Equine Injury Database statistics released

The Jockey Club recently released an updated North American fatality rate for Thoroughbreds based on two years’ worth of data in the Equine Injury Database (EID), the North American database for racing injuries.

The results are from data collected from 87 North American race tracks between November 1, 2008 and October 31, 2010, in Thoroughbred flat racing. Included in the data are horses that suffered a fatal injury during a race and immediately after a race, and those that succumbed to a race-related injury subsequent to race day.

Based on an analysis of 754,932 starts recorded during the two-year period November 1, 2008 - October 31, 2010, the prevalence of fatal injury declined to 2.00 per 1,000 starts, as compared to the 2.04 per 1,000 starts for the one-year period November 1, 2008, - October 31 2009.

Dr. Tim Parkin,  a veterinarian and epidemiologist from the University of Glasgow, who serves as a consultant on the Equine Injury Database, performed the analysis.

He noted that the change in the overall fatality rate stemmed from cumulative two-year data that revealed a statistically significant difference in the prevalence of fatality on both turf and synthetic surfaces versus dirt. The difference in the prevalence of fatality between synthetic and turf surfaces was not statistically significant.

“The addition of 376,000 starts to the database in year two enabled us to statistically validate certain trends seen in the data,” said Parkin. “Trends will continue to emerge and evolve as additional data becomes available for study and as more complex statistical analyses are performed. This will allow us to understand how different variables, alone and in concert, may impact the risk of fatality.”

Other trends gleaned from Parkin’s analysis of the cumulative two-year data, included:

• The prevalence of fatality in 2-year-olds continued to be significantly lower than older horses racing on dirt surfaces. However, on synthetic or turf surfaces, there was no statistically significant difference in the prevalence of fatality between 2-year-olds and older horses.
• The prevalence of fatality continued to be unaffected by distance, weight carried and movement of races off the turf.
• Fillies and mares competing in races that were open to horses of all sexes were not at an increased risk of fatality compared to those competing in races restricted to fillies and mares.                               
  

                   
"These calculations are considered estimates of prevalence because they represent a two-year sample of data and not a complete census" Parkin explains. "The statistics included here do not imply anything about the relative safety of a racing surface or a horse’s age. As the data contained in the EID continues to grow, some of the current statistical conclusions may change as a reflection of increased certainty associated with a larger data set."

“We will continue to publish these national benchmarks on an annual basis to provide the necessary statistical foundation participating racetracks need for monitoring and comparing their individual results,” said Matt Iuliano, The Jockey Club’s executive vice president and executive director.

 “As the database continues to grow, we look forward to the additional information and statistical power it will yield to improve the health and safety of the racehorse."

Read more at www.equinescienceupdate.com/articles/eid10.html

Are pinworms becoming resistant to anthelmintics?

Barely a month goes by without another report of anthelmintic resistance. The usual culprits are the cyathostomins - the small red worms.

Now it seems that the pinworm, Oxyuris equi, might also be developing resistance. Or at least, doubts are being raised about whether anthelmintics are beginning to lose their effectiveness against the parasite.

Compared with the cyathostomins, Oxyuris equi is less important as a cause of disease. Generally, the parasite is not considered pathogenic. However, the female worms cause irritation by depositing their eggs on the skin around the anus of the host. This leads to tail rubbing - and may be mistaken for "sweet itch" (insect bite hypersensitivity.)

Thus far, it has not been necessary to formulate specific control measures against Oxyuris, as it has always been assumed that routine treatment with modern anthelmintics would be sufficient to control it.

However, in a letter to the Veterinary Record, Andy Durham of the Liphook Equine Hospital and Gerald Coles of Bristol Veterinary School mention several anecdotal reports of Oxyuris infection despite recent anthelmintic treatment.

In contrast, earlier studies have shown Oxyuris to be susceptible to commonly used anthelmintics.

Durham and Coles have received enquiries from clients about horses rubbing their tails - despite having been recently dewormed with macrocyclic lactones.

They would like to hear from veterinary surgeons who have encountered similar cases, to assess if this is a widespread problem.

They offer to examine, free of charge, sticky tape preparations from suspected cases.  Veterinary surgeons wishing to submit a sample are asked to contact Dr Gerald Coles, at the Bristol Vet School.

Shivering horses required

University of Minnesota researchers are looking for help to investigate the perplexing condition known as "Shivers"
 
"Shivers" or "Shivering" has been recognised since the heyday of working draft horses.

Even so, little is known about it. Now researchers, led by Dr Stephanie Valberg, at the University of Minnesota, want to put that right.  "We are trying to establish the cause of Shivers, if this condition is inherited, and if dietary therapy is effective."

A research project has been set up at University of Minnesota and the Neuromuscular Diagnostic Laboratory in conjunction with Dr John Baird of the Ontario Veterinary College.

The researchers are looking to collect data on as many Shivers cases as possible. Initially they hope to identify risk factors, and investigate the influence of factors such as gender, breed, diet, exercise, and infection on the development and progression of the disease.

If you want to be involved, and have a horse you know, or suspect, has shivers, the first step is to complete a survey and submit it, together with a video of the horse.

The researchers specify the format the video should follow to ensure that all relevant information is included.

Within three weeks of receipt, the researchers promise to send you a report which will tell you whether or not the horse is affected with the condition.

Confirmed "Shiverers" may then be invited to take part in further research. The plan is for a controlled trial in which the effect of diet on the condition can be examined. If you are chosen to take part in the further study, you will probably be asked to feed an experimental diet for the duration of the study.

Dr Valberg explains: "In our previous studies on conditions such as Polysaccharide Storage Myopathy (PSSM) and Recurrent Exertional Rhabdomyolysis (RER), we have determined that certain dietary changes can be highly effective in alleviating symptoms of disease."   

It is hoped that dietary modifications may have a similar beneficial effect in Shivers.

Dr Valberg continues: "In the case of a diet trial, it would be necessary to have an additional, non-Shivers, horse participate in the trial who is approximately the same age and living in the same environment as the horse with Shivers. This is essential in conducting a controlled, viable study."   

For more details on how to take part in the research go to the shivers research website

For a comprehensive explanation of what is currently known about shivering visit the My Horse University webcast.

Equine genetic research progress

Knowledge of the horse’s genetic blueprint has opened many avenues of research according to a recent report.

The “genome” is the term used to refer to an individual’s full set of DNA.  In the horse, it consists of about 2.7 billion base pairs. DNA carries the genes that code for thousands of different kinds of proteins. The precise characteristics of each gene are determined by the sequence in which four bases  - adenine (A), thymine (T), cytosine (C) and guanine (G) - are laid out along the DNA's double-helix structure.

A special supplement to the scientific journal Animal Genetics has been published to emphasise the importance of the genome to equine research.

The Dorothy R Havemeyer Foundation, a private foundation that conducts scientific research to improve the general health and welfare of horses, funded publication of the supplement. Its founder and sole benefactor was Dorothy Havemeyer McConville, also known as Dorothy Russell Havemeyer.

The Foundation appoints principal investigators to work on specific projects. Currently the focus of research is on equine reproduction, behaviour, and infectious diseases and on the creation of an equine genetic map.

Genetic research has long been a topic of interest to the Foundation, a workshop on the subject having been convened first in 1995,

Dr Ernest Bailey, of the University of Kentucky's Gluck Equine Research Center, wrote in the foreword to the supplement: "In this issue, scientists report research and discoveries made possible using the new genomic information."

"Indeed, the work includes gene discoveries and genetic characterization of horse breeds and sheds light on hereditary conditions that affect performance of horses. But the genome information is also useful to understand non-hereditary diseases and traits as well. Several reports in this issue address gene expression in connection with exercise and laminitis."

Bailey emphasises that using the genome sequence in research will bring many benefits both to the horse and to the economy as a whole.

"As scientists become more familiar with using genomic information for equine studies, we can anticipate more discoveries and the development of new diagnostic tests, therapeutic products and management approaches to improve the health and well-being of the horse."

"This should be remembered as a legacy from the Dorothy Russell Havemeyer Foundation."

The full report is available for download (free).

Effect of temperature on race times

A few years ago, the major racetracks in California introduced synthetic tracks. It was hoped that this would give a more consistent surface and lead to fewer casualties than either turf or dirt tracks. In general, this has proved to be the case.

However, horses often run more slowly on the synthetic surface than on dirt. Furthermore, it has also been noticed that race times vary with temperature.

A study conducted at the Del Mar Racetrack in California monitored the change in temperature during the day and compared it with the speed of horses running on the track. Lead researcher was Dr Mick  Peterson of the Mechanical Engineering Department of the University of Maine.

The research team measured air temperature, the temperature on the track surface and at four depths within the track. These measurements were recorded throughout the day over a 42-day period

They also recorded the fastest times for 6-furlong (1.2km) races, which took place in the afternoons, and the times taken for fast training 'work', which happened in the mornings.

Inspection of the data showed that horses ran more slowly in the afternoons. This correlated with changes in air temperature and the temperature of the track surface and subsurface.

Higher afternoon temperatures were associated with slower racing times. The fastest times recorded during the afternoon races were slower than during the morning work sessions.

Why should this be?  A possible explanation could be found in the characteristics of the wax used to coat the fibres. Within the range of temperatures experienced during the day was the temperature at which the wax started to undergo thermal transformation - i.e. melt.

The scientists suggest that the physical properties of the wax may underlie the effect of temperature on track characteristics.

They suggest that further work in the future should include a study of the various components of the racing surface, to identify the component responsible for the change and to assess any influence it might have on the risk of injury.

New strangles test developed

Scientists at the University of Maine have developed a novel rapid test for strangles.

Current culture techniques require several days to confirm a diagnosis of strangles. The new test, which detects a specific protein on the Streptococcus equi bacterium, can produce a result in a matter of hours.

A grant of nearly $500,000 from the Maine Technology Asset Fund has made the development possible. The project also involves renovations at the UMaine JF Witter Teaching and Research Center to create an animal handling area for disease diagnosis, an equine isolation area, and a technology transfer center classroom with video-endoscopy equipment.  This will be used for training veterinarians as well as being involved in research into infectious diseases.

The grant will also fund the purchase of portable endoscopes for use by Maine veterinarians at farms and stables around the state.

The test has already proved successful in early trials. Now the new funding will allow the scientists to carry out a large scale trial to check its reliability and efficacy before making it commercially available.

Principal investigator is Dr Robert Causey, a veterinarian and associate professor in the University of Maine Department of Animal and Veterinary Sciences.

"There's no doubt that the market for this is potentially global" says Causey. "Wherever there are horses there is this disease. No one has ever tried to do this before. This puts Maine right in the front of strangles research."

"The economic impact of an outbreak can be devastating to a commercial equine facility."

The kits, which are being developed by Maine Biotechnology Services (MBS) in Portland, have an antibody on a membrane that changes colour when exposed to a strangles protein.

The strangles test kit is the first to be developed using this technology. As additional new antibodies are developed by MBS, the test kits could be adapted to more quickly detect and diagnose other equine infections.

Do feral horses have ideal foot conformation?

A natural lifestyle - freedom to roam, and the ability to choose what to eat - does not necessarily result in ideal foot conformation.

The feet of feral horses, such as the North American mustang and the Australian brumby, have been held up as examples of ideal conformation. However, not all feral horses are the same, as work carried out in New Zealand demonstrates.

A report published in the Australian Veterinary Journal documents the shape and abnormalities of the feet of Kaimanawa feral horse population.

Kaimanawa horses are small (133-151cm at the withers), being descended from Welsh and Exmoor-type ponies that have been feral since the 1880's. Other bloodlines were added as the result of escapes from farms and cavalry units so that present day horses are more closely related to the Thoroughbred.

About 1500 animals live in a land of upland plateaux, with steep hills, river basins and valleys, covering an area of about 700sqkm.

The research team took standardised photographs of all four feet and lateromedial radiographs of the left fore foot of 20 adult horses from the Kaimanawa horse population.

They found a wide variation between horses. There was no consistent foot type. Foot abnormalities were surprisingly common. For example, 35% had long toe conformation, 15% had medio-lateral imbalance, and 85% of horses had lateral wall flares.

Other common abnormalities included large hoof wall defects, frog abnormalities and contracted and under-run heels.

The most surprising finding was the radiographic and visual evidence of chronic laminitis. Laminar rings were present on 80% of horses.

Lead researcher was Brian Hampson of the Australian Brumby Research Unit, at the University of Queensland’s School of Veterinary Science. 

"The large range in the morphometric variables and the high incidence of abnormalities in the feet of Kaimanawa feral horses may be related to dietary or environmental influences, or a combination of both" Hampson explains.

"There may be insufficient environmental pressure driving natural selection of foot type. Perhaps their environment, consisting of a soft substrate and with easy access to pasture and water, tolerates a broad range of foot conformation in Kaimanawa horses."

"Clearly this group of feral horses should not be used to guide the direction of foot care practice."

Read more at Equine Science Update.

Challenge of Chorioptes infestation

Infestation with the mite Chorioptes bovis can prove difficult to eradicate. A Swiss study found that two doses of moxidectin oral paste, combined with environmental treatment, failed to eliminate the parasite from heavily feathered draft horses.

The study, led by Silvia Rüfenacht of the Dermatology Unit of the Department of Clinical Veterinary Medicine at the University of Berne, was reported recently in Veterinary Dermatology.

Chorioptes bovis is a particular problem of draft-type horses with hairy legs. The mites live on the skin surface, feeding on skin scales, but may survive for three weeks or more in the environment. They tend to be more of a problem in the winter when horses spend more time housed.

Not only do the mites cause irritation, they may contribute to the development of chronic pastern dermatitis - thickened swollen skin with warty ("verrucose") lumps.

The study was designed to use licenced products and be practical for owners to carry out.

Horses were treated twice, three weeks apart, with 0.4mg/kg moxidectin oral paste. Environmental treatment, carried out on days 0 and 14, consisted of removing all bedding, brushing out the stable, grooming area, and horse transporter. All surfaces, tack, and grooming equipment were treated with anti-parasitic disinfectants.

Horses were examined just before the first treatment (day 0) and 14 days, 6 weeks and 6 months later. The clinician, who did not know which horses were in the treatment  or placebo group, took skin scrapings and assessed the degree amount extent of crusting and skin folds

Initially, all horses showed pruritus (itching) manifest as rubbing, biting or stamping, and this continued throughout the study. Treatment had no significant effect on the number of mites found in skin scrapings, nor on the severity of skin folds.

The only significant finding was that the treated horses showed a decrease in skin crusting over the 6 month follow up period. But that was the only difference between the treatment and placebo groups. There was no other difference in clinical signs or in the number of mites found between the two groups.

Are bacteria involved in stomach ulcers?

Gastric ulceration, affecting the non-glandular portion of the equine stomach, has been the focus of attention in recent years. Ulcers are also found less frequently in the glandular portion of the stomach. In humans such lesions have been associated with bacterial infections.

The micro-organism Helicobacter pyloris has been implicated in a number of human medical conditions, including chronic gastritis, gastric ulcers, and neoplasia. Could similar organisms be involved in gastric lesions in horses? A Danish study has been investigating.

Lead researcher Dr Louise Husted completed the research as part of her PhD studies, with assistance from colleagues at the University of Copenhagen and the University of Denmark.

She examined specimens collected from an abattoir, and found lesions on the glandular mucosa in 36 of 63 stomachs. These included hyperplastic rugae (13), polypoid structures (2), and focal erosions (21).

In general, very few bacteria were associated with the gastric mucosa in either the damaged or normal stomach. No Helicobacter was found.

However, one stomach did contain a single erosion 1x2cm in size, which was colonised by bacteria. No bacteria were found in the surrounding normal gastric mucosa.

Cloning analysis of the bacteria showed them to be a mixed infection of Enterococcus faecium and an Escherichia-like organism, which was identified as most likely to be Escherichia fergusonii.

E. fergusonii has been reported as an emerging pathogen in human medicine and in some animal species.

Dr Husted suggests that further work needs to be done to clarify whether the organism is a significant pathogen in horses.

"Detection of a moderate to high amounts of any bacteria at the glandular mucosa level, as well as in the crypts should be cause for concern as this does not appear to be a normal finding in the equine glandular mucosa".

This study did not involve clinical cases. Dr Husted suggests that further studies of bacteria and their relationship to lesions in horses with clinical signs of gastric ulceration are warranted.

The open access report is available at http://biomedcentral.com/1471-2180/10/84

Fungus attacks cyathostomins

A worm-eating fungus has potential as a biological control for horse worms, according to research from Brazil.

Researchers at the department of veterinary medicine at the Federal University of Viçosa, in Brazil, led by Dr Fabio Braga found that a strain of Duddingtonia flagrans effectively reduced the numbers of viable cyathostomin infective larvae in laboratory tests.

Live L3-stage cyathostomin larvae were placed on plates containing 2% water-agar - 1000 larvae to each plate. To half of the plates 1000 D. flagrans conidia (spores) were added. Conidia were not added to some plates to provide controls.

Daily, the researchers counted ten random microscope fields (4 mm diameter) from both the plates containing D. flagrans and the controls. Within 24 hours there was a marked difference in the number of viable L3 seen. Significantly fewer L3 survived in the plates containing D. flagrans. This difference was maintained throughout the study.

After 7 days, they recovered the viable larvae from both the test and control plates. They found that the plates containing the D. flagrans contained significantly fewer viable cyathostomin larvae. Exposure to the fungus resulted in 93.64% reduction in cyathostomin numbers.

Treatment of persistent mating-induced endometritis

Persistent mating-induced endometritis is a common cause of infertility in mares. Mating initiates an inflammatory response in the uterus. Normally this resolves without treatment. However, about 15% of mares still have fluid present in the uterus 24 hours after mating.

If the inflammation has not cleared by the time the fertilised egg reaches the uterus the pregnancy is unlikely to get established.

Factors that affect the ability of the uterus to remove inflammatory fluid include poor conformation, failure of the cervix to dilate, and abnormalities of uterine contractility.

In problem mares, oxytocin may be used to promote drainage of inflammatory fluid, and intrauterine antibiotics are frequently used.

What about anti-inflammatory drugs?

Research in the Equine Reproduction Laboratory of Colorado State University suggests that dexamethasone treatment for persistent mating-induced endometritis may have an adverse effect on ovulation. Dr Ryan Ferris and Dr Patrick McCue advise dexamethasone use should be limited to only 1-2 days - and the use of lower doses should be considered to avoid possible adverse effects on reproductive function.

In a separate study, Dr Horst Rojer and Dr Christine Aurich working at the University of Veterinary Sciences, Vienna, Austria, suggested that non-steroidal anti-inflammatories might be useful for treating mares with PMIE.

Read more...

"Big Brother " research into horse obesity

Researchers have adopted Big Brother tactics to tackle the growing problem of obesity in Britain’s horse population.

One in three horses, and over 80% of ponies, are currently believed to be in danger of fat-related health risks such as laminitis – the equine equivalent of a human heart attack.

Now a pioneering scientific study is set to put different breeds under 24-hour surveillance to find out what makes some horses pile on the extra pounds.

A research team from Edinburgh Napier University and horse feed manufacturer Dodson & Horrell have teamed up to run the three-year project. Tiny cameras, GPS devices and movement monitors will be attached to the animals in order to analyse every last aspect of their lifestyles.

“The equipment will allow us to distinguish between food-related effort and other exercise – the horse equivalent of a trip to the fridge or the gym,” said study leader Dr Dave Smith, a veterinary nursing lecturer at Edinburgh Napier University.

The research, which is the first of its kind, will be conducted at a Norfolk farm run by charity World Horse Welfare. Around 15 horses will initially graze in paddocks specially seeded with different grasses by retailer Oliver Seeds.

Dr Smith said: “We suspect a major factor in rising obesity levels has been the move from grazing in traditional meadows, which naturally feature a variety of grasses, to monoculture fields more suited to dairy cows.

“However, there are also horse and pony owners who, through overfeeding, are unwittingly killing with kindness. Even horses in ‘show’ condition can be significantly overweight.”

It's not just laminitis that threatens obese horses. Dr Teresa Hollands, Senior nutritionist at Dodson & Horrell, said that previous research had shown that obese horses were also at greater risk of developing skin, muscular and bone problems.

“Owners forget that although they might not be putting food in a bucket, these ponies and horses are over-consuming calories from grass,” she said. “What’s interesting is that some animals that graze together in the same field get fat, while others remain perfectly healthy. What we hope to find out with this study is if there is a horse equivalent of the human couch potato.”

Every chew and canter will be followed online by researchers via webcams attached to each horse.

“We will be watching them around the clock as they go about their natural routines,” said Dr Hollands. “It will allow us to find out who the grazers or gorgers are, exactly how far they travel, how much they eat, and what they eat.

“Once we have that data for each breed we will then be able to advise owners on how best to feed and manage their horses so they don’t get fat and unhealthy.”

Virtual equine treadmill tour

Have you ever wondered what goes on in an equine exercise physiology laboratory? Well, now you can see behind the scenes thanks to the Rutgers Equine Science Center, which has launched a virtual tour of the Equine Exercise Physiology Laboratory.

A photographic storyboard takes visitors through the laboratory, showing the processes involved in completing a graded exercise test and a simulated race test, the two types of equine exercise tests conducted at the treadmill lab.

The virtual tour is presented in three sections: Preparing for an Exercise Test; Performing an Exercise Test; and Exercise Test Data Analysis. Each section contains pictures and descriptions of the various stages of the test.

The equine exercise physiology laboratory is an extremely popular research site on the G.H. Cook Campus of Rutgers University primarily because of the treadmill. By creating the online virtual tour of the lab, visitors to the Equine Science Center website get an inside look at how and why equine scientists use a treadmill, and a complete overview of the entire process.

"We had to turn people away at the laboratory door on Rutgers Day earlier this year; people were standing in line for a half hour to witness our research mare on the treadmill,” said Karyn Malinowski, director of the Equine Science Center. “The treadmill always draws a big crowd as people are eager and excited to see such a majestic and powerful animal galloping full-speed. It is an exhilarating sight.”

According to Malinowski, the virtual tour of the treadmill laboratory, as well as a video demonstration of a horse exercising, offers equine enthusiasts an opportunity to learn about the science and research of the Equine Science Center as well as the thrilling experience of witnessing a horse on a treadmill. Best of all, the tour is available at anytime from the comfort of one’s home.

"At the Equine Science Center, we firmly believe in broadening our horizons as we bring better horse care through research and education,” added Malinowski. “The virtual tour of the exercise physiology laboratory provides another modality to enable us to reach the equine community.”

The virtual tour is accessible through the Rutgers Equine Science Center’s website on the Equine Exercise Physiology Laboratory page.

Horses that won't lose weight may need stricter diet

Some obese horses and ponies may need to have their diets restricted more severely than previously thought in order to help them lose weight according to new research.

The studies were conducted  at the University of Liverpool. They showed that although some obese animals will lose weight, in an appropriate way,  on a diet restricted to 1.25% of body weight (on a dry matter basis), others may need their diet restricted to as little as 1% of body weight in order to shift those surplus pounds. Such animals have been described as being ‘weight loss resistant’ in a  report  presented at the WALTHAM International Symposium in September.

The work has been published as an abstract in the proceedings of the 5th European Workshop on Equine Nutrition and will be written up and published as a full paper in due course. It was funded by the government-initiated Knowledge Transfer Partnership and the WALTHAM Equine Studies Group.

The study, which was conducted over 16 weeks, involved 12 overweight/obese horses and ponies of mixed ages and breeds, with body condition scores of between 7 and 9 (1 being emaciated and 9 being obese). They were individually housed on wood-shavings and provided with a balanced fibre-based diet at 1.25% of body weight. They were allowed daily access to a bare paddock but no structured exercise was given. Eight of the horses achieved a slow, gradual but consistent loss of body weight over the study period, but weight loss was much slower in the remaining four.

These four horses, deemed to be weight loss resistant, were monitored for a further four weeks during which their diet was reduced to 1% of body weight daily. This significantly increased their rate of weekly weight loss, to a level comparable to the weight loss seen in the other eight horses in the original study. It is thought that genetics may account for such individual differences in sensitivity to weight loss. In all cases the horses remained healthy and no stereotypic behaviours were seen.

Dr Caroline Argo explained: “It is important to understand that the appetite of obese ponies will drop to around 2% of body weight (dry matter) yet their body weight will be maintained or they may even continue to gain in weight. If weight loss is to be stimulated, food intake must be limited quite severely.”

Clare Barfoot BSc (Hons) RNutr, the research and development manager for SPILLERS® and a member of the research team added: “Controlled but balanced nutrition, under careful veterinary guidance, is essential to promote weight loss in overweight or obese horses and ponies, especially when exercise is not an option but we have had little evidence-based advice on how far the diet can be restricted safely to help shed weight in stubborn cases until now.”

“In practice where exercise can be used to increase energy expenditure, such severe restriction may not be required; in this situation access to grazing must be reduced, exercise increased and a low calorie high fibre forage fed in a monitored way alongside an appropriately formulated forage balancer.”

The Horse Nutrition Handbook

Pour-on deworming

Topical applications are easy to administer and may reduce the risk of injury to the operator. Pour-on anthelmintics have become popular for treating cattle and have been shown to be effective. However, experts disagree on the value of pour-on preparations for deworming horses.

A study, supervised by Professor Adolfo Paz-Silva at the University of Santiago de Compostela in Spain, and published in the Equine Veterinary Journal, examined the use of a pour-on anthelmintic in naturally infected Pura Raza Galega horses.

Over a 21-week period, the researchers compared the fecal worm egg production in untreated animals and in horses treated with ivermectin pour-on (at double the cattle dose rate.)

The feces were clear of strongyle eggs between 3 and 9 weeks after treatment. Strongyle eggs reappeared in the feces 10 weeks after treatment. Topically administered ivermectin suppressed fecal egg production of Parascaris equorum and Oxyuris equi for the whole of the study period.

The researchers concluded that the pour-on ivermectin preparation was highly successful against gastrointestinal nematodes. They suggest that it appears to provide a useful treatment option for large groups of horses at pasture.

However, a report by Dr Cengiz Gökbulut and others published in Veterinary Parasitology paints less favorable picture.

The study looked at the absorption of ivermectin after oral, topical or intravenous administration and how the mode of administration influenced the efficacy of the treatment.

One group of horses was treated with equine oral ivermectin paste (at 0.2mg/kg); a second with bovine pour-on (at the recommended cattle dose rate of 0.5mg/kg) and a third group was treated with an injectable cattle preparation (given intravenously at 0.2mg/kg).

Compared with the oral paste, the pour-on preparation resulted in lower but more persistent plasma concentrations. It was also less effective at reducing the fecal strongyle worm egg count.

The authors of the report warn that the poor plasma availability after topical application could result in sub-therapeutic levels of ivermectin, which could encourage the development of ivermectin-resistant parasites.

Read more about research into pour-on ivermectin in horses.

Lavender Foal Syndrome test now available.

The Animal Health Diagnostic Center at Cornell University is now offering a genetic test for Lavender Foal Syndrome (LFS).

LFS is a fatal disease of newborn Arabian foals, particularly those of Egyptian Arabian breeding.

Signs shown by affected foals include seizures, nystagmus (involuntary movement of the eyeballs), limb rigidity, paddling movements, and opisthotonus (hyperextension of the head, neck, and spine).

The condition gets its name from the abnormal coat color with which most affected foals are born, variably described as silver sheen, lavender, pale chestnut or pale, dull pinkish grey.

Scientists at Cornell University and the Maxwell H Gluck Equine Research Center have found that Lavender Foal Syndrome is the result of a mutation in a gene called myosin Va (MYO5A). All affected foals tested in the study were homozygous for this mutation (i.e. both copies of the gene were defective).

Lead researcher was Samantha A. Brooks, PhD, assistant professor in the Department of Animal Science at Cornell University's College of Agriculture and Life Sciences.  “Our results suggest that the population frequency of carriers of this deletion is 10.3% in the Egyptian Arabian,” she reports.

“From a practical standpoint, this discovery and the development of a diagnostic test for the LFS allele provides a valuable new tool for breeders seeking to avoid the disease in their foal crop.”

Testing of breeding animals is recommended to identify carrier horses. The breeding program can then be arranged to avoid mating two carriers, and so prevent the birth of an affected foal.

The test can be run on hair roots pulled from the mane or tail, or whole blood samples.

Normally, the AHDC only accepts samples from accredited veterinarians. However, for this test, Arabian owners are encouraged to submit their own pre-paid samples directly to the laboratory.

The Lavender Foal Syndrome test is not restricted to horses within the USA. Shipment of EDTA whole blood samples from abroad requires a USDA permit. However, according to the laboratory no permit is required for sending hair samples.

(Permits may not be available for the import of blood specimens from some countries. Please contact the laboratory (Lisa Bowen-Laue; 607-253-3938) for the appropriate permit if you wish to submit EDTA whole blood for LFS testing from outside the USA.)

Each sample must be sent with a completed LFS assay submission form. Payment, ($47 for each horse tested) must accompany the samples unless they are submitted by a licensed veterinarian.

Information on the new test, including full instructions on how to submit samples, can be found on the LFS page of the Cornell University College of Veterinary Medicine website.

Do shock waves aid healing?

Exuberant granulation tissue ("proud flesh") is a common complication of wounds to the horse's lower limbs. It may delay healing and make scar formation more likely.

Dr Andressa Silveira and colleagues at the University of Guelph in Ontario, Canada, have been examining whether shock wave therapy could be used to promote healing and reduce the risk of exuberant granulation tissue.

They found that wounds treated with unfocussed extracorporeal shock wave therapy (ESWT) seemed to produce less exuberant granulation tissue, and looked healthier than untreated wounds, although they did not heal more quickly.

The researchers made five full-thickness skin wounds, (2.5 cm x 2.5cm) on the dorsal aspect of the metacarpus of both fore limbs of each of six horses.

They treated one leg from each horse with ESWT, and left the other limb untreated to act as a control.

The wounds were treated immediately after they were made and then at weekly intervals for a total of four occasions. Each treatment comprised 625 pulses - distributed evenly around the wound and surrounding healthy skin edges.

The researchers found that control wounds were more likely (1.9x) to appear inflamed than were treated wounds. Untreated wounds also had higher exuberant granulation tissue scores.

However, there was no significant difference between biopsies taken from treated and untreated wounds at weekly intervals throughout the study. Neither did treatment have any effect on wound size.

Further investigations are required before shock wave therapy can be recommended for wound treatment. ESWT may be helpful, but so far, there is not enough evidence to support its use in clinical cases.

Not all bad news about dewormers

There are numerous reports of the spread of resistance to dewormers.  So it is encouraging to receive some good news for a change.

Research carried out by Dr Craig Reinemeyer and others at East Tennessee Clinical Research Inc., has revealed some positive findings.

In separate studies they examined the efficacy of dewormers against Oxyuris equi, and against macrocyclic lactone resistant Parascaris equorum.

Oxyuris equi (equine pinworm) rarely causes serious problems for the horse, but does cause irritation when the female lays the sticky eggs on the skin around the anus of the host. It has been assumed that most routine dewormers will control it. However, anecdotal reports that anthelmintic treatments were not as effective against Oxyuris equi as expected prompted Dr Reinemeyer’s study.

Dr Reinemeyer found that pyrantel pamoate (at 13.2mg/kg) was 91.2% effective, and ivermectin (200mcg/kg) 96.0% effective, against the adult worms. Both products were more than 99% effective against the fourth-stage O. equi larvae.

Unlike O. equi, Parascaris equorum does cause significant problems, especially in foals, in which heavy infestations can lead to intestinal obstruction or rupture.

Recent reports have recorded an increasing problem of reduced efficacy of macrocyclic lactone anthelmintics (such as ivermectin) against these parasites.

In a study of experimentally infected foals, the researchers found that pyrantel pamoate administered at 13.2mg/kg was effective against a macrocyclic lactone -resistant (ML-R) isolate of Parascaris equorum.

Mean ascarid egg counts were reduced by 98.8% two weeks after treatment - compared with a reduction of only 47% two weeks after ivermectin (200mcg/kg). Post mortem examination of intestinal contents showed that the paste formulation of pyrantel pamoate was 97.3% effective against the MLR P. equorum.

It is reassuring to know that these drugs were effective under the specific conditions of the study.  But that’s not to say that they will always remain so, or that the results are representative of all worm populations. The advice to treat for worms only when necessary and to monitor the effectiveness of any treatment still stands.

Measuring tear production

We may need to look again at how we treat eye infections in the light of research that found that horses produce more tears than previously thought.

Tears protect the eye by keeping the cornea moist. The tear film also carries nutrients to the cornea, which has no blood supply of its own.

The same route is also used to deliver medication to the cornea.

How many tears does a healthy horse produce? How quickly is the tear film replaced? There have been few studies into this, yet it is important to know, as it will affect the concentration of drugs applied to the eye - and so may affect their efficacy.

Dr Thomas Chen and Dr Daniel A. Ward examined the rate of production of tears in normal horses' eyes, in a study carried out at the College of Veterinary Medicine, University of Tennessee, Knoxville. They instilled fluorescein dye onto the eye and then collected small samples of the tear film, measured the fluorescein concentration, and noted how it changed with time.

They used two mathematical approaches to analyse the results. One method, which was considered the more accurate, suggested that the rate of tear production was 33.6mL /min. The mean tear film volume was estimated to be 233.74 mL.

The results showed that the tear film was likely to be completely replaced within a matter of 7 minutes. This suggests that current treatment protocols may not be adequate, and that drugs may need to be administered more frequently.

Read more at  the Equine Science Update website

Measuring weight loss

Belly girth measurements provide  a better way of assessing early weight loss according to recent research.

One of the problems faced by owners of overweight horses, is monitoring the response to weight loss programmes. Obviously weighing the horse would be ideal but is often not possible. Weigh tapes placed around the heart girth (just behind the elbow) may not detect any change despite a decrease (or increase ) in body weight, because that is not where the excess fat is deposited.

Two recent weight loss studies have both shown that belly girth measurements are more closely related to changes in bodyweight in early weight loss (after the first week of feed restriction) as opposed to the more commonly used heart girth measurements. Belly girth measurements are taken at the widest point of the belly - approximately two thirds of the way between the point of the shoulder and the point of the hip. They may even be more accurate than some ultrasound fat measurements.

One study conducted last year by researchers at the Department of Veterinary Clinical Science at the University of Liverpool and supported by World Horse Welfare, highlighted the need for a more accurate method for monitoring early weight loss in overweight ponies rather than relying on conventional equine body condition scoring.

A further study comparing two practical weight loss protocols for the management of overweight and obese horses and ponies was conducted earlier this year by the Department of Veterinary Clinical Science at the University of Liverpool. It was funded by the government-initiated Knowledge Transfer Partnership and the WALTHAM Equine Studies Group. It confirmed that the proportional change in belly girth was more closely associated with changes in body weight than the proportional change in heart girth in the early stages of weight loss.

Dr Caroline Argo and Alex Dugdale of the Department of Veterinary Clinical Science at the University of Liverpool said: “It is important for owners to understand that early weight loss is not immediately recognisable as a change in the horse or pony’s overall appearance or body condition score. However, owners do need some assurance that measures taken to promote weight loss are being effective. Simply measuring belly girth at regular (weekly) intervals can provide this. Without such reassurance, we might be inclined to either give up or more alarmingly, harmfully increase our efforts to induce weight loss.”

See Equine Science Update for more information

Equitation science discussed in Sweden

Horse welfare and rider safety can be enhanced by the application of new technology to the training of both horse and rider. That was one of the messages to come out of the 6th International Society for Equitation Science conference held recently in Sweden.

In the past few years there has been a growing interest in equitation science (the science of horse riding and horse training.) A selection of recent research, covering a wide range of topics, was presented at the conference, held this year at the Swedish University of Agricultural Sciences (SLU) in Uppsala.

Presentations covered training and education of horses and riders, from both a scientific and a practical perspective, and highlighted the importance of a thorough understanding of learning theory and physical capacities of the horse to safeguard horse welfare and human safety.

The first day focused on the mental and physical capacity for training and learning in both horses and humans.

The conference, attended by almost 200 delegates, also included practical demonstrations which took place at the Swedish National Equestrian Centre at Strömsholm.

Teachers from Strömsholm and the national stud at Flyinge demonstrated their approach to teaching young riders and training horses. Scientists from SLU presented examples of ongoing research projects, and showed how emerging technologies can measure important variables such as the pressure under saddle and the distribution of lameness.

The last day focused on the latest research in the field of horse welfare and human safety and, in a final panel discussion, the conference explored how these two topics can positively affect each other.

Abstracts of the presentations are available in pdf format for (free) download from the ISES website.

Managing pasture to reduce laminitis risk

A new report provides owners with practical information on how to manage their pasture to reduce the risk of laminitis in horses and ponies.

The search for improved meat, milk and fibre production has led to the development of grasses containing high levels of non structural carbohydrates (NSC- sugar, starch, and fructan).

The non-structural carbohydrate content can increase dramatically if the pasture is exposed to extreme conditions - such as intense sunshine, drought and cold stress. Such pasture presents a high risk for horses and ponies susceptible to obesity, insulin resistance and laminitis.

But with good pasture management, these conditions can be minimised.

The report, entitled "Equine Laminitis - Managing pasture to reduce the risk", is written by US -based agronomist Kathryn Watts and Professor Chris Pollitt, Director of the Equine Laminitis Research Unit at the University of Queensland, and published by Australia's Rural Industries Research and Development Corporation (RIRDC). It outlines how horse owners can reduce the level and concentration of sugar, starch and fructan in their pastures. High levels of these carbohydrates can cause laminitis in horses and ponies.

According to Professor Pollitt, the report represents an important step forward in the understanding of pasture associated laminitis.

“While there are still significant gaps in our knowledge about laminitis, a source of great frustration to horse owners and veterinarians alike, we do know that what the horse or pony has eaten over the last few days, weeks or months may trigger laminitis,” Professor Pollitt said.

Equine Laminitis – Managing pasture to reduce the risk can be purchased in hard-copy for $A25 or downloaded (free) in PDF format. See: www.rirdc.gov.au

Response of aged horses to vaccination

How does age affect the horse’s ability to respond to vaccination?

As with other body systems, the immune system undergoes age-related changes (known as "immunosenescence"). This may make the animal more prone to infections and autoimmune and neoplastic diseases.

A research team from the Atlantic Veterinary College, Prince Edward Island, Canada conducted a study to investigate the  specific systemic antibody response in horses by looking at how they responded to vaccination. They compared the response of young adult horses (aged 4 - 12 years) with aged horses (20years or older).


To investigate the primary immune response to an antigen that the horses would not have experienced before, they used rabies vaccine. Prince Edward Island is rabies-free and none of the horses had been vaccinated  previously for the disease.

They found that healthy aged horses vaccinated against rabies  showed a primary immune response similar to that of younger adults. However, by 6 months after vaccination the rabies antibody titres fell significantly in both age groups.

To test the anamnestic response (the rapid production of specific antibodies on renewed exposure to the antigen) they monitored the response to influenza vaccination. The anamnestic response was significantly reduced in the aged horses. Younger horses showed a significantly greater increase in two classes of anti-influenza antibody (IgGa and IgGb) after vaccination, compared with aged horses. This was despite the older horses having higher antibody levels at the start of the study.

Tiludronate effective for bone spavin

Horses suffering lameness due to bone spavin can show marked improvement following treatment with a tiludronate infusion, in combination with controlled exercise, according to recent research.

Bone spavin is a common cause of hindlimb lameness in horses and ponies. Often both hind legs are affected to some extent. Horses with straight or sickle-shaped hocks seem to be at greater risk of developing the condition.

There is little movement between the lower rows of bones in the hock. However these joints are subjected to considerable compressive forces. This can lead to degenerative changes within the bone and destruction of the joint cartilage

In a paper published in the Equine Veterinary Journal, Dr Martin Gough and others describe a double-blind, placebo-controlled trial involving 108 clinical cases of bone spavin.

The horses were treated at day zero with a single tiludronate infusion or a placebo and reassessed 60 days later after a period of controlled exercise.

Eighty seven horses completed the trials: 42 tiludronate treated horses and 45 placebo cases. By day 60 approximately 60% of the Tiludronate treated horses had improved in lameness by two grades or more, scored on a ten point system.

Tiludronate is believed to work by alleviating the pain associated with abnormal bone lysis.

This research was funded by CEVA Animal Health, manufacturers of Tildren®. For more information visit the website:
www.tildren.com

Making racing safer

What can be done to limit the number of horses dying as a result of racing injuries? It is hoped that  analysis of data on  fatal injuries will offer some suggestions. 

At the third Welfare and Safety of the Racehorse Summit held at Keeneland, Kentucky on June 28 and 29, Dr. Tim Parkin, epidemiologist from the University of Glasgow’s Faculty of Veterinary Medicine, presented a preliminary analysis of racing fatalities in North America from data compiled in the Equine Injury Database (EID).

The analysis was based on data on Thoroughbred flat racing in the EID collected on 73 racetracks between November 1, 2008 and October 31, 2009  - a total of 378,864 starts. Horses that suffered a fatal injury during or immediately after a race, or that died later as a result of an injury that occurred during racing, were included in the analysis.

Among Dr Parkin's findings were:

Starts made by 2-year-olds were less likely to end in fatality than starts made by older horses. Females were not at increased risk of fatality when racing against males. Starts made by females were less likely to end in fatality than starts made by intact males.

No statistically significant difference was found in the incidence of fatality on different surfaces, with different surface conditions, in different race distances, or in horses carrying different weights.

No firm recommendations can be made at this stage. As the data contained in the EID continues to grow, some of the current statistical conclusions may change as a reflection of increased certainty associated with a larger data set.

“This preliminary analysis just scratches the surface,” said Parkin, who serves as a consultant on the Equine Injury Database. “As the number of starts recorded in the database continues to grow, more complex statistical analyses can focus upon multiple variables studied in concert to better understand the myriad of factors which may contribute to fatal and non-fatal injuries. In addition, differences that may not have achieved statistical significance after one year of data collection may do so with additional observations recorded in the database.”

“The work presented today represents a starting point, not a destination,” said Dr. Mary Scollay, equine medical director for the Kentucky Horse Racing Commission and a consultant on the Equine Injury Database. “This begins to answer the question of what is happening. The ‘how’ and ‘why’ remain to be determined.”

for more details see:

http://www.grayson-jockeyclub.org/newsimages/Summitcombinerelease.pdf

Help needed with ragwort survey

British horse riders are being urged to help map the distribution of ragwort in the UK.

The risk to horses of eating ragwort are widely known throughout the equine community. The plant contains poisons that cause progressive liver damage. Even small amounts eaten over time can lead to serious disease.

Despite that, every year the British Horse Society Welfare Department receives numerous reports of horses grazing in fields containing ragwort. “It does seem that the amount of ragwort is on the increase” Lee Hackett, Senior Executive of BHS Welfare,  writes in the latest issue of British Horse, the Society‘s magazine. “This suggests that current control measures aren’t working, but to change things we need evidence.”

In an effort to gain hard data on the extent of the problem, the BHS is organising a snapshot survey during its Ragwort Awareness Week.

Anyone who spots ragwort during the week of 12-18 July is asked to spend a couple of minutes filling in a  simple survey form, which will be available on the homepage of the BHS website.

It is only necessary to report ragwort that is growing in or near to fields being used for grazing horses, sheep or cattle. 

Analysis of the data with mapping software  will show the areas where ragwort is most prevalent.
The number of animals grazing in ragwort-infested fields will also be calculated.

The intention is to repeat the survey in coming years so that trends in the distribution of the plant can be identified.

The BHS has 50 RagForks to give away, generously donated by the manufacturers, eazitools Ltd, who are sponsoring the survey. To be included in the draw for a RagFork you need to include your contact details on the survey form.

More details...

Horse Power CPD supports BEVA Trust & SPANA

Ten senior academics and equine vets from practice have come up with a novel way of raising money to help two worthy equine causes - the SPANA Disabled Riding Centre in Bamako, Mali and the BEVA Trust.

Led by Dr Derek Knottenbelt, they will undertake a 6 day CPD challenge, visiting all 7 British vet schools, to deliver  talks on a variety of subjects.

The lecturers will complete a  whistle-stop tour between the vet schools in convoy, on their motor bikes! They will cover over 1000 miles and deliver around 35 hours of lectures. The lectures are free - but donations are expected.

This marathon effort takes place at the end of July 2010. Places are limited, but anyone can contribute.

Click here to read more about it, or make a donation.

Benefits of exercise on insulin sensitivity

Unless dietary restriction below maintenance energy requirements is also employed, moderate exercise on its own is not enough to counter insulin resistance in obese or overweight horses, according to Dr Rebecca Carter and colleagues at Virginia Tech.

They examined the effects of exercise training alone on overweight or obese, insulin-resistant horses. Feed intake was limited during the study to 100% of maintenance energy requirements.

Eight horses, all either overweight or obese, followed a low intensity exercise program for 4 weeks followed by higher intensity exercise for a further 4 weeks. Finally they had two weeks without exercise (detraining). A control group of four horses received no structured exercise.

The horses’ body weight fell by 2% following the low intensity exercise and by a similar amount after the 4 weeks of higher intensity exercise. However, about half of the body weight lost during the exercise stages was put back on again within the two weeks of detraining with no exercise.

The researchers found no significant difference in glucose or fat metabolism or insulin sensitivity between the exercised and control groups throughout the study.

Dr Carter comments "even though our study did not show long-term training effects of exercise, there still are probably improvements in insulin sensitivity during and shortly after an exercise session. Therefore, ROUTINE exercise (every day) may be beneficial for improving insulin sensitivity."

Read more

Another cloning milestone has been reached by researchers at Texas A&M University with the successful birth of a foal produced using oocytes from a live mare.

Mouse, was born May 5, 2010. The efforts of his owner, Kit Knotts, to find a horse that had the same qualities as her prized Lippizaner stallion Marc, (Pluto III Marcells) led her to Texas A&M University and equine reproduction expert Dr Katrin Hinrichs.

"We have worked on this clone for about two years," said Hinrichs, a professor in the Department of Veterinary Physiology and Pharmacology.  "This is actually our first foal produced using oocytes, or egg cells, from live mares."  She explains that using oocytes from live mares made the process difficult as they had very few oocytes to work with at any one time.

Minnie, the surrogate mare, began to show signs of an early delivery, and was taken to the University of Florida College of Veterinary Medicine for observation and intervention. That’s where Mouse arrived and was cared for by a team of neonatal experts that helped make sure he would make it through this critical time.

Because of the risk of complications and problems in the period just after birth, Dr Hinrichs’ team recommends that foals derived by cloning should be treated as high-risk neonates, and their birth should be closely supervised. Facilities for intensive care should be available in case they are needed.

To read more about the problems faced by cloned foals go to www.equinescienceupdate.co.uk/clone3.htm

Lavender Foal Syndrome

Researchers have identified the genetic mutation responsible for Lavender Foal Syndrome. Lavender Foal Syndrome (LFS), also known as Coat Color Dilution Lethal (CCDL), is a fatal disease of newborn Arabian foals, particularly in those of Egyptian Arabian breeding.

The condition gets its name from the abnormal coat colour with which most affected foals are born, which has been described as silver sheen, lavender, pale chestnut or pale, dull pinkish grey.

Signs shown by affected foals include seizures, nystagmus (involuntary movement of the eyeballs), limb rigidity, paddling movements, and opisthotonus (hyperextension of the head, neck, and spine). The mare often has difficulty giving birth.

A team of scientists from Cornell University and the Maxwell H Gluck Equine Research Center have found that Lavender Foal Syndrome is the result of a mutation in a gene called myosin Va (MYO5A).

The myosin Va transport complex is responsible for the transfer of pigment to the keratinocytes and for transport of transmitter substances in the nerve cells. A mutation affecting the gene could easily result in interference with normal function of melanocytes (responsible for hair color) and nerve cells.

“Our results suggest that the population frequency of carriers of this deletion is 10.3% in the Egyptian Arabian” reports lead researcher Dr Samantha A. Brooks, assistant professor in the Department of Animal Science at Cornell University's College of Agriculture and Life Sciences.

“Given our estimate of the number of carriers in the population we expect that around nine LFS foals would be born in the USA each year”

For more about the research on Lavender Foal Syndrome click here.

Antibiotic resistance in equine faeces

Horses can be a source of antibiotic-resistant bacteria, presenting a threat to human health, according to a recent study.

Mohamed Ahmed, of the Department of Veterinary Microbiology and Parasitology, at Al Fatah, University, Tripoli, Libya, working with colleagues at the Liverpool Vet School, examined fecal samples collected from the University’s equine hospital and from livery yards.

They found antibiotic resistant E. coli in faeces from both locations. From a total of 264 samples, 296 isolates of antibiotic-resistant Escherichia coli were identified.

Not only were hospitalised horses more likely to have antibiotic resistant E. coli in their faeces, they were also more likely than those maintained on livery yards to carry organisms that were resistant to multiple drugs.

Nearly half (48%) of the resistant isolates from the hospital environment showed multiple drug resistance phenotypes, compared with only 12% from the livery yards.

The researchers conclude that, in the UK, horses may provide both recipients, and sources, of antibiotic resistance, MDR, and be an extensive reservoir of antimicrobial resistance genes that could pose a potential threat to human health.

For more details see:

http://www.equinescienceupdate.co.uk/aref.htm

Third Welfare and Safety of the Racehorse Summit

The forthcoming third Health and Welfare of the Racehorse Summit to be held by the  Grayson-Jockey Club Foundation  at the Keeneland Sales Pavilion in Lexington, Ky., June 28-29, 2010, aims to identify ways of enhancing the safety and soundness of Thoroughbred racehorses.

Attendance at the meeting is by invitation only. But you don't need to miss out. Thanks to modern technology and Keeneland.com the public sessions of the summit will be made available to all on a live web stream.

Among the topics to be covered will be an update and preliminary findings on data submitted to the Equine Injury Database. Veterinarian and epidemiologist, Dr. Tim Parkin, of the University of Glasgow, has been analyzing data submitted to the Database, and will provide an update and preliminary findings.

Other topics include a panel discussion on race track surfaces, and updates on the Racing Medication and Testing Consortium, the NTRA Safety and Integrity Alliance, and the Thoroughbred Safety Committee.

There will also be panel discussions on racing equipment and safety,  racetrack environment and training practices, and transitioning thoroughbred racehorses to second careers.


For more information, including the link to the web stream, see:

http://www.grayson-jockeyclub.org/summitDisplay.asp

Deworming horses with Cushing's disease

Horses with Cushing’s disease (also known as pituitary pars intermedia dysfunction ; PPID) are more  likely to have higher fecal egg counts than are healthy horses according to a recent study.

Dr Dianne McFarlane and colleagues compared the response to anthelmintic treatment on fecal egg counts in healthy horses and those with Cushing’s disease.

Twenty-nine healthy horses  (ranging in age from 4 to 35 years ) and 13 horses with PPID (13- 33 years old) were used in the study. The presence or absence of PPID was confirmed by clinical signs and plasma alpha MSH assay (reference range for normal horses <35pmol/L; PPID horses ≥45pmol/L)

The researchers performed faecal egg counts at 2-week intervals before and after treatment with ivermectin.

At 2 and 4 weeks after treatment with ivermectin all horses in the study had negative fecal egg counts.

Horses with PPID had higher egg counts than did healthy horses, both before and at 6 - 12 weeks after treatment.  This difference could not be explained by the PPID horses being older than the control horses, as the researchers found no correlation between age and fecal egg count.

A fecal egg count greater than 200 epg is often taken as an indication that anthelmintic treatment is required. In this study 6 of the 13 horses with PPID reached the 200epg threshold by 10 weeks after ivermectin treatment. In contrast only 2 of 25 control horses had reached the threshold at the same time - a difference that was statistically significant.

“Given similar environmental conditions, horses with PPID were more likely to have higher fecal egg counts than were healthy horses” Dr McFarlane reports.

The findings suggest that horses with PPID may pose a risk for pasture hygiene if not managed properly.

On the other hand, age alone does not appear to increase the horse’s susceptibility to parasitism. However, the researchers point out that only a small number of horses were involved in that analysis. More work is required to confirm that older horses do not need treating differently to younger horses when it comes to deworming.

For more details see:

Fecal egg counts after anthelmintic administration to aged horses and horses with pituitary pars intermedia dysfunction.
D.McFarlane, GM Hale, EM Johnson, LK Maxwell
J Am Vet Med Assoc (2010) 236, 330-334

Prepare for Hendra season Australian horse owners warned

Horses are at increased risk of Hendra virus (HeV) infection at this time of year, the Australian Veterinary Association (AVA) has warned. The disease is usually fatal, and can affect humans that have been in contact with affected horses.

The virus is named after the suburb of Brisbane, Queensland, Australia, in which it was first isolated. In that outbreak in horses at a training centre, 14 horses died. Seven other horses were shown to have been infected and were humanely destroyed. Affected animals typically showed severe lung damage. Two humans were affected, one of whom died.

The natural hosts for the Hendra virus (HeV) are species of fruit bats (commonly known as flying foxes). Antibodies have been found in all four species of fruit bats found in mainland Australia.

“Anyone working with horses should be on the lookout and immediately report any suspected cases of Hendra virus infection over the coming months,” said Dr Barry Smyth, Vice-President of the Australian Veterinary Association.

“Recent mass movements of large flying fox colonies means owners should be especially vigilant.

“Wet weather in some parts of the country has caused flying foxes to take to the air to find food in new areas. An influx of more than 130,000 into Victoria was confirmed by scientists just last week.

“So far cases of Hendra infection have been restricted to Queensland and New South Wales, however there is a potential for the disease wherever there are flying foxes.

Common signs to look out for include respiratory distress, frothy nasal discharge, elevated body temperature (above 40° C) and elevated heart rate. Some horses may show neurological signs including incoordination and head pressing. However, it is important to realise there are no specific signs of infection.

What can you do to limit the risk of horses being exposed to the virus?  “Protective measures include placing feed and water under cover where possible, not placing feed and water under trees when flying foxes are in the area, not using feed that might attract flying foxes (such as fruit and vegetables), and where possible removing horses from fields where flying foxes are active, and fencing off trees where flying foxes roost” Dr Smyth said.

The few cases of human Hendra virus infection have been the result of very close contact with horses infected with the virus. Body fluids or secretions from infected animals are likely to contain the virus.

At the time the people became infected the horses did not appear sick.

“The risk can be greatly reduced by adopting good hygiene practices as a matter of routine and taking increased precautions around any sick horse,” said Dr Smyth.

Experts to advise on equine infectious diseases

Thanks to the opportunities of modern transport, it's not only horses that can travel the world. They may also take with them their infectious diseases.

The recent equine influenza outbreak in Australia showed what can happen when susceptible horses are exposed to infection.

So with all the current scientific knowledge about  vaccination, immunity and infectious disease in horses, What can be done to prevent, control  limit the risk of similar outbreaks disasters events happening in the future.

Recently a group know as the Prevention of Equine Infectious Disease Guidelines Group (PrEquID) has been set up to compile recommendations for preventing and managing major equine infectious diseases, based on current scientific knowledge and available vaccines.

After an initial meeting in November 2009, the group met again in March 2010, to discuss guidelines for Equine Influenza and Equine Herpes virus infections. These diseases are widely considered to have a significant impact on the horse industry, based on disease outcome, economic impact, veterinary care and travel restrictions.

Practical, evidence-based recommendations are currently being finalised and will be made available shortly.

“Our aim is to develop overarching international guidelines for the management of infectious diseases,” said Professor Marian C Horzinek, Chairman of PrEquID. “These should contain practical, evidence-based recommendations for disease control and horse movement.”

Professor Peter Timoney, of the University of Kentucky, added, “the equine industry worldwide is facing an unprecedented threat from the challenge of infectious diseases. It’s a huge industry involving a complex range of stakeholders, including veterinarians, owners, breeders, trainers, shippers and regulators. We must set aside individual and national agendas and concentrate on the bigger picture if we’re to achieve greater international control over the spread of equine diseases and protect our industry for the future.”

The establishment of PrEquID was initiated and sponsored by Fort Dodge Animal Health (a division of Wyeth). With the acquisition of Wyeth by Pfizer in 2009, this initiative is now supported by Pfizer Animal Health.

How does pasture cause lamintis?

Fructans and starch are not responsible for most cases of laminitis, Dr Teresa Hollands told delegates at the Laminitis Awareness 2010 seminar.

Most cases of laminitis occur when horses are eating grass. Pasture associated laminitis accounts for 66% of cases occurring in the UK. But what causes the laminitis?

Experiments have shown that giving large meals of starch or fructans can cause laminitis. Large amounts of these carbohydrates suddenly arriving in the horse’s large intestine disrupt the normal population of bacteria in the gut, leading to a cascade of inflammatory and toxic events.

However, Dr Hollands, nutritionist at Dodson and Horrell, explained that this process is unlikely to be involved in the majority of cases of pasture-associated laminitis.

Firstly, grass contains little starch. Of the pasture plants commonly found in the UK, only clover has significant amounts of starch. Grasses store glucose that they can’t use straight away as fructans.

It has been shown that laminitis can be induced by giving a large bolus of fructan  (5g-12.5g fructan/kg body weight).  That’s about 3.75kg fructan for a 500kg horse.

How much fructan would a horse eat when grazing? Grass contains higher levels of fructan during the winter. Mixed pasture might contain 150g fructan/kg dry matter of grass in the winter (compared with 6.6g/kg in the summer). If a 500kg horse eats an amount of grass equivalent to 2.5% of his body weight, (12.5kg), his total intake of fructans would be about 1.9kg.

So the full daily intake falls short of the levels that have been shown to cause laminitis. And what’s more, as horses are “trickle feeders”, that fructan intake is spread out over 24 hours. So even in the winter when the fructan levels in the grass are highest, the horse is only likely to eat something like 50g fructan/hour. In the summer the figure is likely to be about 5g fructan an hour - a thousand times less than the amount needed to cause laminitis.

What’s more, recent work has shown that fructans are fermented in the small intestine, and so are even less likely to reach the hindgut in sufficient quantities to cause food-induced laminitis.

So how does grass cause laminitis? “We need to move away from thinking about individual components of the diet "  Dr Hollands suggested. “In the end it is the calories that are the main risk factor.”

“Grass provides more than enough calories for most horses in light work.”

She explained that recent work with World Horse Welfare and Napier University used alkanes to measure grass intake.  Every day, some horses ate an amount of grass equivalent to 5% of their body weight. Some individuals increased their body weight by 4% a week.

“So you can see that grass easily provides horses with excess calories,” she said “ leading to gradual accumulation of fat. Excess calories over time equals fat. Not all fat is the same.”

She explained that research had shown that some adipose (fat) tissue is metabolically active. The fat cells (adipocytes) release numerous biologically active substances (adipocytokines), which affect glucose and fat metabolism. When present in excess they can lead to insulin resistance, which in turn can result in laminitis.

“The slow insidious eating of excess grass over years is the problem; not the grass they ate today. People get insulin resistance and diabetes because they have been on a bad diet for years, not because they ate a doughnut today!”

What can you do to prevent laminitis associated with insulin resistance?

First you need to reduce the fat. Give thirty minutes exercise daily with a heart rate of 80 beasts per minute. (“Turnout in the paddock is not enough” she says). Accept that the horse or pony will lose weight (fat) over the winter.  Indeed encourage him to do so by using lightweight rugs only - so that he burns fat to keep warm.

Do not starve the horse. Maintain the bulk intake (at 2.5% of body weight) - otherwise he will be prone to developing stereotypies or gastric ulcers. But reduce the calorie intake - soak the hay for 12hours or feed oat or barley straw.

Make sure horses do not get too much grass. Consider using a muzzle; increase the number of horses (and /or cattle and sheep) on the pasture. It’s important to feed a balanced diet.  Make sure the horses receive adequate proteins, minerals and vitamins by feeding a low calorie commercial feed balancer.

The solution is to reduce obesity, ensure nutrition is optimal, and increase exercise.

Monitoring respiratory disease

Researchers at the University of Glasgow have developed  two new non-invasive methods of monitoring respiratory disease in horses.

The number of times a horse coughs provides a good indication of respiratory inflammation - the more inflammation, the more the horse coughs. But it is often not practical, or cost-effective, for someone to physically count the number of times a horse coughs over an extended period.

The research team, led by Professor Sandy Love,  has developed a technique that uses a digital audio recorder attached to the head collar to monitor cough frequency over a long period of time.

In a study to test the value of the technique, the researchers compared audio recordings, each lasting one hour,  with simultaneous video recordings. A total of nine recordings were collected from seven stabled horses .

The  graph of the  audio file could then be examined to identify coughs. Not only was this a rapid process - a  recording lasting one hour could be analysed within three minutes - the technique was also found to be very accurate.

When they compared the audio and video recordings the researchers found that every cough was correctly identified, and no extraneous noises, such as foot stamping,  were mistaken for coughs.
They point out that the speed of the  analysis could be increased further by using  computer software to automate the analysis.

The project also led to the development of a simple device that could be attached to the horse’s head collar to  collect expired moisture. It was used to study the constituents of exhaled breath to see if any could be used as indicators of respiratory inflammation.

The researchers found that the most useful indicator was the pH of the liquid condensed from the expired breath. There was trend toward a reduced pH (acidification) in horses with lower airway inflammation.

The concentration of gases such as carbon monoxide, nitric oxide and ethane was also measured, but the researchers found no correlation between these substances and inflammation in the respiratory tract.

The work was made possible by funding from The Horse Trust . Paul Jepson, Chief Executive and Veterinary Director of The Horse Trust said, “ "We are delighted that the research we have funded has led to new, non-invasive ways of monitoring respiratory inflammation in horses. These techniques could have a major impact on horse welfare by improving the diagnosis and treatment of this common condition.”

Bladder stone laser treatment

Normal equine urine contains many calcium carbonate crystals. Despite that, it is not common for stones (“calculi”) to form in the urinary tract of horses. They are most often seen in the bladder (“urocystoliths”) or urethra (urethroliths”).

It is possible to remove them surgically, which may require general anaesthesia and carry the risk of complications - in particular peritonitis. Other methods include disrupting the calculi with shock waves or laser.

Researchers at the Virginia-Maryland Regional College of Veterinary Medicine and the School of Veterinary Medicine at the University of California, Davis have described a minimally invasive technique using a laser to break up the urinary calculi.

An optical fibre is passed through the biopsy channel of the endoscope. This is used to direct the beam from the laser onto the bladder stone. The procedure can be carried out without the need for epidural or local analgesia.

The surgeon sweeps the fibre across the surface of the stone to produce a crater or groove until eventually a fragment breaks off. This process is repeated as many times as necessary until the remaining pieces of urolith are small enough to pass out through the urethra.

Larger fragments are removed by grasping them with a wire basket passed through the endoscope. Smaller fragments are flushed out.

The technique was successful for removing all uroliths and fragments in five of a series of seven cases. The authors concluded that laser lithotripsy combined with lavage and retrieval of larger fragments using the endoscope was a safe procedure. They suggest that if no progress is made within the first 30 minutes the case will have to be managed by other means.

Read more at Equine Science Update

Equine atypical myopathy - possible cause found

Researchers at the University of Bern, Switzerland, have identified a possible cause for the often fatal disease atypical myopathy. They found evidence to implicate a toxin produced by the bacterium Clostridium sordellii. The toxin is known to cause severe muscle damage in mice.

The researchers examined heart and skeletal muscle samples from horses affected with Atypical Myopathy using transmission electron microscopy. They found that the changes that were present were similar to those found in mice affected by the toxin.

They also used immuno histochemistry staining techniques to show that the lethal toxin of Clostridium sordellii was present in the muscle fibres of affected animals. Antibodies from horses with Equine Atypical Myopathy and antibodies to the lethal toxin of Clostridium sordellii both bound to muscle fibres taken from horses affected with EAM.

In contrast, neither of the antibodies attached to normal horse muscle fibres or to muscle fibres taken from horses with other types of muscle disease.

The scientists concluded that there is evidence that the lethal toxin of Clostridium sordellii plays a role, either as a trigger, or even as a lethal factor, in Atypical Myopathy.

Read more at Equine Science Update.co.uk