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