New Zealand veterinary journal最新文献

Aims: To assess whether a whole-herd lameness score on a New Zealand dairy farm in spring could predict lameness prevalence on the same farm in summer (and vice versa) and whether a single-herd lameness score could be used to determine whether herd lameness prevalence was < 5% in both spring and summer.

Methods: Prevalence data (proportion of the herd with lameness score ≥ 2 and with score 3; 0-3 scale) from a study where 120 dairy farms across New Zealand were scored in spring and in the following summer were analysed using limits-of-agreement analysis. In addition, farms were categorised as having either acceptable welfare (lameness prevalence < 5% in both spring and summer) or not (lameness prevalence ≥ 5% in either spring or summer or both). The accuracy and specificity of a single, whole-herd lameness score at identifying herds with acceptable welfare were then calculated.

Results: The limits-of-agreement analysis suggests that 95% of the time, the prevalence of lameness in summer would be expected to be between 0.23 and 4.3 times that of the prevalence in spring. The specificity and accuracy of identifying a farm as acceptable on both occasions from a single observation were, respectively, 74% and 92% in spring, and 59% and 87% in summer.

Conclusions: A single, one-off, whole-herd lameness score does not accurately predict future lameness prevalence. Similarly, acceptable status (lameness prevalence < 5%) in one season is not sufficiently specific to be used to predict welfare status in subsequent seasons.

Clinical relevance: Whole-herd lameness scoring should be used principally as a means of detecting lame cows for treatment. A single whole-herd lameness score by an independent assessor should not be used to determine a herd's welfare status.

Aims: To determine whether evidence for infection with Theileria orientalis (Ikeda) could be identified in samples of commercial red deer (Cervus elaphus), horses, and working farm dogs in New Zealand.

Methods: Blood samples were collected during October and November 2019 from a convenience sample of red deer (n = 57) at slaughter. Equine blood samples (n = 50) were convenience-sampled from those submitted to a veterinary pathology laboratory for routine testing in January 2020. Blood samples, collected for a previous study from a convenience sample of Huntaway dogs (n = 115) from rural regions throughout the North and South Islands of New Zealand between August 2018 and December 2020, were also tested. DNA was extracted and quantitative PCR was used to detect the T. orientalis Ikeda major piroplasm surface protein (MPSP) gene. A standard curve of five serial 10-fold dilutions of a plasmid carrying a fragment of the T. orientalis MPSP gene was used to quantify the number of T. orientalis organisms in the samples. MPSP amplicons obtained by end-point PCR on positive samples were isolated and subjected to DNA sequencing. The resulting sequences were compared to previously published T. orientalis sequences.

Results: There were 6/57 (10%) samples positive for T. orientalis Ikeda from the deer and no samples positive for T. orientalis Ikeda from the working dogs or horses. The mean infection intensity for the six PCR-positive deer was 5.1 (min 2.2, max 12.4) T. orientalis Ikeda organisms/µL.

Conclusions and clinical relevance: Red deer can potentially sustain low infection intensities of T. orientalis Ikeda and could act as reservoirs of infected ticks. Further studies are needed to determine whether naïve ticks feeding on infected red deer can themselves become infected.

Case history: Over a period of 2 months in the spring and early summer of 2021, 13 cases of sudden death in cull ewes due to aortic rupture were diagnosed at a small number of New Zealand abattoirs.

Clinical findings: In 12/13 (92%) cases, a large blood clot was present in the thorax, and in one case the blood clot was seen in the tissues dorsal to the heart. There were no obvious signs of external trauma. The pluck (heart and lungs) or fixed aorta was submitted for histological examination in seven cases and in all of these, a tear in the aorta was found. Comparing the microscopic appearance of the proximal aorta in these seven cases to three clinically normal ewes from unaffected farms, the aortic wall thickness appeared thinner in the case ewes than the unaffected ewes. Subjectively, there was increased collagen in the tunica media in 3/7 and decreased elastin fibres in 5/7 case ewes compared to the control ewes. Further investigations on the index farm (where the first cases originated), found that the mean liver and serum Cu concentrations in 10 similarly aged, clinically normal ewes were within the normal reference range for New Zealand sheep. Similarly, the liver Cu concentrations of the seven case ewes were within the normal reference range.

Diagnosis: Aortic rupture due to an unknown aetiology.

Clinical relevance: Clinicians should be aware of this condition as a differential diagnosis for sudden death in older sheep and to assist the Ministry for Primary Industries in establishing the extent of this problem in New Zealand.

Case histories: The medical records of cats and dogs admitted to the Department of Small Animal Surgery of the Centre Hospitalier Vétérinaire Pommery (Reims, France) with a history of vehicular trauma or falls from the first floor or higher were screened for occurrences of a lower urinary tract (LUT) rupture. Signalment, reported injuries, diagnostic imaging findings, and blood test results were extracted from the medical records.

Clinical findings: A total of 585 animals were included in the study: 339 cats and 246 dogs. The overall prevalence of LUT rupture was 1.36% (8/585) and was 1.2% (3/246) in dogs and 1.4% (5/339) in cats. The most common site of rupture was the bladder (5/8 cases). All orthopaedic injuries were pelvic fractures and animals with pelvic fractures were 6.4 (95% CI: 1.67-24.41; p = 0.012) times more likely to incur urinary tract rupture than those without pelvic fractures. However, three cases had LUT rupture without associated orthopaedic injury. All affected patients had free abdominal fluid identified by abdominal focused assessment with sonography for trauma. Serum urea and creatinine concentrations were elevated in 5/8 cases of LUT rupture, and 4/8 cases were able to urinate.

Clinical relevance: Although LUT injury and pelvic fracture were significantly associated in this study, 3/8 cases of LUT rupture in this study had no orthopaedic injury and half retained the ability to urinate. Thus, lack of associated fractures and ability to urinate should not be used to rule out a LUT rupture. The possibility of bladder or urethral rupture should be considered in all patients with a history of severe blunt trauma.

Aims: To describe the personal drivers, sources of information and gastro-intestinal parasite control methods used by a group of New Zealand sheep farmers identified as low users of anthelmintic (AHC), and their perception of the efficacy and impacts of this approach.

Methods: A convenience sample of 13 sheep farmers farming with a policy of reduced AHC use (no pre-determined routine treatments of ewes >19 months old and/or lambs not routinely treated at pre-determined intervals from weaning through to late autumn) were identified. Semi-structured interviews were conducted regarding their farming philosophy, motivations for reducing AHC use, perceptions of the impacts of farming with reduced AHC use, and parasite control practices. Semi-quantitative data were analysed using descriptive statistics for demographic data and categorising participants' use of AHC and non-chemical control methods. Qualitative data regarding participants' motivations, approaches and rationale were analysed by systematic analysis of the transcripts and distillation of key concepts.

Results: Participants had been operating with reduced AHC use for 3 to  ≥20 years. Key motivators for reducing AHC use were a diagnosis of anthelmintic resistance (AR) or concerns about AR developing. Parasite management information came from a wide range of sources. All respondents expressed overall positive views regarding the impacts of reduced AHC use but detailed information was not available.All identified that regular monitoring, based primarily on subjective animal and non-animal factors was important for their parasite control strategy. Most used faecal egg counts (FEC), often in an ad hoc manner. Five never treated adult ewes, two routinely treated ewes prior to lambing with short-acting AHC and the remainder occasionally treated a small number in low body condition. Four routinely treated some or all lambs at 28-30-day intervals from weaning to late autumn while the remainder based their treatment decisions for lambs on monitored information. All placed heavy emphasis on feeding sheep well, ensuring high post-grazing residuals, and cross-grazing.

Conclusions: AR was a key motivator for participants to reduce AHC use, and a range of information sources and decision-making processes were used. Key parasite management practices were monitoring, primarily using subjective assessments, emphasis on feeding stock well and cross-grazing.

Clinical relevance: The rising prevalence of AR will likely result in increasing the motivation for sheep farmers to reduce their AHC use. Veterinarians will play a key role in providing advice and assistance to facilitate changes in parasite management.

Aims: To evaluate the effects of early and late pre-partum shearing of Corriedale ewes carrying single fetuses on placental and lamb development and neonatal lamb behaviour.

Methods: At 70 days of gestation, 37 multiparous Corriedale ewes with known gestation dates were randomly allocated into three groups: S70 (n = 12) and S110 (n = 12), shorn at Day 70 and 110 of gestation, and US (n = 13), that were not shorn pre-partum. Gestation length, lambing duration, placental expulsion time, placental weight, number and weight of cotyledons, and placental efficiency (lamb weight/placental weight) were determined. At birth, body temperature, weight, morphometric measurements, ponderal index (lamb weight/lamb crown-rump length) and behaviour were recorded, with weight remeasured 72 hours later. Four male lambs per group were slaughtered immediately after parturition, and organ weight and perirenal brown fat weight and energy content recorded.

Results: Pre-partum shearing, regardless of timing, increased total dried placental weight per ewe. Pre-partum shearing at Day 70 of gestation increased the number and mean weight of the > 2 to ≤ 3-cm cotyledons, while pre-partum shearing at Day 110 of gestation increased only the weight of these cotyledons. At birth and at 72 hours, lambs from ewes shorn either at 70 days of gestation (birth: 5.5 (95% CI = 4.6-6.4) kg, p = 0.001; 72 hours: 6.4 (95% CI = 6.1-6.8) kg, p = 0.002) or at 110 days of gestation (birth: 5.4 (95% CI = 4.4-6.4) kg, p = 0.001; 72 hours: 6.5 (95% CI = 5.9-7.1) kg, p = 0.001) were heavier than lambs from unshorn ewes (birth: 4.0 (95% CI = 3.3-4.8) kg; 72 hours: 4.8 (95% CI = 3.5-6.1) kg). Lambs born to S70 and S110 ewes suckled sooner (31.5 (95% CI = 14.5-48.5) minutes, p = 0.001; and 39.3 (95% CI = 23.7-55.0) minutes, p = 0.001 respectively), than lambs born to the US group (70.3 (95% CI = 38.6-102.1) minutes). There was no evidence for an effect of pre-partum shearing on gestation length, parturition length, time of placental expulsion, placental efficiency, weight and energy of perirenal brown fat, and lamb temperature at birth.

Conclusions and clinical relevance: Shearing ewes pre-partum may lead to placental changes affecting lamb development and behaviour and associated with higher survival. The findings suggest pre-partum shearing may improve lamb survival, farm profitability and sustainability.

Aims: To describe progress in the reduction of the consumption of antimicrobial drugs by food-producing animals in New Zealand to 2022 and to identify the animal production sectors where progress has been greatest, and those where opportunities remain.

Methods: Data were sourced from official government and industry reports to update previous estimates of consumption (as sales) of antimicrobial products applied to food-producing animals in New Zealand, European countries and the USA. Antimicrobial consumption (AMC) was estimated based on the amount of active ingredient sold, per kg of animal biomass standardised to the probable weight at time of treatment or lifetime mean weight but not slaughter weight (population correction unit; PCU). This methodology is widely used for international comparisons.

Results: The estimated gross consumption of antimicrobials in food-producing animals in New Zealand increased steadily from 2005 to 2013 (from 7.54 to 11.28 mg/PCU). From 2014 to 2018 the estimate flattened to a 5-year rolling mean of 10.40 mg/PCU. In 2019-2021 the consumption dropped. The NZ consumption in 2022 was substantially lower, estimated at 5.84 mg/PCU, 29% less than in 2005 and 45% less than the peak that occurred in 2017.

Conclusions: The use of antimicrobials in food-producing animals in New Zealand is at the lowest rate for nearly 20 years, at 5.8 mg/PCU. Key progress has been made particularly by the poultry industry. Clear future areas to be targeted include prophylactic use of intramammary products applied when drying off dairy cows and a more widespread strategic use in treatment of clinical mastitis.

Clinical relevance: Veterinarians in New Zealand should leverage the significant reduction achieved in AMC by food-producing animals by continuing to improve strategies for antimicrobial use to further reduce the risk of antimicrobial resistance.

Aims: To use a narrative inquiry approach to explore animal owner experiences and feelings during engagement with veterinary services with the goal of understanding what a "good experience" looks and feels like from a client perspective.

Methods: Semi-structured interviews were conducted with 30 animal owners, primarily companion animal owners of New Zealand European ethnicity, via video call or telephone. Interviews were transcribed and analysed using inductive thematic analysis.

Results: The participants narrated both positive and negative experiences with veterinary professionals, the impacts of those experiences and subsequent actions by the client. Four main themes emerged. The first identified features of the practice, beyond the standard provision of veterinary services, that had attracted participants, e.g. specific services offered. The next theme concerned the overall experience for the participants, where clients felt welcomed and cared for at all stages of the interaction. The third theme focused on building and maintaining quality relationships. We found that the principles of relationship-centred care apply and that when these factors were absent, conflict appeared more likely. The fourth theme considered factors that impacted the client-veterinary professional relationship. Our findings suggest that clients were more forgiving of poor outcomes if there was a good match and a strong existing relationship between the veterinary clinic and the client, and if the poor outcome was managed well by the veterinary practice. Managing poor outcomes well was strongly aligned with having honesty and integrity.

Conclusions: The narratives provided insights into client experiences and what is important to them when seeking animal healthcare in terms of the features that a specific veterinary practice offered them and the connections with the personnel at the veterinary practice. Relationship-centred care was key but required a good client fit to the practice to begin with.

Clinical relevance: The themes outlined in this article offer a framework for veterinary practices to assess their current performance against client priorities. By identifying areas for improvement, practices can develop plans to enhance both client satisfaction, and staff and overall practice well-being.

Case history: In early summer, a wild fledgling kererū (Hemiphaga novaeseelandiae) was admitted to a wildlife hospital in Dunedin after falling from its nest and being found on the ground.Clinical findings: The bird was underweight, weighing only 391 g (expected weight > 450 g), and determined to be in poor body condition based on palpation of pectoral muscle mass. There was bilateral periorbital swelling and ocular discharge with caseous material blocking the choana. Samples of the ocular and choanal discharge were collected and submitted for molecular testing. General anaesthesia was required for further radiographic assessment, and the bird was stabilised for 48 hours with oral electrolytes and antimicrobial and analgesic therapy with doxycycline, meloxicam, and tramadol administered orally twice daily via crop tube and voriconazole administered once daily. Chloramphenicol was applied topically to the eyes twice daily. Subsequently, due to the severity of the gross and radiographic lesions, the likelihood of the need for an extended period of treatment, the age of the chick, its weakened and underweight condition and the risk of imprinting, the bird was euthanased while under general anaesthesia.Laboratory and pathological findings: PCR testing ruled out Chlamydia psittaci as a cause of morbidity and instead identified Mycoplasma columborale. On gross post-mortem examination, there was caseous material in the periorbital tissues, sinuses and choana. Samples of the choanal discharge grew a moderate mixed growth of Escherichia coli and Enterococcus faecalis.Diagnosis: Severe pyogranulomatous sinusitis associated with infection with M. columborale.Clinical relevance: This report describes the first isolation of M. columborale in any species in New Zealand and the first diagnosis of mycoplasmosis in a native kererū. The significance of this finding has not yet been determined.