PCR beats serology for leptospira detection

Examining urine using a polymerase chain reaction (PCR ) technique is more reliable than serology for identifying horses infected with leptospirosis, according to scientists in Brazil.

Leptospirosis can cause various clinical signs, including abortion, uveitis, and kidney and liver disease. Sub-clinical infections also occur, in which infected horses show no signs, but carry and excrete the organism.

In a letter to the Veterinary Record, Hamond and others report the findings of a study that assessed the relative merits of serology and urine PCR for detecting Leptospira infection in horses.

Their research looked at four herds in Rio de Janeiro, Brazil. Previous cases of leptospirosis had been recorded in the herds, and none of the horses had been vaccinated against the disease.

Blood and urine samples were collected from all adult horses (144). Leptospira antibodies were found in 66 horses, and 89 horses had Leptospira DNA in the urine.

Over half of the Leptospira-positive urine samples came from horses with no Leptospira antibodies in the blood.

The authors conclude that in horses, “serology is a useful tool for detecting leptospirosis on a herd basis, but individual detection of Leptospira species carriers must rely on PCR.”

Read more at: www.equinescienceupdate.com

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.”

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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