Role of bacteria in chronic laminitis

 

Recent research suggests that bacteria may play a more significant role in chronic laminitis than previously thought.

Its not uncommon for abscesses to form underneath the dorsal hoof wall in horses with chronic laminitis. But whether these are the result of aseptic destruction of the laminae, or the result of bacteria tracking up the horn tubules is a matter of debate.

A study, by Janet Onishi and colleagues, based at Rutgers University, New Jersey, USA, investigated whether horses with chronic laminitis had evidence of sub-clinical infection in the laminar tissue.

“The objective of this study was to establish whether bacteria colonize laminar tissue and whether horses with chronic laminitis have higher or different microbes in the laminar tissue compared to non-laminitic horses” they explained.

Hoof samples were collected in a sterile manner from five horses with chronic laminitis, and from eight horses with normal feet.

The researchers found that laminae from horses with chronic laminitis contained 100 times the number of bacteria than did laminae from unaffected animals.

Only a few bacteria, all Gram-positive organisms, were isolated from the laminae of the healthy horses. In contrast, the laminae from chronic laminitic cases contained many more bacteria. Again Gram-postive organisms predominated, including bacteria in the phylum Actinobacteria, and coagulase negative Staphylococci. Many of the bacteria were identified as potential pathogens.

“The bacteria recovered from laminar tissue of chronically laminitic horses are not only potentially pathogenic, but are also known to form biofilm infections. “

(A biofilm is a complex community of micro-organisms, typically attached to a surface. Bacteria within the biofilm may be less accessible to host defences and antibacterial agents. A common example of a biofilm is dental plaque.)

The researchers suggest that horses may develop chronic laminitis as a result of biofilm infections occurring after an initial episode of acute laminitis. “We propose that treating chronically laminitic horses is difficult because there is a bacterial component to the disease that is not understood.”

Read more at: www.equinescienceupdate.com

Scientists question training method

Research from the University of Sydney questions whether the round-pen (“Join-up”) training method made famous by Monty Roberts is really as humane as its supporters claim.

Lead researcher was Cath Henshall, an animal science masters degree candidate in the Faculty of Veterinary Science.

She explains: “This method of training is widely used around the world and the people that use it claim that it's a humane and kind way to train horses. They also claim that it works because the trainer is able to successfully mimic horse body language and horse behaviour.

“Our study casts doubt on both those claims. We believe that our research highlights the unpleasant underpinnings of round pen horse training and for that reason we caution against its widespread use because it uses fear to gain control of horses."

The technique relies on the trainer using movement and noise to drive the horse around the perimeter of the pen. The trainer gradually reduces their aggressive movements, after which the horse will eventually slow down and approach them.

The researchers used remote control cars to mimic the technique and to eliminate the role of the trainer in imitating the horse's body language.

They believe that the training outcomes were achieved as a result of 'pressure-release' and not the ability of the trainer, or a remote control car, to mimic horse behaviour. "Put simply,” said Henshall, “pressure-release works because the horse finds the pressure applied unpleasant and therefore the removal of the pressure rewarding.”

The response the horse makes immediately before the pressure is removed is what the horse thinks made the pressure go away. When put in the same situation in the future, it is likely to perform that same behaviour to obtain the outcome that it values – safety.

"We 'rewarded' the horses for stopping and turning towards the car with a period of 'safety', when the car didn't chase them as long as they kept facing it. We trained some horses to actually walk up to and touch the car," said Henshall.

“We found that the car is almost as successful as the human trainer, so we think that calls into question whether the horse is responding to the human as though they think the human is another horse. We also confirmed that the reason the training works is for the same reason all horse training and a lot of animal training works. So that it doesn't actually require that you understand horses' body language particularly well. It just requires that you're able to chase and not chase at the right time.”

"Given that we could train horses to produce similar, though not identical responses to those seen in round pen training, but in reaction to non-human stimuli undermines the claim that the human's ability to mimic horse behaviour is an essential component of the technique."

"Although neither Monty Roberts' method nor ours uses pressure applied directly to the horse's body, both apply a form of emotional pressure by scaring and then chasing the horse."

"Our results indicate that because these methods rely on fear and safety, the horse is forced to choose between being repeatedly frightened or remaining with the trainer. We question whether it is humane to rely on fear and its termination to train horses," said Henshall.

"Although it is appealing to think that horses in the round pen choose to follow their trainers because they are responding to us as though we are a horse, we believe that the use of fear has no place in genuinely humane and ethical horse training."

 

Read more at:

www.equinescienceupdate.com/articles/sqtm.html

 

 

Ten minutes of Low-Deep-and-Round may cause stress

Compared to other head and neck positions, horses ridden in hyperflexion, or “low deep and round” are likely to be exposed to higher levels of physiological stress, according to work presented recently at the International Equitation Science Conference in Edinburgh.

Previous studies explored the effects of the hyperflexed head and neck position on the stress and behavioural responses of horses on the lunge or a treadmill. This study, by Dutch and Danish researchers measured a variety of behavioural and physiological responses of horses ridden in hyperflexion and two other common head and neck positions.

Fifteen Danish dressage horses training at medium to Grand Prix level and routinely ridden in the hyperflexed head and neck position were used. In addition to hyperflexion, low deep and round, the standard “on the bit” or competition frame and loose frame in which there was less tension in the reins were also investigated. Each rider performed a pre-determined riding test of 10 minutes duration in walk, trot and canter in each of the three head and neck positions, randomised over the three days of testing.

Heart rate, heart rate variability, salivary cortisol concentration, behaviour and the tension in reins were recorded during the 10-minute test period. Salivary cortisol concentrations were measured 60 minutes before and 0; 5; 15 and 30 minutes after the test.

“This study is the first to test whether there is an acute stress response to the hyperflexed head and neck position in horses ridden in a typical training environment” said Dr Machteld van Dierendonck from Utrecht University. “We found that the increases in salivary cortisol concentrations from baseline were significantly higher after 10 minutes of riding in the hyperflexed position than the increases observed in the competition head position or with the loose frame.“

Cortisol is known as the ‘stress’ hormone and increased cortisol concentrations are routinely used to quantify stress responses in animal welfare studies.

“We didn’t find any significant differences in heart rate, and heart rate variability between the treatments, but we did find that certain behaviours were higher during hyperflexed riding than the other head positions. Rein tension during the hyperflexed and competition head position was significantly greater than during the loose frame position.”

“Compared to previous studies which have used side reins to maintain the hyperflexed position, the low, deep and round position in this study was less hyperflexed.” she said.

“We wanted to test the horses’ response to this method in a typical training environment. Within the parameters of this training situation, we found that the use of the hyperflexed head position, even in horses routinely ridden this way could result in a physiological stress response as measured by salivary cortisol concentrations.”

“Interestingly, riders indicated a loss of balance and steering control in the loose frame”.

Head and neck positions has been the subject of controversy with the FEI conducting two reviews in recent years.

This study was a joint work with Danish and Dutch universities. Janne Winter Christensen from Aarhus University in Denmark, along with Mirjam van Dalum, Mandy Beekmans from Utrecht University were joint researchers on this study.

Read more at www.equinescienceupdate.com

Effect of weather on equine flu outbreak

Analysis of the recent Australian equine influenza outbreak has improved understanding of how the disease spreads.

Researchers from Australia and New Zealand looked back at the outbreak, which took place between August and December 2007. It was estimated to have cost the Australian equine industry over $350 million. Almost 70,000 horses on more than 9000 premises in Queensland and New South Wales were affected. The country had previously been free of the disease.

Simon Firestone, lead researcher and PhD candidate at the University of Sydney's Faculty of Veterinary Science. and colleagues matched meteorological data with information from infected premises to assess the effect of the weather on the spread of infection.

They discovered an association between the occurrence of new cases and the weather conditions three days previously. This coincides with the incubation period for equine flu – the first signs are usually seen from 3 days after the animal becomes infected.

The researchers found that horses were more likely to get infected on drier days when relative humidity was low. There was minimal risk once relative humidity exceeded 80%.

Infection was also less likely on days when the maximum daily air temperature was between 20 and 25°C. Extreme temperatures, either high ( >28°C) or low (<16°C) were associated with the highest risk of infection. Lower minimum daily temperatures were associated with higher risk of infection.

The researchers also found that wind speeds in excess of 30km/hour from the direction of infected premises were associated with increased risk of infection.

 

In conclusion, the authors write: “by combining influenza outbreak and concurrent meteorological data, we have shown how relative humidity, air temperature and wind velocity combined to influence the spread of an actual influenza outbreak.

Read more at equinescienceupdate.com

Standing fracture repair in racehorses

New research shows lower limb fractures in racehorses repaired under standing sedation have a similar outcome to those repaired under general anaesthetic, but with the advantages of less time, cost and risk.

The study, conducted by Richard Payne and Polly Compston at Rossdales Equine Hospital, Newmarket, has been published recently in the Equine Veterinary Journal.

The report includes details of racehorses with lower limb fractures that were repaired by Rossdales Equine Hospital up to June 2011. Thirty four racehorses were included in the report - thirty Thoroughbreds and four Arabs.

After premedication with acepromazine, sedation was maintained with i.v. boluses of detomidine and butorphanol. Local analgesia (high 4- (or 6-) point block) together with a ring block was performed by the operating surgeon.

Non-displaced fractures included in the study were: incomplete sagittal fracture of the proximal phalanx (14/34 ); lateral condylar fracture of the third metacarpus (12/34); medial condylar fracture of the third metacarpus (7/34 ) and 1 lateral condylar fracture of the third metatarsus. Repair was achieved by the insertion of one or more lag screws.

Hospital records, owner and trainer telephone questionnaires and website research were used to evaluate follow-up. The short and long-term results achieved were comparable with those for similar procedures carried out by the same surgeon under a general anaesthetic. Twenty of the horses returned to racing within an average of 226 days.

On average, the time from completion of the repair to the horse returning to racing was actually shorter when carried out under sedation, than similar cases repaired under general anaesthesia. However, the authors point out that horses selected for standing repair were those with non-displaced fractures which would be expected to require less time to heal than those with displaced fractures that required repair under general anaesthesia.

The authors stressed the need for a competent and experienced hospital team to ensure that health and safety concerns did not become an issue.

“Over the past few years we have been developing an increasing number of techniques, which allow us to perform a variety of surgical procedures in the standing horse. This negates the risks associated with general anaesthesia in our equine patients, which are especially relevant for horses with broken legs, because of their risk of re-injury to the site of fracture repair when the horse stands up again after recovery from anaesthesia” said Richard Payne. “Polly’s study showed that the outcome for racehorses that have a standing fracture repair is every bit as good as for those where the fracture is repaired under a general anaesthetic.”

 

Read more at equinescienceupdate.com

Seasonal variation in metabolic rate in ponies

Shetland ponies can drop their body temperature to save energy when food is scarce, according to a study carried out in Germany.

Warmblooded animals can keep functioning in cold conditions, but to do so they expend much energy maintaining their body temperature. Some primitive species seemed able to allow their temperature to fall to conserve energy. It was thought that animals lost this ability as a consequence of domestication. But recent studies have shown that the Przewalski horse, the primitive relative of the modern day horse, seems to have retained the ability to control its body temperature according to the environmental conditions.

Lea Brinkmann and colleagues at the University of Göttingen, Germany, wanted to see if this characteristic was still present in domesticated animals.

They conducted a study to see if Shetland ponies, one of the earliest domesticated breeds, retained the ability to drop their body temperature when food is scarce.

The research team studied a group of ten Shetland ponies throughout the year, monitoring subcutaneous and rectal temperatures, heart rate, general body condition and activity levels.

They noticed that, during the summer, the animals’ subcutaneous temperatures dropped over night, being lowest around dawn, and rose to a peak around mid-day. “This is consistent with a daily shallow hypometabolism,” the team says.

Then at the onset of winter, the researchers divided the ponies into two groups. One group received full rations; the other ponies were fed a restricted diet providing only 30% that of the control group.

The feed-restricted group had significantly lower daily subcutaneous temperatures compared with the control group on cold winter days, when the ambient temperature fell below 0°C. Mean heart rate and locomotor activity closely followed the ambient temperature.

Feed-restricted ponies showed a significant drop in average heart rate (from 52.8 beats per minute in summer) to 29bpm in winter. This response differed significantly from that of the ponies on full rations, suggesting that the feed restricted ponies had a lower metabolic rate.

Ponies were significantly less active in the winter than in the summer.

“Our results show that Shetland ponies exhibit signs of a winter hypometabolism indicated by reduced heart rate and subcutaneous temperature” the team conclude. “Thus, domesticated horses seem to have maintained the capacity for seasonal adaptation to environmental conditions by seasonal fluctuations in their metabolic rate.”

Read more at equinescienceupdate.com

Ticks wanted dead or alive!

The Western College of Veterinary Medicine (WCVM) in Saskatchewan, Canada, have launched a study into tick borne disease in the area.

A research team headed by Dr. Katharina Lohmann has initiated a pilot study into the prevalence of equine granulocytic anaplasmosis (A. phagocytophilum infection) and Lyme disease (Borrelia burgdorferi infection) in Saskatchewan horses. Both bacteria are transmitted in Canada primarily by the black legged tick, Ixodes scapularis. 

Curently, these infections are not common in Canada. There have been only three cases of anaplasmosis reported in horses in the country, one of which was found in Saskatchewan in 2010. 

Dr Lohmann explains that Ixodes scapularis is not thought to be established in Saskatchewan, but individual ticks may be carried in from different areas of the country and from the U.S. by migrating birds.

The first phase of the study will examine blood samples collected from horses in Saskatchewan, Manitoba and Ontario. The research team expect to find antibodies to A. phagocytophilum or B. burgdorferi in about two per cent of horses.

In order to better understand which species of ticks are relevant to horses, the researchers are asking veterinarians and horse owners to submit any ticks found on horses within Saskatchewan.

So far, the species of tick submitted to the survey includes Dermacentor albipictus (winter or moose tick), Dermacentor andersoni (Rocky Mountain wood tick) and Dermacentor variabilis (American dog tick).

The WCVM research team would be pleased to receive ticks of any life stage (including larva, nymph and adult stages) and are actively seeking tick submissions over the next two years (2011-2013).

More details of the tick survey, including how to submit ticks found on horses, are available at:

http://www.usask.ca/wcvm/veterinarians/equine_ticks.php

 

Unexpected outcome of Hendra virus cases

A survey of equine veterinary practices in Queensland Australia has shown that veterinarians are stopping doing equine work because of the risks posed by Hendra virus.

Hendra virus (HeV) infection primarily affects fruit bats, but was first reported in horses in 1994. During the initial outbreak 14 horses died. Seven other horses were shown to have been infected and were humanely destroyed.

Human infections, although uncommon, most  often affect people in contact with horses. Of seven cases of human HeV infection, five have involved equine veterinary personnel conducting post mortem  or endoscopic examinations. In three cases the infection was fatal.

A study, published in Emerging Infectious Diseases, explored the issues faced by  staff of equine veterinary practices relating to HeV infection-control and workplace health and safety.

 

The research team from James Cook University, in Townsville, Queensland, was led by Diana Mendez. They interviewed 21 veterinarians and other staff from 14 equine or mixed practices.

 

They found that twelve of twenty veterinary professionals  (60%) had dealt with one or more cases of HeV infection; seven of them (35%) had dealt with a confirmed case.

One finding that they had not expected was that some veterinarians had given up equine practice because of HeV. Four of 18 vets interviewed said they had stopped doing equine work, and 44% knew of one or more colleague who had stopped doing equine work in the previous year. Concerns over personal safety and legal liability related to HeV were given as the main reason for the decision to leave equine practice.

A vaccine against HeV is being developed. The availability of such a vaccine would go some way to calm the fears of those working in the Australian equine sector.

 

Read more at: www.equinescienceupdate.com

 

Equitation science - the road ahead

 The International Society for Equitation Science celebrates its 10th anniversary this year with a conference in Edinburgh, Scotland. Two days of talks and discussions on the science of horse riding and horse training are planned, followed by a practical day at the Scottish National Equestrian Centre

Details of the scientific program are now available on the ISES website...  

http://www.ises-uk2012.com/programme.htm

How horses recognise humans

Research just published from the University of Sussex demonstrates that domestic horses use a sophisticated cognitive system to identify individuals of species other than their own.

Drs Leanne Proops and Karen McComb, of the School of Psychology's Mammal Vocal Communication and Cognition Research Group, had already shown that horses can combine auditory and visual information to recognise each other.

In their latest research they demonstrated that horses also use this system to distinguish between the different humans they know.

Dr McComb explained: “When we hear a familiar voice we form a mental picture of who spoke. We match visual and auditory cues to recognise specific individuals. Previously we showed that horses also identify other horses cross-modally.

“We now demonstrate how flexible this ability is by showing that horses can also recognise humans in this way, despite people looking and sounding very different to themselves.”

The study was carried out using domestic horses that were accustomed to several different handlers.

Firstly the researchers tested where the horse would look when two voices - one familiar, one unfamiliar - were played from a hidden loudspeaker, either side of which stood the familiar and unfamiliar person.

They found that the horses responded more quickly and looked for longer and more often at the familiar human compared with the stranger when played their voice. They were significantly better at making this match when the familiar person was on the right of their visual field (indicating that the left hemisphere of the brain is involved in this processing).

The researchers then tested how the horses would perform the more complex task of distinguishing between two familiar voices.

This time, the horses were able to match a specific familiar voice to its human handler. This indicates, say the researchers, that the sight of the handler activated a multi-modal memory of that specific individual, allowing each horse to match the sight of a particular person with the sound of their voice.

Horses likely use this recognition strategy naturally to identify numerous individual people in their day-to-day lives.

Read more at: www.equinescienceupdate.com

Clydesdale bog spavin survey

Clydesdale horses would benefit from their owners knowing more about the likely causes of bog spavin, the chronic fluid distension of the tarsocrural (hock) joint.

A survey of Clydesdale owners in the USA and the UK found that most knew of the condition, but were often unaware of its possible significance.

Of the 93 5  horses included in the survey, 10% were reported to show signs of bog spavin. Over half of the affected animals first showed signs of bog spavin before they reached one year of age. This is significant as it coincides with the time when osteochondrosis tends to occur.

Osteochon drosis, a disorder of bone development which results in damage to the articular cartilage, is the most common cause of long term joint swelling in young horses showing little or no lameness. If untreated, the condition may eventually result in osteoarthritis and persistent lameness.

The owners' approach to the condition differed on opposite sides of the Atlantic. In the UK, nearly half of the affected horses were not investigated at all, whereas in the USA over 75% received some investigation – ranging from physical examination by the owner, yard manager or veterinarian, to more specialised techniques.

Radiographic examination was performed on 37.7% of affected horses in the USA , but on just 12.2% in the UK.

Some of the cases of bog spavin identified in the survey could be due to undetected osteochondrosis. The report's authors suggest that a radiographic survey of Clydesdale horses is warranted to establish the true extent of osteochondrosis of the hock joint.

They argue that if more owners knew about the possible causes of bog spavin they might be more likely to investigate and thus identify those horses with osteochondrosis. Arthroscopic surgery could then be offered to appropriate cases to reduce the risk of osteoarthritis.

Read more at www.equinescienceupdate.com

Benefits of early training

New research suggests that exercise early in life benefits musculoskeletal health. It may even have a positive impact on the future racing careers of Thoroughbred horses.

A study, published in the Equine Veterinary Journal, looked at the association of two-year-old training milestones with career length and racing success in a sample of 4683 Thoroughbred horses in New Zealand.

The study found that horses that raced as two-year-olds had significantly more race starts during their careers from three-years-old onwards than those that raced first as three-year-olds or older. Horses that raced as two-year-olds had significantly longer racing careers.

Horses registered with a trainer, trialled or raced as two-year-olds were more likely to have won or been placed in a race than those that achieved these milestones as three-year-olds or older. In addition, horses that first trialled and raced as two-year-olds had greater total earnings than those that first trialled or raced at a later age.

Read more at equinescienceupdate.com

Screening for FIS

Researchers at the Animal Health Trust, Newmarket, have published the results of their work screening endangered horse breeds for the genetic mutation that is responsible for Foal Immunodeficiency Syndrome (FIS).

The good news is that, despite Fell and Dales ponies having been interbred with other breeds, there appears to have been only limited transmission of the defective gene to those other breeds.

The defective gene was found to be widespread in the Fell pony population, being found in 38% of individuals tested. It was found less frequently in Dales ponies (18%).

Researchers also looked at other breeds that had recently interbred with Fell and Dales ponies (Clydesdale, Coloured, Exmoor, Highland, Part-Bred WelshSecD and Welsh Sec D). The defect was only identified in coloured (“Gypsy”) cobs and then only at a low level (1%).

Read more at equinescienceupdate.com

Dieting horses eat bedding

It is no surprise that ponies on a restricted diet resort to eating their bedding. Wood shavings are often suggested as an inedible bedding material, to discourage such behaviour. However, recent research suggests shavings may not be as unpalatable as generally supposed.

In fact, horses and ponies on a severely restricted diet may actually consume considerable quantities of wood shavings, as research conducted at Liverpool University Veterinary School demonstrated.

Figures obtained during the study suggested that at least half of the animals had been supplementing their diet from an alternative “non-feed” source. Almost half (5/12) appeared to have consumed over 1kg of wood shavings a day.

Although some ponies had eaten negligible amounts of shavings, others appeared to have eaten more than 3kg a day.

Read more at equinescienceupdate.com

Racing in the slipstream

Sitting in the slipstream of frontrunners is a winning strategy for jockeys, according to new research.

A detailed study of almost 45,000 racehorses has shown that horses that tuck in closely behind frontrunners during races are most likely to come out on top.

The research, from Dr Andrew Spence at the Royal Veterinary College, London, and published in the Royal Society journal Biology Letters, demonstrates that just as an F1 driver might sit in the slipstream of the car in front, jockeys who deploy this tactic are most likely to have an advantage on competitors when it comes to winning a race

Dr Spence, working with Professor Alan Wilson and colleagues at the Structure and Motion Laboratory, used a unique data set from thoroughbred horse racing to find out just what tactics work. They determined the position and speed of 44,803 racehorses, once per second, in 3,357 races ranging in length from 1006 to 4225m (50.9–292.9 seconds duration) using a validated radio tracking system. They discovered that reducing aerodynamic drag by moving close behind other competitors had a marked effect on horse performance, and hence racing outcome.

 

Read more at: www.equinescienceupdate.com

Choosing where to roll

Kanji Matsui and colleagues investigated the benefits of providing specific rolling areas for grazing horses.

Their study “Do horses prefer certain substrates for rolling in grazing pasture?” was published in the Journal of Equine Veterinary Science. The work was carried out at the Education and Research Center of Alpine Field Science, Faculty of Agriculture, at Shinshu university.

Four native Japanese Kiso horses were included in the study. The researchers observed the horses' behaviour in paddocks with and without rolling areas made of different substrates.

Two experimental paddocks were available for grazing, each 120 x 60 metres. One paddock , (the control) contained pasture only; the other contained three rolling areas – each 5 x 5 metres - made of  dry soil, sand or straw.

The researchers found that horses tended to roll more often, but for less time overall, in the rolling paddock compared with the control paddock. The difference, however, was not significant.

Horses spent significantly less time rolling in the rolling paddock than they did in the control paddock. Most of the rolling took place in the constructed rolling areas..

According to the researchers this indicates the absolute preference of horses for rolling areas. ”Thus, building rolling areas encourages horses to roll in these contained areas, thereby reducing damage to pasture.”

 

The horses appeared to prefer rolling on the dry soil area, rather than on either the sand or straw.

The researchers conclude that “offering a rolling area encourages horses to roll in these areas and keeps the pasture in good condition.” They point out that it also allows an increase in grazing time, which reduces the need for supplementary feed.

They recommend that rolling areas be provided in  pasture for horses and that these rolling areas be constructed of soil.

Read more at equinescienceupdate.com

Archaeologists find earliest metal bit

Excavation of a burial site in southern Israel, has unearthed what is believed to be the earliest known metal bit.

Archaeologists led by Professor Eliezer Oren from Ben Gurion University excavated an equid burial at Tel-Haror, an archaeological site with strata dating to the Middle Bronze IIB Period (1,750-1,650 B.C.). Among the bones they found a metal equestrian bit.

Dr. Joel Klenck, a Harvard University educated archaeologist and president of the Paleontological Research Corporation specialises in the analysis of animal remains. He identified the equid as a donkey by the shape and size of its pedal bones and traits on the grinding surfaces of its teeth.

Klenck points out that the donkey burial at Tel Haror is special since it provides the earliest direct evidence of a metal equestrian bit. He states, “Until the excavation at Tel Haror, archaeologists had only indirect evidence for the use of bits. An example of this indirect evidence is wear marks on equid teeth at the fortress of Buhen in contexts dating to the twentieth century B.C. At Tel Haror, we retrieved the actual metal device.”

He notes the ancient bit caused equids to turn due to the force of the device. Also, round plates on either end of the ancient bit exhibit triangular spikes that pressured the lips if the reins were pulled from one direction.

Read more at equinescienceupdate.com

 

How the zebra got its stripes

Why does the zebra have stripes? Perhaps they provide camouflage in the African savannah; perhaps they break up the animal's outline making it more difficult for predators such as lions.

However, research published recently in the Journal of Experimental Biology suggests that the stripes may confer protection against a different sort of predator.

An international team of scientists, led by Gábor Horváth of the Eötvös University, Hungary, found that the zebra's stripes help ward off biting flies.

Such flies are widespread in Africa, and, as well as spreading disease, they cause annoyance and disrupt grazing.

According to Horváth, these insects are guided to a wet habitat suitable for breeding by homing in on horizontally polarized light, which results when light is reflected off water. However, blood-sucking female flies also locate their victims by following polarized light reflected from their skin.

The research, carried out in Hungary, showed that a horse model with zebra stripes attracted far fewer horseflies (tabanids) than did homogeneous black, brown, grey or white equivalents.

The research team found that as the width of the stripes decreased the horseflies were less attracted. They also found that the width of the stripes on zebras coats fell within the range that was most disruptive to these biting flies.

“Tabanids have been shown to respond strongly to linearly polarized light,” they explain “and we demonstrate here that the light and dark stripes of a zebra’s coat reflect very different polarizations of light in a way that disrupts the attractiveness to tabanids.”

It appears to be the polarisation of the reflected light, rather than the colour , that is significant. The research team found that even on homogeneous grey surfaces the attractiveness to tabanids was reduced if the surface had bands of alternating polarisation.

“We conclude that zebras have evolved a coat pattern in which the stripes are narrow enough to ensure minimum attractiveness to tabanid flies”, says the team. They add, “The selection pressure for striped coat patterns as a response to blood-sucking dipteran parasites is probably high in this region [Africa]”.

Welfare implications of restrictive nosebands

Horse welfare at the Olympic Games is threatened if current trends are allowed to continue, according to the International Society for Equitation Science (ISES). The Society maintains that the practice of over tightening nosebands to avoid penalties in competition is covering up poor training at the expense of horse welfare.

ISES notes that, in the last few decades, there has been a steady increase in the design of nosebands that effectively mask evidence of a horse’s discomfort.

The incentives for athletes to over-tighten nosebands arise from the rules of dressage that penalize displays of discomfort such as open mouths and lolling tongues. These rules were written by the sport’s governing bodies to promote excellent training and the demonstration of qualities such as freedom, harmony, lightness and acceptance of the bit without tension. Restrictive tight nosebands can prevent the horse from displaying unwanted behaviours such as opening, gaping or crossing the jaw, and are enabling competitors to mask signs of tension which judges should penalise as evidence of inferior training. Thus nosebands may hinder effective judging.

Recent research*, by Professor Paul McGreevy and others, suggests that horses wearing tight nosebands undergo a physiological stress response, are sensitized to bit pressure and may have reduced blood flow with potential to cause injuries and tissue damage including nasal bone deformities, even when padding accompanies the noseband such as in the case of so-called crank nosebands.

ISES recommends:

• a return to the established practice of placing “two fingers” under the noseband to demonstrate that it has not been over-tightened. This amount of space under the noseband allows horses to express tension or seek relief from the pressure of the bit and so aligns with the principles of ethical equitation.

• that, for fairness and objectivity, a standard taper gauge should be used by stewards at competition. The taper gauge should be placed without force at the nasal midline and be clearly marked to show the desired stop, which, in alignment with established industry guidance, should be the dimensions of two average adult fingers.

Read more at equinescienceupdate.com

Help sought for Cushing's disease research

Cushing's disease (equine pituitary pars intermedia dysfunction - PPID) appears to be becoming more common as horses live longer. While the true incidence of this disease is unknown, a recent survey of horse owners showed that signs of Cushing's disease were reported in 20 to 30 per cent of horses.

Researchers at the Western College of Veterinary Medicine (WCVM), University of Saskatchewan, are starting to explore a possible new treatment for the condition.To learn more about the incidence and prevalence of Cushing's disease, WCVM equine specialist Dr. James Carmalt has designed an online survey that will be distributed to equine practitioners around the world. Dr. Carmalt and his colleagues at the western Canadian veterinary college will use practitioners' responses from this short, 16-question survey to:

• determine the incidence of disease

• determine the most common treatment protocols being used by practitioners

• evaluate the need for developing new treatment methodologies.

Owners whose horses have been diagnosed with Cushing's disease are urged to bring the survey to the attention of their veterinarian.

http://www.usask.ca/wcvm/veterinarians/cushings_survey.php

Many horses still too fat after winter

 

In the past, horses would lose condition over the winter, start the year in lean condition and gradually recover over the grazing season.

However, a recent survey of groups of horses spending at least six hours out at pasture has shown that more than a quarter were obese at the end of the winter months. 

This alarming trend may suggest that well-meaning winter management strategies such as rugging and a reduction in exercise could be having a detrimental impact on the welfare of horses in the United Kingdom.

The research was conducted by Sarah Giles, Dr Sean Rands and Professor Christine Nicol of the University of Bristol's Animal Welfare and Behaviour Research Group, in collaboration with the WALTHAM^® Equine Studies Group, headed by Professsor Pat Harris. They examined the variations in body condition in small groups of horses during the month of February 2011.

A cross sectional study of 127 horses and ponies was carried out in Somerset . Horses were kept in herds of three or more, and were at grass for at least six hours a day. Their condition was assessed using the nine point body condition score (BCS) system and the five point cresty neck score (CNS). The prevalence of obesity (BCS of 7 or above) was 27.6% with a slightly higher incidence in horses, while the prevalence of cresty neck (CNS of 3 or above) was 48.8% with a higher number of ponies affected.

Read more at www.equinescienceupdate.com

Autumn rise in Atypical Myopathy cases

Once again, Europe is seeing a seasonal rise in cases of Atypical Myopathy.

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

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

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

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

The Atypical Myopathy Alert Group was set up to help owners take preventive measures against the disease. The Group reported that by 23rd December 2011, 116 clinical cases compatible with a diagnosis of Atypical Myopathy had been communicated to Liege University, Belgium, and RESPE (Réseau d’Epidémio-Surveillance en Pathologie Équine: Network of epidemiological surveillance on equine diseases) in France.

Help Solve the Mysteries of Laminitis

Horse owners and veterinarians are asked to collaborate with researchers in a new study into pasture- and endocrinopathy-associated laminitis.

Rather than being based on laboratory research, the study is designed to make use of the wealth of information available in naturally occurring cases of laminitis. Research is already underway under the direction of epidemiologist, Noah Cohen, VMD, PhD at the Texas A&M University College of Veterinary Medicine.

Read more at equinescienceupdate.com

Drug combination may limit joint damage

Research at the University of Sydney suggests that a new osteoarthritis drug combination could significantly extend the working life of racing and other performance horses.

Previous studies has evaluated various medications for the treatment of osteoarthritis in horses, but this is one of the first to show a new drug combination has the ability to slow down damage to joints, rather than just alleviate pain.

"Osteoarthritis is a major cause of wastage in athletic horses, with a significant economic impact on the equine industry," said Dr Toby Koenig, surgical resident at the University of Sydney Veterinary Teaching Hospital, Camden, and lead researcher for the study.

"We found a new combination of three commonly used drugs - pentosan polysulphate, glucosamine and hyaluronic acid - can reduce the damage experienced during strenuous exercise," he added.

"Until now the focus has been on minimising pain for horses suffering from osteoarthritis. We think this new drug combination could have significant impact on the way horses are treated, potentially extending careers of horses in racing, dressage and other competitive events."

Read more at equinescienceupdate.com

More help to avoid positive drug tests

More detection times for commonly used drugs have been released by the British Horseracing Authority (BHA).

According to the BHA, the inadvertent carry over of medication following veterinary treatment is the most common reason for a positive drug test on the day of racing.

An important part of the Authority's drive to keep racing free of drugs is the provision of data to help vets decide when medication should be stopped before racing to minimise the risk of a positive drug test.

"We recognise the need to provide trainers and their vets with this important information to allow them to treat their horses but also avoid race day positive tests."

The BHA has recently announced four new Detection Times for commonly used veterinary medicines; the sedative acepromazine, the sedative /analgesic combination detomidine/butorphanol, the anti-inflammatory treatment prednisolone, and the airway treatment salmeterol.


Read more at equinescienceupdate.com

Research into gene therapy for osteoarthritis

Osteoarthritis, or degenerative joint disease, causes pain and suffering to horses and humans alike.
University of Florida researchers are developing a gene therapy for osteoarthritis in horses, in the hope that the technique will be applicable to people as well. The goal is to create a one-time treatment that gives long-term benefits.
The work involves the use of viruses, called adeno-associated viruses, or AAV, to deliver genetic material to the joints of horses, where it would produce a therapeutic protein directly at the site of the disease.
There is no cure for osteoarthritis. Current medications often only produce limited relief, require repeated administration and may interfere with healing. In contrast, this new gene therapy would require a one-time treatment and would not hinder the body’s healing processes.
Research suggests that the pain, joint inflammation and loss of cartilage associated with osteoarthritis are linked to a protein called interleukin-1. A therapeutic gene used to treat the arthritic joints produces a second protein that naturally counteracts the effects of interleukin-1, but that has not yet translated into effective treatments for patients because of difficulty getting high enough concentrations inside affected joints.
The UF researchers are devising a gene therapy approach that would allow continued production of therapeutic protein within the joints, directly at the disease site.
“We hope that this will be at least the first step in a therapy that will benefit both people and animals,” said Patrick Colahan, a board-certified equine surgeon in the University of Florida College of Veterinary Medicine and co-investigator on the study. “It has the potential to help lots of different species, and from a veterinarian’s perspective, that’s what we’d like.”
Read more at equinescienceupdate.com

Foal heat diarrhoea - no treatment best

New research shows that the bacterial population of the foal's digestive tract undergoes major changes within the first two weeks of life. This change seems to be directly responsible for the "foal heat" diarrhoea that is often seen in young foals.

The work, carried out at the University of Veterinary Medicine, Vienna and the Graf Lehndorff Institute for Equine Science, Neustadt, Germany, found that the onset of diarrhoea was unrelated to the mare returning to oestrus after giving birth.
 
Horse-breeders expect most newborn foals to suffer from diarrhoea. Many methods have been suggested to avoid the problem, including supplementing the mothers’ diets with ß-carotene, which is known to be helpful in preventing diarrhoea in young calves.  However, Juliane Kuhl in the group of Christine Aurich at the University of Veterinary Medicine, Vienna has now shown that this food supplement has no real effect on the incidence of diarrhoea in foals.

Kuhl, Aurich and their collaborators examined the bacteria in the faeces of foals and their mothers, as well as the measuring the levels of antibodies (γ-globulins) in the animals’ blood. 

They found little change over time in the nature of bacteria in the mothers’ faeces, although they did observe dramatic differences in the bacteria in the foals’ faeces. 

Foals are born with very low amounts of bacteria in their intestines but are colonized by E. coli within the first day of their lives.  In contrast, the number of foals with Enterococcus remains low until about ten days following birth, after which these bacteria can be detected in most animals.  Other bacteria such as Streptococcus and Staphylococcus arrive between two and four weeks after birth, by which time the foals’ intestinal flora is essentially indistinguishable from that of their mothers.

Interestingly, the researchers found that the changes in the bacterial flora closely parallel the development of diarrhoea. 

They also found that foals with low γ-globulin levels did not develop diarrhoea more often than those with much higher levels. So, the incidence of diarrhoea cannot be related to a weakened immune system.

Kuhl is careful to note that “we have not yet shown that diarrhoea results directly from the switch in intestinal bacteria, although our data make it seem very likely that this is the case.”

The implication is that the horse is essentially predisposed to develop diarrhoea at a very young age.  As the condition clears up fairly quickly without the need for antibiotic treatment, food withdrawal or food supplements such as ß-carotene, breeders should simply accept that many of their animals will suffer from the condition. 

Read more at equinescienceupdate.com

Comparing hot iron branding and microchipping in foals

Research shows that foals find both hot iron branding and microchip implantation stressful, but the effects of microchip implantation do not last as long.

The study, by R Erber and colleagues, compared the response of groups of foals to the two methods of identification..

Fourteen warmblood foals from the Brandenburg State Stud were divided into two groups. Seven foals were branded with a hot iron on the right thigh; the others had a microchip implanted in the neck.

Throughout the procedure the researchers monitored the foals for signs of stress by recording heart rate, and concentration of cortisol in saliva. They also monitored how the foals behaved in response to the procedures.

Both procedures caused stress. Foals showed an increase in heart rate and in saliva cortisol concentration. In fact, foals showed two peaks in heart rate - initially when they were first restrained, and again when the actual identification (branding or microchipping) procedure was carried out.

Although there was no difference in the degree of stress (measured by salivary cortisol and heart rate) between the two procedures, the researchers point out that it was possible that the foals' response to restraint could have masked that due to the procedure itself.

However, the researchers did find a difference between the two procedures. Hot iron branding resulted in skin necrosis that got worse for three days after application. It also produced an increase in skin temperate.

In fact, not only did foals show an increase in skin temperature at the site of the hot iron branding, they had increased skin temperatures on the opposite thigh and on both sides of the neck as well.

So although both procedures appeared to cause similar degrees of stress, hot iron branding produced more persistent changes. It resulted in skin necrosis that lasted for at least seven days. Hot iron branding also resulted in a generalised increase in body temperature that was not seen after microchip implantation.

Read more at equinescienceupdate.com

Seasonal pasture myopathy research

University of Minnesota researchers are seeking the help of horse owners to find out more about Seasonal Pasture Myopathy. This condition, which is frequently fatal, has been identified increasingly in the Midwestern US.

Horses with Seasonal Pasture Myopathy (SPM) suffer from severe, generalised muscle weakness. They are often unable to get to their feet, or only do so with difficulty. If they are still able to walk, they have a stiff gait - especially of the hindquarters. Affected animals have elevated heart rates, and show profuse sweating and muscle twitching. They often have increased respiratory rates. Dark brown colouration of the urine is characteristic. The mortality rate can exceed 90%.

“We have already seen suspected cases of seasonal pasture myopathy this fall in Minnesota and feel it is an under-diagnosed condition in North America,” said lead researcher Dr. Stephanie Valberg of the University of Minnesota. “Our goal is to work with horse owners to identify which horses are at risk and find the best diagnostic test for this condition.”

The research team need to build up a database of information on cases of the SPM, so that they can start to work out / identify the common risk factors. They hope to be able then to make suggestions of management changes to reduce the risk of the disease condition

If you suspect your horses has (or had) SPM, Dr Valberg's research team would like to hear from you. The first step is to complete a short questionnaire to see if your horse has the condition.

For more details about Seasonal Pasture Myopathy, and details of how you can help research into the condition, go to the University of Minnesota Equine Center website:

http://www.cvm.umn.edu/umec/SPM/home.html

Ancient artists spot on

Ancient cave paintings probably give an accurate portrayal of the horses that roamed the earth at the time, according to new research.

For years, archaeologists have debated whether cave paintings were intended as a realistic portrayal of life as seen by the artist, or whether they were a flight of fancy, having symbolic significance. The latter view was fuelled by the fact that, although genes for bay and black hair colour had been identified in ancient DNA, the gene for spotted coat colouring had not been found.

Now a multicentre research project has found the gene responsible for leopard spotted coat colouration in DNA from prehistoric horses.

The international team of researchers has found that all the colour variations seen in Palaeolithic cave paintings – including distinctive ‘leopard’ spotting - existed in pre-domestic horse populations, lending weight to the argument that the artists were reflecting their natural environment.

Professor Michi Hofreiter, from the Department of Biology at the University of York, said “...our results suggest that, at least for wild horses, Palaeolithic cave paintings, including the remarkable depictions of spotted horses, were closely rooted in the real-life appearance of animals. 

“While previous DNA studies have produced evidence for bay and black horses, our study has demonstrated that the leopard complex spotting phenotype was also already present in ancient horses and was accurately depicted by their human contemporaries nearly 25,000 years ago. 

“Our findings lend support to hypotheses that argue that cave paintings constitute reflections of the natural environment of humans at the time and may contain less of a symbolic or transcendental connotation than often assumed.”

Read more at equinescienceupdate.com

Management affects large intestinal motility

A possible explanation for the increased risk of impaction colic in stabled horses has been revealed by a study that shows that they have lower large intestinal motility compared with horses at pasture.

The research team, led by Dr Sarah Freeman at the University of Nottingham School of Veterinary Medicine and Science, measured the motility of the large intestine at three regions of the large intestine, using transcutaneous ultrasound.

The study involved sixteen clinically normal horses, which were divided into two groups.

Group A: Horses were stabled continuously throughout the study.
Group B: Horses were initially at pasture 24hr/day. Over a 2 week period they were gradually changed to the same stabling/dietary management as group A.

The researchers assessed the motility of large intestine twice daily for two consecutive days. They recorded the number of contractions at each of three sites: the caecum, sternal flexure, and left ventral colon.

Overall large intestinal motility as assessed by transcutaneous ultrasound was lower in stabled horses. In particular, stabled horses showed significantly fewer contractions in the sternal flexure and left ventral colon.

 Read more at www.equinescienceupdate.com

Laminitis due to endocrine disorders

Hormonal disturbance (endocrinopathy) appears to be a common underlying cause of laminitis according to research from Finland.

The study, conducted at Helsinki University Equine Teaching Hospital, looked for signs of endocrinopathy in all cases of laminitis presented for examination. Almost 90% of horses with laminitis had endocrine abnormalities.

Hyperinsulinaemia, associated with obesity was the most common cause, accounting for two thirds of all cases of endocrinopathic laminitis.  Cushing’s disease (or Pituitary Pars Intermedia Dysfunction: PPID) was responsible for a third of the endocrine-associated laminitis cases.

Dr Ninja Karikoski and colleagues examined 36 horses and ponies with laminitis. Thirty-two of them (89%) had signs of endocrinopathy.

Eleven horses had signs of PPID - hirsutism (long curly coat) and increased basal ACTH concentration or typical response to a dexamethasone suppression test.

Twenty-one horses had raised basal levels of insulin in the blood without signs of hirsutism.  All but one of these hyperinsulinaemic horses were overweight. Twelve had a body condition score (BCS) of four, (on a scale from zero to five, where five is obese) and eight had BCS of five.

The researchers conclude that, in this study, most cases of laminitis were associated with an underlying hormonal disturbance.

They suggest that endocrine testing should be performed on all cases of laminitis unless there is a clear inflammatory or gastrointestinal cause.

 Read more at www.equinescienceupdate.com

Jet lag benefits racehorses

A new study has shown that not only do racehorses cope better with jet lag than humans do, but also their performance even appears to be enhanced by it.
  
They research showed that horses adapted very quickly to a shift in time zone. Importantly, this rapid adaptation was not accompanied by an increase in the level of stress, but by alterations in endocrine systems that favour an enhancement of the horse’s physical capacity during the process.
 
In fact, following experimental jetlag, horses experienced improved athletic performance, being able to run at full gallop for an additional 25 seconds before reaching fatigue.
 
This improved performance did not persist, however, and had returned to pre-shift values after 14 days in the new lighting conditions.

 Read more at www.equinescienceupdate.com

Comparing positive and negative reinforcement training methods.

A recent study in Denmark suggested positive reinforcement methods were preferable to negative reinforcement when training horses in potentially stressful situations.

They found that found that horses trained with positive reinforcement methods trained more quickly and showed less evidence of stress. 

What is the difference between positive and negative reinforcement? In Positive Reinforcement (PR), the desired behaviour is encouraged by giving a reward as a consequence of the behaviour.

A particular behaviour can also be encouraged by removing an unpleasant stimulus. This is known as Negative Reinforcement (NR). In this case, the reward is the stopping of a negative stimulus once the correct behavioural response is achieved.

Negative reinforcement differs from punishment, in which an adverse stimulus is given as a consequence of the behaviour. This results in the behaviour becoming weaker or stopping altogether.

Twelve horses took part in the study. All had previous bad experiences with trailer loading and their owners were now unable to load them.

Horses were randomly separated into two groups. The PR group received clicker training and were trained to follow a target (a yellow ball on a stick) into the trailer. For the NR method, an adverse stimulus was applied by pulling on the lead rope, or tapping the hindquarters with a whip. This adverse stimulus was stopped as soon as the horse obeyed.

Throughout the training sessions, the research team recorded heart rate, and noted signs of behaviour and discomfort.

Comparing the two methods, the researchers found that PR provided the fastest response to training. On average, the PR group spent less time on training sessions than did the NR group.

Read more at www.equinescienceupdate.com

Progress towards a vaccine against deadly foal pneumonia

 Rhodococcus equi bacteria can cause “rattles”, a potentially lethal disease in foals which is characterized by chronic broncho-pneumonia with abscesses in the lungs. Other forms of the disease occur including infection of the intestine and lymph nodes.

Affected animals show signs of fever, cough, rapid breathing, and nasal discharge. The disease tends to develop insidiously. Few signs may be apparent until the disease is quite advanced. The organism is often found in soil, particularly in dry dusty conditions.

Treatment usually requires an extended course of antibiotics and/or immune plasma. If the infection is diagnosed too late, antibiotics are often no longer sufficient to cure the disease, and death may occur within weeks.

Despite the severity of this disease, no vaccine against it is yet available. However, researchers in The Netherlands have now developed a promising candidate vaccine.

Read more at equinescienceupdate.com