RIRDC Completed Projects in 2002-2003 & Research in Progress as at June 2003

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3.5 HORSES - COMPLETED PROJECTS
PROJECT No	PROJECT TITLE	RESEARCHER	PHONE	ORGANISATION
1. Information Technology for the Horse Industry
US-95A	Communication and Information Programs for the Horse Industry	Shirley Ray	(02) 9352 6932	The University of Sydney
3. Respiratory Diseases-Improving the Respiratory Health of Horses
UM-47A	Effects of stud management on ecology of virulent Rhodococcus equine	Dr. Glenn Browning	(03) 8344 7342	The University of Melbourne
US-82A	A Longitudinal and Case Control Study of Inflammatory Airway Disease in Young Racing Thoroughbreds	Dr. Jennifer Hodgson	(02) 4655 0760	The University of Sydney
US-96A	Investigations of Equine Herpesvirus 1 Cycle of Infection in Foals	A/Prof. Millar Whalley	(02) 9850 8200	The University of Sydney
4. Nutrition Research-Development Better Ways to Feed Horses
ULA-14A	Glucose synthesis in equine hepatocytes	Dr. Theresa Frankel  Dr. Markandeya Jois	(03) 9479 2180	La Trobe University
UQ-72A	Pasture intake by young horses	Dr. Neil McMeniman	(07) 3365 1108	The University of Queensland
8. Improving Racetracks and Working Surfaces for Horses
PTP-18A	7TH Australian Racecourse Managers Conference, 2002	Arthur Stubbs	(03) 9844 1135	Primary Tasks Pty Ltd
9. Other
EVA-1A	2002 Bain - Fallon Conference (Gold Coast)	Dr. James Gilkerson	(02) 6545 1607	Hunter Valley Equine Research Centre


 

1. Information Technology for the Horse Industry

Project Title:	Communication and Information Programs for the Horse Industry
RIRDC Project No.:	US 95A
Researcher:	Shirley Ray
Organisation:	Faculty of Veterinary Science University of Sydney Sydney, NSW 2006.
Phone:	(02) 9351 6935
Fax:	(02) 9351 3056
Email:	shirleyr@camden.usyd.edu.au
Objectives	To provide a strong communication program to ensure widespread industry support for the RIRDC Equine R&D Program and to enable the results of the R&D to be used by the Australian horse industry.
Background	In 1996, RIRDC commissioned a survey of Australian horse groups in order to formulate research priorities for the RIRDC Equine R&D Program. An important outcome of the survey was that communication came across as an important priority. Until the RIRDC Equine R&D Program commenced in 1995, there was no vehicle for communication with the horse industry and no availability of independent research based information.
Outcomes	· A database of equine organisations. A database for communication with the industry · RIRDC Equine Research News. The newsletter of 8 pages, published quarterly, provides the industry with information on topical research from around the world as well as updates on current RIRDC funded projects, interviews with research workers, workshops and invited reviews. · RIRDC Internet Web Site. An Internet web site for the RIRDC Horse Program which includes links for online purchase of RIRDC publications, download of the RIRDC Equine Research News, search facility for past issues and a subscription facility to receive the RIRDC Equine Research News via the Internet.
Implications	The database contains 1530 unique entries, which comprise horse associations, research institutions and individuals in the Australian horse industry. Since the RIRDC Equine Research News was first published in June 1995, all major horse industry groups have received information about equine research projects that are of interest to the industry groups and also regular updates of research and development projects supported by RIRDC. The Internet web site has provided a way of providing the past and future editions of the newsletter indexed and readily used by researchers, horse organisations, individuals and groups overseas. The web site has received nearly 100,000 hits since it was launched in 1997


 

3. Respiratory Diseases-Improving the Respiratory Health of Horses

Project Title:	Effects of stud management on ecology of virulent Rhodococcus equine
RIRDC Project No.	UM-47A
Researcher:	Glenn F Browning, James R Gilkerson and Gary Muscatello
Organisation:	School of Veterinary Science The University of Melbourne
Phone:	(03) 8344 7342
Fax:	(03) 8344 7374
Email:	glenfb@unimelb.edu.au
Objectives	To develop methods to improve understanding of the factors that make some areas on horse farms a greater risk for development of rattles in foals and apply these to identifying factors that might be addressed by changes in management of farms.
Background	Although rattles is an important disease problem in young foals there are limited options for control. Current methods rely on reducing faecal contamination and dust on studs, but we have little understanding of whether these are the only factors that account for higher infection and death rates on some studs.
Research	This project aimed to develop novel methods for assessing the risk associated with particular horse farm environments. These methods were based on bacteriological sampling of air and soil on studs, then identifying those bacteria capable of causing rattles. Once these methods were developed they were applied to examination of different horse farms and different places on those farms.  The method that was developed was also used to examine the breath of foals with rattles. This suggested that foals may be able to transmit virulent R. equi to each other.
Outcomes	The most dangerous areas on studs for foals are likely to be laneways and holding pens. Control may be aided by reducing the time that foals spend in these areas. In addition areas that had sandy, dry and/or acidic soils seemed to be a greater risk. Some control may also be achieved by avoiding close contact between foals, particularly if they are known to be suffering from rattles. Sampling air from foals may be a sensitive diagnostic technique for the early detection of infected foals.
Implications	Application of methods developed in this project have provided some suggestions for reducing the incidence of rattles and further use of these methods may enable the benefit obtained from different approaches to control to be assessed. Different approaches to treatment may also be able to be assessed.
Publications	Identification and Differentiation of Rhodococcus equi Using a Colony Blotting DNA Hybridization Technique. G. Muscatello, G.F. Browning, submitted. Ecology of Virulent Rhodococcus Equi on Six Victorian Thoroughbred Horse Farms. G. Muscatello, S. Church, T.C. Lowis, K.G. Whithear, G.F. Browning, in preparation. Detection of Virulent R. Equi From The Breath of Foals and Comparison of Concentrations of Virulent R. Equi with that Seen In Environmental Air Samples. G. Muscatello, S. Church, J. Hurley, J.F. Freestone, K.G. Whithear, J.R. Gilkerson, G.F.Browning, in preparation. Detection Of Infection Of Foals With Virulent Rhodococcus equi by Quantitative Breath Sampling and a VapA Specific ELISA G. Muscatello, J.F. Freestone, T.Phumoona, M.W. Heuzenroeder, J.R. Gilkerson, G.F. Browning, in preparation.


 

Project Title:	A Longitudinal and Case Control Study of Inflammatory Airway Disease in Young Racing Thoroughbreds
RIRDC Project No.:	US 82A
Researcher:	Nicholas Malikides and Jennifer L.Hodgson
Organisation:	University of Sydney Univeristy Veterinary Centre, Camden PMB 4 Narellan Delivery Centre, Narellan. NSW. 2567
Phone:	(02) 9351 1768
Fax:	(02) 46 55 1212
Email:	nickm@camden.usyd.edu.au; jennih@camden.usyd.edu.au
Objectives	To determine the incidence of inflammatory airway disease (IAD) in 2-3 year old racing thoroughbreds. 2. To determine stable management and environmental risk factors, including dust endotoxin and (1® 3)-b -D-glucan, associated with the development of this respiratory disease.
Background	Much information is now known about chronic inflammatory airway diseases in horses, as well as infectious airway diseases caused by specific viruses and bacteria. However, little epidemiological research has been performed, particularly under Australian conditions, on acute IAD due to non-infectious agents such as dust toxins, and stable management and environmental factors.
Research	A longitudinal study, in which a case-control study was tested, was performed over 22 months using a cohort of 2 and 3 year old racing thoroughbreds. Historical, stable management and meteorological information, as well as tracheal aspirates for cytological and bacteriological analysis and blood for serological analysis, was collected from 235 horses, on 3 occasions (Day 0, 14 and 28). Furthermore, 54 cases of IAD and 58 controls were identified, and dust samples for determination of endotoxin and (1® 3)-b -D-glucan concentrations, and ammonia and carbon dioxide gases, were collected from these horses. Univariable and multivariable regression modelling was used for analysis of data.
Outcomes	It was estimated that 40.3% of healthy 2 and 3 year old racehorses housed in stables developed neutrophilic IAD within the first 2 weeks. Significant risk factors for IAD included poor box ventilation, high environmental evaporative conditions and feeding straw-like hay. Furthermore, there was a significant exposure-response relationship between average percentage of neutrophils in lower airways and exposure to high dust endotoxin concentrations. Factors not associated with IAD included (1® 3)-b -D-glucan, sex, trainer, stable area, factors related to current training, bedding type, other stable management factors and infection with common respiratory viruses.
Implications	We now have a clearer understanding of the sequence of events leading to lower airway inflammation and subsequent respiratory disease development in young racehorses. In addition, we now know that IAD occurs far more frequently than realised, and we have identified many important risk factors associated with the disorder in young racing thoroughbreds in Sydney. This knowledge should justify implementation of management and therapeutic interventions to reduce exposure to dust and dust endotoxin from feed, bedding and other sources.
Publications	Malikides, N. 2002. Effect of respirable endotoxin on neutrophilic inflammation of proximal airways in young thoroughbred racehorses in the Sydney metropolitan region Proc. of Havemeyer Trust Symposium, Boston.

Project Title:	Investigations of Equine Herpesvirus 1 Cycle of Infection in Foals
RIRDC Project No.:	US-96A
Researcher:	Millar Whalley and Daria Love
Organisation:	Macquarie University and The University of Sydney
Phone:	(02) 9850 8200
Fax:	(02) 9850 8245
Email:	mwhalley@rna.bio.mq.edu.au
Objectives	To investigate the epidemiology of EHV-1 and EHV-4 in vaccinated populations of mares and their young foals and to study the response to vaccination with a commercially available whole virus vaccine.
Background	Previous studies identified mares as the source of infection for their young foals, who then pass infectious virus onto other foals before and after weaning. This cycle of silent EHV-1 infection occurred in the absence of any recorded EHV-1 abortions on the farms under investigation. It was of interest to know whether the introduction of routine vaccination had had an effect on the circulation of these viruses, and had not been previously reported for large populations of horses in the field.
Research	Nasal swab and blood samples were collected from vaccinated populations of over 200 mares, their young, unweaned unvaccinated foals, and also in vaccinated weanlings. Samples were assayed for EHV-1 or EHV-4 DNA and antibody by ELISA. The prevalence of EHV-1 antibody was compared in years prior to and following the implementation of the vaccine.
Outcomes	Cases of EHV-1 and EHV-4 infection were identified by PCR and serologically in vaccinated mares, unweaned unvaccinated foals and also in weanlings. The youngest EHV-1 PCR positive foal was 22 days of age while the youngest EHV-4 PCR positive foal was only 11 days of age. The results provided unequivocal evidence that the cycle of EHV-1 and EHV-4 infection was continuing in vaccinated populations of mares and their young foals. This was supported by serological data.
Implications	The results confirm that although the vaccine may result in a reduction in the period of excretion of virus, and reduce disease experimentally, the vaccine regimen used is not sufficient to prevent EHV-1 or EHV-4 infecting new foals. This then perpetuates the cycle of infection in the population. This information is potentially extremely valuable for farm management who should be made aware of this when considering their management strategies.
Publications	C E Foote, D N Love, J R Gilkerson, J M Whalley (2001) Serological responses of mares and weanlings following vaccination with an inactivated whole virus Equine Herpesvirus 1 and Equine Herpesvirus 4 vaccine. Proceedings of the International Horse Industry Symposium, Sydney 2001  C E Foote, D N Love, J R Gilkerson, J M Whalley (2001) Serological responses of mares and weanlings following vaccination with an inactivated whole virus Equine Herpesvirus 1 and Equine Herpesvirus 4 vaccine. Australian Equine Veterinarian 19, 68-69 J R Gilkerson, C E Foote, D N Love, J M Whalley (2001) Epidemiology of Equine Herpesvirus 1 (EHV-1). Australian Equine Veterinarian 19, 70 C E Foote, D N Love, J R Gilkerson, J M Whalley (2002) Serological responses of mares and weanlings following vaccination with an inactivated whole virus equine herpesvirus 1 and equine herpesvirus 4 vaccine. Veterinary Microbiology 88, 13-25 C E Foote, J R Gilkerson, J M Whalley, D N Love (2002) Seroprevalence of equine herpesvirus 1 in mares and foals on a large Hunter Valley stud farm in years pre- and post- vaccination. Australian Veterinary Journal In press


 

4. Nutrition Research-Development Better Ways to Feed Horses

Project Title:	Glucose synthesis in equine hepatocytes
RIRDC Project No.:	ULA-14A
Researcher:	Drs T. L. Frankel and M. Jois
Organisation:	Department of Agricultural Sciences La Trobe University
Phone:	(03) 9479 2180
Fax:	(03) 9471 0224
Email:	T.Frankel@latrobe.edu.au
Objectives	· provide training in research for an Honours student  · modify the technique for isolation of ovine hepatocytes so it can be used on equine livers · determine the in vitro effects of hormones and other metabolites on glucose synthesis in isolated hepatocytes · determine the effects of diet on the ex vivo rate of glucose synthesis from propionic acid in isolated hepatocytes
Background	Energy sources in horses are those absorbed from the small intestine and the volatile fatty acids (VFA) synthesised in and absorbed from the large intestine. Although it is suggested that about half the circulating glucose is derived from the VFA propionic acid there is no information on its site or rate of synthesis. In ruminants site of production is primarily the liver and factors influencing the rate of synthesis of glucose have been studied in isolated liver cells obtained directly after death. In horses there are no reports of a technique to isolate and study the function of liver cells (hepatocytes) despite the usefulness of the technique for understanding the many metabolic functions of the liver.
Research	This is the first report of the isolation of equine hepatocytes and adapting the method used in sheep proved more complex than originally expected. The variation in liver morphology, especially in the preferred caudate lobe, limited choice of a lobe with suitable in/out blood supply. The left medial lobe was selected after examining a range of livers from different sized horses. Using abattoir tissues rather than livers from purpose selected animals showed that sampling time after death and provision for immediate perfusion of the lobe with an ice-cold EGTA solution was critical for the isolation of viable liver cells. Possible differences (between sheep and horses) in cell structure resulted in relatively longer times of perfusion with greater amounts of collagenase solution. Despite these changes a still unexplained ‘frothing’ occurred in the perfusion fluid and this had the potential to block small capillaries, reducing oxygen supply to cells and causing a reduction in cell viability. If all conditions of isolation were optimal, viability of isolated cells was greater than 95%. Further adaptation from the method used in sheep, was needed before it was possible to demonstrate that viable equine hepatocytes were able to synthesis glucose from propionate at a rate of 0.01 to 0.05 nmol glucose/ mg dry cells/ min. The horse cells required additional nutrients to those required by sheep.


 

Outcomes	Successful development of a method, using abattoir specimens, to isolate hepatoctes with a viability of 95%. The observation that production of glucose from propionate occurred in liver. The project proved to be suitable but challenging for the Honours student who successfully completed her degree.
Implications	The development of this method, especially using abattoir specimens, will allow for investigation of many aspects of liver function in horses not only the controls of glucose production


 
 

Project Title:	Pasture intake by young horses
RIRDC Project No.:	UQ-72A
Researcher:	N.P.McMeniman.
Organisation:	School of veterinary Science University of Queensland, Qld., 4068
Phone:	(07) 3365 2784
Fax:	(07) 3365 1255
Email:	n.mcmeniman@uq.edu.au
Objectives	To determine relationships between characteristics of pastures grazed by horses and the digestibility and intake of the pastures by horses. The project supported the work of a postgraduate student.
Background	Research examining the relationships between pasture characteristics and intake of these pastures by cattle and sheep has led to the development of reasonably robust equations that can be used to predict intake and production performance for these animals. To optimise utilisation of pastures grazed by horses similar relationships need to be developed.
Research	Four experiments were conducted where young horses grazed pastures that had been manipulated to present the horses with pastures that varied in height, yield, species composition, stage of maturity and season of growth. Measurements that were made were liveweight of horses, intake, digestibility and species composition of diets eaten and height, yield, species composition and proportion of green material present in the pastures on offer.
Outcomes	Combined data from all experiments showed a weak but significant relationship between the digestibility of the diets and dry matter intake
Implications	More experimental work is needed to more clearly establish relationships between pasture characteristics and dry matter digestibility and intake.


 

8. Improving Racetracks and Working Surfaces for Horses

Project Title:	7TH Australian Racecourse Managers Conference, 2002
RIRDC Project No.:	PTP-18A
Researcher:	Arthur Stubbs David McLaren Unit 58, Level 2 PO Box 2132 247 Drummond Street Werribee Vic 3030 Carlton Vic 3053
Organisation:	Primary Tasks Pty Ltd Bodmac Consultants Pty Ltd
Phone:	(03) 9844 1135 (03) 9742 7444
Fax:	(03) 9844 4554 (03) 9741 5917
Email:	akstubbs@compuserve.com bodmac@bigpond.net.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, funded by RIRDC, found a wide variation in the level of racecourse management expertise and technical knowledge. In addition, there was 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 subsequent years, at Rosehill, Moonee Valley, Doomben, Morphettville, Melbourne, Randwick, and from August 5-7, 2002, the 7th Australian Racecourse Managers’ Conference, held at Ascot, WA.
Outcomes	53 people attended the conference, including 34 racecourse managers, supervisors and staff from throughout Australia, plus suppliers and consultants to the racecourse industry, research workers and turf specialists. The objective was achieved through discussion of papers on water management for racecourses; industry forums on training tracks and racing industry relationships; occupational health and safety; development of a racecourse database; inspections of Ascot, Belmont and Pinjarra racecourses; a visit to Heytesbury Stud; and general liaison between racecourse managers and other turf managers and specialists.
Implications	The conference will result in increased ability of racecourse managers’ to practise their profession and apply best practices, leading to higher standards of racecourse management. Benefits accrue from improvements in track performance, appearance and life, and associated economic and environmental advantages for racing clubs and the community. The conference also strengthened the resolve of racecourse managers to apply the accepted best practices, modified according to their particular situation, and armed them with the knowledge to justify their actions to the many stakeholders in the racing industry.
Publications	7th Australian Racecourse Managers Conference Proceedings, August,2002


 

9. Other

Project Title:	2002 Bain - Fallon Conference (Gold Coast)
RIRDC Project No.:	EVA - 1A
Researcher:	Dr James Gilkerson
Organisation:	Australian Equine Veterinary Association
Phone:	(02) 9411 5342
Fax:	(02) 9413 3765
Email:	jrgilk@unimelb.edu.au
Objectives	To support the RIRDC Research Colloquium at the Bain – Fallon Conference (Gold Coast)
Background	The Australian Equine Veterinary Association held its annual conference on the Gold Coast in July 2002, which brought together more than one hundred equine veterinarians from Australia, New Zealand, South Africa, South East Asia, the United Kingdom and North America. At this conference, the AEVA hosted the first RIRDC Equine Research Colloquium which highlighted some of the innovative research results that Australian researchers are producing with RIRDC support.
Research	The RIRDC Equine Research Colloquium was the first such forum for Australian researchers to present their work directly to the equine veterinary profession in Australia at their annual conference and was a resounding success. The programme covered research work in musculoskeletal disease, infectious and structural respiratory diseases, pharmacology of non-steroidal anti-inflammatory drugs as well as some preliminary results from an equine surveillance system.
Outcomes	Australian researchers are recognised in the forefront of their respective fields and this Colloquium provided a forum for direct communication of this work to the equine veterinary profession.
Publications	Abstracts from the presentations will be published in the Australian Equine Veterinarian and the notes from each speaker will appear in the Proceedings of the 24th Bain Fallon Lectures, 2002.