Intra-abdominal versus intramuscular application of two ampicillin preparations in cows

Survey of veterinarians in the Netherlands on antimicrobial use for surgical prophylaxis in dairy practice

There is increased concern about the selection pressure of antimicrobial use (AMU) in humans as well in farm animals resulting in antimicrobial (AM) resistance. The introduction of monitoring of AMU in food-producing animals since 2011 has led to a considerable quantitative reduction of AMU in those animal species in the Netherlands. This survey was conducted to explore the possibilities to improve prudent use of AM in the cattle industry. We sent an online questionnaire to 373 veterinarians and asked which antimicrobial prophylaxis they used for their most recently performed cesarean section (CS) and left displaced abomasum (LDA) correction. With a response rate of 30%, we found that older graduates used more AM for CS than recently graduated veterinarians (odds ratio = 2.4 to 2.7 depending on category), whereas antimicrobial prophylaxis in LDA surgeries was significantly different for the available surgical correction methods. The results indicate that the respondents do not adjust the surgical antimicrobial prophylaxis for different conditions of the patient or the environment; 37 (38%) respondents consider that the risks of contamination are similar for CS and LDA. In CS and all LDA correction methods preoperative prophylaxis was significantly less often applied than postoperative antimicrobial treatments (odds ratio = 0.05 and 0.08, respectively). When preoperative prophylaxis was applied, the choice of (combinations of) the AM and the timing of administration were not adequate at the start of the surgical procedure (88% for CS and 90% for LDA). We conclude that considerable qualitative (timing, choice of antimicrobial, route of administration) and quantitative (limit AMU to indicated procedures) improvement on antimicrobial prophylaxis for CS and LDA is possible by appreciation of the risks of the type of surgery (CS, LDA) and its conditions as well as by selecting classes of AM and timing and routes of administration that result in effective drug concentrations at the start of the procedure.

Description of Plasma Penicillin G Concentrations after Intramuscular Injection in Double-Muscled Cows to Optimize the Timing of Antibiotherapy for Caesarean Section

In order to improve the efficacy of penicillin injection during caesarean section, we aimed to identify the optimal timing of its preoperative administration. A study was conducted in 12 adult, non-pregnant Belgian Blue cows. To evaluate the plasma penicillin concentrations, blood samples were taken from the jugular vein at −5, 15, 30, 45, 60, 120, 240, 480 min relative to the intramuscular (IM) injection of 21,000 IU/kg of body weight of penicillin G. Results showed that plasma concentrations at 15 min after IM injection (668.3 ± 73.7 ng/mL) largely exceeded the minimal inhibitory concentration (MIC) of penicillin-sensitive bacteria (MIC < 125 ng/mL). With increasing time, plasma concentrations continued to rise, attaining an increasing proportion of moderately sensitive bacteria (250 ng/mL > MIC < 2000 ng/mL). The maximal concentration was reached between 1 and 4 h (average: 1.495.1 ± 181.7 ng/mL) after IM injection in the majority of cows, and decreased non-significantly to 1002.1 ± 93.2 ng/mL at 8 h. In conclusion, plasma penicillin concentrations at 15 min after an IM injection inhibit penicillin-sensitive bacteria. However, in order to obtain the maximal protective effect of the antibiotherapy, surgery should be started at 1 to 2 h after IM penicillin injection.

Prophylactic antibiotic usage by Belgian veterinarians during elective caesarean section in Belgian blue cattle

The use of prophylactic antibiotics in veterinary surgery reduces the occurrence of postoperative complications. In order to limit the development of antimicrobial resistance in bacteria and to maximize therapy efficacy, antibiotics should be used prudently and efficiently. A survey was sent to Wallonian rural veterinarians in order to assess the use of antibiotics before, during and after bovine elective caesarean section, the most common surgical procedure in Belgian rural practice. Results were analysed in the light of the current guidelines formulated by the Belgian Centre of Expertise on Antimicrobial Consumption and Resistance in Animals. Among 380 contacted veterinarians, 113 answered the survey. All veterinarians use antibiotics during caesarean section. Veterinarians predominantly use penicillin as the first drug of choice, whereas a minority use drugs considered as second or third choice, such as amoxicillin, oxytetracyclin or lincomycin-spectinomycin. Also, 31/113 veterinarians simultaneously use molecules from different antibiotic classes. The majority (100/113) of veterinarians inject antibiotics during or after surgery, while a minority (13/113) administer antibiotics preoperatively. Most veterinarians (67/113) limit the duration of their antibiotic treatment to 1 day. Considering the administration route, most veterinarians (88/113) systematically use the intraperitoneal injection route, which is not registered. Intramuscular injection and injection between muscle layers during surgery are carried out by 82/113 and 43/113 respondents, respectively. Twenty-two respondents apply intra-uterine antibiotics. Most veterinarians (87/113) combine several administration routes. The dosage of antibiotics varies enormously and excessive injection volumes are common, especially when multiple injection routes are combined. Our results show a striking lack of consistency in the antibiotic therapy during elective CS by rural veterinarians. Whereas the drug of choice and the treatment duration were largely in line with the current guidelines, this is certainly not the case for the dosage and the administration route. The intraperitoneal injection of antibiotics cannot be justified. Incorrect dosage of antibiotics should be avoided at all cost. The use of second and third line molecules and the simultaneous use of different antibiotic classes should be discouraged. A major challenge lies in the education of veterinary students and the sensitization of practitioners to avoid or unlearn unnecessary habits concerning antibiotic use. Finally, more clinical trials are needed in order to refine the current guidelines for antibiotic use and to determine the optimal drug of choice, treatment moment and application route in elective caesarean section in cattle.

Cross-sectional study of antimicrobials used for surgical prophylaxis by bovine veterinary practitioners in Australia

Antimicrobials are widely used in veterinary practices, but there has been no investigation of antimicrobial classes used or the appropriateness of their use in bovine practice. This study investigated antimicrobial use for surgical prophylaxis in bovine practice in Australia. A cross-sectional study of veterinarian antimicrobial usage patterns was conducted using an online questionnaire. Information solicited included respondent's details, the frequency with which antimicrobials were used for specific surgical conditions (including the dose, timing and duration of therapy) and details of practice antimicrobial use policies and sources of information about antimicrobials. In total, 212 members of the Australian veterinary profession working in bovine practice completed the survey. Antimicrobials were always or frequently used by more than 75 per cent of respondents in all scenarios. Generally, antimicrobial drug choice was appropriate for the reported surgical conditions. Procaine penicillin and oxytetracycline accounted for 93 per cent of use. However, there was a wide range of doses used, with underdosing and inappropriate timing of administration being common reasons for inappropriate prophylactic treatment. There was very low use of critically important antimicrobials (3.3 per cent of antimicrobials reported). Antimicrobial use guidelines need to be developed and promoted to improve the responsible use of antimicrobials in bovine practice.