New Zealand veterinary journal最新文献

Aims: To use a commercially available, deterministic, whole-farm model to assess the impact on production (milk solids (MS)/ha), greenhouse gas (GHG) emissions (total and per kg MS), and gross margin per ha, from changes in the calving pattern alone or combined with changes in non-pregnancy and replacement rate, for a pasture-based dairy farming system in Waikato, New Zealand.

Methods: A baseline model of a dairy farm was developed. Reproductive data from actual Waikato dairy farms were used to assess the change and variability in GHG production (total and per kg MS), MS/ha and gross margin/ha of the baseline model farm. Two different scenarios were modelled using data reflecting a range in reproductive performance: firstly, calving pattern data from 82 farms were used to model, over the subsequent lactation, the range in outputs associated with these differences. Secondly, calving pattern and non-pregnancy rate data from 70 of these farms were used to model the range in outputs associated with differences in these combined metrics.

Results: Sequentially changing the calving pattern data to reflect the variation in the 82 farms demonstrated relatively small changes in the outputs: higher 6-week calving rates tended to produce more MS per ha and a higher gross margin per ha. These herds also had lower GHG emissions intensity but tended to produce more overall GHG. Including the variance in the calving and non-pregnancy rate also led to small changes in outputs. Herds with higher 6-week calving rates and lower non-pregnancy rates - necessitating the user to manually reduce the replacement rate - resulted in a decrease in emissions intensity and overall emissions. However, despite the large variation in both the non-pregnancy and 6-week calving rate in the actual farm data, there was much less variation in the model's predicted production/ha, gross margin/ha and environmental emissions.

Conclusions: Although these herds demonstrated variation in reproductive performance, and a resultant variance in the replacement rate, the model predicted that the financial, production and environmental outputs were only slightly better for herds with the optimum reproductive performance. In particular, even for herds with the best reproductive performance, overall GHG emissions were only slightly reduced. Thus, our modelling suggests it is the opportunity to further manipulate the farming system - stemming from improvements in the reproductive performance - that is likely to create the greatest gains in the production, financial and environmental performance for a dairy farm.

Abbreviations: CO₂e: Carbon dioxide equivalents; GHG: Greenhouse gas; MS: Milk solids.

Case history: Medical records of a university-based veterinary referral hospital (Maisons-Alfort, France) were reviewed to identify dogs presenting with ureteral stones between 2010 and 2021. Fourteen dogs were included that had a median age of 8.5 (min 2, max 13) years and a median body weight of 6.4 (min 2.5, max 11) kg. Yorkshire Terrier (n = 5) and Shih Tzu (n = 4) breeds predominated.

Clinical findings: The clinical and biological findings included lethargy (n = 10), dysorexia (n = 9), vomiting (n = 8), abdominal pain (n = 6), pyrexia (n = 4), and azotaemia (n = 4). Ureteral stones were located in the right ureter (n = 4), left ureter (n = 6), and bilaterally (n = 4). Dogs had a median of 2.5 (min 1, max > 5) ureteral stones, with 10 dogs having ≥ 2 stones. Twelve dogs had pyelectasis, indicating partial to complete obstruction of urinary flow, but there was no evidence of a difference in renal pelvis dilation between dogs that did or did not have abdominal pain (p = 0.060) or azotaemia (p = 0.024). Calcium oxalate was the most common ureterolith composition, confirmed in five dogs and suspected in five dogs.

Treatment and outcome: Six dogs were managed medically, none of which developed azotaemia or worsening renal pelvic dilation; two dogs experienced spontaneous expulsion of the ureteral calculi. Eight dogs were managed surgically, including five by ureterotomy (temporary stents were placed in four dogs and successfully removed endoscopically 34-75 days after placement), one by placement of a SC ureteral bypass device, and two by nephroureterectomy. Short-term post-operative follow-up revealed that all dogs experienced rapid and complete resolution of clinical signs. Regardless of the treatment modality, the long-term outcome (median follow-up duration 353 days) appeared to be excellent.

Clinical relevance: Ureteral calculi were less commonly associated with azotaemia in dogs, but abdominal pain and pyrexia were relevant clinical findings. Ureterotomy with temporary ureteral stenting was an effective treatment option for ureteral obstruction in dogs, although spontaneous passage of the incidentally identified ureteral calculi was reported.

Case history: The medical records of a veterinary hospital in Italy were reviewed retrospectively for cases of dogs and cats diagnosed with vertebral instability (VI) and treated surgically using a bone plate, screws with bushings, and polymethylmethacrylate (PMMA) that had ≥ 4 weeks' follow-up data. Dogs were a median of 16.15 (min 2.7, max 32) kg and 90 (min 38, max 142) months old, and cats were a median of 4.05 (min 2.7, max 5) kg and 33 (min 5, max 61) months old. The aetiology of VI was primarily traumatic in eight cases (road traffic accidents, n = 6; fall from height, n = 1; bite injury, n = 1) and degenerative in two cases (C1-C2 luxation, n = 1; and lumbosacral instability, n = 1).

Clinical findings: Neurological examinations were performed pre- and post-operatively using the modified Frankel scale. Neurological grades prior to surgery were grade 0 (n = 1), grade 1 (n = 2), grade 3b (n = 6), and grade 5 (n = 1). Diagnostic imaging (CT and radiography) was conducted to classify fractures/luxations, plan surgical interventions and evaluate post-operative progress. VI was localised to the lumbar (n = 2), lumbosacral (n = 1), or thoracic (n = 1) spinal segments of cats and the cervical (n = 1), thoracolumbar junction (n = 1), lumbar (n = 2), or lumbosacral (n = 2) spinal segments of dogs.

Treatment and outcome: All animals were treated surgically with a bone plate, screws with bushings and PMMA for stabilisation, as unilateral constructs (three cats, two dogs) or bilateral constructs (one cat, four dogs). A minor complication (Kirschner wire breakage) occurred in one dog, and a major complication (cement rupture) occurred in one cat; both resolved without surgical intervention and did not compromise stability or cause neurological deterioration.Post-operative neurological assessment revealed improvement in 9/10 cases, with two cases improving by one neurological grade, and seven cases improving by two grades. At the 4-week follow-up assessment, seven cases maintained their discharge status, while three improved by one additional grade at the 16-week follow-up assessment.

Conclusions and clinical relevance: This case series suggests that VI stabilisation with a bone plate, screws with bushings, and PMMA is a viable method producing satisfactory outcomes. Increased exposure surface at the screw/bushing/PMMA interface may increase the strength of the fixation.

Abbreviations: K-wire: Kirschner wire; PMMA: Polymethylmethacrylate; VI: Vertebral instability.

Case history: In a 520-cow, spring-calving, pasture-based Waikato dairy farm, the bulk milk somatic cell count (SCC) increased by approximately 20% from 203,000 cells/mL in the 2020/21 season to 245,000 cells/mL in the 2021/22 season. Analysis of herd test SCC data found that the incidence of intramammary infection increased more than 10-fold from 1.8 to 19.2 cows/30 days at the March 2021 and March 2022 herd tests, respectively.

Laboratory findings: Milk sampling of all quarters of 43 cows with a SCC > 200,000 cells/mL following herd testing in March 2022, identified 12 quarters from 10 cows infected with Staphylococcus aureus. Antimicrobial sensitivity testing by disc diffusion testing found nine of these isolates (from seven cows) were methicillin resistant.

Diagnosis: Whole genome sequencing demonstrated the presence of mecA, a gene encoding an alternative penicillin-binding protein (PBP2a) associated with methicillin-resistant Staph. aureus (MRSA). These isolates were sequence type 5, spa type t002, and all were carrying one or more of the immune human immune evasion cluster genes, scn, chp, sak and sea.

Conclusions: Due to concerns for public safety, the Ministry for Primary Industries, the milk processor and the farm's staff were notified. A comprehensive management plan was implemented which focused on reducing the risk of human exposure by wearing gloves, discouraging consumption of raw milk, and smoking or eating in the milking parlour, alongside measures designed to minimise cow-to-cow transmission such as improving teat spray application, milking machine maintenance, additional sampling, and segregation of likely infected (that is, high SCC and confirmed presence of Staph. aureus) cows. Implementation of the plan resulted in a significantly lower bulk milk SCC and reduced incidence rate of new infections in the subsequent two lactations. However, MRSA was isolated from cows for at least a further 13 months, with some cows remaining infected this entire period despite having been treated with cloxacillin-based antimicrobials at the end of lactation. One staff member had a history of being hospitalised during 2021/22 for significant soft tissue infections.

Clinical relevance: Given the sequence type, spa type, and presence of the immune evasion cluster genes, it is probable that the MRSA was introduced into the herd from a human. Veterinarians need to be aware of the possibility of MRSA within dairy herds and the possible human origin for these infections.

Abbreviations: BMSCC: Bulk milk somatic cell count; MRSA: Methicillin-resistant Staphylococcus aureus; NAS: Non-aureus staphylococci; PBP: Penicillin-binding protein; SCC: Somatic cell count; spa: Staphylococcal protein A; ST: Sequence type.

Aims: To assess the accuracy of the morphological identification of Lucilia cuprina and Lucilia sericata by using molecular analysis as a reference standard test, and to describe the seasonality of these species.

Methods: A convenience sample of L. cuprina and L. sericata flies was caught on eight farms from across New Zealand and stored at room temperature in 70% alcohol. They were first morphologically identified using published keys and then molecularly identified using primers to amplify the 28S rRNA region of the nuclear genome. The accuracy of the morphological identification was then estimated for each species using the molecular identification as a reference standard test. The correctness of the published keys was also tested by re-examining a sample of misidentified flies using enhanced magnification and photography.

Results: The accuracy of the morphological identification for L. cuprina was 0.66 (95% CI = 0.58-0.73) and for L. sericata was 0.7 (95% CI = 0.62-0.77). There was no evidence for a difference in accuracy between species (p = 0.56), and re-examination of the misidentified flies found no faults in the published keys. The study confirmed that L. cuprina has a longer season of activity than L. sericata.

Conclusions: These results emphasise the need to use molecular methods to confirm the identification of these species, especially when dealing with large, stored collections, rather than to rely on morphological identification alone.

Clinical relevance: Without accurate fly identification and knowledge of insecticide resistance status, effective control and prevention of flystrike in New Zealand could be handicapped.

Aims: To evaluate the efficacy of hydrogen peroxide gas plasma (HPGP) in sterilising biologically contaminated nerve-stimulating needles for reuse, which could contribute to sustainability and reduce medical waste.

Methods: Nine sterile, 21-gauge x 4-inch Stimuplex nerve-stimulating needles were inoculated by passing Geobacillus stearothermophilus spore suspension through the lumen and tubing, as an indicator for the efficacy of sterilisation. One additional nerve-stimulating needle was not inoculated as a negative control. All 10 needles were packaged in individual sterilisation pouches with an HPGP-specific biological and chemical indicator. Eight samples were sterilised with HPGP. The remaining inoculated sample was not sterilised as a positive control. Tryptic soy broth (TSB) was aspirated through all 10 needles into individual TSB tubes that were then incubated at 60°C for 48 hours and inspected for a colour change indicating bacterial growth. An aliquot from each TSB tube was plated on agar plates and incubated at 60°C for 24 hours. All colonies grown were speciated by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry.

Results: All chemical and biological indicators confirmed a successful sterilisation cycle. However, in contrast to the indicators, the TSB cultures from all eight inoculated needles post-sterilisation and the untreated positive control, underwent a colour change indicating bacterial growth, and bacterial colonies, confirmed as G. stearothermophilus, were observed on nutrient agar plates from these nine cultures. No bacterial growth was observed on the negative control plate.

Conclusions: HPGP autoclaving, though appropriate for temperature-sensitive equipment, is ineffective for nerve localiser needles.

Clinical relevance: While reducing medical waste is important, it must not compromise patient safety. Not all medical materials can be reliably sterilised. Stimuplex nerve-stimulating needles should remain single-use only and are not suitable for re-sterilisation with HPGP.

Abbreviations: FDA: Food and Drug Administration; HPGP: Hydrogen peroxide gas plasma; MALDI-TOF: Matrix-assisted laser desorption/ionisation time-of-flight; TSB: Tryptic soy broth.

Aims: To report short- and long-term outcomes of dogs with medial coronoid process disease (MCPD) treated by needle arthroscopy-assisted fragment removal (NA-FR) and to identify potential tomodensitometric and arthroscopic criteria associated with functional prognosis.

Methods: Medical records of dogs diagnosed with MCPD by CT and presented to a single veterinary teaching hospital, between 2021 and 2023 and treated with NA-FR were retrospectively reviewed. Data collected and analysed included: subjective lameness scores (0-5 scale) evaluated by surgeons before, and 15 days and 1 month after surgery; modified International Elbow Working Group (mIEWG; 0-12 scale) score determined by CT, modified Outerbridge score (MOS, 0-5 scale) assessed during surgery; and Canine Orthopaedic Index (COI; 16-80 scale) scores collected from owners at the time of presentation, 1 month after surgery and at long-term follow-up (≥ 12 months).

Results: Data from 41 clinically affected elbows (30 dogs) diagnosed with MCPD by CT were included. A decrease in lameness scores compared to before surgery was observed at 15 days (2 (IQR 2-3) vs. 0 (IQR 0-1); p = 0.05) and 30 days post-operatively (2 (IQR 2-3) vs. 0 (IQR 0-2); p = 0.0002). Dogs that were still lame 30 days post-operatively had a higher ulnar MOS than those that were no longer lame (3 (IQR 3-4) vs. 2 (IQR 2-3); p = 0.02). At long-term follow-up (median 24 (IQR 16-32) months after surgery; available for 18/30 dogs), there was a reduction in COI scores (median 21 (IQR 19-24)) compared to the pre-operative period (median 48 (IQR 45-56); p = 0.002). Furthermore, COI scores were higher in dogs having an ulnar or humeral MOS > 2 or mIEWG > 6 compared to those having an ulnar or humeral MOS ≤ 2 or mIEWG ≤ 6 (28 (IQR 25-44) vs. 19 (IQR 18-21), p = 0.004 and 26 (IQR 25-28) vs. 19 (IQR 19-23), p = 0.02).

Conclusions and clinical relevance: MCPD treated by NA-FR showed satisfactory short- and long-term post-operative outcomes. Increased humeral or ulnar MOS scores as well as modified IEWG scores were associated in our study with a poorer long-term outcome. Further assessments are needed to validate this strategy and to establish the criteria for identifying dogs that will best benefit from NA-FR.

Aims: To determine the importance of 11 climate variables on pasture spore count of Pseudopithomyces chartarum, a risk indicator of facial eczema (FE), and to forecast spore counts in New Zealand until 2100, using longitudinal P. chartarum pasture spore count data.

Methods: Between 2010 and 2017, spore counts (n = 6,975) were collected from 862 paddocks spread over 102 farms in the North Island of New Zealand. Historical and projected climate data were obtained from the National Institute of Water and Atmospheric Research. The spore count dataset was merged with climate data from corresponding locations, incorporating time lags of 1-53 weeks. Linear regression models were fitted for describing crude associations, while random forest models were fitted for determining variable importance and predicting future spore counts.

Results: Mixed-effect linear regression models explained up to 11% of the variance of log-transformed spore counts by a single lagged climate covariate. The best-fit random forest model had a testing accuracy of 80% in classifying low or high FE risk (> 20,000 spores) with an R² value of 43%. The random forest models suggested time-dependent importance of soil temperature at 10 cm depth, solar radiation, potential evapotranspiration, vapour pressure, soil moisture and minimum temperature, while no or weak evidence of variable importance was found for maximum temperature, rainfall, mean sea level atmospheric pressure, relative humidity and wind speed. Over the next 80 years, our model predicted an increase in the seasonal mean spore counts in the study farms by a mean of 17% (min 6, max 30%) under the high-end greenhouse gas emission scenario (representative concentration pathways (RCP) 8.5). Every decade was associated with an increase in the probability of high-risk spore counts (> 20,000) by 14-22% for the moderate to high emission scenarios (RCP 4.5-8.5). The model indicated increased peak spore counts across most regions over the next 80 years. Specifically, the entire North Island and three districts in the South Island were projected to have high mean peak spore counts by 2100.

Conclusions and clinical relevance: These findings could be used to target high-risk areas to implement mitigation or adaptation measures for FE. In addition, the study highlights the value of ecological data for forecasting environmental disease risks to enhance preparedness for climate change.