Agricultural and medical uses of antibiotics are both suspected contributors to the problem of antimicrobial resistance, and each has come under considerable scrutiny from the scientists, policy-makers, and the public.

In addition to using antimicrobial drugs for disease treatment, beef producers use them to prevent illness, promote weight gain, and increase feed efficiency. These sub-therapeutic uses have been the subject of criticism, but the precise link between agriculture and antibiotic resistance remains unclear.

One of the greatest obstacles to determining if and how agricultural drug use contributes to the evolution of antimicrobial resistance is a simple lack of information. A minority of producers document their drug use, and no system is in place to support documentation.

Adequate records are also needed for developing prudent use guidelines for antimicrobial drugs and for demonstrating to the public that the cattle industry is actively addressing concerns about antimicrobial resistance.

The Ontario Cattlemen’s Association has responded proactively to these issues. Over the past year, producers have worked with researchers on two OCA-funded studies aimed at gathering information about aspects of antimicrobial drug use.

The first study had a pair of objectives: to gather information about how antibiotics are currently being used in Ontario and to solicit producers’ opinions about antibiotic drugs. The study involved one survey, which was distributed widely to beef farmers in Ontario.

A total of 632 surveys were filled out, representing about of 5% of beef cows and 11 to 13% of steers and heifers marketed in Ontario.

Respondents demonstrated some clear consensus when it came to questions about antibiotic drugs:

• 99.1% agreed that clear instructions on labels were important
• 95.4% felt that the use of antibiotics in feed can lead to antibiotic resistance in bacteria
• 94.4% agreed that it is important to reduce the use of antibiotics
• 94.2% agreed or strongly agreed that bacterial infections cause serious economic losses
• 92.1% agreed that it was necessary to reduce the use of antibiotics in order to slow the development of resistance in bacteria, while only 5% strongly disagreed
• 81.5% disagreed or only slightly agreed that the use of antibiotics in feed resulted in significant weight gain
• 78.0% agreed to some extent that a controversy in the media would change their current antibiotic use practices
• 53.3% reported they had heard of hygiene practices designed to decrease the need for antibiotics
• 48.1% agreed that the cost of antibiotics in feed was low, compared to 51.9% who disagreed

Almost all respondents were aware of the issues surrounding drug resistance. They believed that using antibiotics responsibly, and generally reducing their use, was important. At the same time, the respondents were just as aware of the economic cost of bacterial infections. Perhaps surprisingly, few of the respondents felt that antibiotics in feed truly achieved the goal of increasing weight gain.

The second project is currently underway. Larger in scope than the first study, it has four objectives:

• to find out how Ontario beef farmers are using antimicrobial drugs
• to quantify the amount of antimicrobial drugs being used
• to develop a treatment diary designed for keeping track of veterinary drug use, and
• to get producers’ input on the design of the treatment diary.

A total of 29 farms are currently enrolled in this ongoing project; 16 are feedlot operations and 13 are cow-calf operations. Producers are actively participating in the research by keeping track of their drug use, saving all receipts and medicine containers, and, importantly, providing information and feedback to the researchers.

Complete quantitative data is not yet available for this study. General antibiotic use profiles have been determined and are summarized in Table 2.

The number of producers who reported they had kept records before the study began was low, further supporting the researchers’ efforts to develop a usable treatment diary. After beginning the study, some producers requested a pocket-size version of the diary and others thought a clipboard version would be more useful. Two sizes are now available.

The study also gathered some useful opinion data that is consistent with the the results of the first OCA survey. Producers are aware of antimicrobial resistance and regard it as an important problem: 83.3% view withdrawal periods for antimicrobials as extremely important, and 75% feel that following label instructions regarding dose is extremely important.

In practice, however, dosing is often imprecise. According to the study, 66.7% of producers say that they would use greater amounts of antibiotics than listed on the label. Because ionophores are purchased as a component of feed, many producers do not consider them as a drug. And only 25% of producers weigh their animals before administering treatment; the others make an educated guess to determine the appropriate dosage.