Journal Articles
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Item The characterisation of antimicrobial resistant Escherichia coli from dairy calves.(Microbiology Society, 2023-08) Mwenifumbo M; Cookson AL; Zhao S; Fayaz A; Browne AS; Benschop J; Burgess SAIntroduction. Dairy calves, particularly pre-weaned calves have been identified as a common source of multidrug resistant (MDR) Escherichia coli. Gap statement. E. coli strains isolated from dairy calves and the location of their resistance genes (plasmid or chromosomal) have not been well characterised. Aim. To characterise the phenotypic and genotypic features as well as the population structure of antimicrobial-resistant E. coli isolated from calves located on dairy farms that feed waste-milk to their replacement calves. Methodology. Recto-anal swab enrichments from 40 dairy calves (≤ 14 days old) located on four dairy farms were examined for tetracycline, streptomycin, ciprofloxacin, and third-generation cephalosporin resistant E. coli. Whole genome sequencing was performed using both short- and long-read technologies on selected antimicrobial resistant E. coli. Results. Fifty-eight percent (23/40) of calves harboured antimicrobial resistant E. coli: 43 % (17/40) harboured tetracycline resistant, and 23 % (9/40) harboured chromosomal mediated AmpC producing E. coli. Whole genome sequencing of 27 isolates revealed five sequence types, with ST88 being the dominant ST (17/27, 63 % of the sequenced isolates) followed by ST1308 (3/27, 11 %), along with the extraintestinal pathogenic E. coli lineages ST69 (3/27, 11 %), ST10 (2/27, 7 %), and ST58 (2/27, 7 %). Additionally, 16 isolates were MDR, harbouring additional resistance genes that were not tested phenotypically. Oxford Nanopore long-read sequencing technologies enabled the location of multiple resistant gene cassettes in IncF plasmids to be determined. Conclusion. Our study identified a high incidence of tetracycline and streptomycin-resistant E. coli in dairy calves, and highlighted the presence of multidrug-resistant strains, emphasising the need for further investigation into potential associations with farm management practices.Item Pain Assessment in Cattle by Use of Numerical Rating and Visual Analogue Scales-A Systematic Review and Meta-Analysis(MDPI (Basel, Switzerland), 2024-01-22) Tschoner T; Mueller KR; Zablotski Y; Feist M; Musk GCSubjective pain assessment in cattle is contingent upon the observer's experience and attitude. Studies of pain assessment in cattle by veterinarians and farmers using different pain scales have been published. This systematic review and meta-analysis aimed to describe and compare the pain scores given by veterinarians and producers for different procedures and conditions using either a NRS or VAS. The literature search was conducted with PubMed (MEDLINE) and Agricola, using defined search terms (e.g., peer-reviewed). A total of 842 articles were identified. After screening of duplicates, abstracts, and full texts, a total of 16 articles were included in this systematic review. Different pain scales were used for the included studies (NRS 0-10 for eight studies, NRS 1-10 for six studies, NRS 1-10 and VAS 0-10 for one study, and VAS 0-1 for one study). Most studies (n = 11) originated from the European Union. Mean values for pain scores differed significantly between studies included in the meta-analysis for both NRS 0-10 and 1-10. The findings of this study indicated that comparison of pain scoring used in different studies is difficult due to use of different pain scales and varying nomenclature, and that many variables (such as age and gender) influence pain scoring.Item Effect of Divergent Feeding Regimes During Early Life on the Rumen Microbiota in Calves(Frontiers Media S.A., 2021-10-20) Cristobal-Carballo O; McCoard SA; Cookson AL; Laven RA; Ganesh S; Lewis SJ; Muetzel S; Morgavi DPThe objective of this study was to determine whether divergent feeding regimes during the first 41 weeks of the life of a calf are associated with long-term changes in the rumen microbiota and the associated fermentation end-products. Twenty-four calves (9 ± 5 days of age) were arranged in a 2 × 2 factorial design with two divergent treatments across three dietary phases. In phase 1 (P01), calves were offered a low-milk volume/concentrate starter diet with early weaning (CO) or high-milk volume/pasture diet and late weaning (FO). In phase 2 (P02), calves from both groups were randomly allocated to either high-quality (HQ) or low-quality (LQ) pasture grazing groups. In phase 3 (P03), calves were randomly allocated to one of two grazing groups and offered the same pasture-only diet. During each dietary phase, methane (CH4) and hydrogen (H2) emissions and dry matter intake (DMI) were measured in respiration chambers, and rumen samples for the evaluation of microbiota and short-chain fatty acid (SCFA) characterizations were collected. In P01, CO calves had a higher solid feed intake but a lower CH4 yield (yCH4) and acetate:propionate ratio (A:P) compared with FO calves. The ruminal bacterial community had lower proportions of cellulolytic bacteria in CO than FO calves. The archaeal community was dominated by Methanobrevibacter boviskoreani in CO calves and by Mbb. gottschalkii in FO calves. These differences, however, did not persist into P02. Calves offered HQ pastures had greater DMI and lower A:P ratio than calves offered LQ pastures, but yCH4 was similar between groups. The cellulolytic bacteria had lower proportions in HQ than LQ calves. In all groups, the archaeal community was dominated by Mbb. gottschalkii. No treatment interactions were observed in P02. In P03, all calves had similar DMI, CH4 and H2 emissions, SCFA proportions, and microbial compositions, and no interactions with previous treatments were observed. These results indicate that the rumen microbiota and associated fermentation end-products are driven by the diet consumed at the time of sampling and that previous dietary interventions do not lead to a detectable long-term microbial imprint or changes in rumen function.Item Pharmacokinetics and efficacy of a novel long-acting bupivacaine formulation for cornual nerve block in calves(Frontiers Media S.A., 2022-12-01) Venkatachalam D; Kells N; Chambers P; Jacob A; Ward N; Singh P; Soto-Blanco BLocal anesthetics are commonly used in farm animals to provide analgesia for painful procedures but can cause adverse effects at high systemic concentrations. The pharmacokinetics and efficacy of a long-acting sucrose acetate isobutyrate (SAIB) bupivacaine formulation following cornual nerve block in calves were compared to lidocaine. Fourteen calves were randomly assigned to one of the treatment groups (i) 5% Bupivacaine-SAIB (BUP-SAIB), n = 7; or (ii) 2% lidocaine (LID), n = 7. Cornual nerve block was performed, and duration of effective analgesia was evaluated by nociceptive threshold testing using a hand-held pressure algometer. Blood samples were collected at various time points and plasma concentrations were analyzed by HPLC. Pharmacokinetic parameters were calculated using a non-compartmental model. The mechanical nociceptive thresholds showed that the novel formulation could desensitize the skin around the horn bud for 18.77 ± 8.88 h (range 8-36 h), compared to 0.79 ± 0.34 h (range 0.5-1.5 h) with lidocaine. The mean maximum plasma concentration (Cmax) of bupivacaine was 152.03 (SD 37.34) ng/mL and its Tmax was 0.39 (SD 0.13) h. The half-life of elimination was 32.79 ± 11.00 h and the rate of clearance was 0.12 ± 0.03 L h-1. No toxicity signs were seen after treatment in either group. The novel formulation produced long-lasting analgesia of several times greater duration than that produced by lidocaine. This study showed that the safety and efficacy of the SAIB formulation justifies further studies in a larger population of animals.