Implementing Precision Antimicrobial Therapy for the Treatment of Bovine Respiratory Disease: Current Limitations and Perspectives

Abstract

The therapeutic efficacy of an early treatment protocol with an infection-stage adjusted fluoroquinolone regimen was evaluated in a field study on young bulls (YBs) presenting signs of bovine respiratory disease (BRD). A total of 195 YB (Charolais, Limousin, and Rouge-des-Prés breeds) from 6 farms implementing or not prophylactic antimicrobial treatments (PROPHY or absence) were randomly assigned to 1 of 2 experiment groups based on time of detection of BRD and first-line marbofloxacin regimen, early adjusted dose [Early 2 (E2)] or late standard dose [Late 10 (L10)]. Each YB was administered orally a reticulo-rumen bolus, allowing continuous monitoring of ruminal temperature. In the E2 group, YB presenting early signs of BRD, i.e., an increase in ruminal temperature over 40.2°C and persisting more than 12 h, confirmed by a clinical examination showing no or mild signs of BRD, were given 2 mg/kg of marbofloxacin. In the L10 group, YBs presenting moderate or severe signs of BRD at visual inspection, confirmed at clinical examination, were given 10 mg/kg of marbofloxacin. If needed, YBs were given a relapse treatment. The YBs were followed for 30 days. The proportions of first and relapse treatments were calculated, as well as the therapeutic efficacy at day 10. In the E2 group, the first-line treatments’ proportion was significantly higher (P < 0.05), while the relapse treatments’ proportion tended to be higher (P = 0.08), than in the L10 group. Evolution of clinical scores (CSs) of diseased YB was followed for 10 days. In both groups, CS and rectal temperature decreased significantly 24 h after treatment (P < 0.05). Treatment incidences (TI) representing antimicrobial consumption assessed on used daily doses (UDD) were calculated. Antimicrobial consumption of marbofloxacin and relapse treatments were not significantly different between the groups. These values were strongly influenced by the recourse to a prophylactic antimicrobial treatment, accounting for more than 90% of the antimicrobial amount in the herds implementing prophylaxis. The higher number of treatments in the groups treated on the basis of ruminal temperature monitoring, the accuracy of the detection method, and the necessary conditions to implement precision antimicrobial therapy in the field are discussed in this article.

Antimicrobial Use in Extensive Smallholder Livestock Farming Systems in Ethiopia: Knowledge, Attitudes, and Practices of Livestock Keepers

“…Moreover, the reported frequent use of cow or goat milk in their meal coupled with a relatively high proportion of farmers not being aware of the recommended withdrawal periods of milk and meat after antibiotic treatment may lead to the potential hazard of repeatedly ingested residues altering the intestinal microbiome and promoting emergence and selection for resistant bacteria in the gastrointestinal tract of humans (37,38). Withdrawal times are recommended in order to prevent the presence of drug residues in food products (39).…”

Bovine Immunology: Implications for Dairy Cattle

“…While only a small proportion of animals may show clinical symptoms, treatment is generally applied to the whole herd contributing to improved pathogen control and animal survival ( 176 ). However, such an (metaphylactic) approach may result in contamination of the food chain and the environment with antimicrobial resistance (AMR) factors (bacteria and genes) ( 177 ). Early detection and treatment of diseased animals allows use of substantially lower doses of antimicrobial drugs, thus reducing the AMR concerns; however, methods and tools for reliable early detection have not been developed ( 177 ).…”

“…However, such an (metaphylactic) approach may result in contamination of the food chain and the environment with antimicrobial resistance (AMR) factors (bacteria and genes) ( 177 ). Early detection and treatment of diseased animals allows use of substantially lower doses of antimicrobial drugs, thus reducing the AMR concerns; however, methods and tools for reliable early detection have not been developed ( 177 ). Nonetheless in the age of personalized medicine for humans and pets, it is anticipated that such technologies will be forthcoming for livestock as well.…”

The pharmacokinetic/pharmacodynamic paradigm for antimicrobial drugs in veterinary medicine: Recent advances and critical appraisal

“…This uniformity of dose recommendation might change, if current mass medication approaches to “metaphylaxis” as viewed here, are replaced by early medication of individual animals. Based on rapid progress in so‐called precision medicine and the technical feasibility of treating animals individually, this will become practicable, even at flock and herd levels (Bousquet‐Mélou, 2018; Lhermie et al., 2017).…”