Medical Grade Honey prevents surgical site infections

Abdominal surgery is a major undertaking in horses, and not without significant risks to the patient. Colic operations, especially those that involve opening the gut wall, risk contaminating the wound with bacteria such that surgical site infection (SSI) is a potential complication.

Medical grade honey (MGH) has been used successfully to treat established infections in both humans and animals, and has been shown to improve wound healing of equine lacerations and significantly reduce infection rate.

 

Would the application of MGH help abdominal surgical wounds to heal?

 

A study by Gustafsson and colleagues investigated whether medical grade honey gel, applied on the linea alba during wound closure, would decrease the prevalence of incisional infections in horses undergoing colic surgery.

 

Figure 1: Example of intra-lesional application of
L-Mesitran Soft (MGH) following colic surgery

The linea alba is the fibrous band that runs along the midline of the belly, between the abdominal muscles.  Being composed of fibrous connective tissue it contains no major blood vessels making it a suitable site for incisions for abdominal surgery.

 

In this prospective randomized controlled trial, 108 horses that underwent colic surgery at Koret School of Veterinary Medicine in Israel were enrolled. Horses were randomized to control or treatment (MGH) group. In the treatment group, following closure of the linea alba, MGH gel (L-Mesitran Soft) was placed in the incision followed by routine closure of subcutaneous tissue and skin (Figure 1).

 

Horses were excluded from the study if they needed a second abdominal surgery (n=4) or did not survive for at least two weeks post-operatively (n=15).

 

The clinicians report that a single intra-incisional application of MGH gel strongly reduced incisional infection rate from 32.5% (13/40) in the control group to 8.2% (4/49) in the treatment group (p=0.02).

 

No adverse reactions were observed with the subcutaneous application of MGH after colic surgery.

 

A full report is published in the Equine Veterinary Journal.

 

The authors conclude that intra-incisional application of MGH gel on the linea alba is a simple and rapid procedure that was safe and did not result in any adverse effects. A single local prophylactic treatment with MGH in the abdominal incision during surgery significantly decreased the prevalence of incisional infections in horses undergoing colic surgery. They suggest that more research is necessary to explore this promising approach in indications outside the equine colic field, e.g., in surgeries with a high risk of SSIs.

 

For more details, see:

 

Intra‐incisional medical grade honey decreases the prevalence of incisional infection in horses undergoing colic surgery: a prospective randomised controlled study.

Gustafsson, K., Tatz, A.J., Slavin, R.A., Sutton, G.A., Dahan, R., Abu Ahmad, W. and Kelmer, G.

Equine Veterinary Journal (2020)

https://doi.org/10.1111/evj.13407

 

An interview with Dr Gustafsson is available on YouTube:

https://youtu.be/q2yf7a0f5Ds

Special interest webinars precede National Equine Forum

The National Equine Forum (NEF) will be delivered in a virtual format in 2021. The main Forum, on

Thursday 4^th March, will be preceded by two special interest webinars, to be held in January.

The first webinar “Just in Time – Using Science to Save our Breeds”, (7pm Wednesday 13th January 2021), will be delivered by industry leaders, with opportunities for discussion and questions from the audience.

Chaired by Prof Tim Morris, the webinar will include speakers: Tullis Matson, Simon Cooper, Paul Flynn and Andy Dell.

They will look at the magnitude of the decline of the UK’s native breeds and how their future can be safeguarded. The impact of the extinction vortex on the natural world and how it applies to equine breeds will be covered and the challenging situation of inbreeding in Thoroughbreds explored.

The advantages of DNA analysis will be debated, to show how science can provide breed societies and breeders with support to guide decisions that can increase effective populations. This will be endorsed with a case study to show proof of concept that breeds in decline have a chance to be saved when genomics and kinship analysis are utilised.

The second webinar “Great Weight Debate (equine)”, (7pm Wednesday 27th January 2021), will take a practical look at different perspectives on equine weight management, from across the equestrian sector, including the views of a horse owner, livery yard owner and coach, an equine welfare officer, an equine vet, a nutritionist and a competition judge.

The panel of speakers will aim to identify what is preventing owners/carers from managing horse weight effectively, despite many previous and ongoing attempts from industry to effect change. They will also explore how any obstacles may be overcome and the discussions will be supported by a human behaviour change researcher.

The 29th National Equine Forum, themed Positivity and Progress will be held on Thursday 4th March 2021. The morning session will provide critical insight to welfare, trade and biosecurity, followed by positive innovations for the sector, borne from Covid-19. The afternoon session will provide updates from the two special interest webinars, a session on how new technology is helping riders and a revisit to access and accidents, with amendments to The Highway Code.

Tickets are priced at £5.00 for each webinar and £10.00 for the Forum itself and there is no booking fee. Webinar tickets are available now. NEF tickets will be available in January.

For more details, see:

https://www.nationalequineforum.com/forum-2021/

CT best for identifying foot foreign bodies

 Puncture wounds at the coronary band or in the sole are not uncommon in horses.  Although the site of

the injury may be obvious, it is often less clear whether any foreign material remains buried in the wound.

Researchers at the Philip Leverhulme Equine Hospital, University of Liverpool, conducted a study to compare the value of different imaging techniques for identifying foreign bodies in horses’ feet.

Nadine Ogden and colleagues assessed the ability of three equine veterinarians, experienced in advanced imaging interpretation, to identify foreign bodies buried in the cadaver specimens of horses’ feet. They used five different materials: slate, glass, dry wood, soaked wood and plastic. Each foot had two different foreign bodies implanted, at the coronary band and in the sole.

Computed tomography (CT), magnetic resonance imaging (MRI) and digital radiography (DR) were used to obtain images, which were then examined by the clinicians.

The researchers found little variation between the clinicians studying the images. CT was the most useful imaging modality, having a higher visibility score, sensitivity/specificity, and interrater agreement for detection of all materials; particularly slate, glass, and dry wood, compared to the other imaging modalities.

They found that foreign bodies were often visible on MRI, although the images were generally not clear enough to determine the type of material involved. They also  found that even relatively large foreign bodies consisting of plastic or wood were not detectable on DR.

The work is published in Veterinary Radiology and Ultrasound. The authors comment that although it is not usually necessary to identify the specific material involved, it is important to select an appropriate imaging technique to detect the suspected foreign body.

They suggest that, in cases with negative findings on MRI and DR, where there is a suspected foreign body within the hoof, particularly in cases where plastic or wood fencing or glass materials have been found at the scene of injury, CT examination should be considered.

 

For more details, see:

CT more accurately detects foreign bodies within the equine foot than MRI or digital radiography

Nadine K E Ogden, Peter I Milner, John D Stack, Alison M Talbot

Vet Radiol Ultrasound (2020)

doi: 10.1111/vru.12944

Temperature monitoring with microchips

 Horses undertaking strenuous or prolonged exercise in hot and humid environments may produce heat

more quickly than they can lose it, putting them at risk of postexercise exertional heat illness.

 Investigations into heat production and cooling require a way to monitor body temperature. Ideally this should be easy and safe to do in an excitable horse after exercise.

 In practice, reading the rectal temperature with a thermometer is a common starting point – but may not be ideal, particularly if repeated readings in excited horses are required. The “gold standard” for monitoring is to record the central venous temperature (CVT) using a thermocouple introduced into the jugular vein.  

 Temperature sensitive microchips (percutaneous thermal sensing microchip (PTSM)) can be used to measure tissue temperature in a non-invasive manner. But does the site of implantation affect the accuracy?

 Researchers at the School of Agriculture and Food Sciences, and the School of Veterinary Science, at the University of Queensland, investigated the use of PTSMs for monitoring temperature in horses after strenuous exercise.

 Microchips used for identification purposes are generally implanted in the nuchal ligament in the neck. In a preliminary study, the research team found that temperature recorded by a PTSM chip implanted in the nuchal ligament correlated poorly with the CVT during and immediately after exercise. This was probably due to the poor vascular supply of the nuchal ligament compared to other muscles, they suggest.

 The researchers also found poor correlation between rectal temperature and CVT immediately after exercise and for at least 8 min after exercise. Because of this, and for safety reasons, they suggest that rectal temperature should not be used to measure temperature after exercise.

 Of the implantation sites they tested, they found that the most reliable was the pectoral muscles, which closely matched the CVT, followed by the gluteal muscles and the splenius muscle.

 They conclude that PTSMs provide a simple, safe, quick, accurate, and non-invasive way of measuring body temperature of horses immediately after high-speed exercise. They recommend further studies to validate this method under field conditions and in equine athletes working in extreme environments and intensive activity in various equestrian sports.

 

For more details, see:

 The Use of Percutaneous Thermal Sensing Microchips for Body Temperature Measurements in Horses Prior to, during and after Treadmill Exercise

Hyungsuk Kang, Rebeka R Zsoldos, Solomon M Woldeyohannes, John B Gaughan, Albert Sole Guitart 

Animals (Basel) (2020) ; 10(12):E2274.

doi: 10.3390/ani10122274

Does pain affect Cushing’s test?

 

Research suggests that mild to moderate pain does not interfere with the hormone tests used to diagnose PPID.

A diagnosis of PPID (pituitary pars intermedia dysfunction, also known as Cushing’s Disease) can be supported by assessing the ACTH levels at rest and by measuring the response to a TRH (thyrotropin-releasing hormone) stimulation test.

In PPID, the over-active pituitary gland secretes higher than normal amounts of ACTH and other hormones. But pain itself may also cause increased ACTH levels.

Many horses with PPID eventually develop laminitis. Indeed, many are first suspected of having PPID when they show signs of laminitis. 

Does the pain associated with laminitis affect the value of ACTH as a diagnostic test for PPID? Heidrun Gehlen and colleagues at the Equine Clinic, and the Institute of Veterinary Epidemiology, Freie University Berlin, Germany conducted a study to investigate.

Fifteen horses being treated at the Equine Clinic for colic, laminitis or orthopaedic conditions with low to moderate intensity pain were included in the study. Horses were aged less than15 years, with no signs of PPID.

Samples were collected for basal ACTH concentrations, and a TRH-stimulation test was performed.

The intensity of pain was assessed using a composite, multifactorial pain scale. Each horse served as its own control as it was re-tested after the pain had subsided.

The researchers found no significant difference in the ACTH concentration in horses with pain and the controls, between different pain intensities or between disease groups.

They conclude that “measuring the basal ACTH concentration and performing the TRH stimulation test for the diagnosis of PPID seem to be possible in horses with a treated low to moderate pain condition.”

They suggest that “measurement of ACTH and the performance of the TRH stimulation test for PPID diagnostics can, therefore, be performed on horses in pain as long as they are not suffering from massive pain or showing a significantly disturbed general condition.”

For more details, see:

Can Endocrine Dysfunction Be Reliably Tested in Aged Horses That Are Experiencing Pain?

Heidrun Gehlen, Nina Jaburg, Roswitha Merle, and Judith Winter

Animals (Basel). (2020); 10(8): 1426.

doi:10.3390/ani10081426

Understanding ridden horse behaviour – Free webinar from World Horse Welfare

In this free webinar, Dr Sue Dyson shares some of the research that has looked at signs and behaviours horses display when they are experiencing pain, many of which can be very subtle.

She also discusses the sensitive issue of the impact of rider size on equine performance. Sue explains the influence that riders can have on their horses and what we, as owners, can do to ensure we are able to assess and recognise signs of discomfort and pain as soon as possible.

Webinar: Recognising pain in our ridden horses and the impact of rider weight - YouTube

Investigating possible melanoma therapy

 Betulinic acid shows promise as a possible topical treatment for Equine malignant melanoma (EMM) according to recent laboratory research.

Melanomas are common in grey horses affecting up to 80% of them by the time they are 15 years old. Current treatment options are limited, and often not very successful.

Lisa A. Weber, Jessica Meißner of the Foundation University of Veterinary Medicine Hannover and colleagues investigated the effects of the betulinic acid (BA) on equine melanoma cells and equine dermal fibroblasts in cell culture. They also looked at its spread through isolated equine skin.

 They found that betulinic acid inhibited cell proliferation and reduced cell viability of both equine melanoma cells and fibroblasts.  However, the results did not show a selective effect on cancer cells compared with normal cells.

In isolated skin preparations, they found that BA could penetrate the stratum corneum and spread through the epidermal and dermal layers. 

The research team conclude that “the potent percutaneous permeation of BA in normal skin together with its anticancer effects on equine melanoma cells suggest that this substance may exert antitumoral effects in vivo.”

They suggest that their findings support the use of BA in further preclinical and clinical trials for topical EMM treatment.

For more details, see:

Betulinic acid shows anticancer activity against equine melanoma cells and permeates isolated equine skin in vitro.

Lisa A. Weber, Jessica Meißner, Julien Delarocque, Jutta Kalbitz, Karsten Feige, Manfred Kietzmann, Anne Michaelis, Reinhard Paschke, Julia Michael, Barbara Pratscher, and Jessika-M. V. Cavalleri

BMC Vet Res. (2020); 16: 44.

doi: 10.1186/s12917-020-2262-5

Looking inside the horse’s gut

 A wireless endoscopy capsule can be used to inspect the inside of the horse’s gastro-intestinal tract.

The “ALICAM system” capsule is 11mm in diameter and 33mm long. It contains 4 micro-cameras, mounted at 90° to provide a 360°panoramic view. The cameras are activated by movement  (this helps prolong the battery life and so increase the length of the digestive tract that can be imaged.) When activated, the cameras record images at the rate of 20 /second and store them on the capsule’s internal memory chip.

Images are only available for inspection once the capsule has passed through the digestive tract and has been retrieved from the manure (using radiography).

Researchers at the University of Calgary have been studying the technique.

Five adult horses with no signs or history of gastro-intestinal disease were included in the study. The researchers assessed different protocols for preparing the horses and found that the one giving most useful images was to starve the horse for 24 hours before introducing the capsule.

Satisfactory images were obtained of the pylorus, major duodenal papilla, individual villi, and ileocecal junction. Visualization of large intestinal mucosa was poor.

Among the abnormalities identified on the images were mucosal erosion, ulceration and haemorrhage, areas of thickened mucosa, and evidence of parasitism.

On average, it took 6.5 days from introduction for the capsule to be retrieved in the manure.

The researchers conclude: “this novel endoscopic capsule appears safe, practical, and non-invasive in horses; however, variability in capsule excretion time must be taken into account for clinical application.”

For more details, see:

A wireless endoscopy capsule suitable for imaging of the equine stomach and small intestine

Mei Steinmann, Rebecca J. Bezugley, Stephanie L. Bond, Jill S. Pomrantz, and Renaud Léguillette

J Vet Intern Med. (2020) 34(4): 1622–1630.

doi: 10.1111/jvim.15825

Response to changing meal times

 

How do horses react to changes in their routine? It may come as no surprise that horses notice when their meal is late.

Research by Manja Zupan and colleagues at the University of Ljubljana, Slovenia examined the effect of altering the morning feeding time on eight horses kept in individual boxes.

The study extended over ten weeks. During that time, the morning feed (normally at six o’clock) was given an hour early on Thursdays, and an hour later on Saturdays.

The researchers monitored the effect of the change on the horses’ behaviour.

They found that, when horses were fed early, they spent less time eating hay, more time resting and less often took a look toward the door.

When feeding was delayed, the horses more often performed pawing the ground, kicking, comfort behaviour (such as grooming), and looking toward the door.

They conclude “Our results indicate that deviations from the regular feeding schedule affected the behaviour of horses and compromised their temporal predictability.”

For more details, see:

The Effect of an Irregular Feeding Schedule on Equine Behavior

Manja Zupan, Ivan Štuhec, Dušanka Jordan

J Appl Anim Welf Sci (2020) ;23:156-163.

doi: 10.1080/10888705.2019.1663734

Youtube channel highlights equine behaviour

Three scientists with an interest in equine behaviour have joined forces to launch a YouTube channel called “Equine Science Talk International” dedicated to explaining the discoveries of equine research and what they mean for riders, trainers, and researchers.

Professor Konstanze Krüger of Nurtingen-Geisslingen University is Germany’s first Professor of Equine Management. Her main areas of research are the behaviour of wild living horses, and social learning and social cognition in horses.

She is joined by Dr Laureen Esch, a veterinary surgeon, whose doctoral thesis was on equine behaviour, now specialising in equine dentistry, and Dr Isabell Marr, an independent horse trainer for western riding, who qualified as a stable manager before moving on to study animal biology and biomedical sciences.

Translations are provided by Kate Farmer, a journalist, horse trainer and independent equine behaviour researcher. The videos are available in English and German.

Topics covered include: How do horses interpret the world differently on their left and right sides? Why do some horses become aggressive? The key to successful training, and the meaning of positive and negative reinforcement.

For more details, see:

https://www.youtube.com/channel/UCzNBXlzMAeu83481wEOI6Pg/      (English)

https://www.youtube.com/channel/UC0s5sXLk1W28r_Y9CLswRhw         (German)

Obesity on podcast menu

 

Nutrition, in particular the problem of obesity, is the subject of the latest episode of the Morris Animal
Foundation’s “Fresh Scoop” podcast, which is now available.

Host Dr Kelly Diehl speaks with Dr Patricia Harris who is Head of the Equine Studies Group at the Waltham Petcare Science Institute. She also is on the board of the American Academy of Veterinary Nutrition.

Dr. Harris discusses the equine obesity epidemic and the value of regularly assessing a horse’s body condition. She also offers advice for owners on how to help their horse lose weight as well as strategies to prevent obesity.

Obesity is a globally recognized welfare issue in horses, affecting about a third of the equine population. It is associated with an increased risk of health issues including laminitis and colic, and carries direct negative consequences on horses’ skeletal and immune systems.

“Fresh Scoop” is a monthly podcast from the Morris Animal Foundation aimed practicing veterinarians, veterinary technicians or students, as well as animal-loving science enthusiasts.

Episodes are available on iTunes, Spotify, Google Play Music and Stitcher, as well as the Foundation’s podcast page.

 For more details, see:

https://www.morrisanimalfoundation.org/article/episode-26-equine-nutrition-podcast

US owners sought for horse ageing survey

 Owners are invited to help in a study into the ageing process in horses.

University of Kentucky researchers are looking for owners of horses that live in the USA to take part in an online survey. The survey focuses on horses and ponies aged 15yrs and over, although owners of younger horses can also take part.

Your responses and opinions will greatly help the research team understand more about the health status and management of horses aged 15+ years, and how the aging process in horses is perceived.

Click below to go to the survey:

https://uky.az1.qualtrics.com/jfe/form/SV_bxAeIRSVM6gAOvb

Importing anthelmintic resistance

 A salutary reminder of the danger of importing anthelmintic resistance is given in a recent report.

Martin K Nielsen, Schlaikjer Professor of Equine Infectious Disease at the M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, and others, describe a case of macrocyclic lactone (ML) resistance in a group of Thoroughbred yearlings imported from Ireland to the US.

The findings emphasise that the global movement of horses has the potential to quickly spread ML-resistant parasites around the world.

Anthelmintic resistance to benzimidazole and pyrantel is widespread among the cyathostomins (small redworms). The macrocyclic lactones (such as ivermectin and moxidectin) are generally effective, but there have been occasional reports of resistance.

Thoroughbred yearlings imported from Ireland to the US were found to have evidence of ML resistance when faecal egg count reduction (FECR) tests were carried out. The three batches of imported yearlings had FECR test results ranging from 93.5% to 70.5%. (FECR test is the standard method of assessing resistance in cyathostomins. If the FEC is not reduced by 95% or more after treatment with a macrocyclic lactone such as ivermectin, that is interpreted as evidence of resistance.) When the test was repeated after a further ivermectin treatment in two of the groups the FECR results were even lower.

In contrast, three groups of US bred yearlings had FECR test results of 99-100% after treatment with ivermectin.

Full details of the study are published in the International Journal of Drugs and Drug Resistance. The authors point out that “this case clearly illustrates the importance of quality routine FECR testing, which immediately informed the farm manager of the situation and allowed him to react in time by keeping the populations completely separate, thereby avoiding an introduction of the resistant parasites to the entire facility.”

They strongly recommend that equine operations heed this threat to equine health, and routinely monitor anthelmintic efficacy on a yearly basis. 

For more details, see:

Importation of macrocyclic lactone resistant cyathostomins on a US thoroughbred farm
M K Nielsen, M Banahan, R M Kaplan
Int J Parasitol Drugs Drug Resist (2020)14:99-104.
doi: 10.1016/j.ijpddr.2020.09.004

 Moody mares may benefit from ovariectomy to alter their behaviour and rideability, according to a recent report.

Some mares are difficult to manage and perform poorly as a result. They may be uncooperative or aggressive when handled on the ground. They may kick, buck or rear when ridden or may be aggressive towards other horses.

Unwanted behaviour may result from pain from orthopaedic or other sources. Sometimes it is related to the mare coming in season, in which case it may be improved by suppressing the oestrus cycle.

Some ovarian tumours, although less common, may produce similar effects. Treatment of these cases is likely to involve removing the affected ovary (ovariectomy).

But sometimes there is no obvious explanation for the unwanted behaviour. Would removing both ovaries (bilateral ovariectomy) help?

A study by Daniel Taasti Melgaard, of the Horsholm Equine Clinic, Fredensborg, Denmarkand colleagues looked at whether removing the ovaries from mares with unexplained unwanted behaviour improved the mare’s behaviour or rideability.

Twenty-eight mares underwent surgical removal of both ovaries once the clinicians had ruled out painful causes and after the mares had not responded to a trial period of hormone therapy to suppress oestrus behaviour.

Owners reported that, after bilateral ovariectomy, 80% (8/10) of mares with normal ovaries and 57% (8/14) of mares with ovarian neoplasia were easier to ride. Behaviour was reported to be better in 40% (4/10) of mares with normal ovaries, and in 43% (6/14) of mares with ovarian neoplasia.

A full, open access, report is published in the journal Animals.

The authors emphasise the importance of a thorough diagnostic work up to rule out other conditions, such as orthopaedic, alimentary, vaginal or uterine pathology, before considering ovariectomy for unwanted behaviour.

They suggest that, despite the significant improvement observed in the present study, further research is necessary to confirm whether mares with unwanted behaviour not obviously related to the oestrus cycle and to painful conditions may benefit from ovariectomy to alter their behaviour and rideability.

“In conclusion”, they write, “a significant improvement was observed in rideability and behaviour post- ovariectomy, but no statistical difference in improvement after ovariectomy between mares with ovarian neoplasia and mares with histopathologic normal ovaries was observed. The results suggest that mares with and without neoplasia can equally benefit from ovariectomy to improve behaviour and rideability.”

For more details, see:

Moody Mares - Is Ovariectomy a Solution?
Daniel Taasti Melgaard, Trine Stokbro Korsgaard, Martin Soendergaard Thoefner, Morten Roenn Petersen, Hanne Gervi Pedersen.
Animals (Basel) (2020)
doi: 10.3390/ani10071210

Blankets and food intake

Horses wearing a blanket or rug in the winter ate less hay than did their non-blanketed neighbours, a recent study found.

Healthy horses maintain their body temperature within a narrow range (98.5°F to 101°F / 36.9°C to 38.3°C) despite a wide variation in environmental conditions.

In cold weather they use various physiological and behavioural methods to conserve body heat, such as piloerection, shivering, facing away from the wind. Eating roughage generates heat and so helps maintain body temperature.

Research by Michelle De Boer and others at the University of Wisconsin–River Falls, assessed the effect of wearing a blanket on horses’ feed intake, body weight (BW), and body condition scores (BCSs). A report of the work is published in the Journal of Equine Veterinary Science,

The project was carried out over the winter of 2019-2020, when environmental temperatures typically average about -10°C.

Sixteen adult horses were recruited to the study: eight wore a medium weight blanket; the others did not. All horses lived in a dry lot and were fed grass-legume hay ad lib. The researchers recorded hay intake and monitored horses’ body weight and condition score before during and at the end of the study.

Horses without blankets maintained their body weight and condition score despite the cold weather.

The researchers found that the average estimated dry matter intake (DMI) was lower for blanketed horses (2.31% BW) than for non-blanketed ones (2.51% BW) – equivalent to an average of 1kg daily.

The results suggest horses wearing blankets conserve energy leading to decreased feed intake. Horse owners may save (a small amount of) money from reduced hay and labour costs when using a blanket.

The researchers emphasised that, when blanketing a horse, it is important to monitor them regularly to evaluate health, welfare, and BW and condition.

For more details, see:

Dry Matter Intake, Body Weight, and Body Condition Scores of Blanketed and Nonblanketed Horses in the Upper Midwest
Michelle De Boer, Alexandra Konop, Bailey Fisher, Krishona Martinson
Journal of Equine Veterinary Science (2020) vol 94, 103239 

https://doi.org/10.1016/j.jevs.2020.103239

Challenge of identifying asymptomatic strangles carriers

A recent study found that blood tests (serology) alone did not effectively distinguish asymptomatic strangles carriers from non-carriers.

Symptomless carriers present the biggest risk of introducing strangles to a previously unaffected population.

Most horses throw off the infection, caused by Streptococcus equi, within a few months of an outbreak. But some remain infectious. These carriers usually retain the infection in the guttural pouches at the back of the throat. They carry and excrete the bacteria without showing any sign of disease.

The best way to identify carriers is by culturing a series of swabs from the nasopharynx, or by examining a guttural pouch wash for Streptococcus equi DNA (a qPCR test). Such methods can be time consuming and costly.

Serological testing for S. equi antibodies has become popular in clinical practice to screen for strangles carriers. However, a growing body of research suggests that this method cannot be relied on.

A study by John Pringle and colleagues at the Swedish University of Agricultural Sciences, Uppsala, and the Equine Veterinary Clinic, Destedt, Germany, followed three groups of horses for between six months and two years after strangles outbreaks.  A full report of the work is published in the Journal of Veterinary Internal Medicine.

Carriers were defined as horses from which S. equi could be cultured, or S. equi DNA could be found on qPCR test, in samples from the nasopharynx or guttural pouches.

The researchers compared the clinical appearance, guttural pouch endoscopy, and inflammatory markers between carriers and non-carriers and found no real difference between the two groups. Neither did serology distinguish carriers from non-carriers.

“Of particular concern however was that two of the culture positive carriers 14 months after outbreak A, and the culture positive mare associated with outbreak A tested seronegative,” they report, “suggesting lack of persistence of seropositivity despite carriage of viable S. equi.”

They conclude: “Silent carriers of S. equi do not differ clinically or on markers of inflammation to their noncarrier herd‐mates. Moreover, serology alone will not distinguish carriers in comingled horses.”

For more details, see the Open Access article:

Markers of long term silent carriers of Streptococcus equi ssp. equi in horses
John Pringle, Monica Venner, Lisa Tscheschlok , Andrew S. Waller, Miia Riihimäki
Journal of Veterinary Internal Medicine
https://doi.org/10.1111/jvim.15939

What does “equitation science” mean to you?

 

Do you have your own horse, ride regularly or work in the equestrian industry? Dr Jane Williams, Dr Hayley Randle and Kate Fenner would like to hear from you.

They are interested in knowing more about your understanding and perception of equitation science and if/how it influences you.

If you have 5 minutes spare, they would be very grateful if you could complete their survey.

https://www.surveymonkey.co.uk/r/Equitation_Science

Equine Pain and Welfare App

 

How do you tell if your horse is in pain? You may “know” straight away that something is not right.

But people are not always able to interpret correctly the signs of pain displayed by horses and donkeys. After all, having evolved as prey animals, it is in their interest not to show signs of pain that might bring them to the attention of a predator looking for its next meal.

Dr Thijs van Loon and colleagues at the faculty of veterinary medicine of Utrecht University have been researching pain recognition in horses. Their work resulted in the development of composite pain scales that the researchers showed could be used to accurately measure pain in horses as well as donkeys.

Such scales generally comprise several indicators, including behavoural parameters (such as lying down, rolling and scratching), physiological variables, (heart rate and respiratory rate), and facial expressions, (positioning and movement of the ears, nostrils, eyelids, and mouth).

These signs are particularly useful for detecting pain or discomfort in patients suffering from colic, facial or orthopaedic pain.

Assessment methods developed in the studies have now been distilled into an App, the Equine Pain and Welfare App (EPWA), which provides a reliable way to recognise pain and calculate a pain score.

The App guides the user through a two-minute pain assessment based on facial expressions or a five-minute assessment of body language. Users are advised to contact a veterinarian for horses scoring above five on a scale of 0 to 18.

The scores can be stored on the App, allowing users to monitor changes to a horse's welfare over time.

Other features of the App include a diary where you can keep track of how much your horse eats, the amount of exercise he does and any medication he has.

There is also a handy check of whether your horse is showing signs compatible with PPID (Cushings disease).

The research team say that the current version of EPWA has been downloaded thousands of times already and is helping owners to recognise pain and discomfort in their horses and donkeys, thereby improving their health and welfare.

They are now working to develop a version specifically aimed at working donkeys in rural communities and developing countries. The Working Equine Pain and Welfare App ('W-EPWA') will be provided free of charge in order to encourage its widespread use and improve the health and welfare of horses and donkeys worldwide.

EPWA is a joint initiative of the Faculty of Veterinary Medicine at Utrecht University and Stichting de Paardenkamp. It is available (free) from the usual app stores.

For more details, see:

https://www.epwa.nl

Flying horses: Developing guidelines for health and well-being

 A new study will investigate how to optimise the welfare of horses being transported by air. Horses are among the most travelled domestic species, and although there has been plenty of research into road travel, less is known about how they cope with travelling by air.

Dr Barbara Padalino, associate professor at the University of Bologna in Italy, is leading research into how horses are managed when travelling by plane. The project aims to identify factors that affect the risk of health or behaviour problems, and is funded by the Morris Animal Foundation.

Findings will be used to develop guidelines to optimise the health and welfare for horses traveling by plane, and may result in revised protocols for organisations such as the International Air Transport Association (IATA)

In a statement issued by the Morris Animal Foundation, Dr Padalino said: “Right now, IATA’s guidelines are largely based on the experience of industry professionals with little scientific evidence or validation. They focus on air safety and cargo requirements, with limited provisions for the welfare needs of horses. We need to update flight regulations using evidence collected in a scientific way.”

In this prospective study, researchers will work with horse owners, air cargo operators, flight grooms and veterinarians to determine the incidence of health and behavioural problems observed in overseas air-transported horses. Dr. Padalino’s team will train the stakeholders on how to fill out surveys with questions tailored to their respective roles. For instance, veterinarians will be asked about horses’ body conditions, heart rates and alertness, among other observations, before, during and after a journey.

Data will be collected from departure to five days post-arrival, which is when symptoms usually become apparent.

Dr. Padalino hopes to gather data on about 2,000 horses flying on routes between Europe, the United States, South Africa, Japan, Hong Kong, New Zealand and Australia. She hypothesizes that not only is air transport a mental and physical stressor for horses, but that horses with different temperaments or with less transport experience or training will have a higher incidence of transport-related health problems.

“Researchers and air cargo service providers have rarely had the opportunity to collaborate like this, which has left gaps in our knowledge of the consequences of horses’ movements by air,” said Dr. Padalino. “By working together, I believe we can develop evidence-based guidelines to improve the lives of horses that are flown worldwide.”

Morris Animal Foundation, a leader in advancing animal health, has awarded nearly $1 million in large animal health research grants, supporting 14 projects. Other horse-related research supported this year includes: a study of the variation of the gut microbiome as it relates to the health and wellness in group of feral horses; an investigation into a novel treatment for ocular surface squamous neoplasia; and a study into whether genetic variants can help identify horses at high risk of developing potentially fatal cardiac arrhythmias.

“We were very impressed with the quality of proposals received this year and we believe they have the potential to drive significant improvements in the well-being of our equine companions,” said Dr. Janet Patterson-Kane, Morris Animal Foundation Chief Scientific Officer. “We are very proud to support these enterprising researchers in their endeavours.”

For more details, see:

https://www.morrisanimalfoundation.org/articles?animal_type=6&topic=All

Possible new route of sedation administration

Detomidine has proved to be a useful sedative for horses, facilitating routine tasks like farriery, dentistry and clipping, as well as more involved veterinary procedures. Although it can be administered by injection, the use of a gel formulation applied under the tongue and absorbed through the mucous membranes has become popular.

Some horses may resent application of the product to the mouth. Gel that is swallowed is less effective as it may be broken down by enzymes in the intestinal tract and metabolised in the liver before inducing sedation.

Reza Seddighi and colleagues at the University of Tennessee, have been evaluating the sedative effects of administering the gel onto the mucous membrane of the vagina. 

Six healthy adult mares were included in a randomised, crossover study. 

Each mare was studied on two occasions a week apart. On one occasion each mare received detomidine (10µg/kg) by intravenous injection and on the other by applying the gel intra-vaginally (40µg/kg – the manufacturer’s recommended dose for sub-lingual administration).

The research team monitored the effects – including degree of sedation, distance of muzzle from the floor, ataxia and heart rate. They also collected blood samples at regular intervals to assess the concentration of detomidine and its metabolites.

They found that sedation lasted longer and was deeper when the detomidine was administered intra-vaginally compared with intravenously. 

They conclude that detomidine gel administered intravaginally is a viable method for detomidine gel delivery in mares. They add that further work needs to be done to determine whether changes related to the mare’s oestrus cycle might influence the absorption.

For more details, see:

Evaluation of the sedative effects and pharmacokinetics of detomidine gel administered intravaginally to horses.

Seddighi R, Knych HK, Cox SK, Sun X, Moorhead KA, Doherty TJ.

Vet Anaesth Analg. 2019 Jun 17. pii: S1467-2987(19)30161-8. 

https://doi.org/10.1016/j.vaa.2019.06.002

Saddle Research Trust Conference tickets now available.

Tickets are now on sale for the Saddle Research Trust (SRT) 4th International Conference ‘Welfare and

Performance of the Ridden Horse: The Future’, to be held at Nottingham University (De Vere Conference Centre) on Saturday 11th, December 2021.

Speakers include renowned researchers and long-time SRT supporters, Prof. Hilary Clayton and Dr. Sue Dyson. There will also be some exciting new faces including Dr. Felipe Bragança, who is at the forefront of the new generation of quantitative gait analysis researchers and developers.

Delegates can attend in person or via Livestream, with everyone benefiting not only from the latest research updates, but also the interactive Q&As and polls throughout the course of the day.

SRT Director, Dr. Anne Bondi, said: “The SRT is committed to research, education and dissemination of knowledge, and continues to deliver on its aims throughout these challenging times. Whilst we look forward to welcoming everybody to the conference in person, we are delighted to be offering such a comprehensive livestream contingency package to all our delegates worldwide.’’

For more information, and to buy your tickets, see:

https://www.saddleresearchtrust.com/saddle-research-trust-4th-international-conference-save-the-date/

Cloned colt brings hope of genetic diversity to endangered species

 The birth has been announced of the first successfully cloned Przewalski’s horse.  Born at Timber Creek Veterinary Hospital, in Texas, the colt was produced using DNA preserved for 40 years in the “Frozen Zoo” at San Diego Zoo.

The Frozen Zoo® houses genetic material from thousands of dead animals, safely stored in liquid nitrogen, in the hope that, one day, it might be possible to use it to help save endangered species, or even reintroduce extinct ones.

“A central tenet of the Frozen Zoo®, when it was established by Dr. Kurt Benirschke, was that it would be used for purposes not possible at the time.” explains Oliver Ryder, Ph.D., director of genetics at San Diego Zoo Global.

“Now, the living cells in the Frozen Zoo are contributing to reversing losses of genetic diversity and contributing to population sustainability. The cells of hundreds of Przewalski’s horses reside in the Frozen Zoo, and form the basis for new opportunities in applying scientific research to preserve species into the future.”

By the end of the 1960s, the Przewalski horse, considered to be the last truly wild horse, was extinct in the wild. Some individuals survived in zoos, and an intensive breeding program managed to revive the species, allowing horses to be reintroduced to their natural habitat in the 1990s.

Although there are now over 700 animals roaming the Mongolian steppes, almost all are related to just 12 individuals. This loss of genetic diversity is a cause for concern; maintaining genetic variation is likely to be an important part of ensuring the species’ survival in the future.

The new foal, named Kurt after Dr Benirschke, represents the first time this species has been cloned. He was cloned from a cell line stored in the Frozen Zoo since 1980. That stallion was born in 1975 in the UK, was transferred to the US in 1978 and lived until 1998.

More than just an individual horse, Kurt represents a major milestone for Przewalski’s horse conservation, and it is hoped that in due course he will increase the gene pool of the current population of Przewalski’s horses.

Once he is older, the foal will be moved to the San Diego Zoo Safari Park to be integrated into a breeding herd.

“This colt is expected to be one of the most genetically important individuals of his species,” said Bob Wiese Ph.D., chief life sciences officer at San Diego Zoo Global.  “We are hopeful that he will bring back genetic variation important for the future of the Przewalski’s horse population.”

As he matures and successfully breeds, he can provide a valuable infusion of genetic diversity for the Przewalski’s horse population.

The work was carried out by Texas-based ViaGen Equine (http://viagenpets.com/equine), in collaboration with San Diego Zoo Global (http://SanDiegoZooGlobal.org) and wildlife  conservation organization Revive & Restore (https://reviverestore.org/projects/przewalskis-horse/)

“The work to save endangered species requires collaborative and dedicated  partners with aligned goals,” said Paul A. Baribault, president/CEO of San Diego Zoo  Global. “We share in this remarkable achievement because we applied our multidisciplinary approach, working with the best scientific minds and utilizing precious genetic material collected and stored in our wildlife DNA bio bank.”

The scientists suggest this could provide an important model for future conservation efforts.

Capturing horses with a drone

Feral populations of horses often roam over extensive areas. When it becomes necessary to confine them for management purposes – for contraceptive treatment, for example - it becomes necessary to round them up.

Current methods of trapping are based on chasing the animals into a corralled area – often using helicopters.

Is there another way?  A less stressful, less expensive, and safer alternative? Sue McDonnell  and Catherine Torcivia, of the University of Pennsylvania School of Veterinary Medicine New Bolton Center, believe  that there is.

They investigated whether it would be possible to get free-roaming horses to follow a drone into a corral. They explain “This concept is based on the natural instinctive behavioural tendency of horses to become alert to intruders or novel objects and to respond as a herd according to the level of sympathetic arousal evoked.”

They used a consumer-grade quadcopter drone to lead the university’s herd of 123 semi-feral ponies into corrals. Reporting their work in the journal Animals, they write: “The technique was successful on the first attempt as well as for seven of nine additional attempts over a period of 4 weeks, repeatedly to the same as well as to different destinations. The pace of following was primarily a fast walk, with occasional slow trot. Family integrity was maintained.”

The authors add that “In all cases, one or more stallions were the first to alert to the approach of the drone as well as to initiate following of the drone’s retreat. Those stallions vocalized in a characteristic loud distant call back to the remainder of the herd, which then reflexively coalesced and followed en masse.”

They found that to catch the horses’ interest, the drone was most effective when flying at 2-6 metres above the ground and within 10m ahead of the leading animals.

The authors conclude that their work shows preliminary proof of the concept of repeated capture of horses by leading with aircraft rather than chasing. They now plan to repeat the project on a herd of feral horses in a much larger enclosure than that in which these ponies were living.

“If successfully demonstrated in more extensive rangeland conditions, this method may eventually provide a lower-stress, more repeatable option of capturing feral horses, with implications for improved animal and human safety and welfare.”

For more details, see:

Preliminary Proof of the Concept of Wild (Feral) Horses Following Light Aircraft into a Trap.

McDonnell S, Torcivia C.

Animals (Basel). (2020) Jan 2;10(1). pii: E80.

https://doi.org/10.3390/ani10010080

Cooling hot horses

Horses working hard in hot and humid conditions may suffer heat-related stress, particularly if they have not had time to acclimatise to the environmental conditions. Treatment requires rapid cooling to bring the horse’s temperature down to more acceptable levels. But what is the most effective way of cooling a horse? Different methods have been proposed and opinions vary as to the most effective procedure.

A study from Japan Racing Association’s Equine Research Institute found that a continuous shower of tap water was the most effective method.

Five Thoroughbreds were included in the study, which was carried out under hot and humid conditions (maintained at 31.8 °C +/- 0.1°C with heaters and mist sprays)

The horses were exercised on a treadmill until the temperature measured in their pulmonary artery reached 42°C. They were then cooled down following one of five protocols and their pulmonary artery and rectal temperatures and blood lactate levels were monitored.

Cooling protocols comprised:

• walking, with no additional cooling (control);
• walking, with fans producing an air current of 3.0 m/s
• walking, with the intermittent application of cold water (10°C) with scraping
• walking, with the intermittent application of cold water (10°C) without scraping
• stationary, with the continuous tap water (26°C) application via shower hoses

Researchers repeated the experiment weekly until all horses had experienced each cooling method.

They found that showering with tap water was significantly more effective than any other cooling method.

A full report of the work is published in the Journal of Equine Veterinary Science. The authors conclude: “The essential feature is not the water temperature or the use of scraping but that the horse is kept covered in water cooler than its body temperature over an extended period.”

For more details, see:

A Comparison of Five Cooling Methods in Hot and Humid Environments in Thoroughbred Horses

Yuji Takahashi 1, Hajime Ohmura 2, Kazutaka Mukai 1, Tomoki Shiose 3, Toshiyuki Takahashi

J Equine Vet Sci (2020) 91:103130.

 https://doi.org/10.1016/j.jevs.2020.103130

Early pregnancy loss research

Research from the Royal Veterinary College (RVC) has demonstrated that a chromosomal defect is responsible for a significant proportion of horse pregnancies that fail within the first two months of development.

These findings will pave the way for new diagnostic tests for, what could be, one of the most common causes of pregnancy loss in mares.

Pregnancy loss is a notoriously difficult condition for veterinary surgeons to manage. Up to 10% of confirmed mare pregnancies end in the first two months, and in over 80% of those cases the cause is unknown

In this study, researchers found that aneuploid pregnancies (in which a copy of a whole chromosome is either duplicated or missing) are a key cause of equine pregnancy loss.

The research team, led by Dr Mandi de Mestre, Reader in Reproductive Immunology and Head of the Equine Pregnancy Laboratory at the RVC, collaborated with seven different veterinary practices to gain access to samples from across the UK and Ireland. They found that around 20% of the pregnancies lost were aneuploid. Charlotte Shilton, RVC PhD student who performed the analysis, applied three different genetic approaches to confirm the results.

Work is now underway to identify the underlying cause of these aneuploid pregnancies, with early data from this study suggesting it is most commonly introduced via the egg or sperm. Until now, chromosomal defects such as aneuploidy have only been reported as a rare condition in young horses with developmental disorders.

This study explains why the condition is so rare in horses, with most embryos and fetuses possessing this genetic change dying very early in development, as also occurs in humans. The study highlights the need to reconsider this genetic condition both in pregnancy loss but also for early developmental disorders.

Dr de Mestre said: “Early pregnancy loss remains a very frustrating condition for clinicians to treat as the underlying cause is unknown in around 80% of cases. These findings will allow researchers to develop new diagnostic tests for pregnancy losses, which would offer hope to thousands of owners of breeding mares that suffer this condition.

“A diagnostic test would allow them to make informed decisions on treatment strategies and to advise on whether they should invest in further attempts to breed their mare benefiting both horses and their breeders alike in the future.

She added, ”I would like to thank both the Thoroughbred Breeders Association and our collaborators at Texas A&M University and the participating veterinary surgeons for their support on this project.

 

For more details, see:

Whole genome analysis reveals aneuploidies in early pregnancy loss in the horse

Charlotte A. Shilton, Anne Kahler, Brian W. Davis, James R. Crabtree, James Crowhurst, Andrew J. McGladdery, D. Claire Wathes, Terje Raudsepp & Amanda M. de Mestre

Scientific Reports (2020) vol 10, Article number: 13314

https://www.nature.com/articles/s41598-020-69967-z