Antibiotics Policy Prescription through Prescription Policy in US Agriculture

By Yanan Jia, David A. Hennessy, and Hongli Feng

World War II saw cheap mass-produced antibiotics due in part to developments by Charles Pfizer & Company, helping to manage the many bacterial diseases that proliferate in war-time conditions.1 A decade after the war the same company developed markets for antibiotics in animal protein production as therapy and as growth promoters (Finlay 2004). These markets expanded rapidly through the last decades of the twentieth century as a low-cost means of managing hygiene in farm conditions. Bacteria are short-lived and remarkably adaptable creatures that freely swap DNA content asexually both within and between species so that resistance is inevitable. In 1969 an official United Kingdom government report recommended controls on agricultural antibiotic usage so as to protect efficacy in human medicine (Swann 1969). The half-century since the early 1970s has seen expanded regulation on antibiotics use in agriculture, first in high-income countries and more recently in lower income countries. Underlying this expansion has been the growing prevalence of bacterial resistance to antibiotics, a dearth of innovation in antibiotics, and the underlying constrained revenue problem whereby new antibiotics should be used sparingly in order to protect against resistance development (Laxminarayan et al. 2024). 

The purposes of this article are to describe recent United States regulatory endeavors to delimit the use of antibiotics in agriculture as well as to discuss how that has affected demand for services, in particular information services. The Food and Drug Administration (FDA), the relevant administrative authority, implemented the regulations, which involved assigning practicing veterinarians as stewards on behalf of the public. In this new role, veterinarians have become gatekeepers when weighing the benefits of antibiotics use as an input into producing plentiful food protein against the uncertain and possibly very large costs of increasing selection pressure toward resistance among bacteria. In this role, veterinarian gatekeeping offers an alternative to a corrective tax as a means of deterring against input choice levels that maximize user benefits but involve excessive use for the public good. Perhaps more fundamentally, veterinarians have also become guardians against use borne out of unawareness and uncertainty. Farmers may apply the input because establishing certainty about need is costlier than summarily administering an input whose benefit-to-cost ratio is very high when needed.

Prescription policy in the United States

Since the 1950s antibiotics have been incorporated into animal feed and water to prevent disease and promote growth by facilitating feed conversion to animal produce. Commencing with the Veterinary Feed Directive (VFD) in 2017, the FDA severely curtailed such administrations by disallowing growth promotion as a rationale for including antibiotics in feed or water and by allowing a veterinarian to establish whether disease prevention was a warranted justification under the circumstances. The veterinarian issuing the feed prescription should have standing in the form of an ongoing veterinarian-client-patient relationship (VCPR) so that the veterinarian is well-acquainted with client circumstances. A veterinarian who does not take seriously the antibiotics stewardship assignment may face penalties from either their state licensing board or the federal FDA.

A separate initiative, referred to as prescription regulation (PR), was put in place commencing 2023. As of 2024 a veterinarian must prescribe under VCPR conditions all remaining animal health antibiotics listed as being important for human medicine and formerly available over-the-counter (OTC), once more with attendant professional consequences for inappropriate prescriptions. Although the FDA issued the initiative as guidance, all relevant drug companies chose to impose a prescription requirement as a term of use for their antibiotic when marketing in the United States.

What of demand for testing and professional services?

Animal species differ in regard to antibiotics requirements. Treated ruminants should not see disturbance to their gut bacteria needed for food digestion while dairy produce will be tested and discarded whenever significant amounts of antibiotics are detected. Antibiotics have been used to overcome the sanitary consequences of confined agriculture and so can be viewed as a component of confined animal farming systems, especially when buildings, logistics, and input sources compromise hygiene standards. Nonetheless, and following Jia, Hennessy, and Feng (2024), a stylized description of demand for antibiotics does admit a better understanding of how prescription regulations can affect demand for antibiotics and other inputs into animal production systems.

Figure 1 outlines the decision process countenanced by a herd owner. Leftmost starts with an animal that appears sick and may require antibiotics. The farmer has four choices: (a) call a veterinarian; (b) investigate independently through some self-administered test; (c) do nothing; or, (d) use OTC antibiotics. A self-administered test is the purchase of information about whether the situation merits antibiotics. This might be a mastitis test, of which there are several available, a pen-side respiratory disease test where many have recently become available (Puig et al. 2022), or just a costly private inquiry. Veterinarian services bundle this information (i.e., on what ails the animal) with access to solutions that might include antibiotics or involve other approaches. When available OTC, antibiotics may be directly chosen after private testing or chosen after calling a veterinarian. If the antibiotics are not effective one may need to call a veterinarian in any case even for a second time. 

Figure 1. Information inputs into antibiotics choices.
Figure 1. Information inputs into antibiotics choices.


Prescription regulation simplifies the choice environment (see figure 2). Farmers must call a veterinarian before using antibiotics; that is, a farmer does not have the option to consider whether to use antibiotics or not before calling a veterinarian. In figure 2, the red arrows marked with a stop sign are no longer available options. Calling a veterinarian after using antibiotics becomes less relevant because one may already have called the veterinarian, which means the “Call veterinarian?” box on the top right of figure 2 is likely not needed. However, the four choices are interconnected when an animal appears sick, and so the PR policy that directly regulates antibiotics use will have impacts on other aspects of animal disease management. 

Figure 2. How PR affects information inputs into antibiotics choices.
Figure 2. How PR affects information inputs into antibiotics choices.


PR will likely increase demand for veterinarian services (Tack et al. 2018) because the service is now necessary even when the farmer can independently establish the need for antibiotics or conclude that antibiotics are probably a profitable choice even when they are uncertain about their efficacy. The policy merit of PR is in ensuring a professional screen against: (a) uninformed use that may benefit the farm on-average; and, (b) use for proscribed purposes (i.e., for growth promotion). PR will also likely reduce demand for independent tests because accessing antibiotics involves buying a ‘test’ in any case, as embedded in veterinarian services. In order to comprehensively assess the effects of PR we will need to consider how PR affects the use of veterinarian services, self-tests, as well as changes in the quantity of antibiotics use. The costs of antibiotics and veterinarian services obviously are important decision factors as are the costs of testing, lost productivity from not applying treatment, marginal contribution to antibiotics resistance, the social costs of antibiotics resistance, and impacts on animal welfare. 

Regulation consequences and discussion

Given the broad and large risks of resistance development for society, the technical nature of diagnosis, and the low cost of generic antibiotics, the prima facie case for prescription regulation of antibiotics in agriculture is strong. Nonetheless, whether the means is effective in limiting veterinary antibiotics use to animals has not yet received the scrutiny it deserves; nor have the possible collateral consequences.

The upper panel in figure 3 reports the weight of antibiotics of importance to humans that were consumed per kilogram produced for different food animal species produced in the United States. Clearly the VFD legislation had an immediate short-term effect for cattle, swine, and chickens. Intensity of use for other antibiotics (lower panel) has also decreased as the food retail sector and farmers have responded to market and other pressures to remove where possible antibiotics from production systems. Usage in shorter-lived animals may become very low because for these animals there is less need for antibiotics to protect against damaged growth capacity. The regulations are evidently less burdensome for chickens than for other sectors. Complete removal of antibiotics from production systems is generally not feasible—the business model for organic herds is often to remove treated animals and market their produce as from a conventional herd. 

Figure 3. Biomass-adjusted medically important (top) and not medically important (bottom) antibiotic sales by year and species (mg/kg), 2016–2022.
Figure 3. Biomass-adjusted medically important (top) and not medically important (bottom) antibiotic sales by year and species (mg/kg), 2016–2022.


The VCPR approach to ensuring that antibiotics are used only when necessary is decentralized in placing authority at or close to where knowledge of particular circumstances is greatest. An additional benefit for society as a whole and for the farming community at large is that VCPR strengthens channels whereby diseases that must be reported to authorities, including avian influenza, foot-and-mouth disease, African swine fever and many others, are more likely to be detected early when a veterinarian works closely with a farm enterprise. The matter is important because, and for a variety of reasons, the food-animal veterinarian workforce has declined dramatically in recent decades (Weltzien 2023). 

However, the approach has many limitations. It favors larger farm enterprises because these enterprises can streamline the prescription acquisition process and also because business from these enterprises may be critical for veterinarian firm viability. It also creates incentives to circumvent the veterinary profession. The FDA Office of Criminal Investigations has taken many actions against large-scale circumventions, including against Animal Health International in 2020, Midwest Veterinary Supply in 2023, and Covetrus in 2024. Finally, antibiotic resistance is a global problem so that this sort of regulation cannot be the only approach. These and similar regulations might make US animal protein production more competitive. However, if they contribute to driving meat production away from the United States toward countries that practice lower levels of antibiotics stewardship then selection pressure generating antibiotics resistance could increase. Finally, we should retain perspective by considering PR and VFD as part of the whole tool kit that policymakers have. Other policy tools can induce lower antibiotics use, including taxing the use of antibiotics and subsidizing self-testing or veterinarian services. Weighing the tradeoffs between the intended and unintended consequences of each policy will help make for robust policies. The interested reader will find more detailed and technical analysis of prescription regulation as an approach to managing antibiotics in Jia et al. (2024).


1. Throughout we use antibiotics, which treat bacterial infection, as the popular term understood to mean antimicrobials where in fact the latter category also includes viruses, parasites, and fungi. The legislation discussed in this article addresses the entire class of antimicrobials. Resistance development is a common concern across all damage-causing germs.


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Suggested citation

Jia, Y. D.A. Hennessy, and H. Feng. 2024. “Antibiotics Policy Prescription through Prescription Policy in US Agriculture.” Agricultural Policy Review, Spring 2024. Center for Agricultural and Rural Development, Iowa State University.