Project Title	Drought feeding information manual for the horse industry
RIRDC Project No.:	DAV-156A
Researcher:	David Nash, Angela Avery and Patricia Ellis
Organisation:	Agriculture Victoria Rutherglen Rutherglen Research Institute RMB 1145,  Chiltern Valley Road,  RUTHERGLEN 3685
Phone:	02 60304500
Fax:	02 60304600
Email:	david.g.nash@nre.gov.com.au
Objectives	To provide information for the horse industry on feeding and horse management in times of drought.
Background:	Droughts are very much part of agriculture in Australian. Horse owners, like other managers of livestock, need to be prepared for times of dry conditions and drought. Other animal industries have prepared information available to assist them through drought, until the completion of this manual there was no such information available to the horse industry. A practical guide on horse feeding and management during drought was needed to help owners break the daunting planning phase of a threatening drought down to manageable steps. This manual will enable horse owners to get through drought in the most economic and stress-free way without horses, pasture or soil resources suffering.
Research	This project involved literature review and consultation with experts on drought, horse and pasture management to develop the information in the drought manual.
Outcomes	A practical relevant manual that will assist horse owners manage dry and drought conditions Support for the horse industry during drought conditions
Implications	The horse industry in Australia will be better able to manage their enterprises during drought leading to reduced costs, animal health problems and environmental degradation. The wider community will also see the industry as being responsible and pro-active towards drought.
Publications	The main objective of this project was to publish information on drought for the horse industry. This information is to be printed by RIRDC as a research publication.

 

Project Title	Further studies on abilities of progestagens to maintain pregnancy in mares
RIRDC Project No.:	GEH-1A
Researcher:	Dr. Angus McKinnon
Organisation:	Goulburn Valley Equine Hospital PO Box 2020 SHEPPARTON VIC 3630
Phone:	03 5829 9566
Fax:	03 5829 9307
Email:	aom@mail.sheppnews.com.au
Objectives	To compare the ability of various progestagens to maintain pregnancy in mares. To compare the ability of those progestagens to eliminate oestrous behaviour.
Background	Many or most of us (mare owners, farm managers and veterinarians) have administered progestagens (progesterone like compounds) to mares in an attempt to help them maintain a pregnancy. Years ago (published in the Equine Veterinary Journal in 1993), we found that the most common progestagens (hydroxyprogesterone caproate, also known as Depo Luteine etc.) not only failed to keep mares from showing heat (a properly acting progestagen should be able to do this) but was not able to prevent abortion when we removed the source of progesterone (the corpus luteum in the ovary). This study led us to examine further progestagens for their ability to eliminate oestrous or maintain pregnancy.
Research	What we did was take groups of mares (5 mares in each group) that were pregnant at day 16 and give them progestogen compounds. Two days later we gave prostaglandin (to bring them back into heat). If the treatments worked we would expect the mares to stay pregnant. Just to be certain we also took blood every day and measured the hormone progesterone.
Implications	The result were very interesting. Regumate worked well. All 5 mares treated maintained their pregnancies. The other four groups were a disaster. No mares in each of the other groups maintained pregnancies. All mares came into heat. The average time from injection to abortion was 3.3 (± 1.7) days. All the mares returned to oestrus and ovulated within 11 days after prostaglandin injection. The groups of mares in this study were: 1) medroxyprogesterone acetate 2) hydroxyprogesterone hexanoate 3) altrenogest 4) norgestomet and 5) megesterol acetate. These are commonly used drugs and come under a number if different names. The bottom line from this research is that you should be very careful about which drugs you chose to try and help a mare from loosing her pregnancy. Most do not appear to work.

 

Project Title	Evaluation of the provision of training programs for the horse industry in Australia
RIRDC Project No.:	HOW-1A
Researcher:	Dr William Howey
Organisation:	PO Box 509 SCONE NSW 2337
Phone:	02 9351 7979
Email:	howeywp@brooknet.com.au
Objectives	To investigate and evaluate the delivery and provison of education to the prospective and actual workforce in the horse industry in Australia. Particular attention will be paid to industry input into curriculum development, workplace experiential learning, workplace based training and assessment and employer feedback to the education providers.
Background	During the latter part of 1998 a series of visits was made to major Registered Training Organisation (RTO’s) in all States and Territories providing education and training in the horse industry. Key personnel and were identified and interviewed at each provider institute or college. A database of information relating to courses offered, course information and delivery strategy was collected. Direct or indirect contact with ‘fringe’ or non-mainstream education providers and bureaucracies was established.
Research	Access was made to a national direct mailing database established by Equine Educational of Lochinvar, NSW. Further information was gleaned from The A.E.I.S. Horse Industry Directory and the Australian Equine Education Directory (IDP Education Australia). A total of 130+ letters was sent to all Registered Training Organisations (RTO's) identified and also to a number of Workplace Training Providers and Employers. Strategic visits to the key ‘mainstream’ educational institutions were implemented.
Implications	A full report was written detailing the history and current status of the provision of education and training in the horse industry in Australia. The key Registered Training Organisations and personnel were identified. A comprehensive list of the people, colleges and courses provided throughout Australia was compiled as well as a detailed summary matrix. A work-shop will be facilitated in mid-1999 to discuss the outcomes.

 
 

Project Title	Horses and land use on small properties
RIRDC Project No.:	PTP-12A
Researcher:	Arthur Stubbs
Organisation:	Primary Tasks Pty Ltd Unit 58, Level 2, 247 Drummond Street CARLTON, VIC. 3053
Phone:	03 9844 1135
Fax:	03 9844 4554
Email:	akstubbs@compuserve.com
Objectives	Publication of a booklet giving guidelines for achievement of sustainable land use and efficient horse management on small properties in urban surroundings.
Background:	RIRDC Project PTP-3A, "Sustainable Land Use for Depastured Horses", identified current practices and problems associated with horsekeeping on small properties around urban areas, Guidelines were established for optimum, pasture based, grazing and nutritional strategies in such situations to ensure sustainability of land use and economy of feeding. A booklet was proposed to give more detail about the recommended guidelines, and relevant issues, and be a more effective means of their dissemination.
Research	The emphasis in the book is on sustainable land use, but includes information on matters associated with horse grazing, such as the essential facts about nutrition and aspects of health to do with feeding and grazing, eg., worm control. Chapters include: How Many Horses; Growing Pasture; Managing Pasture; How Much Feed; and Healthy Land, Healthy Horses.  Assistance was sought in drafting and editing from fellow researchers, particularly on nutrition and health, and from land care people, notably those in South Australia.
Implications	The information contained will be of value to those involved with a range of horse activities who have limited land available for housing their animals. A more widespread understanding and implementation of sustainable, pasture based, grazing management for horses will have long term benefits in more effective and sustainable land use, economy of horse management and improved appearance of horse properties.
Publications	"Healthy Land, Healthy Horses – a guidebook for small properties".  RIRDC Publication No. 98/137

 
 

Project Title	4TH Australian Racecourse Managers’ Conference, 1999
RIRDC Project No.:	PTP-13A
Researchers:	Arthur Stubbs John Neylan
Organisation:	Primary Tasks Pty Ltd Turfgrass Technology Pty Ltd Unit 58, Level 2 9 George Street 247 Drummond Street Sandringham Vic 3191 Carlton Vic 3053
Phone:	03 9844 1135 03 9521 6982
Fax:	03 9844 4554 03 9521 6946
Email:	akstubbs@compuserve.com michaelr@turftech.com.au
Objectives	Improvement of inter-club communication and education on issues of racetrack care and maintenance for the development of effective, overall strategies for racecourse management.
Background:	A survey of grass racecourses in Australia in 1995 (RIRDC Project TGT-1A) found a wide variation in the level of racecourse management expertise and technical knowledge, as well as a sense of isolation by many racecourse managers and an expressed need for more information relevant to their jobs.  This led to Racecourse Managers’ Conferences being held in the following three years, at Rosehill, Moonee Valley and Doomben, each attended by many racecourse managers from most States of Australia and New Zealand. The success of these conferences led to the 4th Conference at Morphettville on April 13-15,1999, with the theme, "Managing Racecourses".
Outcomes	93 people attended the conference, including 70 racecourse managers and staff from throughout Australia and New Zealand, plus suppliers and consultants to the racecourse industry, research workers and turf specialists. The conference was again very well received and delegates recommended that a similar forum be organised for 2000. It was considered that the objective had been achieved through the combination of paper presentations, two workshops, input from an American racecourse manager, inspections of three local racecourses and a racehorse stud, and general liaison between racecourse managers from a wide range of situations.
Implications	The conference enabled racecourse managers to gain and exchange information on the latest developments in research, racecourse development and maintenance, people and resource management, and to learn from overseas experiences and inspection of operations at major race and training tracks.  The conference will further racecourse managers’ ability to practise their profession, leading to higher standards of racecourse management with benefits accruing from improvements in track performance, appearance and life, and associated economic and environmental advantages for racing clubs and the community.
Publications	4th Australian Racecourse Managers’ Conference Proceedings,1999

 
 

Project Title	Controlling and reducing airborne dust in horse stables and transporters
RIRDC Project No.:	SAR-14A
Researcher:	Colin Cargill
Organisation:	South Australian research and Development Institute Roseworthy Campus University of Adelaide GPO Box 397 Adelaide, SA 5001
Phone:	08 8303 7782
Fax:	08 8303 7975
Objectives	To review published information on the generation and concentration of dust in horse stables, and to recommend strategies for dust reduction and control.
Background:	Dust is an important airborne pollutant in all forms of animal housing and although the levels of dust recorded in horse stables are lower than in intensive livestock buildings, the horse is more sensitive to dust than other species and the length of exposure is significantly greater. Dust appears to enhance both the prevalence and severity of respiratory diseases, especially conditions such as chronic obstructive pulmonary disease (COPD). It may also aid the spread of other infections.
Outcomes	Dust in animal houses is a mixture of organic material including bacteria, bacterial and fungal toxins and spores, urine, dung, undigested feed, pollen and other feed and animal components. Concentrations in stables range from 0.2 to 17.21 mg/m3 (recommended maximum value of 2.4 mg/m3) for inhalable dust and from 0.15 to 9.28 mg/m3 (recommended maximum value of 0.23 mg/m3) for respirable dust. The important airborne micro-organisms present in stables appear to be a combination of actinomycete and fungal spores. Mesophilic bacteria, such as Corynebacterium spp and Arthrobacter sp, and gram positive organisms such as Micrococci spp, have been isolated in significant amounts as well.  Stocking density (in terms of cubic metres of airspace per horse) and building design are important aspects of dust control and reduction. Ventilation rates have a direct effect on dust levels through increased air movement, which can either dilute the concentration of airborne particles or increase re-suspension of particles and delay settling. Exhaust ventilation is a key factor in removing dust but bedding and the type of feed are more important than ventilation as a cause of dust.  A number of strategies for reducing dust generation and concentration in stables were recommended. These include: Soaking and cleaning hay, pelleting feed or using silage; Using feeding systems where feed is not dropped into a bin; Adding oil to pellets or coating them with oil after manufacture, (but care needs to be taken when manipulating diets); Using wood shavings, diced paper or synthetic material to replace straw as bedding, and replacing bedding frequently; Storing feed in purpose built sheds rather than in stables or barns; Cleaning boxes and stalls daily and removing the horses during cleaning; Designing barns and stables to maximise air exchange rates in still conditions;  Using mechanical ventilation systems designed to minimise turbulence and to remove dust particles from around the horses breathing zone (head height);  Using positive or negative pressure systems that bring air in through a series of holes in the roof and exhaust air at a lower level along the walls; Developing "low dust stables" that are free of hay and straw, with wood shavings spread over a rubber matting on the floor; and  Providing sufficient airspace for each horse.
Implications	Dust is an important factor in the health and fitness of horses. The link between respiratory disease and dust requires further study to understand the effect of bioaerosols on the physiology and immune responses of the horse.  Although data is available from other countries, a survey of horse housing facilities is recommended.

 
 

Project Title	Information Services for the Horse Industry
RIRDC Project No.:	UCS-18A
Researcher:	Associate Professor Martin Sillence
Organisation:	Charles Sturt University School of Agriculture,  Charles Sturt University PO Box 588 WAGGA WAGGA NSW 2678
Phone:	02 6933 2205
Fax:	02 6933 2812
Email:	msillence@csu.edu.au
Objectives	To find a way of meeting the information needs of the horse industry.
Background:	A primary objective of RIRDC is to help the Australian horse industry gain access to ‘state of the art’ information. Departments of Agriculture have not included the horse industry in their normal extension services, so there is no facility for a lay person to initiate an inquiry or find scientific information that is easily understood. This project was carried out in the context of a plan to establish an Equine Information Service.
Research	In part 1 of this project we asked 321 members of the horse industry about their information needs, and how they thought an information service should be operated. In part 2 we identified the best sources of reliable information. In part 3 we examined information services and computer systems used by other industries. In part 4 we formed a business plan for an Equine Information Service.
Outcomes	The horse industry is strongly in favour of an Equine Information Service. Information is currently obtained though books, magazines and word of mouth, with the most popular topics being health, nutrition and training/exercise. Most of the participants would like to be able to obtain information by mail or fax, through an information service that is funded by a combined system of user pays, government subsidy and industry levy. Several industry information services are operating successfully in Australia, and these use a range of computer systems for managing information that vary in price and complexity.  A large amount of horse information has been identified, and much of this is available through the library at Charles Sturt University. We propose that this University establishes an information service in partnership with the horse industry. The service would be accessible by phone, fax or internet and provide comfortable public access areas. The set up cost will be $43, 562 and running costs will be $29, 462 per year. Charles Sturt University will provide free accommodation for the service, and up to $90, 000 over three years towards the literature and running costs. Industry sponsors are being sought for the additional financial support required.
Implications	There is a demand for an Equine Information Service in Australia. Charles Sturt University will establish such a service, if additional industry support can be found.

Project Title	Diagnosis of equine virus diseases using polymerase chain reactions and development of a blood test and vaccine for equine rhinovirus.
RIRDC Project No.:	UM-23A
Researcher:	Professor M.J. Studdert, Dr C.A. Hartley, Dr H.E. Drummer.
Organisation:	The Centre for Equine Virology, The University of Melbourne. Cnr Park Dve and Flemington Rds, Parkville, VIC 3052
Phone:	+61-3-9344-7373
Fax:	+61-3-9344-7374
Email:	m.studdert@vet.unimelb.edu.au
Internet:	http://www.vet.unimelb.edu.au/research/CEV.html
Objectives	To improve existing diagnostic procedures by the development of a comprehensive set of primers for use in polymerase chain reaction (PCR) tests for all endemic equine virus diseases in Australia, and  By the development recombinant DNA technology to engineer antigens for use in a blood test and vaccine for ERhV1.
Background:	It is suggested that 50% of all calls veterinarians make to horses in racing are for viral respiratory disease. These diseases are responsible for many expensive treatments, poor performance and many lost training days. Improved methods that are more rapid and sensitive for the diagnosis of equine herpesvirus 1 (equine abortion virus, EHV1), EHV4 (equine rhinopneumonitis virus), EHV3 (equine coital exanthema virus) the equine gammaherpesviruses EHV2 and EHV5, equine adenovirus 1 (EAdV1), EAdV2, equine arteritis virus, equine rhinovirus (ERhV) are required.
Research	PCR tests have been developed for EHV1, EHV4, EHV3, EHV2, EHV5, ERhV1, EAdV1, EAdV2, equine arteritis virus and equine influenza virus. Of these tests the EHV1, EHV4, EHV2, EHV5 and ERhV1 tests have been implemented into our diagnostic laboratory at the Centre for Equine Virology. The remaining tests require further rigorous validation on clinical material before they can be confidently used in this setting. Implementation of these PCR tests in the laboratory has reduced the time required to obtain and report a result once a sample has been received. Furthermore, the use of PCR has enabled the retrospective diagnosis of ERhV1 as the cause of several outbreaks of febrile respiratory illness in horses in which no virus could be isolated.
Outcomes	Substantial progress was also made in the development of recombinant DNA technology to engineer antigens for use in a blood test and vaccine for ERhV1. Insect cells were engineered to produce the structural proteins of ERhV1.
Implications	This system has been shown for other proteins to enable extremely high levels of expression of recombinant proteins which are structurally very similar to their authentic couterparts. High levels of unprocessed ERhV1 capsid proteins have now been expressed and further work is currently underway to establish expression of the processed ERhV1 capsid proteins and to establish their suitability for use as a blood test and vaccine.
Publications	1. Li, F., H. E. Drummer, N. Ficorilli, M. J. Studdert, and B. S. Crabb. 1997. Identification of noncytopathic equine rhinovirus 1 as a cause of acute febrile respiratory disease in horses. Journal of Clinical Microbiology. 35:937-943. 2. Reubel, G. H., and M. J. Studdert. 1997. Identification, cloning and sequence analysis of the equine adenovirus 1 hexon gene. Arch Virol. 142:1193-212. 3. Reubel, G. H., and M. J. Studdert. 1997. Sequence analysis of equine adenovirus 2 hexon and 23K proteinase genes indicates a phylogenetic origin distinct from equine adenovirus 1. Virus Res. 50:41-56. 4. Reubel, G. H., and M. J. Studdert. 1998. Benefits and limitations of polymerase chain reaction (PCR) in veterinary diagnostic virology. Vet Bull. 68:505-516.

 
 

Project Title	Methods of quantitative assessment for intra pulmonary blood accumulation in racehorses with EIPH
RIRDC Project No.:	UM-36A
Researcher:	Professor Ron Slocombe, Dr. Shaun McKane
Organisation:	University of Melbourne School of Veterinary Science,  Princes Highway, Werribee, 3030.
Phone:	03 9742-8264
Fax:	03 9741-0401
Email:	r.slocombe@vet.unimelb.edu.au
Objectives	To develop quantitative in vivo methods for measuring the volume of extravascular blood present in the lungs of horses after a single known blood inoculums of blood into normal horse lungs and in animals with experimental EIPH. To determine the extent and nature of sequential structural changes to lungs after inoculation with known volumes of blood, and correlate this with changes in lung cell populations seeen typically with field cases of EIPH.
Background:	Although the causes for EIPH are well known, this problem remains very important in the racing industry because little is known about how blood is removed from the lungs once haemorrhage develops, and the ability to identify the extent of haemorrhage after exercise remains limited. Treatment therefore remains inadequate. This project explores ways to estimate both the extent of haemorrhage after episodes of EIPH and also identify the effects of blood on lung structure and function.
Research	Studies were conducted to evaluate the sequential events important in the removal of blood after segments of lung were inoculated with blood or controls using saline. We also investigated whether mild inflammation was a risk factor predisposing lung segments to further episodes of EIPH. The usefullness of radiolabelled erythrocytes as a marker for haemorrhage was investigated using scintigraphy scans of the thorax.
Outcomes	Blood is cleared slowly from the lungs by 2 mechanisms after installation, both are not completely effective, and blood causes residual inflammation and scarring that persists for at least 21 days. Lung inflammation was shown to be a risk factor for EIPH. Scxintigraphy using technetium labelled eryhtrocytes was not found to be a practical way of determining the extent of haemorrhage in lungs after episodes of EIPH.
Implications	Our data suggests that horses at risk of severe EIPH should be allowed additional time for the lungs to heal prior to racing. In addition, inflammtion of lung tissues predisposes to EIPH and therefore efforts to minimize lung damage due to environmental and infectious factors in routine management of racehorses is warranted. Methods to estimate the severity of EIPH in living animals remain inexact and further research is required to address this issue.
Publications	McKane,S.A., Bayly, W.M., Sides, R.H., Kingston, J.K. and Slocombe, R.F. Autologous blood infusion into the lungs interferes with gas exchange and performance in exercising horses. WEAS Conference, Ontario, Canada, 1998. Slocombe, R.F. and McKane, S.A. Exercise-induced pulmonary haemorrhage - part 1. The Veterinarian May p10-12, 1998. Slocombe, R.F. and McKane, S.A. Exercise-induced pulmonary haemorrhage - part 2. The Veterinarian June, p12-15, 1998. McKane, S.A. and Slocombe, R.F. Sequential changes in bronchoalveolar cytology after autologous blood inoculation. Equine Vet J. (ICEEP 5 supplement) accepted for publication. 1999. McKane, S.A. Physiologic and pathologic effects of Exercise-Induced Pulmonary Haemorrhage on the equine lung. PhD dissertation, University of Melbourne, 1999.

 
 

Project Title	Studies on the intestinal absorption of immunoglobulins and the effects of passive immune status on neutrophil function in foals
RIRDC Project No.:	UMU-18A
Researcher:	Sharanne Raidal
Organisation:	School of Veterinary and Biomedical Sciences Murdoch University,  WA 6150
Phone:	08 9360 2356
Fax:	08 9310 7495
Email:	sharanne@numbat.murdoch.edu.au
Objectives	To further understanding of immunity in the newborn foal by: Determining whether the type of fluid fed to foals immediately after birth can prolong the time when colostrum can be effectively administered to boost immunity. Evaluating the effect of age and passive immune status on the development of white blood cell function in foals. Examining the effects of intravenous plasma administration to healthy and septic foals on white blood cell function.
Background:	Foals usually acquire immunity from their dams by the ingestion of colostrum immediately after birth. The failure of this passive transfer of maternal immunity to the foal is the greatest risk factor for the development of infectious disease in the first weeks of life. Our understanding of foal immunity and susceptibility to disease is poor. Almost exclusively, studies to date have focused on the antibody (IgG) status of foals and little work has been completed evaluating other aspects of foal immunity, such as white blood cell function. We know that antibodies in colostrum are absorbed from the foal’s small intestine for a short time after birth. We do not know what determines when antibodies can no longer be absorbed and we do not know if the absorptive process can be prolonged. Plasma transfusion is routinely advised when foals fail to absorb an "adequate" amount of colostral antibodies. However, we do not know that this procedure is effective at reducing the incidence of septic disease or whether it has any beneficial effect for the foal other than a transient increase in circulating antibody levels.
Research	Research was conducted in two parts. Firstly the effect of delaying the ingestion of colostrum was evaluated in foals fed a glucose and electrolyte solution or a milk replacer. Colostrum was milked from each mare and fed to her foal from 12 hours after birth. The amount of IgG absorbed and aspects of white blood cell function were assessed for each foal. In the second part of the study, the effect of plasma transfusion of healthy and septic foals with failure of passive transfer of immunity was assessed, again by evaluation of circulating IgG concentrations and white blood cell function.
Outcomes	Delayed ingestion of colostrum was associated with levels of IgG that are currently considered inadequate for the prevention of septic disease. However, the administration of colostrum at 12 hours post partum was associated with the absorption of approximately 50% of administered IgG and improved cell function in adult cells assayed with foal serum. Plasma transfusion resulted in a significant increase in circulating IgG concentration, the response to treatment being better in healthy foals than septic foals. Treatment was not associated with a beneficial effect on white blood cell function for healthy foals, but there was a transient benefit on neutrophil function in septic foals. Passive immune status (IgG concentration) correlated poorly with white cell function at all sampling times in both parts of the current study, suggesting that other factors are important determinants of immunity in the foal.
Implications	The findings of the first part of the study support current recommendations that colostrum should be administered to foals within 12 hours of birth. However, even delayed ingestion of colostrum may be beneficial. If colostrum cannot be provided immediately after birth, the choice of fluid given to foals does not influence the subsequent efficiency of IgG absorption. The second part of the study did not support routine plasma transfusion of healthy foals with failure of passive transfer of immunity. Conversely, treatment of septic foals had a transient positive effect on cell function, suggesting that multiple transfusions should be considered during the course of therapy. Although the association between low circulating IgG levels and foal sepsis is well proved, the results of the current study suggest that consideration of IgG levels alone as a marker of foal immunity may be simplistic.

 
 

Project Title	Control of intraocular inflammation by topically applied non steroidal anti-inflammatory drugs (NSAIDS)
RIRDC Project No.:	UQ-59A
Researcher:	SM Taylor & IA Shiels
Organisation:	Department of Physiology and Pharmacology University of Queensland,  ST LUCIA, QLD 4072
Phone:	07 3365 3124
Fax:	07 3365 1766
Email:	s.taylor@mailbox.uq.oz.au
Objectives	To develop a laboratory-based test to evaluate new anti-inflammatory drugs to treat equine recurrent uveitis.
Background:	Equine recurrent uveitis is a recurring inflammation in the eye which can cause blindness. The disease is treated with anti-inflammatory drugs, mostly steroidal and nonsteroidal compounds. The disease is difficult to control because of the ongoing pathology, and current therapy is inadequate. A range of novel anti-inflammatory drugs are being synthesised and there is a need to have a test to screen these compounds without having to use painful procedures in laboratory animals.
Research	A model of uveitis was developed to screen drugs for anti-inflammatory activity in the laboratory. The technique uses eyes removed from cadavers and their viability is maintained for a number of hours by perfusing nutrient fluid through the vasculature. The tissues respond to inflammatory substances infused into the eye. The induced inflammatory signs can then be blocked, or reversed, by drugs administered to the eye. One of the new compounds tested has been shown to have better anti-inflammatory activity than existing nonsteroidal drugs and is being prepared for clinical trials.
Outcomes	The development of this test has enabled the evaluation of a number of new drug compounds quickly and cheaply. The test does not require animal suffering.
Implications	The test should speed the evaluation of new products at less cost. Compounds with activity would then require further evaluation in animal models and clinical trials.
Publications	A manuscript has been accepted for publication in the Australian Veterinary Journal

 
 

Project Title	Studies on host-parasite interactions in disease (strangles) induced by streptococcus equi subspecies equi
RIRDC Project No.:	US-24
Researcher:	Paul J Canfield
Organisation:	Department of Veterinary Anatomy and Pathology,  University of Sydney,  NSW 2006
Phone:	02 9351 2020
Fax:	02 9351 7421
Objectives	To understand the very early interactions between the horse and the causative bacterial agent of strangles ie Streptococcus equi subspecies equi and in so doing, lay the foundation for further studies aimed at development of improved control strategies including development of newer generation vaccines.
Background:	It has been estimated that strangles accounts for a minimum direct loss to the industry of $6.5 million annually. Indirect costs in reduced export opportunities and adverse publicity associated with outbreaks of the disease in horses exported from Australia to other countries would bring the losses much higher. Thus, strangles has been rated by the industry as amongst the most important endemic disease in horses and many sectors within the industry have expressed their wish for effective control of this contagious disease. Current control involves the use of killed vaccines and management procedures that rely primarily on recognition of clinical cases of infection. Such procedures often result in horses with early strangles being introduced into groups on farms or into racing stables and subsequent outbreaks occurring. Furthermore, carrier animals are now considered to exist and there is no means available currently to identify these animals.
Research	This report describes the experimental reproduction of strangles in groups of horses and the subsequent host cell interactions with the strangles organism.
Outcomes	The experimental reproduction of the disease allowed documentation of the very early clinical signs of strangles and led to the recognition that significant changes could be detected in the lymph glands in the head before any other signs of strangles were obvious and much earlier than reported by any previous work. It also found that specific parts of the nasal passages of horse were involved in strangles infection and that changes in tissues associated with the carriage of strangles organism could be recognized at these specific sites.
Implications	These results should allow much earlier detection of horses incubating strangles and be of considerable benefit in the management of the disease. The research also suggested a means for development of a diagnostic test to detect carrier animals.

 

Project Title	Lower respiratory tract disease in racehorses
RIRDC Project No.:	US-33A and US-41A
Researcher:	Dr R.M. Christley, Dr J.L. Hodgson, Dr J.L. Wood, Prof. S.W.J. Reid, Prof. R.J. Rose, Prof. D.R. Hodgson
Organisation:	University of Sydney University Veterinary Centre  PMB #4 Narellan Delivery Centre NARELLAN NSW 2567
Phone:	02 4655 0777
Fax:	02 4655 6942
Email:	jennih@camden.usyd.edu.au
Objectives	To better define the risk factors associated with development of lower respiratory tract disease in racehorses. These risk factors included the association of infectious organisms (viruses, bacteria and mycoplasma) with respiratory disease in Australian horses.
Background:	Respiratory disease continues to be a major problem in the thoroughbred racing industry. A recent survey of racehorse trainers found coughing to be one of the most serious problems facing the industry. While there have been a numbers of studies examining the possible causes of respiratory disease in racehorse, there is scant information regarding the relative contribution of each of these causes to the respiratory disease observed. This deficiency has obvious implications for the treatment, control, and management of coughing horses.
Research	We used a matched, case control study to investigate the role of specific infectious agents in causing respiratory disease in racehorses in Sydney. In this study, cases were identified by the presence of coughing. These horses were compared to a control population (non-coughing horses) in order to identify risk factors for coughing and to evaluate the association between coughing and clinical, pathological and microbiological findings.
Outcomes	A number of risk factors were identified for coughing. Young horses in early training were at greatest risk of coughing. Horses that had raced within the previous week or had been transported more than 14 days previously were also at increased risk. There was no association between coughing and recent exposure to viruses, including Equine Herpesvirus-1 and –4, and Equine Rhinoviruses-1 and –2. Approximately 40% of horses had a significant number of bacteria isolated from their lower airways which would suggest a role of these agents in lower respiratory tract disease. However, approximately 60%% of horses had no evidence of an infectious cause to the respiratory disease.
Implications	The findings from these studies should greatly change our current concepts of respiratory disease in athletic horses. The finding that viruses appear to have a minor role in causing disease in this group of horses may influence some of the current control strategies such as vaccination. In addition, while bacteria may be associated with coughing in a proportion of cases, a majority of horses had no evidence of bacterial infection. This would imply that antibiotics may be currently being over-prescribed and that steps to specifically diagnose the cause of respiratory disease in horses should be recommended.
Publications	Christley RM, Hodgson DR, Rose RJ, Reid SWJ, and Hodgson JL (1999) Comparison of bacteriological and cytological findings of tracheal fluid samples collected by percutaneous aspiration and via an endoscope using a plugged guarded cather. Equine Veterinary Journal, 31, 197-202. Christley RM (1998) Respiratory disease in racehorses; what is it? Equine Research Seminar, Post Graduate Foundation in Veterinary Science, University of Sydney, pp1-7. Christley RM, Wood JLN, Reid SWJ, Hodgson DR, Rose RJ, Hodgson J (1999) Risk factors for coughing in thoroughbred racehorses. In: Proceedings of the Society for Veterinary Epidemiology and Preventative Medicine, Eds: MV Thrushfield and EA Goodall. (In press).

 
 

Project Title	In vitro biomechanical properties of equine digital flexor tendons
RIRDC Project No.:	US-52A
Researcher:	Mr. Andrew Dart
Organisation:	University Veterinary Centre Camden.  PMB 4 Narellan Delivery Centre,  NARELLAN NSW 2567
Phone:	02) 46 550777
Fax:	(02) 46 551212
Email:
Objectives	To evaluate the biomechanical and biochemical properties of normal and healing equine superficial digital flexor tendons (SDFT). In addition the effect of a novel product, recombinant equine somatotropin was assessed on normal and healing tendons.
Background:	Superficial digital flexor tendon injury is a major cause of musculoskeletal injury affecting up to 30 % of horses in race training. Healing of SDFT injuries tends to be slow, with re-injury common. It has been reported that only approximately 20-60 % of affected horses may successfully return to racing with up to 80 % of horses sustaining re-injury. Recent investigations in tendon pathology have found age and exercise related changes to occur in equine tendons. These degenerative alterations may predispose the tendon to injury. The mechanisms of age related changes in musculoskeletal tissue composition and mechanical behaviour are diverse and complex. However, the role of declining circulating concentrations of various growth factors has been incriminated.
Research	Three experiments were performed examining the in vitro biomechanical properties of the metacarpal region of forelimb equine superficial digital flexor tendons. Experiment 1 was aimed at determining the in vitro biomechanical properties of forelimb SDFT from horses without evidence of clinical tendonitis. Experiment 2 examined the effect of equine recombinant somatotropin (eST) on the in vitro biomechanical properties of normal tendons. Experiment 3 examined the effect of eST administration on the in vitro biomechanical properties of healing tendons.
Outcomes	Despite the problems associated with in vitro biomechanical testing, the methodology was shown to be repeatable, and, to provide objective data on the biomechanical properties of tendons in response to various treatments. The lack of detectable effect of eST on the biomechanical properties of normal, mature SDFT may be related to a number of factors. The equine SDFT has been shown to reach maturity at approximately 2 to 3 years of age. It is possible that mature tendons have a reduced capacity to respond to an eST stimulus given the cellular changes that are apparent with maturity and within the metacarpal region of SDFT. In addition previous exercise history and eST dose rate may have influenced biomechanical response of the tendons. Further investigations into tendon responses to eST at different dose regimens, in immature animals, and under controlled exercise programs may be indicated. The biomechanical results support diminished structural properties in the eST treated healing tendons. This may be due, in part, to an immature or biomechanically inferior, disorganized collagenous matrix. Future histological and immuno-histochemical analysis will help to determine the exact effect of eST on collagen synthesis and ultrastructural organisation.
Implications	Despite the apparently negative findings of this study, the pharmacological basis behind the use of eST in healing of collagenous tissue injuries, including tendonitis is relatively sound. Further investigations may be warranted using the described techniques, however a longer treatment period prior to biomechanical testing may yield more favourable results.

 
 

Project Title	Serological investigation of Equine influenza in Australia
RIRDC Project No.:	US-58A
Researcher:	Dr Jennifer Hodgson
Organisation:	University of Sydney University Veterinary Centre Camden PMB 4 Narellan Delivery Centre NARELLAN NSW 2567
Phone:	(02) 4655 0745
Fax:	(02) 4655 6942
Email:	jennih@camden.usyd.edu.au
Objectives	To determine the status of Equine Influenza in Australian horses using serological investigations.
Background:	Equine Influenza (EI) is a major cause of respiratory disease of horses in Europe and North America where it accounts for extensive losses to equine industries both in terms of money and performance. Australia is one of the few countries in the world that is free of EI and the current quarantine protocols for entry of horses into Australia have been designed to ensure this continued freedom. In addition, exportation of horses from Australia is considerably facilitated by the absence of this viral infection. Recently, however, freedom of Australian horses from EI virus infection has been questioned by countries importing horses from Australia, and also by the Office International des Epizootiques (OIE). Consequently, demonstration of our continued freedom was of great importance for our equine import and export industries.
Research	In order to investigate the status of EI in Australia we collected two serum samples from 248 horses in the Sydney Metropolitan Region. This was part of a larger study investigating respiratory disease in racing thoroughbreds. The design of the investigation was a case control study, where identical samples were collected from cases (horses with signs of respiratory disease) and controls (horses that were clinically normal). In this way, differences between cases and controls could be assessed. By collecting samples form horses exhibiting signs of respiratory disease (coughing), we increased the likelihood of detecting antibodies to EI virus, as coughing is the most common sign associated with this infection. Two samples were collected from each horse in order to detect rising antibody titres which is indicative of recent infection. The collected serum samples were frozen and sent to the Animal Health Trust (AHT) in Newmarket, England for processing. The AHT is the official European Laboratory for assaying serum samples for presence of antibodies to EI virus. The assay routinely performed at the AHT is called the Haemagglutination Inhibition (HI) assay and this test is considered the gold standard for detecting antibody to EI virus with a very high sensitivity and specificity.
Outcomes	None of the serum samples assayed had evidence of antibodies to EI virus. This was in contrast to other respiratory viruses assayed (including Equine Herpesviruses-1 and –4 and Equine Rhinoviruses-1 and –2) where there was evidence of recent seroconversion in a low number of horses. By assaying serum samples from 248 horses we estimated that we would detect the presence of antibodies to EI virus in the Australian horse population with 95% confidence should these antibodies be present in as few as 1-2% of horses. However, there are several strong arguments that suggest our degree of confidence in detection of EI was in fact much higher. First, Thoroughbred race horses were the ideal population to sample as they are among the most likely candidates to have been exposed to EI virus had it been introduced to Australia. In addition, this population is extremely mobile, with horses from Sydney, Melbourne and Brisbane frequently co-mingling at race meetings. Consequently, as this virus is highly infectious and the Australian equine population is naïve, we would have expected a very rapid spread of the virus and evidence of this serologically in the Sydney horses, even if the virus were introduced in another part of the country. Finally, coughing is the most commonly reported sign associated with EI virus infection. As our study included 100 horses with respiratory disease as defined by coughing, this would increase significantly the likelihood of detection of this virus.
Implications	This study has demonstrated that there was no serological evidence of equine influenza in racehorses in the Sydney Metropolitan region, including horses demonstrating signs of respiratory disease. Due to the highly infectious nature of the virus, and the frequency with which horses in race-training con-mingle with horses both from Sydney and other parts of Australia, this data lends strong support to our continued freedom from the EI virus in Australia. These results should offer persuasive reassurances to our equine trading partners.