All you need to know about equine hormonal disorders?

Up to date information on equine hormonal disorders has just become easier to find thanks to the Equine Vet

Journal and Equine Veterinary Education. They have compiled a free online collection of their recent articles on Equine Endocrinology to raise awareness of these common disorders and to provide a source of references all in one place.

“Raising awareness of the benefits of early diagnosis [of these conditions] and sharing the latest research on these and other associated conditions are imperative to provide horse owners with the best diagnostic and treatment programmes for their horses” said Professor Celia Marr, Editor of Equine Veterinary Journal.However. “It is easy to under-estimate obesity: horse owners need to think about improving management of their horses’ feeding and exercise in order to avert problems before they become a veterinary issue.”

The virtual supplement is available (free) at:

http://onlinelibrary.wiley.com/journal/10.1001/%28ISSN%292042-3306/homepage/equine_endocrinology_virtual_issue.htm

Filling a gap in equine history

Scientists have announced the discovery of a new species of fossil horse from 4.4 million-year-old fossil-rich deposits in Aramis, Ethiopia.The findings have been reported in the Journal of Vertebrate Paleontology.

The animal had limbs with three toes and was about the size of a small zebra. It has been named  Eurygnathohippus woldegabrieli after Giday WoldeGabriel, a geologist at Los Alamos National Laboratory. The research team wanted to recognize his many contributions in unraveling the geological complexities of the deposits in the Ethiopian Rift system where fossils of some of our oldest human ancestors have been found.

The horse fills a gap in the evolutionary history of horses but is also important for documenting how old a fossil locality is and in reconstructing habitats of human forebears of the time, said Scott Simpson, co-author of the research and professor of anatomy at Case Western Reserve University's School of Medicine, in Cleveland, Ohio. "This horse is one piece of a very complex puzzle that has many, many pieces."

The researchers found the first E. woldegabrieli teeth and bones in 2001, in the Gona area of the Afar Region of Ethiopia. This extinct species of horse was among the diverse array of animals that lived in the same areas as the ancient human ancestor Ardipithecus ramidus, commonly called Ardi.

"The fossil search team spreads out to survey for fossils in the now arid badlands of the Ethiopian desert," Simpson said. "Among the many fossils we found are the two ends of the foreleg bone—the canon—brilliant white and well-preserved in the red-tinted earth."

A year later, they returned and found part of the connecting shaft, which was split lengthwise but provided the crucial full length of the bone. The long slender bone indicates this ancient species was an adept runner, similar to modern zebras, and analyses of their teeth indicated they relied heavily on eating grasses in the grassy woodland environment.

E. woldegabrieli had longer legs than ancestral horses that lived and ate in forests about 6 million to 10 million years ago, Simpson said. The change helped them cover long distances as they grazed and escape lions, sabre-tooth cats and hunting hyenas that would run down their prey.

Other fossils they found included teeth, which are taller than their ancestors' and with crowns worn flatter—more signs the horses had adapted to a grazing life. Analyses of the isotopic composition of the enamel confirmed that E. woldegabrieli was a dedicated grazer with a coarse diet similar to that of modern zebras, wildebeests, and white rhinoceroses.

"Grasses are like sandpaper," Simpson said. "They wear the teeth down and leave a characteristic signature of pits and scratches on the teeth so we can reliably reconstruct their ancient diets."

Raymond L. Bernor, from the Laboratory of Evolutionary Biology at the Howard University College of Medicine in Washington D.C., led the fossil analysis. The bones, which are kept at the National Museum of Ethiopia in Addis Ababa, Ethiopia, showed this animal differed significantly from both horses more than 5 million years old, and those 3.5 million years old and younger. Members of the youngest group are even taller and have longer noses, further adaptations toward living in open grasslands, the researchers say.

More information:
Eurygnathohippus woldegabrieli, sp. nov. (Perissodactyla, Mammalia), from the middle Pliocene of Aramis, Ethiopia.
Bernor RL, Gilbert H, Semprebon GM, Simpson S, Semaw S.
Journal of Vertebrate Paleontology, vol. 33, no. 6; pages 1472-1485
doi: 10.1080/02724634.2013.829741

Equine influenza: Are we protecting our horses effectively?

Should we be doing more to protect our horses against equine influenza?

Vaccination against equine influenza became mandatory for racing Thoroughbreds in the United Kingdom in 1981. Since then major outbreaks have been few and far between. Vaccination has two aims: to protect the vaccinated individual from becoming ill and to limit the spread of infection by reducing the amount of virus a vaccinated horse will shed if it does become infected.

The flu virus can change the proteins on its surface, a process known as antigenic drift. These surface proteins are the structures that are recognised by the immune-system. If they change, a vaccine that has been produced to recognise proteins on older virus strains will be less effective. The World Organisation for Animal Health (OIE) monitors field surveillance data and recommends suitable vaccine strains to be included in commercial vaccines. None of the vaccines currently on sale in UK have the most recently recommended strains and only one in the US achieves this.

Read more...

New Codes of Practice for 2014

Codes of Practice for the 2014 equine breeding season have been published by the Horserace Betting Levy Board. The Codes set out voluntary recommendations to help breeders, in conjunction with their veterinary surgeons, to prevent and control specific diseases in all breeds of horse and pony. Information can be found on Contagious Equine Metritis, Equine Viral Arteritis, Equine Herpesvirus, Equine Coital Exanthema, Equine Infectious Anaemia, Dourine and Strangles.

The sections on Equine Herpesvirus and Strangles have been updated and expanded for 2014. For more details see:

http://codes.hblb.org.uk/index.php/page/2

3D printing future for therapeutic shoes?

Australian vets and scientists from CSIRO (Commonwealth Scientific and Industrial Research Organisation)  have given a surprise Christmas gift to ten-year old mare, Holly, who suffers from chronic laminitis.

She recently took the first steps in her new 3D printed titanium shoes that were custom designed to fit her foot. 

The team of 3D printing experts worked with horse podiatrists to scan Holly's feet and design the “horse-thotic” which aims to support the foot and encourage it to heal, whilst making Holly comfortable.

Holly has had laminitis for three years. Horse vet and farrier, Dr Luke Wells-Smith from the Equine Podiatry and Lameness Centre, said his team saw the 3D printed shoe CSIRO built for a race horse earlier this year and started to think about using 3D printing to rehabilitate lame horses.

"The new shoes will work to redistribute weight away from the painful areas of the laminitic foot and give Holly, and horses like her, the chance to recover," he said.

"Many attempts have been made in the past to cure laminitis but it’s the 3D scanning and design part of this process that is so exciting to us.

"Christmas is looking a lot merrier for Holly this year. She should be walking normally and without pain in just a few weeks," said Luke.

CSIRO's 3D printing expert, John Barnes, said scanning the hoof would allow them to manufacture a shoe that is the ‘perfect fit’ for these complicated foot diseases, giving the horse the best possible chance for rehabilitation," he said.

"We know that 3D printing has the potential to create so many advanced biomedical products, but rehabilitation of horses has been a completely new area of work for CSIRO.

"We’re glad that this technology is opening so many doors and is now helping to aid the rehab process for these animals and get them walking comfortably again," he said.

See the video:

http://csiro.au/Portals/Media/Hollys-Christmas-wish-comes-true.aspx

Limiting roughage access may limit fertility

Ensuring that mares have access to roughage throughout the day and night has beneficial effects on reproductive efficacy according to a recent report.

Horses have evolved as "trickle feeders" and are adapted to eating little and often. Modern management methods frequently interfere with this natural feeding routine, and have been implicated in causing welfare problems and  health issues such as gastric ulcers and colic.

Now evidence has emerged to suggest that restricting the availability of ro ughageto just part of the day can be detrimental to breeding performance.

The study, “Temporal feeding pattern may influence reproduction efficiency, the example of breeding mares” by Haifa Benhajali and colleagues has been published in the journal PLOS One.

One hundred Arab breeding mares on the national breeding facility of Sidi Thabet, near Tunis, in Tunisia, were included in the study. They were randomly divided into two groups whose management differed only in the timing of availability of roughage. Mares were housed individually except for a period of six hours when they were turned out into a paddock. They had free access to water, a small amount of cut grass was given at midday, and 4kg of barley was fed overnight.

The “Continuous feeding pattern” group (CF) had access to hay both when turned out and when housed for the rest of the day and night. They received 5kg hay in the stable at night and 5kg hay when turned out. The “standard feeding pattern” group (SFP) received 10kg hay only when housed. So the total amount of roughage provided each day for both groups was the same.

The researchers found a significant difference between the two treatment groups. Those receiving hay throughout the day had fewer oestrus abnormalities and higher fertility. The conception rate in the CF mares was 81% compared with 55% in the SFP mares.

They conclude that “temporal patterns of feeding may be a major and underestimated factor in breeding.”

For more details see:

Temporal feeding pattern may influence reproduction efficiency, the example of breeding mares.
Benhajali H, Ezzaouia M, Lunel C, Charfi F, Hausberger M.
PLoS One. 2013 Sep 30;8(9):e73858. 

doi: 10.1371/journal.pone.0073858

How risky is medicating joints?

Injecting medication directly into the joint is a common procedure for treating injuries in competition horses. It carries a risk of introducing infection into the joint. However, a recent report suggests that with adequate preparation serious consequences are uncommon.

Lewis Smith and colleagues examined clinical records of all horses given intra-articular injections by nine ambulatory veterinary surgeons over a five year period. The vets were based at a specialist equine practice in Newmarket England dealing mainly with Thoroughbred racehorses. Data relating to intra-articular injections for diagnostic purposes were not included in the study.

The site of injection was prepared using standard aseptic technique, but usually the hair was not clipped.  All injections were made using scrupulous aseptic injection technique.

During the study period, 9456 injections were performed, including corticosteroids (92.3%) antibiotic (amikacin)( 94.8%) and polysulphated glycosaminoglycans (PSGAGs)(0.15%).

Twelve horses developed complications after medication. Four of those developed joint sepsis, but all returned to work after having the joint flushed.

Analysis of the data showed that administration of PSGAGs into the joint, was significantly associated with joint infection. Overall, intrasynovial medications that included amikacin were less likely to develop joint sepsis, but the difference was not significant if the PSGAGs were excluded from the analysis.

The authors concluded that the risk of  sepsis being induced inadvertently following intrasynovial medication was extremely low. They advised that intrasynovial medication with PSGAGs should be  avoided unless antimicrobials are given at the same time.

For more details see:
Risks of synovial sepsis following intrasynovial medication in ambuatory practice, 2006-2011: 9456 intrasynovial injections. Smith, L., Palmer, L., Shepherd, M., Steven, W.N., Dallas, R., Baldwin, G., Sommerville, G., Hawthorne, T. and Ramzan, P.
Equine Veterinary Journal (2013) 45, Suppl. 44, 6  (no11)

NEW LAMINITIS STUDY

A new research project aiming to help horse owners reduce the impact of laminitis is being undertaken by the Animal Health Trust (AHT) in partnership with the Royal Veterinary College (RVC).

The study, which will extend over four years, is being funded by World Horse Welfare. It will take a closer look at management factors that may contribute to the development or recurrence of laminitis within the British horse and pony population. Through modifying these contributing factors, it is hoped that horse owners can significantly reduce the impact of this important welfare problem.

The AHT and RVC plan to create a website where owners from all over the country can register their horses and ponies and assist in the regular gathering of information related to potential risk factors for laminitis, over a period of two years.

This will help establish a timeline of events and gain a better understanding of the factors leading to laminitic episodes.

The study, to be conducted by PhD student Danica (Dee) Pollard, will follow-up on previous research conducted by Dr Claire Wylie in which factors such as rapid weight gain, increasing time since last deworming, box rest in the previous week and new access to grass in the past month increased the risk of laminitis.

Dr Wylie’s study also revealed that factors such as feeding of additional supplements and transport in the previous week were associated with a reduced risk of laminitis. 

These are factors that could all be changed by the owner, and this is why they are of particular interest to the new study.

Dee Pollard, based at the AHT, said: “This will be a very exciting opportunity for owners to be at the frontline of equine health research and contribute to a study which aims to provide evidence-based preventative strategies to combat laminitis.”

Horse owners interested in taking part in the research project are asked to register their interest via email to danica.pollard@aht.org.uk

Acceptability of smaller microchips

Although microchips are widely used for identifying horses throughout Europe, there is still some resistance to their use, with questions being raised about stress during implantation, inflammation at the site of implantation, and reliability of detection.

In response to this criticism, microchips that are even smaller have been developed. They may be less stressful to implant, but do they work as well? Recent work has looked at whether such chips are reliable and if their implantation causes signs of stress.

The study, carried out at the Brandenburg State Stud at Neustadt (Dosse), Germany, was  reported by Manuela Wulf and others in a recent edition of the Veterinary Record. Forty adult mares were implanted,  on the left side of the neck, with a reduced-size microchip (10.9×1.6 mm). (Conventional microchips are 11.4×2.2 mm). Three different scanners were used to detect the microchips  immediately, and on three further occasions up to 28 weeks after implantation.

The researchers found that scanners differed in their ability to read the microchips, although all scanners detected all chips on every occasion when scanned from the side of implantation. One scanner read all microchips successfully from both sides of the neck on four occasions up to 28 weeks after implantation.  Two other scanners detected all of the chips from the side of implantation, but were less successful reading from the “wrong” side of the neck.

Did the horses find the implantation procedure stressful? The researchers monitored heart rate, heart rate variability and saliva cortisol levels during the implantation process in twelve of the mares. They also recorded the same information while pressing at the implantation site with a cannula without penetrating the skin. So each mare acted as its own control. They found a slight increase in heart parameters in both chip implantation and controls, but no change in cortisol levels.

The report's authors conclude that reduced-size microchips are highly reliable for identification of horses. “Compared with conventional microchips, the reduction in size did not impair readability. Microchip implantation is no pronounced stressor for horses.”

For more details see:
Reduced-size microchips for identification of horses: response to implantation and readability during a six-month period.
Wulf M, Aurich C, von Lewinski M, Möstl E, Aurich JE.
Vet Rec. 2013 Nov 9;173(18):451.
 doi: 10.1136/vr.101824

Riding Arena Footing and Management Webcast

Ever wondered what's involved in providing a top quality arena surface, or wanted to know more about the materials to use?

Here's your opportunity. There's a free webcast on “Riding Arena Footing and Management” from MyHorseUniversity on November 26, 2013 at 7 PM ET.

Dr. Ann Swinker, Associate Professor in Equine Sciences, Penn State University and Horse Extension Specialist has been involved in the horse business for over 35 years. She will discuss the physical properties of the various footing materials that are available and the advantages and disadvantages. She will also consider the management of arena surfaces, the principles of maintenance and the signs that a surface needs to be changed or replaced.

You can register for the webcast now. Don't worry if you miss it; you can still catch it later, as it will be archived on the website and will continue to be available (free).

For more details go to ....

http://myhorseuniversity.com/resources/webcasts/ridingarenafooting

Benefit of targeted worming

Worming only those horses that need it can be cost effective, even taking into account the cost of performing faecal worm egg counts, according to research published in the Veterinary Record.

It is now widely acknowledged that a targeted approach to worm control is preferable to interval dosing regimes. Current recommendations are that only those horses carrying a moderate or high worm burden are treated; thus ensuring that worms are not exposed to anthelmintics needlessly.

Faecal worm egg counts (FECs) are used to determine which horses need (or don't need) treating. To many owners this may seem an unnecessary expense. However, recent work has shown that using FECs in this way helps reduce the overall cost of worming.

Hannah Lester, with colleagues at the Moredun Research Institute, and the Universities of Bristol, Liverpool and Edinburgh, monitored FECs at 3 monthly intervals over a nine month period. In all, 368 horses from 16 separate yards were involved in the study.

Horses with FECs greater than 200epg were treated, with pyrantel (in March and June) and ivermectin (in September). All horses received moxidectin/praziquantel in December.

The researchers compared the cost with that of a standard interval regime of two treatments with moxidectin and two of moxidectin and praziquantel - which is what had been common practice in the study population.

They  estimated the cost of the two approaches by using average prices for anthelmintic products and faecal egg counts that they obtained off the internet. Even allowing for the cost of faecal egg count reduction tests  (ie repeating the FEC after each treatment to check the anthelmintic had been effective)  they found that, over the year, there was an average saving per yard of £294.44.

They conclude: “these findings support the notion that targeting anthelmintic treatments at those individuals with strongyle FEC of 200epg or greater facilitates a reduction in selection pressure for anthelmintic resistance. Moreover, the results show that such a strategy has a high chance of reducing the financial cost compared with that associated with more traditional interval treatment regimens, and horse owners should, therefore, be discouraged from the view that it is cheaper to treat all horses prophylactically over time.”

Read more: equinescienceupdate.com

Emergency ventilation system developed

Respiratory or cardiovascular arrest in outdoor animals poses a huge challenge to veterinarians. Ventilation equipment is generally hard to operate and requires electricity and compressed air, and is not easily transportable. 

Anaesthesiologists at the University of Veterinary Medicine, Vienna (Vetmeduni Vienna) have developed an inexpensive device that can be used to ventilate large animals. They report that it is easy to transport and can save animal lives in emergencies.

In work recently published in  Equine Veterinary Education, the scientists confirm that their emergency ventilator is effective in horses. 

Yves Moens is Head of the Vetmeduni’s Clinical Unit of Anaesthesiology and Perioperative Intensive Care Medicine. He and his colleagues have long been concerned by the number of horses that die avoidable deaths because of the lack of a suitable ventilation device. The device they designed is similar to the bellows used to inflate air mattresses but has been adapted by the addition of a manually operated expiratory valve.

Although it can only provide 2.5 litres of air, the researchers believed that it would provide sufficient ventilation if the bellows were activated several times in quick succession. They tested this idea on five anaesthetised Haflinger horses during castration surgery and showed that gradual ventilation with the 2.5 litre pump was sufficient to keep the animals alive.

 “It improves the safety of large animals in the field, both during routine anaesthesia and in emergencies. It will also help veterinarians to provide emergency first aid in these circumstances and respect the guidelines for good practice", says Moens. “The respiratory pump is inexpensive and easy to use and will help veterinarians treat their patients in the field.”

Read more : equinescienceupdate.com

How accurate is thermography of horses’ legs?

Infrared thermography is increasingly being applied to investigate the cause of lameness in horses.  The equipment is easy to handle and the method is fast and safe, both for the animal and for the vet.  But is it accurate? 

Recent work by Simone Westermann at the University of Veterinary Medicine, Vienna shows that the technique is surprisingly tolerant of variation in the position of the equipment, i.e. how far from the horse and at what angle to the animal the infrared camera is held. 

In fact, the results were almost completely unaffected by 20° changes in camera angle and increases of up to 50 cm in the distance of the camera from the animal.  At a distance of 1m from the horse a 20° change in camera angle corresponds to about 35 cm.  This represents the effective horizontal tolerance in positioning of the camera.  As Westermann says, “vets should have little difficulty in remaining within this limit, so the method is applicable in practice”. 

Surprisingly, the results showed that horses’ left and right forelimbs show minor differences in temperature and Westermann cautions that “it might be important to take these into account before reaching a final diagnosis.”

The technique is thus reliable and robust, at least in terms of variation in where the camera is located. 

However, it turned out to be extremely sensitive to even very gentle drafts.  A wind speed of less than 1 m/s causes a drop in measured temperature of about 0.6°C, while winds of 1.3-2.6 m/s cause a drop of 1.5°C and winds of 3-4 m/s cause a drop of 2.1°C.  The discrepancies are more than sufficient to lead to a wrong diagnosis, although even the highest wind speed tested is hardly perceptible:  it would barely cause leaves on trees to move.

Westermann is keen to note the relevance of her work for vets who work on horses.  As she says, “It turns out that it is not too important to be sure that the camera is in exactly the correct position before taking measurements.  But it is essential to perform thermography on horses in a room that is completely free of draughts.  If you don’t, your diagnosis will be completely unreliable.”

More information : equinescienceupdate.com

Antibacterial action of honey

Wounds to the lower limbs of horses can prove challenging to manage.  Recently there has been a growing interest in the use of honey in such cases.

Not all honey is the same. Its antibacterial quality depends on the type of honey and the conditions under which it was harvested and processed. Most honey contains hydrogen peroxide, which has antibacterial properties. Some types of honey contain other active components. For example, manuka honey is believed to have antibacterial properties due to high concentrations of methylglyoxal, a compound usually found in only low quantities in other types of honey.

Manuka honey, produced by bees foraging on manuka plants (Leptospermum scoparium), native to Australia and New Zealand, has been the subject of considerable research. Honey from other sources is often used in practice, but there has been little research into how effective it is.

Researchers at the University of Glasgow have been examining various different types of shop-bought honey to determine if they were free from bacterial contamination and suitable for use on equine wounds. They also investigated the effect of various examples of uncontaminated honey on the growth of equine pathogens, and  found that, in laboratory tests, certain varieties of honey are able to inhibit bacterial growth even at very low concentrations.

They found that many commercial sources of honey were contaminated with bacteria. The most commonly identified contaminating organism was Bacillus spp. However, potentially pathogenic organisms  (Proteus and Enterobacteraceae) were identifed in two honey samples.

Uncontaminated honey samples were subjected to further investigation to assess their antibacterial properties. Eight of the eleven samples tested were effective against all 10 bacterial isolates at concentrations from 4 to 16%. Overall, medical grade Manuka honey and a locally produced heather honey performed best.

The researchers conclude that many honeys have antimicrobial properties, and may be effective in the treatment of wound infections. They note that the concentrations at which honey samples inhibited microbial growth were much lower than is likely to occur at the surface of an infected wound treated with honey.

However, they advise that “the use of shop-bought honey on wounds should be avoided, as contamination with potentially pathogenic microbes appears to be common. Honey sourced within the UK is as, and in some cases more, effective than medical grade honey sourced in New Zealand.”




Read more at equinescienceupdate.com/articles/aah.html

New laminitis research findings

Laminitis continues to be a significant welfare problem of horses and ponies, causing widespread suffering. Investigations into the underlying causes and disease processes involved in the condition are ongoing.

The benefits of  feeding a balanced diet alongside appropriate forage, grazing restriction and regular low intensity exercise whenever clinically possible in the management of laminitis prone horses and ponies have been highlighted by new research.

Four separate studies have shed new light on the possible role of grass fructan in the development of laminitis; the influence of water temperature when soaking hay to reduce the water-soluble carbohydrate content; a possible link between recurrent laminitis and reduced anti-inflammatory capacity, and the potential anti-inflammatory benefits of exercise.

Read more at equinescienceupdate.com

Controlling forage intake with hay nets

Horses have evolved to spend much of the day grazing. However, modern systems of horse management often restrict the time available. This may contribute to problems such as gastric ulceration and can result in behavioural problems.

Sometimes it is desirable to reduce the intake of roughage – either to make the horse's ration last longer, or to limit its overall intake.

Recent research from the University of Minnesota shows that using hay nets with smaller holes is effective for limiting the rate of roughage ingestion in horses.

Eight horse were involved in the study. They were were housed in individual box stalls, and fed hay off the floor (control treatment) or from hay nets with one of three different sized holes. The mesh size ranged from 15.2cm (large), to 4.4cm (medium) and 3.2cm (small).

During the trial period, hay was available for two four-hour periods each day.

Horses were allowed to become accustomed to each type of net for 2 days, before intake was recorded over three days. They then had two days of a wash out period during which they were as a group in an outdoor paddock.

The researchers found a significant difference in the rate of consumption between all treatment groups. Horses fed hay off the floor (control) consumed hay at the rate of 1.49kg/hr. Consumption of hay from hay nets was 1.33kg/hr, 1.11kg/hr, 0.88kg/hr for large, medium and small sized holes respectively.

They found no difference between the large mesh net and control for the amount of hay consumed (both 95%% of hay offered); but medium and small hay nets restricted hay intake to 89% and 72% respectively.

They conclude that their results demonstrate that the medium and small sized nets were effective in decreasing both rate and amount of forage consumed by adult horses.





More information at equinescienceupdate.com

Geldings behaving badly

Some horses display stallion-like behaviour despite appearing to have been castrated. Before embarking on exploratory abdominal surgery, how do you distinguish between those with a retained testis (cryptorchid or “rig”) and those that just behave badly?

One technique is to assess resting serum testosterone concentrations to identify horses with functioning testicular tissue.

Recently published research suggests that testosterone levels vary through the year and that this should be borne in mind when interpreting the results. Apparently, spring is the best time to use a serum testosterone assay to confirm the presence of a suspected retained testicle.

Researchers at the Gluck Equine Center, University of Kentucky, and the University of California Davis (UCD), examined data from blood samples submitted from suspected cryptorchids to the clinical endocrinology laboratory at UCD.

Serum from 179  suspected cryptorchids with serum testosterone greater than 100pg/ml were included in the study. In the UCD laboratory, testosterone levels lower than 50pg/ml are interpreted as evidence of absence of testicular tissue, while levels >100pg/ml confirm the presence of testicular tissue.

The research team found that serum testosterone concentration varied with season, being higher in spring than at other times of the year and lower in fall compared with summer and winter. Concentrations of testosterone reached a peak in May and were lowest in November.

They also noticed a significant association between age and testosterone concentration – with testosterone levels  being lower in cryptorchids less than two years old. Testosterone levels also declined  in horses older than nine years old.

They advise that borderline low testosterone concentrations found late in the year might still be positive – so a further test should be performed the following spring if the animal continues to display stallion-like behaviour.

Horsecare smartphone app released

US veterinarian Doug Thal has developed a new smartphone app to help horse owners with equine health matters.

The aim of the app is not to replace the owner's veterinarian, but rather to improve the quality of communication between horse owner and vet, for the benefit of the horse, he says.

Dr. Thal believes that horses receive the best care from well-educated owners that have a strong relationship with their veterinarian. “In fact, good communication with your veterinarian at the onset of equine healthcare problems will likely give you more options, cost you less in the long run, and enable you to do the best by your horse“.

Horse owners are increasingly turning to the internet for information about horse health, he says. Sometimes they do so instead of calling the veterinarian. Too often this approach results in inappropriate or delayed treatment, and may eventually cost more.

Dr Thal, an equine veterinarian for 20 years, states that the Horse Side Vet Guide™ (HSVG) provides easy access to essential equine healthcare information, powered by a constantly growing knowledge base. “The idea that a horse owner could make an observation and immediately access credible information about that observation- literally “horse side” – is the driving concept behind this product”.

All the text records in HSVG  are downloaded to the phone, and so are available at any time, even without access to the internet. Videos, providing short demonstrations of skills that might be needed in an emergency, as well as anatomy images and tables of normal values, are also stored in the quick reference section. However, in order to keep the size of the app reasonable, access to many other videos, media, and outside resources do require an internet connection.

Horse Side Vet Guide is currently available for iPhone and costs $4.99.  An Android version is being developed.

Further details are available from: http://horsesidevetguide.com/

Australian search for anthelmintic plants

Scientists in Western Australia have been investigating the anthelmintic effect of various plant extracts. In a laboratory investigation, they screened extracts of 37 plants to see if they inhibited the development of cyathostome eggs. The results have been published in the journal Veterinary Parasitology.

Extracts from seven species completely inhibited larval development. A further ten species  resulted in 90% inhibition compared with controls.

The research team then took the seven most effective plants extracts and tested how their inhibitory effects were affected by diluting them. The most effective plants,  Alectryon oleifolius and Duboisia hopwoodii, had IC50 (concentration that resulted in a 50% inhibition of development) of 47.2μg/ml and 30.9 μg/ml respectively. In comparison, ivermectin had an IC50 of 0.0000817μg/ml - considerably more effective.

Further tests showed that the effective constituents of many of the plant extracts were likely to be tannins. Tannins may limit palatability, so plants whose anthelmintic  properties rely on them may not be ideal candidates.

However, the researchers identified two plants, Acacia melanoxylon and Duboisia hopwoodii, with anthelmintic properties that were not reliant on tannins.

A further consideration was that the plants may contain other constituents with possible adverse effects.  For example,  D hopwoodii, the most effective plant tested in this study, contains alkaloids such as nicotine and nornicotine, which are toxic for animals.

The search for plants with anthelmintic properties for use in horses is still in the early stages. This study looked at the effect on larval stages, while any anthelmintic would have to be effective against adult worms. Further work also needs doing to identify the active    constituents of the plant that are responsible for the anthelmintic effect.

Eventually, it may be possible to isolate and concentrate the active compound. The researchers calculated that a daily intake of 120g of the anthelmintic plants would expose parasitic worms in the horse's colon to concentrations of 1400 μg/ml – the concentration used in the initial screening test. So it would be feasible exert control over the helminth population by grazing pasture containing the plant or including it in the diet as a feed additive.

They conclude: this study “suggests that Australian plants may be useful in forming part of an integrated parasite management program for horses, but more studies are needed before developing appropriate applications.”

www.equinescienceupdate.com

Road safety: does bright clothing help?

Wearing lights when out riding on roads could be safer than wearing reflective or fluorescent clothing according to research presented at the International Society of Equitation Science annual conference, July 2013.

Rose Scofield, from Duchy College, Cornwall, UK conducted a questionnaire-based study to investigate the value of bright reflective clothing in reducing the risk of ”near misses” between horses and vehicles.

She distributed questionaires through equine websites and forums, receiving 426 replies. Participants answered questions regarding the fluorescent or reflective equipment they and their horses were wearing, and whether they had been involved in near miss incidents.

Scofield grouped the responses according to whether the respondents had experienced a “near miss” with traffic or not. Then she examined whether or not they had been wearing reflective and /or fluorescent clothing.

Most riders who responded to the questionnaire did use some reflective equipment or clothing when riding on the road.

However, when she analysed the data, what she found was perhaps surprising. Reflective clothing, worn either by the rider or the horse, appeared to have no significant effect on the likelihood of a “near miss”.

60% of riders reported a near miss. But the proportion wearing reflective clothing on either the horse or rider was similar to that of those who did not experience a near miss.

However, significantly fewer near misses were reported by riders wearing lights.Of all the riders, 8.2% wore lights and did not experience a near miss, whereas 3.6% had a near miss despite wearing lights.

“This suggests that wearing lights should possibly be recommended when riding on the roads to enhance the safety of both rider and horse and contribute to the welfare of the leisure horse in particular.” 

“The use of lights by a rider and horse combination may prove a sound contribution to the welfare of the leisure horse in avoiding possible road accidents.”

For more details see:
Road safety: is there a relationship between ‘near misses’ and the use of rider and horse reflective/fluorescent equipment?
Rose M. Scofield, Hannah Savin, and Hayley Randle,
Proceedings of the International Society of Equitation Science (2013) p30