Distribution of prion protein genotypes in breeds of sheep in New Zealand

AIM: To use an established high through-put genotyping procedure to gain an estimate of the frequency of alleles of the prion protein (PrP) gene in some common sheep breeds in New Zealand. METHODS: Using a genotyping procedure based on matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF), DNA samples from 3,024 sheep from New Zealand, including breeds such as Romney, Texel, Coopworth, Merino and mixed breed, were isolated, genotyped and the results analysed. RESULTS: The 15 scrapie genotypes commonly reported, and derived from the five commonly reported allelic variants (ARR, ARQ, AHQ, ARH and VRQ), were all observed in the samples analysed. The estimates were indicative of the frequencies in the population of alleles present in breeds of sheep in New Zealand. There was a significant difference between the frequencies of alleles between breeds, but the ARQ, followed by the ARR allele, were, except in Carwell sheep, the most common alleles present. CONCLUSION: This study gave an indication of the percentages of PrP gene alleles in sheep in New Zealand, including data previously unreported from breeds in this country. It is of interest because of the relatively large size of the sheep population in New Zealand compared with many countries, and it provides some useful information on the genetic susceptibility or resistance of the sheep population in New Zealand to scrapie. The frequencies of the alleles can be different for an individual breed compared between countries.     

Distribution of prion protein genotypes in breeds of sheep in New Zealand

AIM: To use an established high through-put genotyping procedure to gain an estimate of the frequency of alleles of the prion protein (PrP) gene in some common sheep breeds in New Zealand.

METHODS: Using a genotyping procedure based on matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF), DNA samples from 3,024 sheep from New Zealand, including breeds such as Romney, Texel, Coopworth, Merino and mixedbreed, were isolated, genotyped and the results analysed.

RESULTS: The 15 scrapie genotypes commonly reported, and derived from the five commonly reported allelic variants (ARR, ARQ, AHQ, ARH and VRQ), were all observed in the samples analysed. The estimates were indicative of the frequencies in the population of alleles present in breeds of sheep in New Zealand. There was a significant difference between the frequencies of alleles between breeds, but the ARQ, followed by the ARR allele, were, except in Carwell sheep, the most common alleles present.

CONCLUSION: This study gave an indication of the percentages of PrP gene alleles in sheep in New Zealand, including data previously unreported from breeds in this country. It is of interest because of the relatively large size of the sheep population in New Zealand compared with many countries, and it provides some useful information on the genetic susceptibility or resistance of the sheep population in New Zealand to scrapie. The frequencies of the alleles can be different for an individual breed compared between countries.     

特克赛尔肉羊与小尾寒羊的杂交试验

通过特克塞尔公羊与小尾寒羊母羊杂交,产羔率达到213.04%,和对照组小尾寒羊的产羔率230.43%差异不显著;在哺乳期内,特寒F1羔羊的的生长发育指标优于小尾寒羊,胸宽、胸深和尻宽比小尾寒羊高19.95%、11.54%、19.29%（p〈0.01）,4～6月龄育肥期内,特寒F1的净增重为11.77kg,比小尾寒羊的8.51kg提高了38.3%（p〈0.01）,杂交优势明显。特寒FI的胴体重为21.65kg,屠宰率达到51.08%,比小尾寒羊提高5.57个百分点,产肉性能明显优于小尾寒羊,增收111.84元。特寒F1的GR值13.11mm,按新西兰羊肉分级标准,属于中等水平。     

Effects of a quantitative trait locus for muscle hypertrophy from Belgian Texel sheep on carcass conformation and muscularity

A QTL for muscle hypertrophy has been identified in the Belgian Texel breed. A population of F2 and backcross lambs created from crosses of Belgian Texel rams with Romanov ewes was studied. Effects on carcass traits and muscle development of the Belgian Texel breed polygenes and Belgian Texel single QTL were compared. In both cases, carcass conformation and muscularity were improved. The Texel polygenic environment improved conformation mainly through changes in skeletal frame shape. Segments were shorter and bone weight lower. Muscles were more compact, shorter, and thicker. The single QTL affected muscle development. Thickness and weight of muscles were increased. Composition in myosin changed toward an increase of fast contractile type. The relative contribution of hind limb joint to carcass weight was increased. Differences in skeletal frame morphology among the three genotypes of the single QTL were small. Conformation scoring was mainly influenced by leg muscularity. Back and shoulder muscle development, which largely contributed to variability of muscularity, were less involved in the conformation scoring. Lastly, the QTL explains a small part of differences between these Belgian Texel and Romanov breeds for conformation or muscle development. A large part of genetic variability remains to be explored.     

Reproductive performance of ewes mated to rams heterozygous for the Massey I (t1) centric fusion (Robertsonian) translocation

One hundred Scottish Blackface ewes were mated to New Zealand Romney rams heterozygous for the Massey I (t1) centric fusion (Robertsonian) translocation. The lambing percentage of ewes lambed was 131 and the segregation of normal to balanced heterozygous lambs was 1:1. No chromosomally unbalanced lambs were born. Nine heterozygous females were mated to a heterozygous male and produced two homozygous, three heterozygous and seven normal lambs. The homozygous male had hypoplastic testes. The results indicate that there is no significant reduced fertility with 53XYt1 rams but that fertility of 52XYt1t1 rams should be further investigated.     

Seroprevalence of Toxoplasma gondii in mainland and sub-Antarctic New Zealand sea lion (Phocarctos hookeri) populations

AIMS: To investigate the seroprevalence of antibodies to Toxoplasma gondii in New Zealand sea lions (Phocarctos hookeri), as a potential contributor to reproductive failure.

METHODS: Archived sera were sourced from New Zealand sea lions from two recolonising mainland populations in the Otago Peninsula (n=15) and Stewart Island (n=12), as well as a declining population at Enderby Island (n=28) in the New Zealand sub-Antarctic. Sera were tested for antibodies to T. gondii using a commercially available ELISA (with samples considered positive if the sample to positive ratio was?>30%), and latex agglutination test (LAT; with titres ≥1:32 considered positive). Western blot analysis was used to validate the results of a subset of 14 samples.

RESULTS: Five samples from sea lions in mainland locations were confirmed positive for antibodies to T. gondii. Two adult females exhibited high LAT antibody titres (min 1:2048, max 1:4096) on both occasions when sampled 1 and 2 years apart, respectively. No animals from Enderby Island were seropositive.

CONCLUSIONS: Toxoplasma gondii infection is unlikely to be a major contributor to poor reproductive success in New Zealand sea lions. However, continued surveillance is pertinent to assess subclinical and clinical impacts of the parasite on these threatened populations. The commercial tests evaluated here, with further species-specific threshold refinement could provide a fast, inexpensive and reliable indicator of T. gondii exposure in New Zealand sea lions.     

A portable, contact animal fundus imaging system based on Rol's GRIN lenses

Objective To demonstrate a cost‐effective, portable, and simple‐to‐use fundus imaging system for laboratory animals. Animals Studied Albino rats, pigmented mice, albino guinea pigs, and New Zealand white rabbits. Procedure A contact fundus imaging system was designed and constructed using standard optical and mechanical components: a digital camera, an otoscope, a fiber optic light source, and standard optical lenses and mounts. Digital fundus video and photography of two albino rats, two pigmented mice, two New Zealand white rabbits, and two albino guinea pigs were obtained. For all animals examined, pupils were dilated and local anesthetic was administered. Results Digital images of the fundus were obtained in all animals. Contrast of retinal vasculature and overall image quality varied from one species to another, as the axial length, ocular optics, and retinal reflectance varied significantly across species. Light intensity and focus were optimized via the light source and lens focusing mount to produce high‐quality images for each animal. Conclusions The portable, cost‐effective contact fundus imaging system was easy to use for fundus examination of laboratory animals.     

Meat quality traits were unaffected by a quantitative trait locus affecting leg composition traits in Texel sheep

A QTL affecting leg muscle and fat traits has been identified within the New Zealand Texel population. The QTL maps to a region on OAR 2 with a two-marker haplotype test established at markers BULGE20 and BM81124. These markers encompass the likely position of Growth Differentiation Factor 8 (GDF8). The pleiotropic effects of this QTL on meat quality traits are tested. Objective measures of meat quality including pH, color (L*, a*, and b*), and tenderness (as assessed by Warner-Bratzler shear force measurements) were assessed on longissimus and semi-membranosus muscles of 540 progeny from six Texel sires. Four of these sires were subsequently identified as segregating for leg muscle and fat traits. For these segregating sires, comparison of progeny that had inherited the favorable haplotype from their sire with those that had received the alternate haplotype revealed no significant differences in the meat quality traits assessed. This finding suggests that the muscling QTL does not have pleiotropic effects on meat quality. A general scan for meat quality QTL was carried out using genotype data for eight markers from FCB128 to RM356 flanking 122cM of OAR 2 using Haley-Knott regression. This analysis revealed two QTL for a single sire. A QTL detected in the region of Marker INRA40 for color L* mapped to a site close to the muscling QTL, but there was evidence to suggest it is at a distinct locus. The QTL in the region of Marker RM356 might map distal to Marker RM356, as no peak was observed. This QTL, which seems to affect pH, color a*, color b*, and Warner-Bratzler shear measurements, requires further characterization.     

Serratospiculosis in a New Zealand Falcon (Falco novaeseelandiae)

CASE HISTORY: An adult New Zealand falcon was presented with metacarpal fractures in the left wing. CLINICAL FINDINGS: In addition to the fractures, radiographs revealed an area of opacity in the air sacs. A few days after hospitalisation and initiation of treatment of the fractures, the bird developed signs of respiratory disease; the area of opacity was found to have increased in size and density. Treatment with antibiotics and nebulisation was commenced; the bird initially responded but respiratory signs subsequently worsened and the bird died. At necropsy, air sacculitis and bronchopneumonia were associated with numerous nematodes in the air sacs, which were morphologically consistent with Serratospiculum guttatum. DIAGNOSIS: Serratospiculosis CLINICAL RELEVANCE: The discovery of this parasite and the associated disease for the first time in New Zealand indicates that it should be considered in the differential diagnosis of respiratory disease in falcons and possibly other raptors in New Zealand.     

Bilateral optic nerve hypoplasia in a pup.

A 6-week-old Beagle failed to respond to visual stimulation. Examination revealed fixed dilated pupils and hypoplasia of both optic disks. Results of electroretinography were normal. Radiography of the skull revealed small optic nerve foramina. Histologically, the outer layers of the retinas were normal, the retinal ganglion cells were scarce, and the nerve fiber layers, optic nerves, and optic chiasm were hypoplastic.     

Does control of bovine viral diarrhoea infection make economic sense?

AIM: To provide an economic analysis of the costs of control or eradication of bovine viral diarrhoea (BVD) against the estimated costs of the disease. METHODS: A decision-tree approach was adapted to an analysis of the costs of bovine viral diarrhoea virus (BVDV) infection and that of three main control options (vaccination, test-and-cull, and increased biosecurity) and their combinations, to the dairy industry in New Zealand. The model was based on an average herd of 322 milking cows. Endemic, epidemic and sporadic effects of BVDV infection were modelled in the herd, to derive an estimate of costs. RESULTS: The cost of BVDV infection to an infected average-sized dairy herd in New Zealand was estimated to be NZ $11,334 (or NZ $35.19 per cow) per annum, and NZ $48,311 over 10 years. Based on these calculations, the estimate of the annual cost of BVDV infection to the dairy industry in New Zealand was in excess of NZ $23 million per annum. While all of the control options required financial input, the rate of return compared with the cost of BVD, when viewed over a 10-year term, was as high as 123%. CONCLUSIONS: All control options offered considerable savings compared with the cost of BVD infection, and control is economically favourable. Uncertainty over the likely efficacy of the control options under field conditions in New Zealand would not allow a firm choice of one option over another at this stage, and more work on determining the efficacy of those control options in New Zealand is needed.     

New Zealand's cetaceans and pinnipeds

The 8 species of baleen whale in New Zealand waters range in length from 6 to 30+ metres, and the 25 species of toothed whale range up to 18 metres. A single porpoise species is known in New Zealand sub-Antarctic waters. The baleen whales and many of the toothed whales are migratory, and New Zealand straddles their well-defined routes: a combination which allowed whaling to flourish. The toothed whales are the more gregarious and may indulge in mass strandings. Current research aims to investigate the biology of all of the whale species. The otariid, or eared seals found in the New Zealand region are the New Zealand sealion and the New Zealand fur seal. The commonest of the phocid, or earless seals on the New Zealand coast are the elephant and leopard seals. All of these breed in the southern parts of the region but range further north. The fur seal population is rising slowly, but the small population size of the New Zealand sealion gives cause for concern. Marine mammals form an important part of the fauna of the New Zealand region, and veterinary knowledge and general research should be increased.     

Comparison of the histology and immunohistochemistry of vaccination-site and non-vaccination-site sarcomas from cats in New Zealand

AIMS: To compare the histology and immunohistochemistry of vaccination-site sarcomas (VSSs) with non-vaccination-site sarcomas (NVSSs) in cats in New Zealand. To determine whether VSSs in cats in New Zealand have similar histological and immunohistochemical features to those previously described in feline vaccine-associated sarcomas (VASs) in North American studies. METHODS: A retrospective survey of skin biopsies submitted between 2004 and 2006 was performed to identify cutaneous sarcomas from both vaccination and non-vaccination sites in cats. Vaccination sites included the interscapular, shoulder, or dorsal or lateral cervical and thoracic regions. All sarcomas were examined histologically, and smooth muscle actin and desmin were assessed immunohistochemically. Features previously described in VASs were assessed and compared. RESULTS: Sarcomas from 34 cats were identified, 10 of which occurred at vaccination sites. Compared with NVSSs, VSSs were more likely to be located in the hypodermis and have greater cellular pleomorphism, higher mitotic rates, more frequent peripheral lymphocytic aggregates and multinucleated giant cells. VSSs were also more likely than NVSSs to show partial myofibroblastic differentiation, demonstrable using immunohistochemistry. The histological and immunohistochemical features of VSSs in cats in New Zealand are consistent with those previously described in VASs in cats in North America. CONCLUSIONS: The results of this study suggest that VASs occur in cats in New Zealand. CLINICAL RELEVANCE: The occurrence of VASs in cats in New Zealand would provide further support for restriction of the vaccination of cats to the minimum necessary to protect health, and adoption of the New Zealand Veterinary Association guidelines on vaccination.     

Serratospiculosis in a New Zealand Falcon (Falco novaeseelandiae)

CASE HISTORY: An adult New Zealand falcon was presented with metacarpal fractures in the left wing.

CLINICAL FINDINGS: In addition to the fractures, radiographs revealed an area of opacity in the air sacs. A few days after hospitalisation and initiation of treatment of the fractures, the bird developed signs of respiratory disease; the area of opacity was found to have increased in size and density. Treatment with antibiotics and nebulisation was commenced; the bird initially responded but respiratory signs subsequently worsened and the bird died. At necropsy, air sacculitis and bronchopneumonia were associated with numerous nematodes in the air sacs, which were morphologically consistent with Serratospiculum guttatum.

DIAGNOSIS: Serratospiculosis

CLINICAL RELEVANCE: The discovery of this parasite and the associated disease for the first time in New Zealand indicates that it should be considered in the differential diagnosis of respiratory disease in falcons and possibly other raptors in New Zealand.     

The seroprevalence of canine respiratory coronavirus and canine influenza virus in dogs in New Zealand

Abstract

AIM: To determine whether canine respiratory coronavirus (CRCoV) and canine influenza virus (CIV) are present in dogs in New Zealand.

METHODS: Serum samples from 251 dogs of varying age, breed and clinical histories were tested for the presence of antibodies to CRCoV and CIV, using indirect fluorescent antibody (IFA) analysis. The population sampled represented a wide geographic area but principally encompassed the central and lower North Island of New Zealand.

RESULTS: Seventy-three of the 251 samples (29%) were seropositive for CRCoV. Dogs <2 years old were less likely to be seropositive for CRCoV than older dogs. None was seropositive for CIV.

CONCLUSIONS: This study revealed the presence of antibodies to CRCoV in dogs in New Zealand. Young dogs are less likely to be seropositive than older dogs, probably due to increased opportunity for exposure to CRCoV over time. Serum antibodies to CIV were not detected in any of the dogs sampled, suggesting that this virus is unlikely to be present in dogs in New Zealand.

CLINICAL RELEVENCE: Canine respiratory coronavirus is present in New Zealand. Although the role of this virus in canine infectious tracheobronchitis has not been fully elucidated, evidence suggests that it may have a causal role in this disease. Veterinarians should consider CRCoV as a differential diagnosis in cases of respiratory disease in dogs in New Zealand. While CIV appears not to be currently present in New Zealand, veterinarians should consider infection with this virus as a differential diagnosis in dogs presenting with respiratory signs.     

New Zealand’s Cetaceans and Pinnipeds

The 8 species of baleen whale in New Zealand waters range in length from 6 to 30+ metres, and the 25 species of toothed whale range up to 18 metres. A single porpoise species is known in New Zealand sub-Antarctic waters.

The baleen whales and many of the toothed whales are migratory, and New Zealand straddles their well-defined routes: a combination which allowed whaling to flourish. The toothed whales are the more gregarious and may indulge in mass strandings. Current research aims to investigate the biology of all of the whale species.

The otariid, or eared seals found in the New Zealand region are the New Zealand sealion and the New Zealand fur seal. The commonest of the phocid, or earless seals on the New Zealand coast are the elephant and leopard seals. All of these breed in the southern parts of the region but range further north. The fur seal population is rising slowly, but the small population size of the New Zealand sealion gives cause for concern.

Marine mammals form an important part of the fauna of the New Zealand region, and veterinary knowledge and general research should be increased.     

Dairy farming financial structures in Hokkaido, Japan and New Zealand

The productivity and financial performance of dairy farms in New Zealand and Japan (Hokkaido) were analyzed. By recomposing the official statistics on the dairy industry relative to Japan, New Zealand has low milk yield productivity per cow, but higher per hectare performance because of their seasonal breeding and pasture grazing systems. In the revenue and expenses analysis, New Zealand had a high cash surplus ratio compared with Hokkaido. In the cost analysis, for expenses on a “per kg of raw milk” basis, New Zealand milk production costs are 29% of those in Hokkaido. More than 60% of the production costs were attributable to feed, interest charges and wages in New Zealand. In Hokkaido, the feed cost alone accounted for 73% of the total cost. There is also a remarkably high interest expenditure in New Zealand caused by non‐subsidized fund procurement from finance organizations. In the financial analysis, New Zealand dairy farms have only approximately 50% of the total assets per cow compared with farms in Hokkaido. But total liabilities per cow in Hokkaido are twofold to threefold greater than in New Zealand. The difference between total assets and total liabilities shows that Hokkaido dairy farmers have an equity that is 50–200% greater than New Zealand dairy farmers. In the management analysis, New Zealand has a low turnover ratio of gross assets caused by the seasonal breeding system. In conclusion, New Zealand has higher per hectare production performance than Hokkaido, but has a low utilization of gross assets caused by a seasonal breeding system based on pasture grazing.     

Ocular anomalies and holoprosencephaly in a lamb

The brain and eyes from a 1-day-old, male mixed-breed lamb with bilateral microphthalmia were examined. Bilateral ventral colobomata of choroid, sclera, retina and optic nerve were accompanied by agenesis of the optic nerve, and dilated lateral and third ventricular cavities that communicated with the subarachnoid space. Abundant neuroretinal tissue extending through the colobomatous defect to retro-orbital connective tissue, the meningeal surface and ventricular system were identified by histologic examination. Positive immunolabeling of these structures for recoverin (a photoreceptor marker) established the retinal origin of ectopic structures. The optic nerve was replaced by a short fibrous stalk containing glial nests. Sections of brainstem revealed extensive architectural disorganization. A developmental abnormality resulting from defective optic nerve and retina compartmentalization, accompanied by abnormalities of midline development consistent with the holoprosencephaly syndrome, was diagnosed. These lesions are consistent with signaling defects in the sonic hedgehog signaling pathway. Genetic and toxic causes of sonic hedgehog signaling defects are discussed.     

Congenital cardiac defects in calves

In a 14-year study of calves with cardiac defects, 36 had 78 congenital cardiac defects: ectopia cordia cervicalis (n = 10 defects), common aortic trunk (n = 3 defects), dextraposed aorta (n = 8 defects), duplicated major trunks (n = 1 defect), hypoplastic aorta (n = 2 defects), interventricular septal defect (n = 11), interatrial septal defect (n = 2), left ventricular hypoplasia (n = 10), patent ductus arteriosus (n = 5), patent foramen ovale (n = 5), right ventricular hypoplasia (n = 10), cor triloculare biatriatum (n = 1), endocardial fibroelastosis with calcification (n = 3), and valvular hematomas (n = 7). All septal defects were high in location and ranged from 5 to 35 mm in diameter. One calf with a septal defect also had bilateral microphthalmia.