Gene for PSSM type 1 in European draught breeds

PSSM is a metabolic disease that results in the accumulation of glycogen and abnormal polysaccharide in muscle.

A genetic mutation of the glycogen synthase1 gene (GYS1) has been identified as the cause of some cases of PSSM in quarter horses and North American draft breeds. This form of the disease has been classified as type 1 PSSM.

A recent study has now also found the GSY-1 mutation in continental European draught breeds.

With the cooperation of the breed societies, Dr John Baird and colleagues sampled Ardenner, Belgian Draft, Breton horse, Comtois, Trait du Nord, Hispano-Breton, Netherlands Draught horse, and German cold bloods.

Overall 62% of continental European draft horses possessed the GYS-1 mutation. The mutation was present in all breeds sampled and in all six countries (Belgium, France, Spain, Germany, Sweden and the Netherlands.)

Of the breeds in which more than 15 animals were tested, the Belgian trekpard had the highest number of horses with at least one copy of the GSY1 gene (92.1%). Over a third of the Belgian trekpard tested were homozygous for the GSY1 allele - that is they carried two copies of the defective gene. The mutation was also present in over 50% of the animals tested from the Comtois (79.8%), Netherlands trekpard (73.9%), Rheinisch-Deutsches kaltblut (68%) and Breton (64.4%) breeds.

"What is striking from the present study" say the authors" is that a high percentage of horses derived from continental European draught breeds, in fact, often the majority of horses tested in each breed, were positive for the GYS-1 mutation."

However they stress that, as the research was not based on random samples, it cannot be relied on to give an accurate assessment of the prevalence of the GSY-1 mutation in continental European breeds.

For more details see: http://www.equinescienceupdate.com/articles/gpedb.html

Latest stem cell research results

Stem cell treatment reduces the rate of repeat injuries when used for treating superficial flexor tendon injuries in racehorses, according to research at the Royal Veterinary College.

Professor Roger Smith developed a technique for harvesting stem cells from the bone marrow, multiplying them in the laboratory and then implanting them back into damaged tendon.

So far, the procedure has been used in over 1500 horses throughout the world. Monitoring the healing process using ultrasound scans showed that the hypoechoic "core" lesion filled in quickly, although a reduced longitudinal striated pattern usually persisted.

A study of the clinical outcome in 113 treated racehorses, found that the re-injury rate was significantly lower in stem cell treated horses than in conventionally treated horses.

Histopathological examination of 17 tendons from post mortem samples obtained from horses that  had undergone stem cell implantation showed both good quality healing with minimal inflammatory cells, and crimped organised collagen fibres.

A further experimental study found that stem cell treated tendons had more normal mechanical  characteristics and their shape, appearance and composition were also improved. Tendon cross-sectional area, cellularity, crimp pattern and DNA content were all significantly better in the treated tendons than in the saline controls. Read more at www.equinescienceupdate.com

Obesity in English horses

Obesity is likely to be just as common in horses as it is in the human population.

A University of Nottingham study found that at least one in five leisure horses was overweight or obese. Owners were likely to underestimate body condition score.

Veterinary student Helen Stephenson assessed the prevalence of obesity among horses whose owners were registered with an equine veterinary practice.

Questionnaires were sent to five hundred horse owners, and 160 were returned. None of the horses was kept for breeding, livery, riding stables, or competition, so all were classed as being used for leisure only.

One in five owners indicated that their horses were either overweight or obese.

The owners were asked about their perceptions of their horses’ body condition, and asked to score this from zero to five, with a score of more than three indicating overweight.

The researchers then assessed the body condition of 15 randomly selected horses to see if the owners had under or overestimated the horse’s weight.

They assigned an average score that was significantly higher for these horses; eight of the owners had scored their horse at least one grade lower than the researcher had, indicating that the owners had underestimated their horses’ weight.

Based on the researchers’ findings, the authors estimate that the true prevalence of overweight/obesity was likely to be 54% rather than the 20% indicated by the questionnaire responses.

Read more at www.equinescienceupdate.com/obeng.html

Feral horse survival under changing environmental conditions

Australia´s recent heavy rain presents an opportunity to examine how feral horses are affected by the weather.
 
Magdalena Zabek has been working with the Australian Brumby Research Unit (ABRU), keeping a photographic record of their work. Now she is looking to complete a study of her own into the effect of a period of plentiful rainfall on the feral horses of central Australia (“brumbies”) following nine years of severe drought.
  
Currently the brumby population is estimated to grow at around 20% annually. It seems likely that the foaling rate in 2011 will be higher, due to the more favourable conditions during the 2010 breeding season.
 
In the ABRU December 2010 newsletter, she writes: "Information from this study will provide valuable information about fluctuations in numbers of feral horses due to the changes in availability of food and water, which is crucial knowledge when implementing population control methods. The study will also contribute to the development of better welfare outcomes for feral horses."
 
"The sudden increase in numbers will have an enormous impact on the feral population when the favourable climatic conditions change because the fragile semi-arid ecosystem is not able to meet the food and water requirements of feral animals during periods of less favourable conditions. When resources become scarce due to drought, the feral horses are forced to travel ever increasing distances to obtain adequate food and water, and, as a result, may die."
 
The findings of the study should help direct strategies used to manage feral horses, and hopefully reduce suffering and death during periods of drought.

Read more in the ABRU December 2010 newsletter.
http://www.wildhorseresearch.com/Documents/Newsletters/December%202010.pdf
 
For more information about Magdalena´s art work see:
http://www.magdalenas-art-work.22web.net

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.