New Zealand veterinary journal最新文献

Aims: To quantify the production effects of outbreaks of clinical salmonellosis in seasonal calving, pasture-based dairy herds in New Zealand, from which non-Brandenburg Salmonella enterica subsp. enterica were isolated, and to use these results to undertake a financial analysis of their consequences.

Methods: In this retrospective cohort study, we collated routinely available data for cow demographics, disease treatment, and accumulated whole of lactation milk solids (MS) yield from five spring-calving, pasture-based dairy herds that experienced naturally occurring clinical salmonellosis outbreaks in milking cows over the study period from 1 June 2021 until 31 May 2022. We used multivariable generalised linear models to estimate the effects of cow-level risk factors for clinical salmonellosis and the effects of disease on accumulated whole of lactation MS yield and risk of removal by culling or death. The financial consequences of salmonellosis were estimated with a partial budget model using the study results and publicly available information.

Results: The median herd incidence risk of clinical salmonellosis over the study period was 2.6% (min 0.5, max 7.0%). The adjusted marginal mean incidence risk for disease for cows of age 2, 3-4, 5-6 and ≥ 7 years of age were 0.93% (95% CI = 0.39-2.18%), 0.98% (95% CI = 0.49-1.93%), 3.5% (95% CI = 2.15-5.63%) and 4.8% (95% CI = 3.06-7.40%), respectively. In three of the four herds with milk production records, there was no measurable effect of disease on MS yield and in a single herd, the adjusted marginal mean effect was a reduction in affected cows of 150 (95% CI = 98-202) kg (p < 0.001) accumulated MS yield per cow (36%). In a study of median-sized hypothetical herds, under six different scenarios differing in the level of impact of salmonellosis on MS yield and with differing incidence risks of disease, we estimated a total herd-level increase in expenditure and decrease in income for the season in which the outbreak occurred of NZ$1,873-NZ$13,444.

Conclusions: This preliminary study suggests that the financial consequences of clinical salmonellosis in New Zealand dairy herds are highly variable and are driven mainly by the incidence risk of disease and its effect on milk production.

Clinical relevance: Our results provide a preliminary guide to the range of biological and financial impacts of salmonellosis outbreaks in New Zealand dairy herds, which can aid in the planning of future research and inform farmer decision-making on control measures.

Aims: To assess the association between the sample/positive (S/P) ratios from a milk IgG ELISA, specific for Staphylococcus aureus and the somatic cell count (SCC) in cow composite milk samples taken at routine herd testing, and the association between the S/P ratio and milk solids (MS; kg fat + protein/cow/day) in cows in a pasture-based, seasonal-calving, New Zealand dairy herd.

Methods: Data from cow-composite milk samples were retrospectively analysed to determine the associations between the S/P ratios from a milk IgG ELISA specific for S. aureus, SCC (transformed to linear scores (LS) for analysis), and MS from cow-composite milk samples collected on four occasions across two lactations. A generalised linear mixed model was used to assess the effect of age, breed, month in lactation, and their interactions on the S/P ratio. To assess agreement between cows defined as infected based on S/P and on SCC, cows were classified as uninfected or infected using test positive cutpoints ≥ 0.38 for the S/P ratio and ≥ 150,000 cells/mL for SCC, and the agreement between these categories was compared by Gwet's agreement coefficient (AC). A generalised linear mixed model was used to assess associations between S/P and MS production with age, breed, and herd test date, with their interactions as explanatory variables, and cow as a random effect.

Results: The S/P varied by month of lactation, and there was an interaction between age and breed. There was a moderate agreement between the dichotomised S/P ratios and the dichotomised SCC (Gwet's AC = 0.59 (SE = 0.02); p < 0.001). When the MS production of cows defined as S/P test negative, suspicious or positive was analysed, there was an age by S/P interaction whereby there was no association between S/P category and MS amongst 2-year-olds, while in older cows, test-positive cows had lower MS than test-negative cows.

Conclusions: This observational study demonstrated moderate agreement between S/P ratio and SCC. Additionally, there were negative associations between the S/P ratio and MS amongst older cows and in late lactation. Thus, the S/P ratio of an S. aureus-specific IgG ELISA is correlated with a well-defined marker of mastitis (SCC) and with milk yield depression. Further assessment of these associations using microbiology, and investigation of associations between the antibody results and long-term survival in the herd would further strengthen the validity and utility of the test.

Aims: To review the Vets on Farm (VoF) programme, provided to support veterinarians and farmers after New Zealand's North Island weather events of early 2023, by interviewing participating veterinarians and farmers about their experiences with the programme, and to use their responses to develop recommendations to optimise support following future natural hazard events.

Methods: Within the VoF programme, veterinarians had conducted multiple on-farm visits to provide services (farm systems review, feed budgeting, disease management) and collect diagnostic samples.Subsequently, between October 2024 and January 2025, semi-structured interviews were conducted with participating veterinarians and farmers. Interviews covered background information about the respondent, delivery of and services offered/received via VoF, effects and outcomes of VoF, support, and suggestions for future support programmes. Interviews were audio recorded and transcribed. Thematic analysis was used to identify themes and sub-themes, based on which recommendations were developed.

Results: Nine veterinarians and seven farmers from six regions in the North Island were interviewed. Themes were identified in relation to the following topics: benefits and challenges for veterinarians, benefits and challenges for farmers, programme design, and management. Benefits reported by veterinarians included improved relationships with farmer clients, better knowledge of their needs, opportunities to offer clients an expanded range of resources, and satisfaction at being able to help. Challenges included increased demands on time and workload, lack of guidance on selection of participating farmers, and ending the programme without appearing to abruptly withdraw support. Benefits for farmers included strong engagement with their veterinarian, relevant and timely advice on farm management, information from diagnostic test results, and social support. Challenges included workload, stress, and some mismatches between farmer needs and the services available. The general principle of the VoF support was well received.

Conclusions: The in-depth interviews provided rich information and a high level of agreement between veterinarians and farmers. The framework of VoF, including its templates, systems, resourcing and communications, may provide a valuable resource basis for future programmes; however, greater flexibility around allocation of money per farm, testing and services would have allowed better tailoring to farm-specific needs. Follow-up evaluation of farm performance would provide valuable information on the effectiveness of interventions and emerging needs.

Clinical relevance: Veterinary work with clients following extreme events includes providing social support. Training and supervision for veterinarians' social support role needs consideration.

Qualitative research is increasingly recognised as an essential component of veterinary inquiry, especially when exploring the complex human, ethical, and contextual factors that influence animal health and welfare. This primer offers a practical and straightforward guide to the most commonly used qualitative methods in veterinary settings, including interviews, focus groups, and open-ended surveys as methods of data collection, and reflexive thematic analysis as one approach to data analysis. Aimed at veterinary practitioners and researchers with limited prior experience in qualitative approaches, it explains the reasons for using these methods and how to conduct them rigorously, and highlights common pitfalls to avoid. Drawing on published examples from veterinary science, the article clarifies the process of qualitative data collection and analysis, emphasising reflexivity and ethical responsibility. Although qualitative research does not produce statistically generalisable results, it offers valuable insights into how veterinary professionals and clients experience and understand their world. By providing readers with the foundational tools to design, evaluate, and conduct high-quality qualitative research, this guide helps build a more comprehensive evidence base for informed veterinary decision-making.

Aims: To describe a novel knotless subcuticular suture technique using traditional smooth suture material, and to demonstrate its safety by comparing the post-operative complications with traditional interrupted cruciate skin sutures.

Methods: Forty-four dogs undergoing ovariohysterectomy were randomised into two groups, whereby the skin was closed using either a knotless subcuticular suture (NKSS; n = 22) pattern or traditional cruciate skin sutures (CSS; n = 22). The surgical wounds were assessed using a semiquantitative scoring system 10-14 days post-operatively. Data was analysed for variables associated with any wound reaction first using univariable comparisons. Then, to address small event counts and complete separation, multivariable analysis was conducted using Firth's penalised logistic regression.

Results: Wound reactions occurred in 0/22 dogs with NKSS vs. 5/22 (22.7%) with CSS (p = 0.048). The univariable odds of reaction calculated using Haldane's correction were lower with NKSS (OR = 0.071 (95% CI = 0.0037-1.37); Fisher's exact p = 0.0796). Only suture type was retained in the logistic regression, with findings for the protective effect of NKSS consistent in direction but with greater precision (OR  = 0.071 (95% CI = 0.000-0.693); p = 0.0190).

Conclusions: In this prospective cohort, the absolute risk of any wound reaction was 0% with NKSS and 22.7% with CSS. Findings are compatible with reduced odds of wound reactions for NKSS, but precision is limited by the small sample size and few events. Larger, blinded studies are required before firm conclusions about comparative safety can be drawn.

Clinical relevance: The novel knotless subcuticular suture technique was safe and effective for the skin closure of ovariohysterectomy incisions in dogs, and it may result in lower superficial wound reactions.

Aims: To investigate potential resistance to anthelmintics containing triclabendazole in naturally acquired Fasciola hepatica (liver fluke) present on a sheep and beef farm in New Zealand.

Materials and methods: A necropsy study was conducted with three groups of mixed-age Romney ewes naturally infected with F. hepatica. Ewes were either left untreated as controls or treated with a single oral dose of either a combination of 0.2 mg/kg moxidectin and 10 mg/kg triclabendazole or 10 mg/kg triclabendazole alone, both at the manufacturer's recommended dose. At necropsy, 49 days later, livers were collected for total adult liver fluke counts.

Results: All ewes in the trial had live liver fluke (min 1, max 148 flukes/liver). The efficacy was 30% for moxidectin plus triclabendazole and 21% for triclabendazole alone, confirming triclabendazole resistance on this farm.

Conclusion: This is the first reported case of triclabendazole-resistant liver fluke in New Zealand.

Clinical relevance: The finding of triclabendazole-resistant liver fluke in New Zealand should alert farmers and veterinarians to consider triclabendazole resistance as a potential cause of treatment failure, and adapt the farm liver fluke management and treatment regimens. In addition, resistant fluke could be widespread around New Zealand due to livestock being sold from this farm.

This article considers how artificial intelligence (AI) could support, within a New Zealand context, the contribution of private veterinarians to protecting animal health and welfare during emergency responses. These may include veterinary involvement in natural disasters, such as fire and flood, or formal emergency animal disease responses, which are the responsibility of different government departments.An emergency response in New Zealand that impacts the health and welfare of animals, relies heavily on privately operated veterinary practices, which typically lack the coordination and support required for effective engagement. Drawing on historical events such as the response to the recent incursion of Mycoplasma bovis, this article reviews systemic limitations of the current emergency response process, such as fragmented data flows, unclear roles, and insufficient planning, and explores how AI could address these challenges.Key concepts of AI are introduced, including predictive modelling and decision support, and their relevance is considered within the veterinary context. Recent developments, such as multimodal models, generative reasoning models, and mobile-friendly architectures, offer opportunities to enhance preparedness, support faster decision-making, and improve coordination. However, technical advances alone are insufficient to resolve previous limitations. AI tools are only advantageous if embedded in day-to-day workflows, supported by well-governed data-sharing arrangements, and accompanied by clear guidance on their interpretation and limitations. Challenges relating to ethics, commercial incentives, and operational integration remain considerable.Progress in this area depends on collaboration between veterinarians, technologists, and policymakers as part of existing activities to prepare for an emergency response. By aligning commercial and public-good objectives and clarifying how everyday veterinary activity contributes to system-wide resilience, AI could become a practical tool in the profession's growing role in emergency response.This review identifies strategic opportunities for veterinarians to shape and deploy AI technologies that support animal welfare, improve coordination, and strengthen national resilience during an emergency response to an event involving animals. Realising this potential will require early cross-sector collaboration, durable ethical oversight, and a clear articulation of shared value across both routine and emergency veterinary practice.