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

Urine DNA profiling

Scientists will soon be able to use DNA profiling techniques to confirm the identity of racehorses that have tested positive to drugs.

Such a test would dispel any doubt about sample substitution and confirm that a sample did in fact come from a particular horse, helping to either confirm the identity of horses returning positive drug samples, or exonerating horse and trainer.

The report “DNA Profiling of Horse Urine Samples to Confirm Donor Identity” resulted from studies carried out by Paula Hawthorne and colleagues at the University of Queensland, and was funded by the Australian Government's Rural Industries Research and Development Corporation (RIRDC). The research team tested various techniques for DNA profiling on seven urine samples and compared the results with those from hair samples taken from the same horses.

They found that storage time and temperature had a significant effect on the success of the DNA profiling. Urine could be stored at 4°C for no more than two days (or frozen at -20°C or -80°C) before processing. Samples stored at 4°C for a week or more yielded no profiles.

The most successful technique, a commercially available test, allowed them to identify all twelve microsatellites, in four urine samples - all from male animals. As only seven samples were examined overall, it was not possible to tell whether that was a coincidence, or whether it really is more difficult to extract DNA from mare’s urine.

All DNA profiles from the urine samples matched those from the hair taken from the same horses.

There is still more work to do - for example, the researchers point out that drugs in the urine may interfere with DNA profiling. So once the best method of DNA profiling has been established, further tests will be required to assess whether the results are affected by drugs likely to be found in the urine.

However, the authors of the report suggest that once the optimum method has been finalised it should not take long to integrate it into existing procedures of racing drug-testing laboratories.

The full report is available for purchase or free download. See:
https://rirdc.infoservices.com.au/items/09-076

Risk of Atypical Myopathy cases this spring.

“There seems to be an increased risk of cases of Atypical Myopathy during the spring, when the disease has occurred during the previous fall” warns Dr Domonique Votion, of the University of Liege.

In the last few months of 2009, Western Europe experienced the largest ever series of cases of the disease, according to the Atypical Myopathy Alert Group (AMAG).

No less than 371 cases were notified to the AMAG. Of those horses, 265 died, giving a survival rate of just 22%. Most cases were reported in France (124) Germany (92), and Belgium (64).
Thirty-five cases were identified in the UK.

Horses with Atypical Myopathy suffer from severe, generalised weakness. They are often unable to get to their feet, or only do so with difficulty. If they are still able to walk, they do so with a stiff gait - especially of the hindquarters. Muscle tremors and generalised or patchy sweating may be seen.

Affected animals have elevated heart rates. They often have increased respiratory rates, with difficulty on expiration. The rectal temperature is usually below normal. Dark brown colouration of the urine is characteristic.

Despite the severity of the signs, horses often still seem keen to eat and will try to grasp hay that is held close to their mouth.

Often the first sign of disease is stiffness, especially of the hindquarters. However, it is not unusual for severely affected cases to be found dead on the pasture with no previous sign of illness.

For more details about the Atypical Myopathy and the Atypical Myopathy Alert Group see:

http://www.myopathieatypique.be

Disease surveillance report

The latest equine disease surveillance report published jointly by the UK Government’s Department for environment food and rural affairs (Defra), Animal Health Trust (AHT) and the British Equine Veterinary Association (BEVA), is now available. The report covering the period October - December 2009 has been uploaded recently to the Animal Health Trust website.

The Defra/AHT/BEVA equine quarterly disease surveillance report collates equine disease data arising from multiple diagnostic laboratories and veterinary practices throughout the United Kingdom. The current edition includes data from 30 laboratories and offers a unique insight into equine disease occurrence in the UK.

A form is available on the AHT website for registration to receive reports free of charge, via e-mail, on a quarterly basis.

See:

http://www.aht.org.uk/equine_disease.html

EMS research: help needed

Do you have a horse or pony with Equine Metabolic Syndrome? If so, scientists at the University of Minnesota's Equine Genetics and Genomics Laboratory would like to hear from you.

EMS is characterized by three main features: obesity or regional accumulation of fat (particularly in the crest or over the rump), insulin resistance and laminitis.

Some horses, often considered to be "easy keepers" by their owners, are more at risk of EMS than others. It is likely that the genetic make-up of the horse affects its susceptibility to the condition.

The aim of the study is to better understand the role in EMS of factors such as breed, gender, age, environment (diet and exercise) and genetics. To achieve this, the researchers need to collect data from as many horses with EMS as possible. So, they are keen to encourage horse owners and their veterinarians to get involved.

If you are interested in taking part in the Equine Metabolic Syndrome research project, the first step is to complete a short online survey. Within about one month, if your horse is considered suitable for the project, you will be asked to complete a second survey. This will ask for further information about the horse and about another horse, unaffected by EMS, that lives on the same property. This horse will serve as a "control". Ideally the control horse should be of similar breed and age, have no history of laminitis, not be overweight and show no signs of Cushing's syndrome (delayed shedding, increased drinking/urination).

The third step is to submit a blood sample to the laboratory, for biochemical analysis and DNA evaluation.

To identify the underlying genetic susceptibility to EMS, the scientists will compare genetic markers between horses with and without EMS. The genetic differences that are highly correlated to having EMS can be used as genetic markers for the disease.

The long-term goal is to use these EMS genetic markers to detect horses susceptible to EMS and laminitis before they have clinical signs. It may then be possible to change the management of susceptible animals to reduce the risk of them developing disease.


For more details about the study

http://www.cvm.umn.edu/equinegenetics/ems/research/index.htm

Rapid ringworm diagnosis

Scientists in South Korea have described a rapid method for diagnosing ringworm (dermatophytosis.)

Fungal culture is the “gold standard” method for identifying the species of dermatophyte involved, based on the colony characteristics and microscopic appearance. It is accurate but time consuming. Samples may have to be cultured for up to three weeks before the organism can be identified.

It’s not necessary to know the species before starting treatment. Indeed, to prevent the spread of infection, treatment is usually started pending the results of laboratory investigations.

However, there are occasions when it may be useful to know the identity of the dermatophyte involved, as it may help to identify the source of the outbreak. For example Trichophyton mentagrophytes can be found in soil and be carried by rodents.

Researchers at the Colleges of Veterinary Medicine at Seoul National University and Konkuk University compared a rapid molecular PCR assay with conventional fungal culture for diagnosing ringworm.

They found that the PCR analysis of the fungal DNA was superior to traditional fungal culture for diagnosing dermatophyte infection, “ in terms of sensitivity, specificity and particularly rapidity.”

Read more at www.equinescienceupdate.co.uk/rmmdd.htm

Exercise and pregnant mares

In humans, moderate exercise in pregnancy seems to do no harm and may help limit excessive weight gain and maintain fitness for the birth. What about horses? Many pregnant mares are ridden and subject to moderate training up to the later stages of pregnancy.

A research team from the University of Maine and the Equine Science Center, Rutgers University, New Jersey compared the response of pregnant and non-pregnant mares to a graded exercise test.

Six unfit standardbred mares were assessed when nine months pregnant and again eight months later after weaning. The exercise test was carried out on a treadmill inclined at 6%. The speed increased in steps of one minute each at 4m/s, 6m/s and 7m/s.

At each stage of the graduated exercise test, mares had lower heart rates when pregnant than after weaning. Plasma lactate concentrations rose less in response to exercise when mares were pregnant than when they were not. The researchers speculate that this might be due to greater cardiovascular efficiency during pregnancy.

Resting plasma cortisol levels were lower during pregnancy than when the mares were not pregnant.

When exercised, pregnant mares showed no increase in cortisol levels. In contrast, when they were not in-foal, the mares showed a normal increase in plasma cortisol during and after the exercise test.

Neither did exercise have an effect on foetal heart rate. This suggests that the unborn foal is not stressed by the mare undertaking moderate exercise.

The researchers conclude: “these data suggest that pregnant mares benefit from greater cardiovascular efficiency during pregnancy. They should be able to perform limited moderate exercise without any major deleterious effects on their unborn foals or themselves during late gestation.”


Read more...

Tick-borne disease in Danish horses

Tick-borne infections are common in Danish horses. A survey published in Acta Veterinaria Scandinavica showed that many Danish horses carry antibodies to Borrelia burgdorferi sensu lato (the group of Borrelia species known to cause Lyme disease) and Anaplasma phagocytophilium (the cause of equine granulocytic anaplasmosis).

The study, overseen by Dr Anders M Bojesen of the Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Denmark aimed to evaluate the seroprevalence of B. burgdorferi s. l. and A. phagocytophilium in Danish horses.

Overall, 29.0% horses were seropositive for B. burgdorferi s. l. and 22.3% were seropositive for A. phagocytophilium. This was a higher proportion than had been found in previous studies in neighbouring countries.

There was no significant correlation between risk factors investigated, including breed, gender, age, use and housing and the occurrence of antibodies against B. burgdorferi s. l.

However the researchers did find that older horses were more likely to have been infected with A. phagocytophilium. Compared with horses aged between 1-4 years old, those aged 11-20 years were 2.3 times more likely to be seropositive for A. phagocytophilium, and horses over 21 years old were 3.3 times more likely to be seropositive.

Horses seropositive for B. burgdorferi s. l. were likely to be seropositive for A. phagocytophilium and vice versa.

The researchers conclude “these findings warrant further attention to these infections in horses particularly with regard to improved means for detection of active infections, which may contribute to a better understanding of these diseases and their impact on horse behaviour and welfare.”

More details...

New equine respiratory condition described

Danish Researchers have identified a new cause of respiratory disease in horses. They found the bacterium Stenotrophomonas maltophilia in samples collected from horses with chronic lower airway disease.

Stenotrophomonas maltophilia, a Gram-negative bacterium, has been found increasingly in human medicine, especially in patients with impaired immune systems. Until recently the organism has been recorded only rarely in animals.

In a paper to be published in The Veterinary Journal, Lotte Winther, a PhD student in the Department of Large Animal Sciences at the University of Copenhagen, and colleagues present data from seven horses with respiratory disease associated with S. maltophilia infection.

All cases had a history of chronic coughing. Endoscopic examination revealed copious mucopurulent exudate in the lower trachea. Culture of the tracheal exudate produced grey, slow-growing colonies, which were identified as S. maltophilia by both culture and DNA testing.

Many antibiotics commonly used to treat equine respiratory infections were not effective against S. maltophilia.

The findings suggest that S. maltophilia can act as a respiratory pathogen. The researchers advise that the organism be included in the differential diagnosis of horses with respiratory disease associated with copious mucopurulent exudate.

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