Bovine asymmetric hind limb paresis, a presumptive in-utero plant poisoning

Summary: A new locomotory disturbance of cattle is described. The condition has occurred sporadically since the mid-1980s. Affected herds had all grazed flood plain pastures in a restricted area of north-western New South Wales. Calves were either born with clinical signs or developed them by 4 months of age. The disease was characterised by a slowly progressive, irreversible, asymmetrical, paresis of the hind limbs. Affected cattle experienced persistent hyper-extension of the hip and stifle joints. Macroscopic and microscopic examination of the nervous and musculoskeletal systems failed to demonstrate abnormalities that would account for the clinical signs. The disorder shares many similarities with bovine spastic paresis. It is suggested that the pathogenesis of the disorder is nervous, and probably involves nigro-striatal, medulla oblongata, and spinal dysfunctional inputs. An in-utero plant poisoning was suspected but no specific plant association was determined.     

Development and trial of a bovine herpesvirus 1 - thymidine kinase deletion virus as a vaccine

SUMMARY An Australian bovine herpesvirus 1 (BHV1) isolate with a defined (427 base pair) deletion in the protein coding region of the thymidine kinase gene was obtained by standard marker rescue procedures. After selection in the presence of the nucleotide analogue 5iodo-deoxy-uridine the virus was analysed by hybridisation with three differential oligonucleotide probes, restriction endonuclease profile studies and DNA sequence analysis. The virus elicited an immune response in recipient animals after either intramuscular or intravenous administration and produced no significant deleterious side-effects when administered at a dose sufficient to stimulate the host immune response. The safety and immunogenicity of the recombinant BHV1 virus 39B1 were similar to those reported for other registered BHV1 vaccines and the virus would appear to be suitable for the production of a vaccine seed lot and more exhaustive field trials as a prelude to commercial vaccine production and registration.     

Practices and opinions of New Zealand beef cattle farmers towards bovine viral diarrhoea control in relation to real and perceived herd serological status

ABSTRACT

Aims: To investigate the seroprevalence of infection with bovine viral diarrhoea (BVD) virus among 75 beef herds and seroconversion in cattle during early pregnancy, and to determine the practices and opinions of farmers towards BVD control and their association with real and perceived herd serological status.

Methods: Blood samples were collected before mating in 75 beef herds across New Zealand from 15 unvaccinated heifers that had delivered their first calf that season. Serum samples were tested for BVD antibodies using ELISA individually, and after pooling samples for each farm. Animals that were antibody-negative were retested at either pregnancy diagnosis or weaning. Farmers were asked to complete a detailed survey about herd demographics, BVD testing and vaccination practices, and opinions towards national BVD control.

Results: Based on the pooled serum antibody ELISA results, there were 28/75 (37%) negative herds, 15/75 (20%) suspect herds, and 32/75 (43%) positive herds. Of 1,117 animals sampled 729 (65.3%) tested negative for BVD virus antibodies; when retested, 47/589 (8.0%) animals from 13/55 (24%) herds had seroconverted. Among 71 famers providing survey responses 11 (15%) believed their herd was infected with BVD, 24 (34%) were unsure and 36 (51%) did not think their herd was infected. Only 19/71 (18%) farmers had performed any BVD testing within the past 5 years and 50/70 (71%) had not vaccinated any cattle for BVD. Support for national BVD eradication programme was strong in 51/71 (56%) respondents, but the biggest challenge to BVD control was considered to be famer compliance. Compared to farmers who did not think their herd was infected, more farmers who thought BVD was present in their herds had previously tested for BVD, would consider testing all replacement calves, and would support establishing a national BVD database; fewer would consider purchasing BVD tested or vaccinated cattle only.

Conclusions and clinical relevance: Only 15% of the beef farmers in this study believed their herds were infected with BVD virus and few of them had undertaken BVD screening. Nevertheless many were supportive of implementing a national BVD control programme. It is likely that the lack of farmer awareness around BVD and the failure of farmers to recognise the potential impacts in their herds are hindering progress in controlling the disease in New Zealand. There are opportunities for New Zealand veterinarians to be more proactive in helping beef farmers explore BVD management options.     

Identification of equine herpesvirus 3 (equine coital exanthema virus), equine gammaherpesviruses 2 and 5, equine adenoviruses 1 and 2, equine arteritis virus and equine rhinitis A virus by polymerase chain reaction

OBJECTIVE: To develop rapid (< 8 hour) tests using polymerase chain reaction (PCR) for the diagnosis of equine herpesvirus 3 (EHV3; equine coital exanthema virus), equine gammaherpesviruses 2 (EHV2) and EHV5, equine adenovirus 1 (EAdV1), EAdV2, equine arteritis virus (EAV), equine rhinitis A virus (ERAV; formerly equine rhinovirus 1) DESIGN: Either single round or second round (seminested) PCRs were developed and validated. METHODS: Oligonucleotide primers were designed that were specific for each virus, PCR conditions were defined and the specificity and sensitivity of the assays were determined. The application of the tests was validated using a number of independent virus isolates for most of the viruses studied. The PCRs were applied directly to clinical samples where samples were available. RESULTS: We developed a single round PCR for the diagnosis of EHV3, a seminested PCR for EHV2 and single round PCRs for EHV5, EAdV1, EAdV2 and RT-PCRs for EAV and ERAV. The PCR primer sets for each virus were designed and shown to be highly specific (did not amplify any recognised non-target template) and sensitive (detection of minimal amounts of virus) and, where multiple virus isolates were available all isolates were detected. CONCLUSION: The development and validation of a comprehensive panel of PCR diagnostic tests, predominantly for viruses causing equine respiratory disease, that can be completed within 8 hours from receipt of clinical samples, provides a major advance in the rapid diagnosis or exclusion diagnosis of these endemic equine virus diseases in Australia.     

提高辣椒离体再生不定芽伸长率的研究

通过调整培养基中的几种生长调节剂种类及其浓度组合，以及不同添加物，诱导不定芽分化与植株再生，有效地提高了不定芽的伸长率．结果表明：选用辣椒9～11d苗龄的带柄子叶在培养基MB＋BA5．0mg／L＋IAA1．0mg／L十GA31．0mg／L＋蔗糖3％＋琼脂6．5g／L十椰乳5％＋AgN035．0mg／L上培养，分化频率达97．8％；芽丛在MB＋ZT1．0mg／L＋IAA1．0mg／L＋GA31．5mg／L十椰乳5％＋AgN035．0mg／L培养基上伸长率达76．0％；幼苗在Ms＋IAA0．1mg／L＋NAA0．2mg／L培养基上能正常生根，生根率最高100％，并成长为健壮的再生植株。     

The absence of neuromas in beaks of adult hens after conservative trimming at hatch

Objective To determine the effects of the amount of beak removed and cauterisation time on neuroma formation in hens.
Design A pathology study with controls.
Animals Twenty domestic fowl were beak-trimmed. Three non-beak-trimmed domestic fowl were used as controls.
Procedure Beaks of two age groups with two levels of beak removal and either 2 s or 4 s cauterisation, were investigated macroscopically and microscopically for deformities.
Results Scattered trauma-associated neuromas were present in the beaks of pullets 10 weeks after moderate trimming at hatch. Neuromas were not present in beaks of adult hens that had been similarly trimmed. Sensory corpuscles were present 10 and 70 weeks after moderate trimming, though fewer in number than in intact control hens. In contrast, trauma-associated neuromas persisted in beaks of 70-week-old hens that had been severely trimmed at hatch. A range of deformities that were absent in moderately trimmed hens, were observed in hens with severely trimmed beaks. Receptors were not seen in severely trimmed beaks.
Conclusion Beak-trimming at hatch induces the formation of neuromas, regardless of the amount of tissue removed. There is a critical amount of beak tissue that can be removed, beyond which trauma-associated neuromas will not resolve, but will persist in mature hens.     

低O 2和高CO 2对草莓采后酯类生物合成的作用模式

草莓(Fragria ananassa Duck.cv.Chandler)果实于采收当天分别放在:①空气;②0.25%O_2;③21%O_2+50%CO_2;④0.25%O_2+50%CO_2(用 N_2平衡)四种流动气体条件(5℃)下1～7d,以研究气调贮藏对草莓的挥发性物质和发酵性酶活性的影响。在三种气调贮藏条件下,果肉中乙醛、乙醇、乙酸乙酯、丁酸乙酯的浓度较空气处理明显增加而乙酸异丙酯和乙酸丁酯的含量下降。气调贮藏处理增加了丙酮酸脱羧酶(PDC)和乙醇脱氢酶(ADH)的活性但略微减少了醇酰基转移酶(即酯化酶,AAT)的活性。低 O_2、高 CO_2条件下草莓中乙醇的大量累积加速了乙酸乙酯的生物合成。由于 AAT 活性的降低及过量的乙醇与其他醇类化合物对相同羧基化合物的竞争作用导致其他乙酸酯类产物的减少。