one active ingredient at its daily dose to one animal on one day. For the observed population (the farm) the number UDD can be calculated as the number of UDD under the observed period. To calculate the treatment frequency, the number of UDD is divided by the population size. As the population size in many farms vary during the year due to the production cycle, it is crucial to access information on the population size for each specific farm.

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