New Zealand veterinary journal最新文献

Case history: Necropsies on Toggenburg goats culled from a small farm in the Manawatū district of New Zealand, performed at Massey University (Palmerston North, NZ) over a period of 29 years (1991-2019), revealed soft tissue mineralisation, particularly of cardiovascular tissues. The farm spans 10 acres and runs between 15 and 30 Toggenburg goats. The goats are predominantly on pasture comprising a variety of types.

Pathological findings: Necropsies were performed on all adult goats (n = 45) that died or were euthanised. Histopathology was performed on 42 goats (93%), of which 33 (73%) included sufficient tissues diagnostically relevant to soft tissue mineralisation. The most significant gross findings were in various arteries, with the aorta most commonly affected, followed by the heart and lungs. The aortic intima showed prominent, multifocal to coalescing, raised, wrinkled, white plaques. Microscopically there were multiphasic lesions of mineralisation, chondroid, and osseous metaplasia in the elastic arteries, aorta, heart and lungs. A lumbar vertebra from one goat had prominent, basophilic, fibrillar, tangled matrix lining Haversian canals and lamellae.

Laboratory findings: Blood samples were collected from 15 adult goats in the affected herd and from 10 adult Toggenburg goats from an unaffected herd. Samples were collected by jugular venipuncture at 2-month intervals for 12 months (April 2018-March 2019). Concentrations of calcium, phosphorus, 25-hydroxyvitamin D₂ and D₃ (25OHD₂, 25OHD₃) in serum were analysed. The concentration of total 25OHD in serum was 34.2 (95% CI = 18.9-49.4) nmol/L (p < 0.001) higher in goats from the affected herd than in goats from the unaffected herd. Serum 25OHD₂ concentration was 46.2 (95% CI = 39.2-53.2) nmol/L higher (p < 0.001) in goats from the affected herd compared to the unaffected herd. Serum Ca concentrations in affected goats were 0.101 (95% CI = 0.005-0.196) mmol/L higher (p = 0.039) than unaffected goats, but remained within the reference range. There was no evidence of a difference in serum 25OHD₃ and P concentration between the herds.

Vegetation survey: All paddocks on the property were surveyed every 2 months along evenly spaced line transects, and then further traversed perpendicularly to form a grid. No known calcinogenic species were identified. Known plant sources of vitamin D identified on the farm included mushrooms (species not defined), Dactylis glomerata, lichen, pine pollen, and algae.

Diagnosis: Soft tissue mineralisation and enzootic calcinosis.

Clinical relevance: Veterinarians are alerted to the possibility of either enzootic calcinosis in goats and the potential occurrence of calcinogenic plants in New Zealand; or chronic vitamin D toxicosis of non-plant origin.

Aims: To examine the relationship in dairy cattle between serum and faecal Zn concentrations and daily intake of Zn supplemented with an oral drench; and whether total daily intake (TDI) of Zn in dairy cattle can be predicted from single measurements of Zn concentration in serum or faeces.

Methods: A convenience sample of 20 animals from three stock classes (lactating cows, dry cows, heifers), that had not received Zn supplementation in the previous 60 days, was enrolled in the study. From Days -7 to -1, animals received no Zn supplementation. On Day 0, 15 animals per class were assigned daily drenching with increasing doses of ZnSO₄.7H₂O while five remained controls. From Days 0-6, treatment animals received 12.5 mg/kg LWT of Zn/day; from Days 7-13, 25 mg/kg LWT Zn/day and from Days 14-20, 37.5 mg/kg LWT Zn/day. Animals co-grazed within each stock class. Pasture, serum and faecal samples were collected at the start and at weekly intervals before each increase in Zn supplementation. Mixed and non-parametric models were used to assess treatment effects and whether daily intake of Zn could be predicted from Zn concentrations in serum and faeces.

Results: Dosing with 0, 12.5, 25.0 and 37.5 mg Zn/kg LWT resulted in serum Zn concentrations of 12.1, 16.7, 27.2 and 35.8 µmol/L in heifers, 13.3, 17.1, 26.4 and 40.0 µmol/L in dry and 11.9, 12.1, 23.4 and 27.2 µmol/L in lactating cows. Dosing with the same amounts of Zn resulted in faecal Zn concentrations of 2.95, 21.72, 40.32 and 53.27 mmol/kg DM in heifers, 2.81, 23.77, 55.16 and 68.20 mmol/kg DM in dry and 3.00, 12.71, 34.86 and 57.53 mmol/kg DM in lactating cows, respectively. Treatment elevated serum and faecal Zn concentrations above controls (p < 0.001). Supplemented lactating cows had lower serum Zn concentrations than dry cows or heifers (p < 0.01). Supplemented dry cows had faecal DM Zn concentrations higher than heifers or lactating cows (p < 0.05). Analysis showed serum and faecal Zn concentrations could predict TDI of Zn (p < 0.001). Concentrations of Zn in faeces estimated TDI of Zn within a narrower predictive interval than serum Zn concentrations.

Conclusions and clinical relevance: Concentrations of Zn in serum and faeces were positively associated with TDI of Zn in dairy cattle and could predict TDI of Zn. When using serum and faecal Zn concentrations to estimate TDI Zn, stock class must be accounted for.

Aims: To apply molecular typing to DNA isolated from historical samples to determine Leptospira spp. infecting farmed and wild mammals in New Zealand.

Materials and methods: DNA samples used in this study were extracted from urine, serum or kidney samples (or Leptospira spp. cultures isolated from them) collected between 2007 and 2017 from a range of domestic and wildlife mammalian species as part of different research projects at Massey University. Samples were included in the study if they met one of three criteria: samples that tested positive with a lipL32 PCR for pathogenic Leptospira; samples that tested negative by lipL32 PCR but were recorded as positive to PCR for pathogenic Leptospira in the previous studies; or samples that were PCR-negative in all studies but were from animals with positive agglutination titres against serogroup Tarassovi. DNA samples were typed using PCR that targeted either the glmU or gyrB genetic loci. The resulting amplicons were sequenced and typed relative to reference sequences.

Results: We identified several associations between mammalian hosts and Leptospira strains/serovars that had not been previously reported in New Zealand. Leptospira borgpetersenii strain Pacifica was found in farmed red deer (Cervus elaphus) samples, L. borgpetersenii serovars Balcanica and Ballum were found in wild red deer samples, Leptospira interrogans serovar Copenhageni was found in stoats (Mustela erminea) and brushtail possums (Trichosurus vulpecula), and L. borgpetersenii was found in a ferret (Mustela putorius furo). Furthermore, we reconfirmed previously described associations including dairy cattle with L. interrogans serovars Copenhageni and Pomona and L. borgpetersenii serovars Ballum, Hardjo type bovis and strain Pacifica, sheep with L. interrogans serovar Pomona and L. borgpetersenii serovar Hardjo type bovis, brushtail possum with L. borgpetersenii serovar Balcanica, farmed deer with L. borgpetersenii serovar Hardjo type bovis and hedgehogs (Erinaceus europaeus) with L. borgpetersenii serovar Ballum.

Conclusions: This study provides an updated summary of host-Leptospira associations in New Zealand and highlights the importance of molecular typing. Furthermore, strain Pacifica, which was first identified as Tarassovi using serological methods in dairy cattle in 2016, has circulated in animal communities since at least 2007 but remained undetected as serology is unable to distinguish the different genotypes.

Clinical relevance: To date, leptospirosis in New Zealand has been diagnosed with serological typing, which is deficient in typing all strains in circulation. Molecular methods are necessary to accurately type strains of Lept