Drivers of Antimicrobial Use Practices among Tennessee Dairy Cattle Producers

Abstract

Nonjudicious antimicrobial use (AMU) and inadequate antimicrobial stewardship are known modifiable factors driving the occurrence of antimicrobial resistance (AMR). A mixed methods approach using a combination of focus groups and survey questionnaires was used to explore the AMU practices of Tennessee (TN) dairy cattle producers. Specifically, the objectives of the study were to determine the following: (1) the most common drivers for using antimicrobials, (2) perceived alternatives to antimicrobials, (3) knowledge of and perceptions regarding AMR, (4) and the appropriate avenues for receiving information on prudent AMU. Two focus groups were conducted, one in July 2017 and the other in March 2018. The questionnaire was simultaneously made available to participants both in print form and online from January 26, 2018, through May 11, 2018. Twenty-three dairy producers participated in the focus groups and 45 responded to the survey. Eight (18.6%) producers never used bacterial culture and sensitivity testing (C/S) to select antimicrobials, more than half (25 producers (58.1%)) sometimes used C/S, four (9.3%) used C/S about half the time, five (11.6%) most of the time, and one (2.3%) always used C/S. The most common drivers for using antimicrobials were disease and animal welfare, pathogen surveillance, economic factors, veterinarian recommendation, producer's experience and judgment, drug attributes, and the Veterinary Feed Directive. Good management practices, vaccination, use of immunomodulatory products, and use of appropriate technology for early disease detection were considered alternatives to AMU. Four (9.1%) dairy producers were very concerned about AMR, 27 (61.4%) moderately concerned, and 10 (22.7%) not concerned. The veterinarian was considered to be a trusted source of information on prudent AMU. Use of C/S test results for antimicrobial selection is widespread among TN dairy producers. There is a need to popularize/promote selective dry cow therapy among TN dairy producers.

Antimicrobial Resistance of Major Bacterial Pathogens from Dairy Cows with High Somatic Cell Count and Clinical Mastitis

“…Based on this study, Gram-negatives are more resistant than Gram-positives but whether this difference is due to intrinsic resistance of Gram-negatives to some of these antimicrobials or due to the development of resistance under the presence of antimicrobials prescriptions need further investigation. The fitness to thrive under antimicrobials may be acquired and promoted due to the frequent imprudent use of antimicrobials in dairy farms in the study area since an unregulated imprudent antimicrobial use pattern was reported among dairy farmers in Tennessee [ 62 ]. However, we do not have antimicrobials use patterns of farms included in this study to support this finding.…”

Veterinary Herd Health Consultancy and Antimicrobial Use in Dairy Herds

“…The first point to be presented here, “Treatment practices” ( Figure 1 , intrinsic, common factor), appeared to be an important point for both veterinarians and farmers, with a range of attitudes on how to approach treatment. Several studies suggest that veterinarians and farmers both agree that sick animals need treatment [( 29 ), 44–5, ( 30 ), p. 86, ( 31 ), p. 4, ( 32 ), p. 7], yet motives seem to differ between the two groups. According to Speksnijder et al [( 29 ), p. 44], veterinarians regard diseased animals from a professional and ethical point of view, with treatment primarily related to their perceived obligation as a veterinarian to ensure animal health and welfare.…”

“…Other perceptions about “Treatment practices” have also been identified in the literature ( Figure 1 , intrinsic, common factor). Several studies found that both veterinarians and farmers believe that vaccination plays a key role in reducing AMU [( 32 ), p. 11, ( 31 ), p. 7, ( 35 ), p. 5–7, ( 36 ), p. 3232–7]. However, vaccination was perceived as ineffective among farmers in Washington State [( 36 ), p. 3234].…”

“…Dairy farmers interviewed in Tennessee believed that there was no connection between AMU in agriculture and public health risks. Instead, this risk was perceived as being linked to AMU in the human sector [( 31 ), p. 7]. Renunciation of responsibility by both veterinarians and farmers can therefore act as a barrier to changing AMU.…”

Perceptions of Tennessee cattle producers regarding the Veterinary Feed Directive

“…The VFD only authorizes the use of medically important antimicrobials in feed and water for therapeutic purposes, under the supervision of a licensed veterinarian. In Tennessee (TN), we found that the VFD, and other factors such as producer’ experience and peer support, and antimicrobial drug attributes drive AMU [18, 19]. A previous review that evaluated evidence on the unintended consequences of AMU restrictions in food animals recommended that more research should be conducted to evaluate, document, and report the unintended consequences of interventions targeting AMR reduction [9].…”