Ancient wild horses help reveal past

An international team of researchers has used ancient DNA to produce compelling evidence that the lack of genetic diversity in modern stallions is the result of the domestication process.

Modern domestic horses show abundant genetic diversity within mitochondrial DNA, which  is inherited only from the female. In contrast there is practically no variation in the DNA sequence on the male-inherited Y-chromosome.

Several hypotheses have been proposed to explain this difference, but to be able to test them it is necessary to know about the degree of variation in the ancestral horse population. The only way to get this information is by studying ancient DNA.

The research team, which was led by Professor Michi Hofreiter from the University of York, UK, has carried out the first study on Y chromosomal DNA sequences from extinct ancient wild horses and found an abundance of diversity.

The results, which are published in Nature Communications, suggest the almost complete absence of genetic diversity in modern male horses is not based on properties intrinsic to wild horses, but on the domestication process itself.

Professor Hofreiter said: “Unlike modern female domestic horses where there is plenty of diversity, genetic diversity in male horses is practically zero.

“One hypothesis to explain this suggests modern horses have little Y chromosome diversity because the wild horses from which they were domesticated were also not diverse, due in part to the harem mating system in horses, implying skewed reproductive success of males. Our results reject this hypothesis as the Y chromosome diversity in ancient wild horses is high. Instead our results suggest that the lack of genetic diversity in modern horses is a direct consequence of the domestication process itself.”

Read more : http://www.equinescienceupdate.com/articles/awhhrp.html

Identifying the cause of Foal Immunodeficiency Syndrome

Researchers in the UK have now published details of their work which resulted in the development of a genetic test for Foal Immunodeficiency Syndrome (FIS, otherwise known as Fell Pony Syndrome).

By comparing the genetic material from affected foals, known carriers with no clinical signs, and normal animals, the research team were able to track down the mutation responsible to a particular portion of chromosome 26. Further studies showed that the genetic defect affected the sodium/myo-inositol cotransporter gene (SLC5A3).

In the report of their work published in PLoS Genetics, they explain: "This gene plays a crucial role in the regulatory response to osmotic stress that is essential in many tissues including lymphoid tissues and during early embryonic development. We propose that the amino acid substitution we identify here alters the function of SLC5A3, leading to erythropoiesis failure and compromise of the immune system. FIS is of significant biological interest as it is unique and is caused by a gene not previously associated with a mammalian disease. "

"Having identified the associated gene, we are now able to eradicate FIS from equine populations by informed selective breeding."

Read more at www.equinescienceupdate.com

Effect of blinkers

How do horses respond to partial loss of vision?

In a study at Texas A & M University, eight driving horses were assessed to see if they responded differently to stimuli when wearing blinkers or not. A racing hood with half cup blinkers was used to restrict the field of view behind the horse. A similar racing hood without blinkers was used as a control.

One experimenter administered one of four stimuli while standing about nine strides behind the horse:

• a length of steel chain was dropped onto an aluminium sheet
• a children's toy gun was fired
• an aluminium can containing coins was shaken
• an umbrella was rapidly opened

The horse's heart rate was recorded after each stimulus.

They found that wearing blinkers was significantly associated with an increase in heart rate when worn by horses experiencing a noise for the first time. On the other hand, blinkers were significantly associated with a decrease in heart rate when worn by horses exposed to a primarily visual stimulus (the umbrella opening).

"It would seem logical that wearing blinkers would be advantageous when a visual distraction is hidden by the blinkers. Because the horses cannot see the object, he has no reaction to this object which is potentially frightening" they comment.

However, sounds are different. "This paper shows that horses wearing blinkers react more when they are exposed to unexpected noises." They point out that this reaction is not necessarily seen by an observer - most of the horses in the study showed little visible reaction to the noise stimuli. There was, however, a dramatic increase in heart rate.

The researchers suggest that this model of restricted vision could be used to investigate how horses react to other visual deficits such as total blindness, or the changes that occur after cataract surgery.

More details at www.equinescienceupdate.com

Catching things from horses

Two unusual cases of horse to human transmission of bacterial infections remind us of the importance of good hygiene practices when handling horses.

One report from the Netherlands concerns the suspected transmission of Methicillin-resistant Staphylococcus aureus (MRSA) type ST 398, from a foal to a 16 year old girl. The girl, who was confined to a wheelchair, developed an infected wound from which a strain of MRSA, identified as belonging to type ST398, was isolated.

Investigations into the source of the infection showed that the girl had had intensive contact with a Friesian foal. She had not been admitted to hospital in other countries, nor had she been in contact either pigs or calves - the common source of human infection with this type of MRSA.

Swabs from other members of the girl's immediate family and other animals in the household were negative for MRSA

The type of MRSA involved,  ST398, is one which is associated with livestock and has been spreading in Europe and North America. It is the most common type of MRSA identified in horses in the Netherlands.
 
The authors suggest that the foal was the most likely source of the infection. In fact, the foal itself had been hospitalised in an equine clinic two months earlier for treatment of a wound infection.

Another report describes a surgical operation that became infected with Streptococcus equi.

S. equi, the cause of strangles in horses, is a cause of great concern to many horses' owners, but is rarely a danger to humans or other domestic species.

The patient, a professional racehorse trainer, underwent treatment for an aortic aneurysm - a condition in which the walls of the main artery leaving the heart are weakened and balloon outwards. If untreated there is a risk of sudden rupture leading to sudden death.

A specialised endovascular technique was used, in which a stent, a tubular framework,  was inserted into the femoral artery in the groin, and passed up the artery until it came to lie within the affected vessel.

The stent became infected and the causative organism was identified as Streptococcus equi.

Read more at www.equinescienceupdate.com

Faecal egg counts after tapeworm treatment

It may be more useful to look for tapeworm eggs the day after treatment rather than before. Research carried out by Johanne Elsener of Wyeth Animal Health and Alain Villeneuve of the Faculté de Médecine Vétérinaire, Université de Montréal looked at whether treating for tapeworms one day before carrying out a faecal examination improved the chance of identifying infected animals

The study involved horses of differing ages on a single stud farm - from weanlings to adult breeding mares and stallions.

All horses were presumed to be naturally infected with Anoplocephala perfoliata - as tapeworm-infected animals had been identified previously on the farm.

The horses were weighed and dosed according to weight.

The researchers examined faecal samples before and 24-48 hours after treatment with a paste containing praziquantel (and moxidectin). Faecal samples were examined using a modified Wisconsin sugar centrifugation technique - performed by a technician who was unaware of the treatment given to each .horse.

Overall, the researchers found that they were twice as likely to detect tapeworm eggs in the faeces of horses 24 - 48 hours after treatment with praziquantel than they were before treatment.

In adult horses (mares and stallions) the difference was statistically significant. Young horses (weanlings, yearlings and two year olds) showed a numerical increase in positive horses after treatment, but the difference was not statistically significant.

The two-year old horse group had the highest proportion of positive faeces, (66% horses were positive before treatment)

The researchers conclude that sampling after treatment may give a better idea of the true prevalence of tapeworm infection.

More details at equinescienceupdate.com

Does soaking make hay safer for laminitics?

An important part of treatment and prevention of laminitis is to limit the water soluble carbohydrate (WSC) intake. To achieve this, access to pasture is restricted and the horse or pony is fed hay instead.

But even hay may not be safe for horses with laminitis. Most authorities suggest that horses and ponies prone to laminitis or with insulin resistance should ideally receive hay that has a water soluble carbohydrate concentration not exceeding 100g/kg on a dry matter basis (DM)

However, in northern Europe pasture grasses often contain high levels of WSC (>300g WSC/kg DM), which may result in hay with WSC content up to 200g/kgDM.

It is often suggested that soaking the hay may reduce its water soluble carbohydrate content and thus make it safer for laminitis-prone horses and ponies. However, the studies that have supported this approach have often used large quantities of water and, as well, the hay may have been chopped prior to soaking.

Often owners do not go to such lengths. What is the effect of soaking hay when carried out according to common practice?

Dr Annette Longland, Clare Barfoot and Dr Pat Harris conducted an investigation into whether the degree of soaking that is in common use in the UK would have an effect on the WSC content of various hays.

The study looked at the loss of WSC and crude protein from a range of British hays, which were either shaken or left compacted in the "flake" and then soaked in just enough water to cover the hay, for various lengths of time.

The authors found that soaking hay for up to 16 hours produced variable and incomplete loss of WSC.
As would be expected, the dry matter content of the hays fell after soaking - there was a significant reduction in DM content after 20 minutes soaking, and a continued fall with longer periods of soaking.

However, regardless of the duration of soaking or whether the hay was shaken up or left compacted the WSC content of most of the hays remained above the recommended limit for laminitics of 100g/kgDM.

The researchers found no significant difference between the compacted or shaken hays. They conclude that soaking cannot be relied on to make hay suitable for feeding to laminitic horses.

They recommend that hay for animals prone to laminitis be analysed for WSC content, and only hay that is low in WSC is fed to horses prone to laminitis. Soaking can be used as an extra safeguard.

How does a brumby stallion spend his day?

Magdalena Zabek's latest report on the feral horses of central Australia is now available. Click here to read

Research confirms effectiveness of grazing muzzles

Using a grazing muzzle appears to be more effective than restricting access to pasture, for reducing the amount of grass eaten by ponies, according to a recent study.

Pasture intake by the ponies grazing for three hours without muzzles averaged 0.8% (with some eating close to 1%) of their bodyweight, which is the equivalent of up to two thirds of the recommended daily dry matter intake  for many ponies on restricted diets.

In contrast, the pasture intake of the ponies when wearing muzzles was around 0.14% of bodyweight over three hours, representing an average reduction of 83% compared to when they were not wearing muzzles.

Read more at www.equinescienceupdate.com

Making sense of flexion tests

Flexion tests are often used as part of a prepurchase examination or a lameness work-up to evaluate lameness or assess the likelihood of future lameness problems. But what does a positive flexion test tell us about which structures are involved?

Research published in the Equine Veterinary Journal suggests that the fetlock is probably responsible for a positive response to flexion test of the lower limb. Structures below that joint are less likely to be involved.

Dr Clodagh Kearney and colleagues conducted a study on eight warmblood horses. These were all clinically sound, but had gone lame after being subjected to a flexion test of the lower limb. Flexion tests were performed under standardised conditions.

The response to the flexion test was assessed after performing various nerve blocks, which desensitised different regions of the limb. One clinician performed the nerve blocks; others performed the flexion tests and assessed the degree of lameness. So the clinicians assessing the lameness did not know which nerve block had been carried out (or on which leg).

They found that a nerve block of the palmar digital nerves, just above the cartilage of the distal phalanx, had minimal effect on the lameness induced by the flexion test. A nerve block just below the fetlock at the level of the distal abaxial sesamoid bones produced a similar response. However, there was a marked improvement in flexion test induced lameness following a low four point block just above the fetlock.

The researchers conclude that the fetlock joint and surrounding structures contribute strongly to the outcome of a flexion test of the lower limb in a non lame horse. "From a clinical point of view, it is reasonable to suggest that the flexion test of the distal limb may be sensitive for investigating the metacarpophalangeal joint region, but may be less relevant for structures distal to this joint."

Read more at www.equinescienceupdate.com

Treponemes found in canker lesions

Japanese research has found evidence of treponemes in equine canker by looking for specific portions of RNA characteristic for the organisms.

Canker is a chronic proliferative condition of the horse's foot - affecting the frog and bars and sole. In severe cases it may extend to involve the hoof wall. Similar conditions in cattle and sheep have been shown to be associated with spirochete bacteria - in particular treponemes.

Dr Kyaw Kyaw Moe and colleagues examined samples from lesions in two horses and compared them with samples from an unaffected horse.

They found spirochetes in microscopic sections of the canker lesions. They also found 114 clones in the affected horse samples and none in samples from normal horses.

The clones could be classified into 19 separate groups - corresponding to many different treponemes, including those implicated in bovine papillomatous digital dermatitis.

Despite this the researchers were unable to culture the organisms. This is not surprising as treponemes are slow growing and are often overgrown by more rapidly growing bacteria.

The research confirmed the presence of treponemes in canker lesions in two horses and their absence in a normal horse. However, as the study was based on only a couple of cases, the researchers could not confirm that treponemes are the cause of canker - further work is required involving more cases.

Read more at equinescienceupdate.com

Effect of psyllium on glucose and insulin

Psyllium, a sort of "super-bran", is already used in horses, particularly for treatment and prevention of sand colic. When mixed with water, it swells to up to 10 times its original volume, turning into a jelly-like substance which is thought to ease the passage of sand through the digestive tract.

Researchers at Montana State University conducted a trial to see if adding psyllium to a horse's diet had an effect on glucose and insulin metabolism. It had been noticed previously that psyllium had a beneficial effect on insulin sensitivity, when taken by people with insulin resistance. So they wanted to investigate whether a similar effect occurred in horses.

They used 16 healthy horses (8 mares and 8 geldings), which they divided into 4 groups of 4, each containing 2 mares and 2 geldings. All horses were fed a diet of mixed grass hay and a commercial whole grain feed twice a day. Psyllium pellets were added to the grain ration of three groups at 90g, 180g, or 270g daily. The fourth group received the same diet, but without added psyllium.

On the 60th day the researchers withheld food from the horses overnight. In the morning they collected blood samples before the morning feed and then every 30 minutes for six hours, to monitor the blood glucose and insulin concentrations.

The researchers found that on average, horses that had been receiving psyllium for 60 days had lower average peak glucose levels after feeding and lower average glucose levels. Psyllium-fed horses also had lower peak insulin levels and lower average insulin levels after feeding compared with horses that had not received psyllium.

Dr Shannon John J Moreaux, Assistant professor of Equine Science at Montana State University, and one of the research team commented. "Psyllium could be especially beneficial to obese, insulin-resistant horses, or horses that are predisposed to developing laminitis because of metabolic syndrome". He added that it was commercially marketed and readily available to horse owners, and when fed daily, may help to maintain lower post-feeding blood glucose and insulin levels.

This was a small study carried out using normal horses. Before we can conclude that psyllium will benefit insulin resistant horses, further research is needed using affected horses.

However, if it proves to be effective in insulin resistant horses it could provide a useful addition to the strategies available for managing this condition.

Read more at equinescienceupdate.com

Is your vet a health risk?

Vets that work with horses are more likely than other vets to carry methicillin-resistant Staphylococcus aureus (MRSA), according to an Australian study.

The researchers, led by Dr David Jordan, collected nasal swabs from 771 individuals, who were also asked for details of the type of work they did and with which species.

Analysis of the data showed that veterinarians that worked mainly or exclusively with horses were more likely the carry MRSA in their nostrils.

MRSA was present in 5.8% of those taking part in the study. However, the data revealed differences depending on the type of work the individuals performed.

Positive swabs were obtained from 11.9% of veterinarians who spent a lot of their time on horse work. (This was 13 times that of the vets involved in industry or government work. Less than 1% of them had positive swabs).

The figures were even higher among people who worked only with horses.  The results showed that 21.35% of them had nasal swabs positive for MRSA. (They were 23 times more likely to have their nostrils colonised by MRSA than were vets working for government or industry.)

Considering the extent of carriage of MRSA and the seriousness of the disease it can cause in humans and animals, Dr Jordan recommended that vets should take more precautions to prevent the spread of MRSA

"The higher than normal prevalence of MRSA carriage among veterinary clinicians in Australia is a cause for concern in the profession and warrants further investigation for specific risk factors, particularly for vets who work with horses"

He suggests that guidelines specific for equine work are needed. These should include: "enhanced personal hygiene during handling of animals; better sanitary management of premises, equipment and waste; greater awareness of biosecurity during handling and surgical procedures; and reform of use of antibiotics - especially those of importance in human medicine such as the fluoroquinolones, third generation cephalosporins and gentamicin."

Read more at www.equinescienceupdate.com

Hendra virus vaccine progress

Australian scientists have succeeded in developing an experimental vaccine to protect horses against Hendra virus.

Hendra virus (HeV) was first isolated in September 1994 from an outbreak at a training complex in Hendra (a suburb of Brisbane, Queensland, Australia) after which the virus was named.

During that initial outbreak 14 horses died. Seven other horses were found to have been infected and were humanely destroyed. Two humans were affected, one of whom died.

In five of the 14 known outbreaks, the infection has spread to people. The virus has killed four of the seven people infected.

Fruit bats (Pteropus spp), commonly known as flying foxes, have been identified as the natural host for the Hendra virus.

“Our trials so far have shown that the vaccine prevents the infection of horses with Hendra virus,” said Dr Deborah Middleton from the Australian Animal Health Laboratory (AAHL).

Stopping the disease in horses could also help protect people from the disease.

"All the human infections have come from contact with infected horses," Dr Middleton explains. So if you can control the disease in horses, you break the transmission cycle to people as well as protecting the health of horses.

Studies so far have shown that the vaccine will prevent horses becoming infected. It also protects them from developing the disease and shedding the virus.

Further work, including field trials and product registration, is still required. However, if all goes well, the vaccine may be available as soon as 2012.

Dr Barry Smyth, President of the Australian Veterinary Association, said that both vets and horse owners would welcome the news on the vaccine.

“It’s important that veterinarians and horse owners continue with precautions that reduce the risk of spreading the virus and that they report suspected cases immediately,” Dr Smyth said.

Read more at: www.equinescienceupdate.com

Saddle research uncovers new theory in asymmetry

The Saddle Research Trust (SRT), believe they have discovered a new theory in rider asymmetry, which they feel will have implications for equine performance and welfare.

Following a series of pilot studies carried out in conjunction with educational establishments throughout 2010, the charity claims to have evidence that highlights previously unidentified areas and measurable characteristics of saddle performance.

Anne Bondi BHSI, Director for the trust explains: “The initial objective of our early pilot studies was to measure the effect of the rider asymmetry using a variety of scientific measuring systems open to the trust. It soon became apparent that a more complex pattern of interaction was occurring, one that could not just be explained by a rider sitting crookedly.”

Humans are not perfectly symmetrical, and most riders are aware of being right or left handed. This ‘handing’ often creates a loss of symmetry in the rider in the vertical plane.

“After observing this common occurrence we began to examine further the effect the saddle has on the rider and their posture” she continues.

A similar lack of symmetry also exists in the horse in the horizontal plane. The movement of a horse’s back and limbs creates movement in the saddle, generating an unstable platform for the rider. This forces riders to adopt a compensatory action - accentuating the already asymmetrical posture. The horse also compensates for carrying the asymmetrical rider by counterbalancing.

According to the SRT, this is far more complex than a ‘chicken and egg’ situation. It involves a mixture of symptoms involving asymmetries in the horse, rider and saddle, but more significantly the interaction between them.

"Our studies to date have shown a clear lack of synchronisation in this three-way interaction, and it is our understanding that the degree to which this occurs is greatly affected by saddle design and fit."

“We have raised many new questions about the effect of saddles on asynchrony, as well as identifying measurable characteristics in saddle performance. Although our work is in its infancy we believe it will have far-reaching effects on all levels of equestrianism.”

Read more at www.equinescienceupdate.com

Bedding dope test risk

Flunixin excreted in the urine may be ingested with bedding, risking prolonging the time taken to clear the drug from the body.

Owners and trainers should be aware that horses may recycle anti-inflammatory drugs such as flunixin in the stable environment. This may prolong the time the drug is detected in the urine - thus increasing the risk of positive dope test.

Flunixin is a non-steroidal anti-inflammatory drug commonly used in horses. The rules of many disciplines prohibit its presence in the blood or urine of horses on the day of competition.

Detection times have been established for some medications to help veterinarians advise owners and trainers on how long before a competition treatment should be withdrawn to minimise the risk of the drug being found in the urine. However, research in France shows that the problem can be complicated by horses absorbing flunixin from bedding that has been contaminated by urine containing the excreted drug.

Work at the Laboratoire des Course Hippiques, found that, even if bedding is removed completely and the floor brushed out, there is still a risk of a "rebound" increase in urine flunixin levels.

Dr Marie Agnès Popot and colleagues looked at the excretion profiles of flunixin in urine collected from horses under various systems of stable management. They gave flunixin as either a single intravenous dose (1mg/kg) or as an oral paste (0.5mg/kg twice daily for 3 days).

Horses were housed in stables from which the bedding was either completely removed on a daily basis, or only "skipped out" (removing only soiled bedding on a daily basis, and cleaned completely once a week.)

The largest rebound in urine flunixin concentration was seen in those horses kept in stables that were not cleaned completely on a daily basis. However, removing all the bedding and sweeping the floor could not totally prevent rebound in flunixin levels. The only circumstance in which a rebound in urine flunixin levels did not occur was when the drug was given intravenously and the horse was moved to a clean stable after 24 hours.

"Flunixin is mainly eliminated by renal clearance and a large amount of flunixin is eliminated in urine within the first 24 hours following administration" the researchers explain in a report in the Journal of Veterinary Pharmacology and Therapeutics. "Then, for horses housed in unclean boxes, the conditions  exist for the possibility of prolonged recycling; the only way to break recycling is to move the horse in  another separate box after the first 24 hour of treatment, rendering unavailable the flunixin excreted in the urine for the first 24 hour."

They conclude that attention to stable hygiene can drastically reduce the risk of spurious drug excretion profiles for drugs such as flunixin that are mainly eliminated in the urine.

Read more at www.equinescienceupdate.com

Focusing on the next obstacle

Elite riders' eye movements may be key to show jumping success. Research from Nottingham Trent University found that an experienced show jump rider focused on the jump up to 3.05 seconds earlier before take off than did a less experienced non-competitive rider.

http://www.ntu.ac.uk/news_events/news/releases/eyegaze.html

Mares behaving badly

Plant oils might provide the answer to mares that are unruly when in season.

Some mares become unruly and difficult to manage when in season and perform poorly as a result. Various methods of controlling this behaviour have been suggested. Most are based on suppressing the oestrus cycle.

Sandra Wilsher and Professor Twink Allen at the Paul Mellon Laboratory of Equine Reproduction, Newmarket, England, were investigating the mechanisms of maternal recognition of pregnancy.

They found that intrauterine administration of oestrogen in fractionated coconut oil prevented mares returning to oestrus, However, they also found that the coconut oil alone (without oestrogen) had a similar effect, as did peanut oil.

Fractionated coconut oil was most effective when given 10 days after ovulation - luteolysis was delayed in 11/12 mares (92%). It was not as effective on days 8-12., although the difference was not statistically significant. When administered on the 6th day after ovulation, it inhibited luteolysis in only 25% of mares. 

Oestrogen in mineral oil, or mineral oil on its own did not block luteolysis when given 10 days after ovulation.

So it seems unlikely that embryonic oestrogens are important in the maternal recognition of pregnancy.

Fractionated coconut oil and peanut oil each contain various different fatty acids.  The researchers were unable to identify an individual component that was responsible for inhibiting luteolysis.  Instead, they suggested that it is likely that a range of fatty acids are capable of causing luteal persistence.

Further work is required to determine how the vegetable oils have this effect. However, it does seem that they may provide a practical way of preventing unruly behaviour in oestrus mares.

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

Sublingual detomidine for needle-shy horses

How do you sedate a needle shy horse? Recent research suggests that detomidine, a sedative commonly used in horses, can be effective when administered under the tongue.
 
Detomidine is a popular choice for sedating horses, capable of producing profound sedation when administered intravenously.

Previous studies have shown that detomidine is not effective when administered by stomach tube, and is variably effective when mixed with food. However it seems to be absorbed through the gums and appears to be effective when given sublingually.

Recent research looked at the value of sublingual detomidine for sedating horses known to need sedation to permit routine management or veterinary tasks - such as farriery, routine dentistry, passage of a stomach tube or clipping.

The study by Dr Rachel B Gardner and colleagues was published in the Journal of the American Veterinary Medical Association.

Horses used in the study were all known to require sedation or strong additional restraint - such as a twitch - to allow the procedures to be carried out.

The treatment group comprised 129 horses treated with detomidine sublingually, at a dose of 0.04mg/kg (double the usual dose when given intravenously).

A further 42 horses were treated with a gel which appeared identical, but did not contain detomidine. The study personnel did not know whether they were administering the detomidine gel or the placebo.

The efficacy of the treatment was assessed according to whether it allowed the required procedure to be carried out. Treatment was only considered successful if the procedure could be completed without resort to further sedation or the use of a twitch.

The procedures were completed successfully in 98 of 129 (76%) of detomidine treated horses compared with only 3 of the 42 (7%) of control horses. Little or no ataxia was reported in 70% of detomidine treated horses

Sublingual detomidine was most successful for sedating horses for manual teeth floating and hoof trimming and shoeing. It gave a lower success rate for clipping with electric clippers - only half of the detomidine-treated horses could be clipped successfully.

For more details see:

Efficacy of sublingual administration of detomidine gel for sedation of horses undergoing veterinary and husbandry procedures under field conditions.
RB Gardner, GW White, DS Ramsey, JE Boucher, WR Kilgore, MK Huhtinen
J Am Vet Med Assoc (2010) 237, 1459 - 1464

No benefit in metformin IR study

A study into the pharmacological management of insulin resistance using metformin, failed to demonstrate any benefit.

The research was conducted by the School of Animal and Veterinary Sciences, Charles Sturt University in New South Wales, Australia and the Department of Clinical Studies, New Bolton Centre, University of Pennsylvania, PA, USA, in collaboration with the Waltham Equine Studies Group. Lead researcher was PhD candidate Kellie Tinworth.

In insulin resistance, insulin seems unable to exert its normal effect. This is particularly noticeable in relation to glucose metabolism. As a result, the body releases increasing amounts of insulin, ending up with normal or raised blood glucose levels despite high concentrations of insulin.

Insulin resistance appears to be a significant risk factor for conditions such as laminitis.

Therefore, it is important to prevent IR from developing, or to manage it before it contributes in turn to the development or progression of other potentially life-threatening conditions.

While the correct management of energy intake and exercise levels is thought to be essential, in some cases medication is also considered, especially when increased exercise is not possible.

No licensed drugs are currently available for treating insulin resistance in horses and ponies. Metformin has been suggested as a possible treatment for the condition. It appears to enhance insulin sensitivity of peripheral tissues without stimulating insulin secretion.

The research team hoped to confirm that metformin had a positive effect on insulin and glucose dynamics in insulin-resistant ponies, so that it could be used as a positive control in other studies.

Six ponies that were insulin-resistant, but not obese, took part in the study. Three ponies were allocated to the treatment group, and they received metformin (at 15mg/kg bodyweight orally, twice daily) for 21days. The control group received a placebo.

After a "wash out" period, the trial was repeated with the ponies being swapped between the treatment and placebo groups.

The response to metformin (and the placebo) was assessed using a frequently-sampled intravenous glucose tolerance test (FSIGT).
 
The researchers found no measurable benefits of metformin. No significant change was noted in any of the indices of insulin sensitivity. Neither was there any change in bodyweight, body condition score or cresty neck score.

Read more at: www.equinescienceupdate.com/articles/nbmir.html

Role of bacteria in periodontal disease

Bacteria may be more important in the development of periodontal disease in horses than previously thought, according to research carried out at the University of Edinburgh.

Equine periodontal disease is a common condition in horses affecting around 60 percent of horses over the age of 15 years. The disease is painful and can have a big impact on a horse's quality of life, affecting the animal's ability to eat and its performance.

Bacteria are known to be a cause of periodontal disease in humans, cats and dogs, but it is less clear what role they play in the disease in horses. Mechanical factors, such as food being packed between the horse's teeth due to abnormal growth and spaces have been considered to be the primary cause.

Research, carried out by Alistair Cox, is believed to be the first to describe the microscopic anatomy of equine periodontal disease.

Cox examined the skulls of 22 horses that had been submitted for post mortem examination. Although none of the horses had received treatment for periodontal disease, 16 had some form of periodontal disease.

"This research, funded by The Horse Trust, highlights how common periodontal disease is in horses. Yet many horses don't receive treatment so are likely to be suffering in silence. I would advise all horse owners to get their vet or equine dentist to regularly check their horse to see if it is developing the condition," he said.

Cox identified bacteria, including spirochaetes, that were associated with periodontal disease. Spirochaetes are known to be important in human and canine periodontal disease, but this is the first study to identify them in association with the condition in horses.

"This study shows that bacteria may be more important than was previously thought in the development of equine periodontal disease,” said Cox

"More research is needed to understand whether bacteria or mechanical factors are the main cause of the disease. Once we have a better understanding of why and how the disease develops, we can do more to prevent horses from developing this painful condition."

Read more at: http://www.equinescienceupdate.com/articles/rbpd.html

FIS test success

One year on, the test for Fell Pony Syndrome, has been acclaimed a great success.

As the genetic test identifies carrier animals, it can be used to prevent affected foals being conceived.  The disease only appears when both parents carry the mutation. Breeders can avoid producing affected foals by ensuring that they do not breed two carriers together.

Of the almost 1000 animals tested, 47% of Fell ponies and 10% of Dales ponies were found to carry the mutation for the disease.

The fatal disease is now known as Foal Immunodeficiency syndrome (FIS), as cases are not confined to one breed. Affected foals die or are euthanased, usually before they reach three months of age.  

Since February 2010, when the test became available, nearly 1000 samples have been tested. Three quarters of the samples came from Fell ponies. Of those tested, 47% of Fell ponies and 10% of Dales ponies were found to carry the mutation for FIS.

The test was developed as the result of research led by Dr June Swinburne of the Animal Health Trust, Newmarket. 

"This test, developed using funding from The Horse Trust, has been a massive success among the Fell and Dales pony breeding communities," she said. "We hope the test will prevent unnecessary suffering among Fell and Dales pony foals as breeders can now easily prevent the conception of foals with FIS. As so many breeders tested their breeding stock last year, we hope there will be very few foals affected by this horrendous disease in the future."

Read more at: http://www.equinescienceupdate.com/articles/fists.html

Does restricting grazing really reduce grass intake?

A recent study suggests that limiting access to pasture may not be effective at reducing grass intake by ponies

 

Recent research, about to be presented at a biannual nutrition meeting in the US, suggests that ponies given reduced access to pasture can eat considerable amounts of herbage during the time they are turned out. Indeed they may even increase their intake during this time as they become accustomed to the routine.

Intake of large amounts of fructan, and other rapidly fermentable carbohydrates by grazing ponies has been linked to the development of laminitis.  It has become common practice to restrict ponies’ access to pasture, especially at key times of the day/year in order to reduce the risk.

The study, which was conducted at the Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, in collaboration with the WALTHAM Equine Studies Group, aimed to investigate the effect of grazing restriction on herbage intake and grazing behaviour in ponies.

The grazing behaviour of eight ponies was measured daily over a six week period to assess their voluntary intake of herbage and to monitor the effects of restricting their access to pasture. Two groups of four pony mares were used. Group A had 24 hour access to pasture. The ponies in group B had three hours of pasture access daily and were stabled for the remaining 21 hours, with free access to haylage and water.

Herbage intake was estimated during the three hours when all the ponies were at pasture by monitoring the change in weight of each individual over the period. Grazing behaviour was analysed from video footage of the two groups using interval sampling. The ponies in the restricted grazing group had higher estimated grazed herbage intakes than those with 24 hour access to pasture .during the three hours studied. The difference was significant during the final week, when the restricted grazing group consumed 40% of their total daily dry matter intake as grass in the three hours at pasture. This compared with an intake of grass of around 25% of their daily dry matter ingested during the first week.

 

Clare Barfoot, research and development manager at SPILLERS®, said: “This suggests that ponies with reduced access to pasture are capable of ingesting considerable amounts of grass during the time they are turned out and may indeed progressively increase their intake during this time, indicating that the behaviour could be learned. The implication is that reducing ponies’ time out on normally managed pastures with the view to limiting the intake of rapidly fermentable carbohydrates may not be as effective as first thought.”

Reference:

Changes in proportions of dry matter intakes by ponies with access to pasture and haylage for 3 and 20 hours per day respectively for six weeks. 

 J. Ince,A. Longland,C. J. Newbold,P. Harris.  

Journal of Equine Veterinary Science (2011) (in press)

Vancomycin-resistant bacteria in equine manure

Horses are not likely to play a major role in the spread of one type of antibiotic resistant micro-organism, to humans, according to a study in North West England.

Work reported at the International Conference on Antimicrobial Research in Valladolid in Spain November 2010 looked for vancomycin resistant enterococci (VRE) in equine faeces.

Lead researcher Dr Mohamed O Ahmed presented the results of the study, which looked at faecal samples from 66 hospitalised and 72 non-hospitalised horses.

Enterococci are enteric bacteria found in the digestive tract of many humans and animals. They may be responsible for urinary tract or wound infections (i.e. nosocomial infections). Also in patients with suppressed immune systems, they can cause serious conditions such as infection of the heart valves (endocarditis) and brain (meningitis).

Enterococci are naturally resistant to many antibiotics. One of the few last-choice antibiotics used for treating people with serious enterococcal infections is vancomycin.

Vancomycin-resistant enterococci is an emerging nosocomial organism, reportedly of zoonotic nature. There are several strains of vancomycin-resistant enterococci. The genes conferring resistance have probably been acquired from other types of bacteria that don't cause disease, but are already vancomycin resistant.

If specific vancomycin-resistant strains were present in horse faeces (i.e. VanA and VanB phenotypes) they could act as a zoonotic source of infection.

Overall, the researchers identified 47 suspected VRE isolates from a total of 264 faecal samples. Of those, only 9 were confirmed by polymerase chain reaction (PCR). Seven were confirmed as VanC genotype. Six of these were found in samples from hospitalised horses.

They identified one isolate each of VanA and VanD genotype. Both of these were in non-hospitalised horses, but neither could be typed by PCR.

The VanA genotype has been reported predominantly as the one involved in human infections. However, the VanC genotype, which was found most frequently in this study, is not commonly isolated in cases of human infection.

The researchers conclude that it is unlikely that horses play a major role in the transmission of VRE to humans in that specific geographic area. Also, the fact that most of the VRE isolates were found in hospitalised horses, suggests that hospitalisation could increase the risk of transmission between horses and possibly to humans too. Future research may be needed to look into this.

Read more at www.equinescienceupdate.com

Study finds whipping racehorses pointless

Whipping has no effect on the likelihood of a horse winning or being placed, according to a recent report. The authors conclude that whipping tired horses in the name of sport is very difficult to justify.

Dr David Evans and Professor Paul McGreevy based their findings on the horses’ speed, the number of times they were whipped and their place in the field. The information was gathered from five sprint races (over 1200-1250 meters) at the racetrack at Canterbury, New South Wales. 

“When we compared the sectional times 600-400m, 400-200m, 200m – finish, horses ran fastest in the 600-400m section, during which no horses were whipped”  Dr Evans explained. “Horses achieved their highest speeds during the last 600m of the races without being whipped.”

 “Increased whip use was most frequent in the final two 200 metre sections when horses were fatigued.''

“Analysis of the data showed that the strongest predictor of racing success was where a horse was placed at the 400m and 200m marks. Neither whip counts in the final 400m or 200m, nor velocity in the final 200m, significantly explained the probability of finishing 1st, 2nd or 3rd,” Prof McGreevy added.

“That said, it remains possible that whip use in the final stages of a race really does improve relative performance at a stage when all horses are slowing, but more frequent and sensitive methods of measuring velocity may be required to detect such a cause and effect linkage.” 

The authors conclude, “These data make whipping tired horses in the name of sport very difficult to justify.”

For more details see:

http://www.equinescienceupdate.com/articles/sfwrp.html

Equine Guelph survey research

Equine Guelph offer you the chance to influence their research and education programs so they meet the needs of the equine industry. 

Complete their survey and you can enter a draw for one of two gift certificates for an Equine Guelph online course of your choice (valued at $549.00) 

http://www.surveymonkey.com/s/industrysurvey_enews_1

Mistletoe for treating equine sarcoids?

 Could a festive winter decoration provide the cure for equine sarcoids?

Sarcoids are the most common skin tumour of horses. They are difficult to treat, and may recur after treatment.  A new therapeutic option has been suggested by a Swiss study, which found that an extract of mistletoe was an effective treatment.

The findings have been reported in the Journal of Veterinary Internal Medicine. Lead author was Ophélie Christen-Clottu of the Research Institute of Organic Agriculture, Frick, Switzerland.

The study compared the response of sarcoids to treatment with an aqueous extract* of the pine mistletoe (Viscum album ssp. austriacus) and a placebo.

Mistletoe contains compounds, like lectins and viscotoxins that have been shown experimentally to have cytotoxic and growth inhibiting properties and immune modulating activity. Extracts are used as an adjunct to treatment of cancer in human medicine.

The treatment consisted of injections of 1ml of mistletoe extract in increasing concentrations (from 0.1mg/ml to 20mg/ml) administered 3 times a week for 15 weeks. Control animals were injected with 1ml of saline at similar intervals.

The researchers monitored the location, number, and type of sarcoids present for a year after the start of the study. Neither they nor the horse owners knew which horses were treated with the mistletoe preparation or the placebo until the end of the study.

Fifty-three horses, with a total of 444 sarcoid lesions, were treated - with either mistletoe extract or placebo. Forty-two horses were treated as monotherapy and 11 horses were treated with mistletoe extract or placebo after selective surgical excision of some sarcoids.

Five of the treated horses developed mild oedema at the site of injection when the higher concentration injections were given. This swelling disappeared within a few days without treatment.   No other adverse effects were noted.

At the end of the study, sarcoids were no longer visible in 9 of 32 mistletoe extract treated horses and 3 of 21 placebo control horses. This difference was not statistically significant. However, another 4 horses in the VAE group showed reduction in more than half of the sarcoids.

So, overall, 41% of horses in the treatment group showed complete or partial regression of the sarcoids - which was significantly different from the response in the placebo group.

The curative effects were higher in verrucous sarcoids than by other types of sarcoids. On advantage of VAE treatment is the systemic effect: if treatment is successful, all tumors of one horse can regress. The disadvantage of the therapy was  that response to treatment was slow - being seen only after the end of the 15 week treatment period in many cases.

They conclude that mistletoe extract proved effective for treating clinically diagnosed equine sarcoid in this study. They suggest that it can be recommended particularly when excision may not be appropriate, for example for sarcoids around the eyes or for cases with multiple sarcoids.

See: www.equinescienceupdate.com/articles/mftes.html

Striving to prevent foal pneumonia

News that a vaccine against Rhodococcus equi is entering the final stages of development offers the hope of preventing this serious respiratory condition of foals.

R equi causes chronic broncho-pneumonia with abscesses in the lungs, typically affecting foals less than six months old. Other forms of the disease occur including infection of the intestine and lymph nodes.

Rhodococcus equi does not only infect horses. It is an opportunistic human pathogen associated with diseases that result in suppression of the immune system.

The organism is found in soil, especially in the presence of horse faeces, which provides the substrate on which it feeds. It is well equipped to resist desiccation. Foals are infected by inhaling contaminated dust.

Treatment is difficult. The organism is resistant to many common antibiotics. It lives within the macrophages, making it difficult for antibiotics to reach it.  A long course of suitable antibiotics - such as erythromycin and rifampin - is required to effect a cure.

As yet there is no effective vaccine. However, on January 27, 2011, Intervet / Schering-Plough Animal Health announced that a vaccine against Rhodococcus equi infection in foals was entering the final stages of development.

The vaccine is based on a special non-pathogenic strain of the bacterium. Four genes have been deleted from its genome, to make the bacterium incapable of causing disease, but still able to stimulate immunity.

Preliminary studies have shown that the genetically modified strain is safe, and unable to cause disease in foals as well as in calves chickens, pigs rats and mice.

Approval has now been given for field trials to commence. These will start shortly in Germany. In the first phase of the study, a group of foals will be vaccinated with the candidate vaccine and will be compared to a group of non-vaccinated foals. The number of R equi infections will be evaluated in each group.

An effective vaccine against R equi would be a great step forward in the control of this disease.

see: http://www.equinescienceupdate.com/articles/revt.html

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.

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"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.