Báo cáo nghiên cứu khoa học " Diagnosis and control of diarrhoea in suckling pigs - MS 2 "

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Dự án này được thiết kế để cải thiện năng suất của người chăn nuôi lợn quy mô nhỏ ở Việt Nam thông qua quản lý sức khỏe được cải thiện, đặc biệt là lợn con trong thời gian trước khi cai sữa. Bổ sung cho kế hoạch quản lý y tế các dự án sẽ phát triển và thực hiện các xét nghiệm nhanh chẩn đoán thích hợp cho những nguyên nhân chủ yếu của preweaning tiêu chảy để cải thiện tốc độ và tính chính xác của chẩn đoán phòng thí nghiệm. Phần thứ ba của dự án...

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Nội dung Text: Báo cáo nghiên cứu khoa học " Diagnosis and control of diarrhoea in suckling pigs - MS 2 "

Ministry of Agriculture & Rural Development CARD Project Progress Report 001/04VIE: Diagnosis and control of diarrhoea in suckling pigs MS 2: FIRST SIX-MONTHLY REPORT
1. Institute Information Diagnosis and control of diarrhoea in suckling pigs Project Name National Institute of Veterinary Research (NIVR) Vietnamese Institution Dr. Truong Van Dung Vietnamese Project Team Leader The University of Queensland/Victorian Department of Australian Organisation Primary Industry Dr Darren Trott, Dr Ian Wilkie, Dr Steve Driesen, Dr Australian Personnel Tony Fahy April 13th 2005 Date commenced January 2007 Completion date (original) April 2007 Completion date (revised) April – October 2005 Reporting period Contact Officer(s) In Australia: Team Leader Dr Darren Trott 617 336 52985 Name: Telephone: Senior Lecturer School of 617 336 51355 Position: Fax: Veterinary Science Organisation School of Veterinary Science The Email: d.trott@uq.edu.au University of Qld In Australia: Administrative contact Melissa Anderson/Katherine Burt Telephone: 61 7 33652651 Name: Manager Research Projects Office Fax: 61 7 33651188 Position: School of Land and Food The Email: m.a.anderson@uq.edu.au Organisation University of Qld k.burt@uq.edu.au In Vietnam Dr Cu Huu Phu 84 4 8693923 Name: Telephone: Head of Bacteriology Department Fax: 84 4 8694082 Position: NIVR cuhuuphu@netnam.org.vn Organisation Email:
2. Project Abstract This project is designed to improve productivity of smallholder pig farmers in Vietnam through improved health management, particularly of piglets during the pre-weaning period. Additional to the health management plan the project will develop and implement appropriate rapid diagnostic tests for the principal causes of preweaning diarrhoea to improve speed and accuracy of laboratory diagnosis. The third part of the project seeks to improve the production and efficacy of locally-manufactured E. coli vaccines. In the first six months of the project, test farms have been successfully selected, management changes have been instigated and data is currently being collected. One workshop has been conducted. Laboratory staff have been trained and provided with rapid diagnostic reagents for identification of all the major causes of preweaning diarrhoea. Diagnostic antisera is currently being produced in rabbits against the unusual fimbrial type that appears to be unique to Vietnam, which is a necessary prerequisite for vaccine production quality control as well as laboratory and field testing. 3. Executive Summary This project began with three major objectives: 1. Production and testing of locally-produced vaccine 2. Develop a management plan for preweaning diarrhoea using a continuous improvement model 3. Improve diagnostics for preweaning diarrhoea During the first six months of the project, progress has been made towards all three objectives according to the project logframe. Vaccine strains have been characterised and diagnostic antisera prepared against the unusual Vietnamese serotype O8 strains that appear to carry a novel unrecognised attachment antigen. Test and control farms have been selected and audited and are supplying production figures for the pig health recording system put in place to monitor improvements as well as diagnostic submissions to NIVR to determine the importance of different causes of preweaning diarrhoea. A range of management strategies have been implemented on farm to improve environmental conditions and animal health. Members of NIVR laboratory staff have been extensively trained and competency tested in diagnostic techniques including bacteriology and serology, ELISA and PCR. A new PCR thermocycler was purchased for the project and is now being extensively utilized. Several training sessions have been delivered to producers, veterinary and industry staff. 4. Introduction & Background Diarrhoea during the suckling period has been recognised as the principle health problem affecting both smallholder and commercial pig production in Vietnam. Previous research has confirmed the presence of a new fimbrial type in E. coli strains causing colibacillosis in Vietnam that would not be controlled by existing vaccines. Existing vaccines are currently imported into Vietnam at considerable cost. In addition, there are many other causes of suckling diarrhoea, the
significance of which is currently unknown in Vietnam, which are all affected by husbandry and management during farrowing and lactation. Project 001/04VIE (Diagnosis and control of diarrhoea in suckling pigs) began with three objectives to solve this problem: 1. Production and testing of locally-produced E. coli vaccines 2. Development of a management plan for preweaning diarrhoea using a continuous improvement (CIP) model 3. Improved field and laboratory diagnosis of preweaning diarrhoea 5. Progress to Date 5.1 Implementation Highlights 1) Australian study tour by Vietnamese scientists March 12th to 30th 2005 a) Brisbane: Tour of University of Qld School of Veterinary Science, University of Qld Molecular Biosciences Precinct and Department of Primary Industry Toowoomba Veterinary Diagnostic Laboratory (Introduction to veterinary diagnostics and Australian animal health surveillance network). In addition, we organised for a shipment of surplus laboratory equipment items and consumables held at the TVL to be sent to NIVR. b) Bendigo: Pig Health and Research Unit and autogenous vaccine production laboratory, Intervet Ltd Commercial Vaccine Manufacturing plant, visits to various piggeries (technology transfer of rapid diagnostic tests, vaccine production, transfer of surplus equipment and consumables). 2) First study tour of Vietnam by Australian scientists. All Australian collaborators attended a meeting of stakeholders on the 16th April 2005 at the National Institute of Veterinary Research to discuss the project aims and objectives. The following milestones were achieved during this visit. a) Technology transfer and provision of reagents to NIVR staff for laboratory diagnosis. Methodologies were developed for diagnosis of colibacillosis (microbiological techniques, diagnostic antisera and PCR protocols), Clostridium perfringens (microbiological techniques), coccidiosis (faecal floats for egg counts), rotavirus and transmissible gastroenteritis (diagnostic ELISA kits). A sample submission form for the project was designed and implemented and laboratory results obtained for specimens taken during the farm visits in Thai Binh province, which served the purpose of providing specimens for training of NIVR laboratory personnel (see farm audits for laboratory results). During the six-month project, a total of 154 swab specimens and 65 faecal specimens have been received. b) Selection of test and control piggeries in Thai Binh province and in the South. Several large farms were visited and assigned to test or control groups for the purpose of recording production data (data loggers were placed in two of the farms), with the long-term goal of turning the test farms into model piggeries for training purposes. Sow cards were introduced for the purpose of accurate record keeping. The farms were audited by Australian scientists and faecal specimens were obtained from any suckling pigs with diarrhoea for laboratory investigation.
c) Enteric diseases workshop. The first enteric diseases workshop was delivered simultaneously in English and Vietnamese by Dr Tony Fahy and Dr Do Ngoc Thuy to an audience of producers, researchers and veterinarians in Thai Binh province. This was a good opportunity to see how our methods were received and what we needed to modify for future training workshops. Concerning the level of production and profitability of the pig industry in Vietnam, we identified a disparity between what our audience said they were achieving and what we actually saw on farm. Many production problems could be reduced by simple changes in management, but these were not being adhered to. We identified that further general scientific training of veterinarians in veterinary extension and the ability to independently conduct farm audits, problem solve and recommend and supervise management changes was required. From this initial workshop we formulated our philosophy of “training the trainers” for future workshops and CARD applications for the next round. 3) Second trip to Vietnam by Australian scientists. Farm audits were conducted by Australian scientific staff during the period of peak humidity and temperature. 4) Purchase of new PCR machine for NIVR. A new PCR machine together with $8,000 worth of free laboratory equipment was sent to NIVR Bacteriology Department in July 2005. This piece of equipment is now being used to rapidly identify ETEC virulence factors in E. coli isolates from cases of colibacillosis as part of the general improvement in enteric disease laboratory diagnosis at NIVR. 5) Further characterization of NIVR ETEC vaccine strains. Virulence factors in the selected vaccine strains, particularly the unusual pathogenic O8 strains that express all three enterotoxins but contain no recognised fimbriae were independently confirmed by the Pig Health and Research Unit. Interestingly, so far we have not identified these unusual O8 strains in any of the farms where we have conducted our audits. Contact was made with Dr John Fairbrother, St Hyacinthe, Quebec who is the world authority on enterotoxigenic E. coli infections in pigs and he has expressed an interest in hosting Dr Do Ngoc Thuy to conduct further studies on identifying the unknown fimbrial antigen in the O8 strains. This will have important ramifications for the vaccine production phase of this project, which is due to begin in January 2006. Diagnostic antisera was prepared at NIVR in rabbits for positive identification of the unusual serotype O8 5F- E. coli strains using standard whole cell immunization and cross absorption methodologies. However the sera obtained from the rabbits was not specific against the 5F- O8 strains. In the second six months of the project, the immunization procedure will be repeated using a crude fimbrial extract that may be more specific for the novel uncharacterized attachment antigen. At this stage of the project based on the farm audits we have undertaken, we have identified the following major constraints on pig production in Vietnam that can be alleviated through the adoption of our management and continuous improvement plan: Lack of written production records Failure to reach reproduction targets Poor ventilation and cooling systems which limit the feed intake of progeny and breeders. Lack of written records on average daily gain, FCE, and pigs marketed /sow/yr. Restrict feeding of all classes of stock from lactating sows through to finisher pigs. Lack of written data on mortalities and age at death. Incorrect vaccination strategies for those diseases for which there are effective vaccines. Lack of specialist veterinary and extension staff to instruct and advise farmers.
Lack of model demonstration farms in each province to train the trainers. Binh Dinh Department of Agriculture has offered their farm (Number 9) for such a purpose. The final two points cannot be fulfilled during the current CARD project (001/04VIE) but are major objectives in new project applications selected from the most recent CARD round (004/05VIE and 020/05VIE). There is a strong possibility that these projects could be integrated with 001/04VIE. 5.2 Smallholder Benefits 1) Improved diagnostic capability for enteric diseases at NIVR. 2) Development of model farms that will be used for smallholder farmer training workshops during year 2 of the project. 3) Development of a training workshop advocating accurate record keeping and continuous improvement. 3) Production of antisera to rapidly identify the unusual O8 strains and further characterization of vaccine strains as a necessary precursor to production of a cheap, effective E. coli vaccine. 5.3 Capacity Building During the first six months of the project, there has been a considerable investment in technology and know-how into the NIVR bacteriology laboratory for improved, rapid diagnosis of enteric diseases in suckling pigs. Test and control farms have now been identified for the adoption of the management and continuous improvement plan. Further characterization of the vaccine strains has been undertaken in preparation for production for field trials in 2006. 5.4 Publicity An article on the initial study tour to Australia by Drs Truong Van Dung, Cu Huu Phu and Do Ngoc Thuy appeared in the Bendigo News. Now that the project has been set up and is running successfully, further publicity opportunities in Vietnam will be taken during a visit in January 2006 in preparation for the smallholder workshops. These will cover the creation of the model farms, comparison of production data between test and control farms and the importance of accurate diagnosis by NIVR scientists. 5.5 Project Management Operational project management has been shared between the National Institute of Veterinary Research Bacteriology Department, the Victorian Department of Primary Industry and The University of Queensland. The Faculty Research Projects Office in the School of Land and Food at The University of Queensland, who have many years experience in managing international agricultural research projects, is responsible for administration of the project. 6. Report on Cross-Cutting Issues
6.1 Environment Some attention to piggery waste disposal has been made during the initial farm audits (for example, the observation that piggeries using open flush systems may be more susceptible to disease outbreaks). As management changes are initiated following further farm audits, improved feed conversion, reduced disease and improved production will all have a positive effect on environmental waste. The majority of scouring piglets are still treated with antimicrobials, which may in many cases be inappropriate, considering that only a small number of cases of E. coli colibacillosis (neonatal diarrhoea at 1-4 days and 2-3 week old scours) and Clostridium perfringens enterotoxaemia have been diagnosed in specimens submitted to NIVR from our test and control piggeries. Recommending treatment with Baycox at 3-4 days instead of at 7 days will limit the production limiting effects of coccidiosis. Improvements in farrowing pen management and creep design are also likely to have an effect on endemic TGE and rotavirus, which appear to be quite common. Inappropriate usage of antimicrobials is likely to promote the development of resistance, therefore implementation of our management plan is likely to result in reduced reliance on antimicrobials. During the smallholder workshops planned for 2006, closer attention can be focused upon environmental sustainability by exploring the integration of our management plan with biogas reactors, manure composting and fish farming. 6.2 Gender and Social Issues We have observed that women represent the majority of the labour workforce in the piggeries we have audited. Consequently, we have noticed that the standard of hygiene in the majority of piggeries was excellent. Improvements in production are therefore likely to have positive flow- on benefits for gender and social issues in terms of greater job satisfaction and greater roles in management and decision-making. 7. Implementation & Sustainability Issues 7.1 Issues and Constraints As indicated above, the major constraint to the success of our project is the lack of appropriately trained veterinary extension workers who can conduct independent farm audits accurately and efficiently so that necessary management changes will be adopted to improve production and profitability. 7.2 Options We are in the process of developing a farm audit checklist that can be used to “train the trainers” as well as give an objective assessment of the major constraints to production at each farm visited. Use of this checklist will enable our scientists to evaluate the level of competency of Vietnamese personnel conducting the audit. However, to fully implement this methodology it will require extensive training of Vietnamese scientists in Australia, which is being undertaken in the new CARD projects (004/05VIE and 020/05VIE). 7.3 Sustainability Not applicable to comment on at this stage of the project.
8. Next Critical Steps Key steps in the next six months of the project: 1) Production and efficacy testing of locally produced E. coli vaccine 2) Field trials of new vaccine on test piggeries 3) Preparation of smallholder workshops and field days to be delivered in 2006 based on the management and continuous improvement model developed on large piggeries 4) Organise publicity of project in Vietnam 5) Extensive consultation with MARD representatives to utilize existing networks for delivery of outcomes (National Centre for Veterinary Extension) 9. Conclusion At this stage of the project, all the initial objectives have been achieved. We have identified a major constraint to full implementation of our management plan (appropriate training of veterinary extension workers). Our current budget is not enough to cover the extra cost of intensively training this small number of high potential young Vietnamese scientists, however funds are available for this purpose in the new CARD projects. There are excellent opportunities for integrating the three CARD projects focusing on improving the livelihood and profitability of smallholder pig producers. The Australian team now assembled has considerable expertise and experience (ie Australia’s leading pig health and production experts), to transfer to Vietnamese scientists, thus enabling them to drive the continuous improvement model.