RIRDC Completed Projects in 1999-2000 & Research in Progress as at June 2000

3.5 HORSES  -  RESEARCH IN PROGRESS
PROJECT No	PROJECT TITLE	RESEARCHER	PHONE	ORGANISATION
FLP-1A	Learning within the Equine Industry	Mr. Laurie Field	02 9498 8278;	Field Learning Pty Ltd
DAV-118A	Improved Pasture: More than just grass for horses to exercise on?	Ms Angela Avery and Mr David Nash	02 60 304500	Agriculture Victoria Rutherglen
UCS-22A	Pasture intake and selectivity by grazing horses	Dr. Michael Friend	02 6933 4006	Charles Sturt University
UM-29A	Molecular epidemiology of Rhodococcus equi	Dr. Glenn Browning	03 9344 7342	The University of Melbourne
UM-40A	Epidemiology of equine rhinovirus type 2 (ERhV2)	Dr. Carol Hartley	03 9344 7375	Centre for Equine Virology
UMA-15A	Improved vaccine strategies for management of equine herpesvirus diseases	A/Prof. Millar Whalley	02 9850 8200	Macquarie University
UMA-16A	Investigation of Potential EHV-1 Vaccines Using the Mouse Model of Infection.	Dr. Catherine Walker	02 9850 8219	Macquarie University
UMU-22A	Identification of infectious respiratory disease in horses as a basis for better management of cases	A/Prof. Graham Wilcox	08 9360 2448	Murdoch University
UNE-62A	Safe and effective grain feeding for horses	Prof. James Rowe	02 6773 2225	University of New England
UQ-43A	The influence of season on follicular dynamics and the relationships with endocrinology and oviduct physiology in the mare	Dr. Neil McMeniman	07 3365 1108	The University of Queensland
UQ-45A	Nutrition of grazing broodmares, their foals and young horses	Dr. Neil McMeniman	07 3365 1108	The University of Queensland
UQ-46A	Assessment and prevention of toxicity from indospicine contaminated horsemeat	Dr. Michael Pass	07 5430 2840	University of Queensland
UQ-71A	Novel anti-inflammatory drugs to treat inflammatory diseases in horses	Dr. Stephen Taylor	07 3365 3124	The University of Queensland
UQ-72A	Nutritent intake and growth of young horses	Dr. Neil McMeniman	07 3365 1108	The University of Queensland
UQ-75A	The pathogenesis and prevention of equine laminitis	Dr. Christopher Pollitt	07 3365 2063	The University of Queensland
US-53A	Respiratory ventilation and tracheal sounds in horses with airway disease	Dr. David Evans	02 9351 2474	The University of Sydney
US-77A	Training and Fitness in Athletic Horses	Dr. David Evans	02 9351 2474	The University of Sydney
USA-6A	Diagnosis of and protection against infections caused by Rhodococcus equi	Dr. Mary Barton	08 8302 2933	University of South Australia


 
 
 

Project Title	Learning within the Equine Industry
RIRDC Project No.:	FLP-1A
Start Date:	1/07/98
Finish Date:	30/12/99
Researcher:	Mr. Laurie Field
Organisation:	Field Learning Pty Ltd 29 Pearson Ave GORDON NSW 2072
Phone:	02 9498 8278; 0407 459 055
Fax:	02 9498 6394
Email:	orglearn@ozemail.com.au
Objectives	· To develop a better understanding of the ways in which various sectors of the equine R&D industry learn. In doing so, it will highlight opportunities for supporting learning within the industry.
Current Progress:	· Fact-finding meetings with a variety of horse industry representatives have been held to date. · Questionnaire entitled "Getting information about horse care and the treatment of illness" was distributed in the last issue of RIRDC Equine Research News. The deadline for return is Friday 7 May 1999. 64 completed questionnaires received in first week after distribution. · Meetings have been held with those involved with Pony Clubs, Thoroughbred Racing and the Australian Stockhorse Association to discuss the project and the logistics of questionnaire distribution through the relevant publications. This questionnaire will be ready for desktop publishing and printing by the end of April.  A counter and visitors’ book has been placed on the RIRDC Equine Research and Development website. This has been supplying insufficient data for our needs and will be supplemented by an on-line questionnaire. This has been developed, and will be operating from early May.

Project Title	Improved Pasture: More than just grass for horses to exercise on?
RIRDC Project No.:	DAV-118A
Start Date:	30 June 1996
Finish Date:	31 December 1999
Researcher:	Angela Avery and David Nash
Organisation:	Agriculture Victoria Rutherglen RMB 1145, Chiltern Valley Road Rutherglen VIC 3685
Phone:	02 60 304500
Fax:	02 60 304600
Objectives	· To determine the extent to which different pasture types stocked at different rates can meet the growth requirements of young horses. · To compare supplementary feeding ("normal practice") with pasture-based feeding systems.
Current Progress:	From April to December, the project Improved Pastures for Horses: More than just grass for horses to exercise on, measured the growth (liveweight gain, height and various leg dimensions) of 36 filly foals from weaning. This is the largest grazing experiment ever conducted on temperate pastures in Australia.  Preliminary analysis of the results has shown that fillies grazing improved pasture at moderate stocking rates can reach a heavier liveweights and greater heights than fillies raised on unimproved pasture or supplementary feeding targeted at moderate growth rates. A second year of measurement has just commenced with 36 colt foals.  Pasture, grazing behaviour and soil measurements have also been taken to gain a complete understanding of the horse-grazing system. The project has received strong industry support; 72 foals have been donated by the horse industry for the duration of the experiment, supplementary feed has been donated by MITAVITE and industry has freely given their time to assess horses. Media coverage for the project has been extensive with the highlight being three screenings of a report on the ABC’s Landline series.


 

Project Title	Pasture intake and selectivity by grazing horses
RIRDC Project No.:	UCS-22A
Start Date:	1/07/97
Finish Date:	31/12/99
Researcher:	Dr. Michael Friend
Organisation:	Charles Sturt University School of Agriculture PO Box 588 WAGGA WAGGA NSW 2678
Phone:	02 6933 4006
Fax:	02 6933 2812
Email:	mfriend@csu.edu.au
Objectives	· To gain an understanding of the intake and selectivity of temperate pastures by horses. · To undertake an assessment of the ability of pasture species and mixes to meet the nutritional demands of young growing horses.
Current Progress:	Initial attempts during 1998 to administer alkanes to weanlings via a molasses lolly met with difficulties in acceptance. After attempting several different methods of administering the lollies the approach was abandoned in favour dosing the weanlings with an alkane suspension using the technique of Marais et al. (1996). Weanlings were successfully dosed twice daily using this method in November 1998. Four weanlings in each of the 4 pasture treatments of DAV-118 were dosed and faecal samples collected over a four day period commencing from day 5 after initial dosing. Weanlings for 1999 have arrived and introduced to the experimental plots. Intake estimates will be made in May, July, September and November of 1999. Pasture and faecal alkane concentrations will then be analysed in order to determine intake and selectivity of weanlings during 1998 and 1999. Reference Marais, J.P., Figenschou, D.L., Escott-Watson, P.L. and Webber, L.N. (1996). Administration in suspension form of n-alkane external markers for dry matter intake and diet selection studies. J. Agric. Sc., Camb. 126: 207-210


 
 

Project Title	Molecular epidemiology of Rhodococcus equi
RIRDC Project No.:	UM-29A
Start Date:	1/01/97
Finish Date:	30/12/99
Researcher:	Dr. Glenn Browning
Organisation:	The University of Melbourne Veterinary Preclinical Centre University of Melbourne PARKVILLE VIC 3052
Phone:	03 9344 7342
Fax:	03 9344 7374
Email:	g.browning@vet.unimelb.edu.au
Objectives	· To determine if there is a relationship between Rhodococcus equi strains and morbidity and mortality patterns on different studs. · To identify protein(s) which specifically identify virulent strains and to develop a diagnostic assay based on these protein(s).
Current Progress:	Characterisation of strains of Rhodococcus equi has continued, with comparisons made to international isolates as well as isolates made in the last stud season. There are close similarities of some Australian isolates with those from other countries. Statistical comparisons of the data indicates that there are particular strains which are most common particular studs, but we are unable to associate specific strains with more severe disease.  We have been unable to identify any major antigen specifically produced by Rhodococcus equi under restrictive conditions including iron deprivation, elevated carbon dioxide concentrations and higher temperatures, and so have started construction of an expression library of genes of virulent Rhodococcus equi , which will be probed using sera from diseased foals to identify genes which are most likely to be associated with disease.  We are specifically focussed on genes which occur on the virulence plasmid, which is currently being sequenced by workers in several countries. We have established active collaborations with researchers in Japan and Canada and have obtained reagents from them to further the project. The collaboration with workers in Japan has led to one joint publication which has been submitted to the Journal of Clinical Microbiology.

Project Title	Epidemiology of equine rhinovirus type 2 (ERhV2)
RIRDC Project No.:	UM-40A
Start Date:	6/07/98
Finish Date:	30/07/00
Researcher:	Dr. Carol Hartley
Organisation:	Centre for Equine Virology Dept of Veterinary Science PARKVILLE VIC 3052
Phone:	03 9344 7375
Fax:	03 9344 7374
Email:	c.hartley@vet.unimelb.edu.au
Objectives	To determine the epidemiology of ERhV2 in Australian horses. To design diagnostic tests for ERhV2 based on polymerase chain reaction (PCR) and enzyme linked immunosorbent assay (ELISA). To investigate the potential of an ERhV2 vaccine based on recombinant baculovirus expressed virus-like particles.
Current Progress:	In order to gain some understanding of the exposure of Australian horses to ERhV2, one hundred random samples of equine serum recently submitted to the CEV were tested in virus neutralisation assays. 42 % of the serums showed the capacity to neutralise ERhV2, indicating that these horses have had some history of exposure to this virus. 40 % of samples tested were negative (titres <10) and the neutralisation titres of 17 samples could not be determined due to the toxic effects of the serum at high concentrations. There was no evidence for cross neutralising antibody between ERhV1 and ERhV2 or vice versa. To design a PCR based diagnostic test for ERhV2, oligonucleotide primers were designed based on the genome sequence of the prototype strain of ERhV2 (Wutz et al. 1996). An RT-PCR was performed on 14 strains of ERhV2 obtained from Cornell University and The University of Kentucky. A product of the expected size (1061 base pairs) was obtained from the prototype strain, but no products were observed from any of the other strains, suggesting the sequence in the region to which the primers bind is highly variable between strains. New primers have been designed to more conserved regions of the ERhV2 genome, in order to design a diagnostic RT-PCR able to detect all strains of ERhV2.

Project Title	Improved vaccine strategies for management of equine herpesvirus diseases
RIRDC Project No.:	UMA-15A
Start Date:	1/07/98
Finish Date:	30/06/01
Researcher:	A/Prof. Millar Whalley
Organisation:	Macquarie University School of Biological Sciences SYDNEY NSW 2109
Phone:	02 9850 8200
Fax:	02 9850 8245
Email:	mwhalley@rna.bio.mq.edu.au
Objectives	· Improvement of reproductive efficiency and respiratory health in horse populations through reduction of incidence of herpesvirus abortion and respiratory infection. · Improved preventative strategies against infectious dieases of the horse, and lower costs. · Possible establishment of generic vaccine technology applicable to different diseases affecting horses.
Current Progress:	We have recently completed the sample collection phase of a prospective cohort study of mares and foals on a large Hunter Valley stud farm. The aims of this study were to estimate the incidence and prevalence of EHV-1 and EHV-4 infection in a group of mares and their foals and to compare these results, in a vaccinated population, with the results published in 1997 from a group of unvaccinated foals. This study will allow us to examine the response to vaccination of a group of foals as well as to evaluate the effect of vaccination on the incidence and prevalence of infection. Sample testing and data collation and analysis is currently underway.  As part of the vaccine development, we have developed a quantitative assay for EHV-1 glycoprotein antigens using monoclonal antibodies, and antigen prepared by CSL Ltd. is currently being tested in formulations in mice, prior to testing in horses. We have also demonstrated the potential of DNA vaccination for horses. After intramuscular injections of DNA encoding EHV-1 glycoprotein, horses developed a specific antibody response.  In addition, protective responses following DNA immunisation in mice were dramatically enhanced by boosting with recombinant protein. This strategy will subsequently be investigated in horses.


 
 

Project Title	Investigation of Potential EHV-1 Vaccines Using the Mouse Model of Infection.
RIRDC Project No.:	UMA-16A
Start Date:	1/02/99
Finish Date:	31/07/99
Researcher:	Dr. Catherine Walker
Organisation:	Macquarie University Department of Biological Sciences NSW 2109
Phone:	02 9850 8219
Fax:	02 9850 8245
Email:	cwalker@rna.bio.mq.edu.au
Objectives	· To investigate the potential of vaccines using the mouse model of EHV-1 infection.
Current Progress:	We have refined the respiratory and abortion mouse models of EHV-1 disease into functional systems which can examine the effects of various immunogens prior to their being trialled in the horse. Our research group has generated a series of recombinant baculovirus subunit, deletion mutant (DISC) and DNA-based potential vaccines, which is ‘cutting edge’ technology.  The mouse model experiments have determined that a protective immune response can be achieved by immunising with vaccines using a) recombinant expressed protein to just one of the envelope proteins of the virus b) DNA encoding just one of the viral envelope proteins c) a genetically engineered virus which has an envelope glycoprotein gene missing and thus cannot replicate and cause infection. An immunisation regimen which employs BOTH expressed protein and DNA as vaccines has been demonstrated to markedly enhance protection from challenge. Experiments are currently in progress to establish optimal formulations of the recombinant protein antigens.

Project Title	Identification of infectious respiratory disease in horses as a basis for better management of cases
RIRDC Project No.:	UMU-22A
Start Date:	1/07/97
Finish Date:	30/06/00
Researcher:	A/Prof. Graham Wilcox
Organisation:	Murdoch University School of Veterinary Studies MURDOCH WA 6150
Phone:	08 9360 2448
Fax:	08 9310 4144
Email:	wilcox@numbat.murdoch.edu.au
Objectives	· To investigate the association between viruses and respiratory disease in horses in Western Australia by  (a) clinically defining respiratory conditions of unknown or suspected viral aetiology and  (b) examining the association between viruses and each of these clinical conditions. · To multiple sample affected horses to determine the effect of the stage of the disease process and site of sampling on the ability to detect viruses associated with each clinical condition.
Current Progress:	The possible role of viral agents in horses presented to Murdoch University Veterinary Hospital for evaluation of respiratory disease and/or poor performance has been evaluated.  A history was obtained for each horse and a complete clinical examination and endoscopic inspection of the upper respiratory tract were performed. Bronchoalveolar lavage (BAL), tracheal wash (TW), nasal swab and peripheral blood leucocyte samples were collected from each horse and examined for viruses using a combination of polymerase chain reaction (PCR) and conventional isolation techniques in cell culture.  Cytologic examination of BAL and TW samples was a good indicator of horses with inflammatory airway disease but correlated poorly with virus isolation. The prevalence of virus infection in sampled horses was low. Affected horses could usually be identified by signalment (usually 3 year olds or younger), history (acute onset of disease and presence of in-contact affected horses) and physical examination.  The sampled population has recently been extended to include younger horses commencing training and weanlings. The prevalence of latent infection of peripheral blood leucocytes with equine herpesviruses in this population was quite high.

Project Title	Safe and effective grain feeding for horses
RIRDC Project No.:	UNE-62A
Start Date:	1/01/98
Finish Date:	30/06/00
Researcher:	Prof. James Rowe
Organisation:	University of New England ARMIDALE NSW 2351
Phone:	02 6773 2225
Fax:	02 6773 3275
Email:	jrowe@metz.une.edu.au
Objectives	· To reduce the risk and incidence of foot problems, related to laminitis and connected with feeding cereal grain, through understanding which grains are most likely to cause problems and which methods of feed treatment are most effective in reducing these risks.
Current Progress:	The review of grain characteristics and processing techniques will be published in a special edition of the Australian Journal of Agricultural Research available in July 99.  We have completed two experiments to provide better estimates of nutritive value of different grains for horses. In the first experiment, with Bianca Wilson of Orange, we measured the digestibility of two cultivars of oat grain (high and low-lignin in the hull) and results will be available shortly. In the second experiment we compared oats, barley, triticale and sorghum in terms of their digestibility in different parts of the digestive tract. Analytical work on both studies is near completion.  A preliminary analysis indicates the in-vitro assay for intestinal starch digestion accurately distinguishes and rank grains. The results confirm that triticale is highly digestible and sorghum is poorly digested. Barley was better than sorghum but not as digestible as oats or triticale. In the next stage we will use our in-vitro system to test grains, processed to enhance intestinal digestion of starch before checking ‘best-bet’ methods for efficacy in-vivo. We are confident that we can deliver new methods of selecting and processing grain for safer feeding of horses.

Project Title	The influence of season on follicular dynamics and the relationships with endocrinology and oviduct physiology in the mare
RIRDC Project No.:	UQ-43A
Start Date:	24/08/95
Finish Date:	1/9/99
Researcher:	Dr. Neil McMeniman
Organisation:	The University of Queensland School of Veterinary Science ST LUCIA QLD 4072
Phone:	07 3365 1108
Fax:	07 3365 1288
Email:	n.mcmeniman@mailbox.uq.edu.au
Objectives	· To provide basic information on the relationship between seasonal ovarian activity, endocrinology and oviduct functon in an attempt to improve reproductive efficiency in the mare.
Current Progress:	This project is a long-term study examining the endocrinological events that occur in the mare around ovulation. The uterine tube (or oviduct) is a very complex organ responsible for the housing of sperm from the male, transporting the female egg to the site of fertilisation, coordinating the events leading to conception and nourishing the young embryo while it travels to the uterus. There is an enormous lack of basic knowledge about this organ and the events that occur within it and this study will significantly contribute to this knowledge.  The information will be most applicable to scientists working in the area of infertility and breeding technologies. One spin-off from the project has been the identification of mares that respond differently to the new ovulating agent deslorelin (OvuplantTM, Peptech Animal Health, NSW).  We have found that the majority of mares respond normally, by ovulating within 48 hours of receiving the drug when used as specified. However, if the mare has a functional corpus luteum producing progesterone, the response to deslorelin will be delayed. Also there is a small population of mares that fail to ovulate. These mares have a significantly different hormonal environment that may help to identify these mares.  The physical changes that occur within the uterine tube are still being studied. A final report on results obtained and interpretation of their meaning will be presented in September 1999.

Project Title	Nutrition of grazing broodmares, their foals and young horses
RIRDC Project No.:	UQ-45A
Start Date:	1/07/95
Finish Date:	30/06/99
Researcher:	Dr. Neil McMeniman
Organisation:	The University of Queensland School of Veterinary Science ST LUCIA QLD 4072
Phone:	07 3365 1108
Fax:	07 3365 1288
Email:	n.mcmeniman@mailbox.uq.edu.au
Objectives	· To determine the extent to which pastures can support economical production of quality foals and young horses.
Current Progress:	The major part of this project compared the growth, from six months to two years of age, of Australian Stock horses that were either continuously or rotationally grazed with that of horses that were hand fed to maintain a liveweight gain of approximately 0.7 kg per day. The liveweights of the hand fed horses at the end of the experiment were significantly higher than those of the pasture fed horses.  However, the final skeletal size of the three groups of horses, as reflected by their heights at the wither, were not significantly different. The mean body condition score and depth of fat over the rump of the hand fed horses were significantly greater than their hand fed counterparts while the muscle area of the Longissimus dorsi at the twelfth rib was not significantly different between groups.  This suggests that the main reason for the difference in liveweights of the hand fed and grazed horses was due to the hand fed horses being fatter than the grazed horses. These results show that satisfactory growth of horses can be obtained from pasture. Details of the nutrient content of pastures on a commercial stud in south east Queensland during the period of the trial have been determined. These data indicate that, providing adequate pasture is available, grazing brood mares and young growing hoses should obtain all of the nutrients required for satisfactory production from these pastures. Further sampling of pastures from studs in the Scone region is continuing. A final report on this project will be prepared by September 1999.

Project Title	Assessment and prevention of toxicity from indospicine contaminated horsemeat
RIRDC Project No.:	UQ-46A
Start Date:	1/07/95
Finish Date:	31/12/99
Researcher:	Dr. Michael Pass
Organisation:	Faculty of Science University of Queensland Lacked Bag No. 4 Maroochydore, DC, 4558
Phone:	07 5430 2840
Fax:	07 5430 2887
Email:	mpass@usc.edu.au
Objectives	· To develop a method for detecting indospicine residues in horsemeat that is suitable for screening large numbers of samples under commercial conditions. · To develop a definitive system for detection of indospicine residues in horsemeat that can be used under commercial conditions for confirmation and accurate quantitation of indospicine detected by the above screening test. · To provide information on the mechanism of indospicine toxicity that can be used by the horsemeat industry to counteract threats to our export trade by countries importing horsemeat from Australia.
Current Progress:	Progress has been made in transferring the laboratory based HPLC method for detecting indospicine in horsemeat to the commercial environment. It was used to test potentially contaminated meat destined for export. We were able to confirm within 24 hours of receipt of the meat samples that they were free of indospicine and the meat was subsequently exported. This episode raised the issue of pre-slaughter testing as a means of identifying contaminated animals.  To investigate the efficacy of pre-slaughter testing, experimental animals were fed indospicine. Analysis of plasma and meat indicated that concentrations of indospicine in plasma were consistently higher than concentrations in meat. The finding is significant in that it supports the idea that pre-slaughter testing of plasma may be a more sensitive means of identifying contaminated animals.  Progress has been made in developing the ELISA assay for indospicine. Despite the selectivity of the antibodies for indospicine, the sensitivity of the assay for horsemeat extracts is still inadequate due to interfering substances. However, the finding that plasma concentrations of indospicine are consistently higher than meat concentrations, indicates that testing of plasma by the ELISA method may be satisfactory for screening animals for indospicine contamination. This is currently being pursued.


 
 

Project Title	Novel anti-inflammatory drugs to treat inflammatory diseases in horses
RIRDC Project No.:	UQ-71A
Start Date:	1/09/98
Finish Date:	1/09/01
Researcher:	Dr. Stephen Taylor
Organisation:	The University of Queensland Dept of Physiology and Pharmacology BRISBANE QLD 4072
Phone:	07 3365 3124
Fax:	07 3365 1766
Email:	s.taylor@mailbox.uq.oz.au
Objectives	· To test novel classes of anti-inflammatory drugs that will reduce the impact of inflammatory diseases of the lung, eye and joint on the normal structure of affected tissues in horses. By reducing fibrosis, oedema, cellular hyperplasia and changes in the phenotype of resident cells, the long term impact of inflammatory diseases, like pneumonia, arthritis and uveitis, on performance and well being will be reduced.
Current Progress:	Biological activity of PLA2 inhibitors. An BSc Honours student is working on this part of the project in 1999 to characterise the pharmacology of PLA2 inhibitors and their potential for use in equine diseases. The perfused eye model and rat uterus have been used to quantify activity of the drugs and compare activity with the nonsteroidal antiinflammatory drugs ketoprofen, flunixin, piroxicam and indomethacin.  Previous experiments showed PLA2 inhibitors were potent inhibitors of prostaglandin-induced contractions in the rat uterus in vitro, but it has now been shown that this activity is related to the stage of the oestrus cycle of the rats. Variable potency of the PLA2 inhibitors has been demonstrated in a perfused eye model of uveitis also, suggesting that there are other cellular mechanisms involved in this inflammatory mediator cascade. We are now investigating the events that lead to the release of prostaglandins and leukotrienes and the role of secretory and cellular PLA2 enzymes in this process. New compounds with potent inhibitory activity against secretory PLA2 have been synthesised by the Drug Design and Development Centre and will be made available for testing.

Project Title	Nutritent intake and growth of young horses
RIRDC Project No.:	UQ-72A
Start Date:	1/07/98
Finish Date:	30/06/01
Researcher:	Dr. Neil McMeniman
Organisation:	The University of Queensland School of Veterinary Science ST LUCIA QLD 4072
Phone:	07 3365 1108
Fax:	07 3365 1288
Email:	n.mcmeniman@mailbox.uq.edu.au
Objectives	· To determine whether weanling horses grazing lush spring pastures can suffer a check in growth and whether this check is due to the fact that the high soluble carbohydrate containing diets contain insufficient fibre. The consequences in terms of subsequent growth and skeletal development to a check in growth will be determined. · The project will also provide information on the effect of pasture maturity and yield on intake and growth of young horses. · Information on which pasture species young horses prefer to consume will also be obtained.
Current Progress:	The field work associated with the first study to investigate the effect of pasture yield on intake of young horses has been completed. Horses were grazed on three predominantly lucerne based pastures each having a different pasture yield and height. The alkane marker technique was used in this study and alkane concentrations in pasture and faecal samples from the study are being determined. Pasture dry matter and species intake will be calculated from these results. A similar study with a lush temperate grass species (rye grass) is about to commence. To further validate the alkane marker technique as a method of determining dry matter intake and digestibility and species composition of diets a series of pen studies is being conducted. Results from these studies should also provide data to allow for more accurate prediction of digestibility using the in vitro digestibility technique that is being used in our laboratory.


 

Project Title	The pathogenesis and prevention of equine laminitis
RIRDC Project No.:	UQ-75A
Start Date:	1/07/98
Finish Date:	30/06/02
Researcher:	Dr. Christopher Pollitt
Organisation:	The University of Queensland School of Veterinary Science ST LUCIA QLD 4072
Phone:	07 3365 2063
Fax:	07 3365 1899
Email:	c.pollitt@mailbox.uq.edu.au
Objectives	· To determine the role and control the activity of matrix metalloproteinases in the pathogenesis of laminitis so that a product can be developed which will prevent and treat the disease. · To determine the role of changes in the pattern of glucose metabolism in the pathogenesis of laminitis as a basis for predicting and preventing laminitis.
Current Progress:	mRNA has been isolated from hoof and used as templates to perform RT-PCRs for MMP-2. As in other mammalian MMPs, equine MMP-2 had the conserved "cysteine switch" and the "catalytic zinc binding site" and showed 92% homology with human MMP-2. Synthesised peptides of MMP-2 are being used to raise anti MMP-2 monoclonal antibodies to locate and show upregulation in laminitis.  The MMP-2 primers will be used to perform in situ hybridisation and Northern analysis on laminitis affected tissues. Using our HPLC detection protocol we have completed the pharmacokinetics of the potent glucocorticoid triamcinilone in 6 horses showing persistence for 12 days after a single dose and induction of a parallel hyperglycaemia and hyperinsulinaemia. An electron microscopic study using the in vitro hoof explant laminitis model has commenced to determine what ultrastructural events in the lamellar basement membrane occur as lamellar tissues separate.  We have discovered the supernatant of cultured Streptococcus bovis isolated from equine faeces induces in vitro laminitis by activating MMP-2. This bacterium proliferates in the large bowel during the development of grain induced laminitis and may produce a pyrogenic exotoxin that reaches hoof lamellae via the circulation to activate MMP-2 and trigger laminitis.

Project Title	Respiratory ventilation and tracheal sounds in horses with airway disease
RIRDC Project No.:	US-53A
Start Date:	1/10/97
Finish Date:	1/12/99
Researcher:	Dr. David Evans
Organisation:	The University of Sydney Dept of Animal Science SYDNEY NSW 2006
Phone:	02 9351 2474
Fax:	02 9351 3957
Email:	davide@doolittle.vetsci.su.oz.au
Objectives	· To investigate the use of two techniques for field studies of airway function during and/or after exercise of moderate intensity.
Current Progress:	A new method of measuring breath by breath air flow has had to be developed over the last six months to enable completion of the experiments. This new technology is now being used to study instantaneous velocities of respiratory gas flow during inspiration and expiration in resting and exercising horses, and during recovery after exercise.  Measurements of respiratory air flow at each nostril has also been successfully combined with measurements of tracheal sounds in Thoroughbred horses exercising on a treadmill. Studies of the tracheal sounds during and after field exercise in Thoroughbred horses at Randwick racecourse have been completed. Current treadmill experiments are investigating respiratory sounds, and respiratory gas flow rates and volumes in normal horses and horses with reversible, induced laryngeal hemiplegia. These experiments are using techniques not previously conducted in Australian horses, such as recordings of breath by breath air flow, and the generation of tidal breathing flow volume loops during exercise.  Tidal breathing flow volume loops relate the air flow rate to the phases of breathing during a respiratory cycle, and enable calculation of peak inspiratory and expiratory flow rates, and flow rates at intermediate proportions of the tidal volume.

Project Title	Training and Fitness in Athletic Horses
RIRDC Project No.:	US-77A
Start Date:	1/12/98
Finish Date:	31/08/99
Researcher:	Dr. David Evans
Organisation:	The University of Sydney Dept of Animal Science SYDNEY NSW 2006
Phone:	02 9351 2474
Fax:	02 9351 3957
Email:	davide@doolittle.vetsci.su.oz.au
Objectives	a. The objective of this project is technology transfer, or the transfer of information to industry participants.  b. A book will be written which will serve as a reference for those in the horse training industry. The book will collate the results of research on horse training and fitness assessment, and present the information in a format suitable for industry participants.
Current Progress:	A literature review has been completed. Consultations with several industry participants have been conducted concerning suitable topics for inclusion in the book.

Project Title	Diagnosis of and protection against infections caused by Rhodococcus equi
RIRDC Project No.:	USA-6A
Start Date:	3/02/98
Finish Date:	30/03/00
Researcher:	Dr. Mary Barton
Organisation:	School of Pharmacy and Medical Sciences University of South Australia GPO Box 2471 ADELAIDE SA 5001
Phone:	08 8302 2933
Fax:	08 8302 2389
Email:	mary.barton@unisa.edu.au
Objectives	· To develop an accurate, reproducible and easily performed serological test for early diagnosis of R.equi infections in foals. · To identify antigenic epitopes that may be further investigated as potential vaccines to protect foals from infection.
Current Progress:	An ELISA has been developed for the detection of IgG antibodies to R. equi outer membrane proteins. PCR has also been developed for the detection of the vapA (virulence-associated protein) gene, as well as for the detection of the 16S rRNA gene of R. equi.  A biotinylated peptide bank based on the VapA protein sequence has been prepared by Chiron diagnostics, Victoria and this peptide bank will be used to screen sera from R .equi infected horses using ELISA techniques. The ELISA technique developed has the potential to be useful as a relatively quick and easy diagnostic test for R .equi infections in horses but must first be evaluated in the field. Electron microscopy studies were carried out on various clinical isolates of R. equi (both equine and human) some of these isolates were found to possess pili-like appendages and phage –like particles. More studies will be carried out to determine the clinical significance of the pili-like appendages and phage-like particles. These results support the view that human and equine isolates are different ie R equi is not a zoonotic organism as is sometimes suggested. The groEL gene of R. equi ATCC 6939 was successfully cloned in E. coli DH5a and is currently being sequenced. This gene will be used in the development of a DNA vaccine which initially be trialed in a mouse model and will hopefully be useful in the prevention of R. equi disease in horses.

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Last updated: 9 August 2000
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