newsletter of the rirdc horse program 12/013 MARCH 2012

Transcription

1 newsletter of the rirdc horse program 12/013 MARCH 2012 IN THIS ISSUE: RESULTS FROM AUSTRALIA S LARGEST DRUG ADMINISTRATION STUDY NOW AVAILABLE BUILDING UNDERSTANDING OF LAMINITIS INVESTIGATING STRINGHALT

2 PAGE 2 RIRDC EQUINE RESEARCH NEWS MARCH 2012 INDUSTRY PROFILE EQUINE VETERINARIANS AUSTRALIA Jeffrey Wilkinson is the Executive Officer of Equine Veterinarians Australia (EVA), the peak industry body for vets working in all fields of equine medicine and a wide range of horse industries. It is a major contributor to the Rural Industries Research and Development Corporation s (RIRDC) Horse Program. WHAT IS EVA? EVA has more than 1000 members Australia wide and has just celebrated its 60th birthday. The main focus of EVA is to provide resources to equine vets, such as Continuing Professional Development (CPD) education, information dissemination, advocacy to government and industry stakeholders, and a collegial body where likeminded professionals can share and develop ideas and projects. To maintain their annual State Veterinary Surgeons Registration Board status, vets need to participate in CPD, and EVA provides this vital role. For example we recently brought a French professor to Australia who is a world expert on equine ultrasound and he ran a workshop at Agnes Banks Equine Clinic for our members. We have also begun running a number of webinars for vets, so that busy and remotely located members can participate without the need to spend time travelling. We have a subgroup for young vets and students. For these members we run mentoring programs, seminars, workshops and clinical sessions as well as social functions and outings. We now offer four scholarships for young members who demonstrate outstanding ability and commitment in equine medicine. WHAT IS BAIN FALLON? Our main event is an annual conference, held in July. This is known as the Bain Fallon Memorial Lectures and in 2012 will be held at the Brisbane Convention Centre. This is an opportunity for vets to come together and learn about the latest developments in equine research from around the world. The program often includes presentations on RIRDC Horse Program supported research. WHY DOES EVA SUPPORT THE HORSE PROGRAM? EVA believes in the importance of ongoing scientific research into equine veterinary medicine, and that s why we support the RIRDC Horse Program. We believe the research is strategic and important. EVA itself doesn t carry out any research, but we are able to support Jeffrey Wilkinson it through other organisations and we are also regularly in contact with government on the direction of research priorities. WHAT ARE THE RESEARCH PRIORITIES FOR EVA? We have a particular interest in zoonotic diseases (diseases that can be transferred from animals to humans, or other species) as they have the potential to impact upon both horses and vets as they treat them. Hendra virus is an example that is of great concern for everyone working in the industry, particularly given the unprecedented number of incidents in Queensland and New South Wales last year. EVA is pleased to see the level of commitment to Hendra research, including the $9 million that was recently allocated to study Hendra and importantly the risk factors for humans. This includes a $750,000 contribution from RIRDC, 50% of which is from the Horse Program funds. Other priorities for EVA include reproductive science as this is so essential in driving the economics of the equine industry, and increasingly we see interest in equine behavioural research. RIRDC S HORSE PROGRAM IS AUSTRALIA S NATIONAL HORSE RESEARCH AND DEVELOPMENT PROGRAM A PARTNERSHIP BETWEEN INDUSTRY AND GOVERNMENT THAT DELIVERS SIGNIFICANT BENEFITS BACK TO YOU. CONTRIBUTORS: The Australian Government, Australian Racing Board, Racing Information Services Australia, Australian Thoroughbred Breeders Club, Australian Stock Horse Society, Howard Insurance, Equine Veterinarians Australia, Tyreel Stud, Logan Livestock Insurance, International Racing Transport, Equestrian Federation of Australia

3 MARCH 2012 EQUINE RESEARCH NEWS PAGE 3 HORSE RESEARCH NEWS BUILDING UNDERSTANDING OF LAMINITIS By administering insulin to horses, further inroads have been made into the understanding of laminitis. Previous RIRDC supported research proved that high blood concentrations of insulin precipitate laminitis, particularly in ponies. The results of this recent project show that the theory also applies to horses. The project report Insulin Induced Laminitis an investigation of the disease mechanism in horses, outlines important findings into how the insulin associated type of disease (endocrinopathic laminitis) develops and progresses. The research was led by Dr Chris Pollitt at the University of Queensland, with support from Rural Industries Research and Development Corporation (RIRDC) Horse Program. Laminitis is a debilitating condition that affects the sensitive lamellar structures between the inner hoof wall and the pedal bone. It s a common form of lameness and causes significant loss in the horse industry. By developing targeted treatment and management strategies the findings from this research will help reduce these losses. Insulin-Induced Laminitis An investigation of the disease mechanism in horses RIRDC Publication No. 11/116 Researchers induced laminitis in groups of Standardbred horses by administering insulin to cause prolonged hyperinsulinaemia (where excess insulin is circulating in the blood). All the horses in the experiment group developed the disease within a short time period. Observations were made on the progression of the condition, in particular the crucial development phase that precedes the onset of clinical lameness. Samples from the lamellar region of affected hooves were also examined after the disease was established. As a result of the findings, veterinarians now know that high blood concentrations of insulin put horses at risk. They can use this knowledge to better manage insulin-resistance and to predict the likelhood of laminitis development. The monitoring and reduction of insulin concentrations in horses by vets and horse owners should reduce the incidence of endocrinopathic laminitis and the financial impact on the industry. Exercise and dietary management are the cornerstones of reducing insulin resistance. Controlling hyperinsulinaemia is particularly important for the horse breeding industry as the equine obesity (equine metabolic syndrome) can affect fertility as well as causing laminitis. Recommendations resulting from the study for vets and horse owners include: Reduce insulin concentrations well below 200µIU/ml in horses and ponies with hyperinsulinaemia using controlled diet and exercise regimens. Maintain a lean body weight for horses and ensure body condition scores are in the mid to low range Monitor pasture species and seasonal variation of pasture growth to avoid excessive consumption of carbohydrate rich pasture. Insulin Induced Laminitis an investigation of the disease mechanism in horses is available on the RIRDC website for download (free) or purchase ($25). RIRDC publication number 11/116. TO BUY RIRDC BOOKS AND REPORTS: Standard bred horses under observation during the study. Order online at or call Many books and reports are also available to download free of charge from * see glossary on page 8

4 PAGE 4 RIRDC EQUINE RESEARCH NEWS MARCH 2012 RIRDC HORSE RESEARCH RESULTS FROM AUSTRALIA S LARGEST DRUG ADMINISTRATION STUDY NOW AVAILABLE The critical need by vets for reliable information when treating horses that are about to race or compete has been addressed by the largest and most comprehensive drug administration study ever completed in Australia, funded by the Rural Industries Research and Development Corporation (RIRDC) Horse Program. Illness and training injuries in racing and equestrian events are common, but appropriate treatment can be hampered by uncertainty about excretion and detection times for many therapeutic drugs. A new report The Pharmacokinetics* of Equine Medications provides information on 12 commonly used equine drugs including the time taken for each drug to reach its maximum concentration in the blood, its rate of metabolism and removal from the blood stream, and the time taken for the drug to be eliminated from the body via the urine. The results published in the report will allow racing authorities to provide relevent stakeholders with appropriate, accurate and reliable detection times for therapeutic substances. This work will also be shared internationally, enabling Australia to contribute to the international standardisation of drug testing protocols. Fact sheets for vets and a report for regulators will also be available later this year. Queensland University of Technology Professor of Biosciences, Martin Sillence, said pinpointing the length of time it took for the most commonly used therapeutic drugs to work their way out of a horse s * see glossary on page 8 Stock image system provided greater certainty for horse owners, trainers and vets. Because horses are prohibited from racing with any trace of drugs in their system, the administration of therapeutic drugs to horses in need of care has been risky business, Professor Sillence said. With no accurate schedule to indicate how long drugs take to work their way out of horses systems, a fair amount of guesswork has always been involved. This means it s been all too easy to unwittingly be caught out with a winning horse on race day, that s subsequently found to have traces of a drug in its system. The new schedule should change all this, Professor Sillence said. This is the final report of a RIRDC Horse Program-supported project which began in 2008 in collaboration with three universities and four Australian Racing Analytical Laboratories under the banner of Equine Therapeutics Research Australia (ETRA). The project was governed by a committee of industry stakeholders to prioritise which substances should be tested.

5 MARCH 2012 RIRDC EQUINE RESEARCH NEWS PAGE 5 Martin Sillence photo courtesy of QUT The Pharmacokinetics of Equine Medications More than 20,000 samples of blood and urine were analysed from the trials of 18 commonly used compounds. Drugs were tested in groups of horses to increase the accuracy of the results. The data were then modelled to determine the pharmacokinetic parameters for each drug. A supplementary report will be published soon to provide data on the 6 remaining compounds tested. This project was funded by voluntary industry contributions and the RIRDC Horse Program. Additional funding was supplied by the project participants and by a number of direct industry sponsors. The Pharmacokinetics of Equine Medications is available on the RIRDC website for download (free) or purchase ($25). RIRDC publication number 11/117. RIRDC Publication No. 11/117 RIRDC HORSE COMMITTEE Dr John McCaffrey (Chair) Consultant Equine Veterinarian Dr Nigel Perkins (Research Manager) Director AusVet Animal Health Services Ass/Prof Guy Lester Head of the Equine Section Department of Veterinary & Biomedical Sciences Murdoch University Leslie Young Managing Director Doncaster Bloodstock Services Racehorse owner, manager, breeder and journalist Elizabeth Owens Sales and Marketing Manager Symbio Alliance Animal nutritionist, Australian national champion dressage rider Dr Dave Alden Senior Research Manager Established Rural Industries RIRDC Helen Moffett Project Manager RIRDC

6 PAGE 6 RIRDC EQUINE RESEARCH NEWS MARCH 2012 RIRDC HORSE RESEARCH INVESTIGATING STRINGHALT It is widely accepted that Australian stringhalt in horses is linked to consumption of the plant Hypochoeris radicata (commonly known as flatweed or false dandelion). However, a pilot study led by Charles El-Hage at the University of Melbourne will assist in changing the focus on further important research on stringhalt, finding there is in fact little evidence to link known fungal toxins associated with or in flatweed to the nerve damage observed in horses suffering from stringhalt. Australian stringhalt is a condition that baffles vets and horse owners alike it has been documented for over 120 years in south-eastern Australia with little progress in determining a cause for the abnormal gait of affected horses. Horses suffering from it demonstrate extreme hyperflexion* of the hindlimbs. The limb may even make contact with the belly as the horse tries to move forward and develop a goose stepping gait in severe cases. Affected horses are unable walk, graze or exercise without some difficulty and require long periods and often therapy for full recovery. The vast majority of studies implicate H. radicata as being prevalent in paddocks where horses develop Australian stringhalt, commonly after prolonged dry summers, in pastures of poorer quality soils. H. radicata is widespread in south eastern Australia where a large percentage of the horse population resides. The suggestion has been that a fungal mycotoxin* associated with H. radicata may be responsible for the condition, as mycotoxins are known to cause neurological* disease in grazing animals on pastures following prolonged dry periods. The objective of the latest research was to establish whether H. radicata was a potential source of neurotoxins, and thus the cause of the condition. It also aimed to determine if toxins * see glossary on page 8 in the plant could be induced by environmental stress, such as drought. A thorough analysis was conducted of six batches of H. radicata plants from a range of environmental conditions and growth stages to maximise detection of potential toxins. The research was funded by the Rural Industries Research and Development Corporation (RIRDC), the University of Melbourne s Faculty of Veterinary Science, Department of Land and Food Resources and Metabolomics Australia (School of Botany). The results, outlined in the report Investigation into the Cause of Australian Stringhalt, showed a lack of evidence that known selected mycotoxic alkaloids*, or toxins, were present in drought stressed H. radicata plants implicated in cases of stringhalt. This has implications for horse owners and vets in the prevention and treatment of the condition. For example, horse owners are often advised to feed a variety of supplements to treat or prevent stringhalt but the study suggests that the practice of feeding mycotoxin binders may be unlikely to protect horses from developing stringhalt. However, this is a pilot study and further work to identify a specific toxin continues. The isolation of unidentified primary and secondary metabolites* possibly Investigation into the Cause of Australian Stringhalt RIRDC Publication No. 11/127 produced in response to drought stress confirms the epidemiological* evidence that the flatweed H. radicata should be avoided by owners to assist the prevention of stringhalt in grazing horses. Until a particular toxin is identified, horse owners can take steps to protect horses from Australian stringhalt by improving pastures to reduce the prevalence of H. radicata within paddocks where horses graze and restricting access to pastures infested with H. radicata following prolonged dry weather conditions. Investigation into the Cause of Australian Stringhalt is available on the RIRDC website for download (free) or purchase ($25). RIRDC publication number 11/127.

7 MARCH 2012 RIRDC EQUINE RESEARCH NEWS PAGE 7 NEW REPORTS AVAILABLE Stimulating Muscle Activity to Reduce Roaring in Horses In Vitro Optimisation of Conditions for Laryngeal Reinnervation Surgery RIRDC Publication No. 11/098 TREATMENT OPTIONS FOR ROARING HORSES A new report has tackled the very urgent need for a safe and effective treatment for recurrent laryngeal* neuropathy* or roaring in performance horses by establishing a system to investigate treatment options that may reduce recovery time from surgery. Funded by the Rural Industries Research and Development Corporation (RIRDC) Horse Program, the study was led by Professor Eleanor Mackie, Dr Charles Pagel and Dr Catherine Steel from the University of Melbourne. Recurrent laryngeal neuropathy (RNL) results in laryngeal paralysis or roaring and impacts the ability of affected horses to perform strenuous exercise. Currently, the most popular surgical procedure for the treatment of RNL in horses is plastic surgery of the larynx, although complications from this technique are common and can be serious. Another form of treatment, laryngeal reinnervation* can also be effective in restoring racing performance following RNL. However the extended recovery time using this treatment has meant the option has not received wide acceptance. It is also suggested that the use of nerve and muscle growth factors in conjunction with laryngeal reinnervation surgery will result in improved outcomes, and this study aimed to establish a system for testing pharmaceutical compounds for future use in addition to reinnervation surgery. The study established a system for testing the ability of compounds to improve muscle fibre formation and increase nerve fibre density. Using this system two compounds were identified that significantly increased muscle differentiation, and another was found to significantly increase nerve fibre density in cultures. The results of the study suggest that administration of a combination of these compounds during laryngeal reinnervation surgery may improve muscle repair and reinnervation, although additional research is required to determine if recovery time from surgery is accelerated. The report, Stimulating Muscle Activity to Reduce Roaring in Horses is available on the RIRDC website for download (free) or purchase ($25). RIRDC publication number 11/098. EVALUATING SOFT PALATE DISEASE Dorsal displacement of the soft palate (DDSP) is a commonly occurring obstructive upper respiratory disease of horses that causes the temporary restriction of airflow during intense exercise. This results in loss of power and respiratory distress. Until now, the preferred method of diagnosis for DDSP has been treadmill video-endoscopy, an invasive technique that requires laboratory conditions, thereby limiting wider routine evaluation of the disease. A project, jointly funded by the Rural Industries Research and Development Corporation (RIRDC) Horse Program, Randwick Equine Centre and the Faculty of Veterinary Science at Soft Palate Disease in Horses Tracheal Stethoscopy as a diagnostic and evaluation tool RIRDC Publication No. 09/079 Sydney University, was undertaken to investigate tracheal* stethoscopy* as a diagnostic tool for DDSP. The aim was to develop a technique that would allow for in-field diagnosis of the disease. The project found that the frequency components of the tracheal stethoscope signal were an unreliable indicator of DDSP due to signal noise. However the time based components of the signal, specifically measuring the progression of inspiratory* and expiratory periods during intense exercise, is highly indicative of DDSP. As a result of this project, equipment can now be developed that allows DDSP evaluation to form part of a regular training routine without disruption or freighting of horses to treadmill facilities. Importantly, it also allows testing to be done under racing conditions as opposed to on a treadmill, as there is evidence to show these conditions are not equal. The report Soft Palate Disease in Horses Tracheal Stethoscopy as a diagnostic and evaluation tool is available on the RIRDC website for download (free) or purchase ($25). RIRDC publication number 09/079.

8 PAGE 8 RIRDC EQUINE RESEARCH NEWS MARCH 2012 CURRENT RIRDC HORSE PROJECTS Intra-articular medication as risk factor for musculoskeletal injury Researcher: Chris Whitton Maternal metabolic status and the occurrence of OCD in Thoroughbred foals Researcher: Wayne Bryden Organisation: University of Queensland Short term and future athletic performance of the critically ill equine neonate Researcher: Jane Axon Organisation: Scone Equine Hospital Horse industry engagement on the future of RIRDC Horse Program Researcher: Julie Fiedler Organisation: Horse SA Treatment of placentitis in thoroughbred mares: efficacy of altrenogest Researcher: Joan Carrick Organisation: Scone Equine Hospital In vitro optimisation of conditions for laryngeal reinnervation surgery Researcher: Eleanor Mackie Investigation into the aetiology of Australian Stringhalt Researcher: Charles El-Hage The Science of Horse Training: Implications for rider safety and horse welfare Researcher: Paul McGreevy Diagnosis and control of small strongyle parasites of horses Researcher: Nicholas Sangster Organisation: Charles Sturt University Determining reliable excretion rates for therapeutic drugs in horses Researcher: Martin Sillence Organisation: Queensland University of Technology The role of kisspeptins in vernal transition management in mares Researcher: Scott Norman Organisation: Charles Sturt University Finite element analysis modelling of third metacarpal bone invivo stresses Researcher: Chris Whitton Oncotic and Haemostatic Effects of a Modified Fluid Gelatin in Normal Horses Researcher: Darien Feary Respiratory disease and biomarkers in the foal Researcher: Garry Muscatello Virus and horse specific risk factors for EHV1 neurological disease Researcher: Carol Hartley Antimicrobial susceptibility patterns of bacterial isolates from horses Researcher: Tony Mogg An adenoviral vector vaccine against Rhodococcus equi Research: Mary Barton Organisation: University of South Australia Bone repair in thoroughbred racehorses: effects of training and rest Researcher: Chris Whitton Developing training programs to prevent injury in young racehorses Researcher: Lisa Kidd Organisation: University of Queensland Climate Change for Horse Owners Researcher: Julie Fiedler Organisation: HorseSA Working towards a more accurate diagnosis of inflammatory airway disease Researcher: Cristy Secombe Organisation: Murdoch University What role does rotavirus play in equine diarrhoea in Australian horses? Researcher: Sally Symes Laminitis treatment by regional drug delivery to the horse s foot Researcher: Chris Pollitt Organisation: University of Queensland Gene expression in horses with Recurrent Laryngeal Neuropathy (RLN) Researcher: Liz Walmsley Use of the guinea pig as a laboratory model for EAFL (Extension of PRJ-530 and 2592) Researcher: Judy Cawdell-Smith Organisation: University of Queensland Epidemiological investigations into the 2007 Equine Influenza outbreak Researcher: Navneet Dhand SCHOLARSHIPS: An evidence-based approach to improving insulin Researcher: Kellie Tinworth, Organisation: Charles Sturt University MORE INFORMATION ON RIRDC HORSE PROJECTS CAN BE FOUND AT GLOSSARY Alkaloids One of a large group of nitrogenous substances found naturally in plants. They may be poisonous and many have extracts that are pharmacologically active*. Epidemiological data data relating to the incidence, distribution, and control of diseases. Hindlimb hyperflexion movement of a limb beyond the normal limit. Inspiratory Relating to the act of breathing in. Laryngeal relating to the larynx, commonly called the voice box. Mycotoxins a group of highly toxic products of fungi produced under certain favourable environmental conditions. Neuronal relating to neurons. Neurons are also called nerve cells and are the primary cells of the nervous system. Neurological Related to the nervous system. E.g., neurological assessment refers to looking into the way in which the nervous system is working. Neuropathy a disease or dysfunction of one or more peripheral nerves. Pharmacologically active any chemical or substance that affects the function of the body of a human or animal. These substances can be artificial or natural. Pharmacokinetics the study of drug concentration in the body over time. Reinnervation to supply a new, functioning nerve supply to the paralyzed organ. Stethoscopy also known as sonography; it is the analysis of sound using an instrument that produces a graphical representation of its component frequencies. Tracheal relating to the windpipe; the tubelike portion of the breathing or respiratory tract that connects the larynx with the lungs. RIRDC EQUINE RESEARCH NEWS IS THE OFFICIAL NEWSLETTER OF THE RURAL INDUSTRIES RESEARCH AND DEVELOPMENT CORPORATION HORSE R&D COMMITTEE. Subscription is free, and available in either printed or electronic form. To subscribe, please send your details and newsletter preference (printed or electronic) to: RIRDC Equine Research News PO Box 4776 KINGSTON ACT 2604 Phone: Fax: rirdc@rirdc.gov.au Website: ISSN: X