USA: Data on antimicrobial use by swine operations

The data USDA collected and studied will help animal health officials – as well as the human health community and consumers – better understand how antimicrobial drugs are used on livestock farms. The studies include details on what antimicrobials were used, why they were used and how they were administered. They also include data on recordkeeping, decision making and veterinarian involvement.

The main findings of these studies include:

• The majority of feedlots (87.5 percent) gave cattle antimicrobials in feed, water, or by injection in 2016.
• The majority of swine sites (95.5 percent) gave market pigs antimicrobials in feed, water, or by injection in 2016.
• The main reasons for antimicrobial use on swine sites and feedlots were for animal health – such as to prevent, control, or treat respiratory disease – although the reasons for antimicrobial use varied across species, route of administration, and age of animals.
• The majority of swine sites and feedlots had a veterinarian-client-patient relationship and used the services of a veterinarian in 2016

The information from these studies provides a baseline for how livestock producers used antimicrobials prior to a U.S. Food and Drug Administration (FDA) rule change in January 2017, which makes two important changes to how antimicrobial drugs can be used in animal agriculture. The rule eliminates the use of “medically important” antimicrobials – ones that are used for human health – for growth promotion in food-producing animals. It also requires veterinary oversight when using medically important antimicrobials in animal feed or water. These steps will promote judicious use of antimicrobials, which may reduce the chances of the development or spread of antimicrobial resistance to these important drugs and help to protect human health. The FDA rule change does not apply to antimicrobials that are used only in animals.

Antimicrobial Use and Stewardship on U.S. Swine Operations, 2017

• Over 75 percent of all sites gave market pigs antimicrobials in water. Of sites that had nursery-age pigs, about 50 percent gave the pigs antimicrobials in water. Of sites that had grower/fi nisher-age pigs, about 60 percent gave the pigs antimicrobials in water.
• For sites that gave nursery-age and grower/fi nisher-age pigs antimicrobials in water, the highest percentages gave them for respiratory disease and diarrhea. Gentamicin, penicillin G, and oxytetracycline were the antimicrobials given in water to nursery-age pigs by the highest percentages of sites. Oxytetracycline and lincomycin were the antimicrobials given in water to grower/fi nisher-age pigs by the highest percentages of sites.
• More than 90 percent of all sites gave market pigs antimicrobials in feed. About 90 percent of sites that had nursery-age pigs gave the pigs antimicrobials in feed, and about 83 percent of sites that had grower/fi nisher-age pigs gave the pigs antimicrobials in feed. As was the case with antimicrobials used in water, the highest percentages of sites gave nursery-age pigs antimicrobials in feed for respiratory disease and diarrhea. About 50 percent of sites that had grower/fi nisher-age pigs gave the pigs antimicrobials in feed for respiratory disease, and more than one-third of sites gave them for growth promotion.
• Chlortetracycline/tiamulin and carbadox were the antimicrobials given in feed to nurseryage pigs by the highest percentages of sites. Chlortetracycline/tiamulin, bambermycin, and chlortetracycline alone were the antimicrobials given in feed to grower/fi nisher-age pigs by the highest percentages of sites.
• More than 90 percent of sites that gave antimicrobials in water or feed recorded at least some information about how antimicrobials were administered. About 92 percent of these sites recorded the date that antimicrobials use in water began, and about 94 percent recorded the antimicrobial used. About 97 percent of sites that gave antimicrobials in feed recorded the date treatment began and the antimicrobial used.
• Most sites consulted a veterinarian when making decisions on antimicrobial use. For example, on about 88 percent of sites that gave antimicrobials in water, a veterinarian decided when to use antimicrobials in water, and on about 92 percent a veterinarian decided which antimicrobials to use in water. Similarly, on about 87 percent of sites that gave antimicrobials in feed, a veterinarian decided when to use antimicrobials in feed, and on about 91 percent a veterinarian decided which antimicrobials to use in feed. About 65 percent of sites had a veterinarian visit their site from July 1 through December 31, 2016, and almost all sites (98.2 percent) had a veterinarian-client-patient relationship (VCPR).

Antimicrobial Use and Stewardship on U.S. Swine Operations, 2017