Lean animals can also be at high risk of laminitis, concludes new study

It’s not just obese ponies who can be at high risk of laminitis, a newly published study has
confirmed. Obesity, despite its significant health hazards, may not be a reliable indicator of poor metabolic health and associated laminitis risk, because lean animals have been shown to be at high risk too.  

Adiponectin, a hormone coming from fat deposits, can be measured in the blood, and is thought to improve sensitivity to insulin.  Previous work has shown that low blood concentrations of adiponectin reflect an increased risk of laminitis.  Decreased concentrations of the hormone have been found in association with obesity, but this new work has shown that decreased levels of adiponectin can also be found quite commonly in lean, native-breed ponies.

 

In this latest study, led by Marine Barnabé , data collected during three previous studies involving native-breed ponies, were retrospectively analysed.  Funding for the study was provided by Waltham Petcare Science Institute and the Royal Veterinary College Mellon Fund. An open-access report is published in the Equine Veterinary Journal

 

Total adiponectin was compared between 734 ponies of different body condition score (BCS) classification (ideal-weight, overweight, and obese), breed, and body shape, with and without a history of laminitis. Age, breed, sex, weight, height, and weight:height ratios were recorded. BCS was assessed on a scale of 1 to 9 and was determined by a single assessor. Blood samples were collected from non-grain fed but not forage fasted animals to determine basal insulin and total adiponectin. 

 

The results showed that total adiponectin was weakly positively correlated with BCS, height, weight, and weight:height ratio. There were significant differences in adiponectin concentrations in ponies with different BCS group classification, body shape, and breed. More of the obese (54.6%) than ideal-weight ponies had normal total adiponectin concentrations and a greater percentage of ideal-weight (38.6%) than obese ponies showed low adiponectin concentrations. 

 

“This study together with our previous work has provided us with the important take-home message that you cannot presume that just because your horse or pony is lean or of ideal bodyweight it is automatically at reduced risk,” said Sarah Nelson, Product Manager at Mars Horsecare, home of the SPILLERS brand. 

 

“They may still have insulin dysregulation and/or low adiponectin concentrations and so be at an increased risk of laminitis. If you are concerned it is important to speak to your vet and have your horse or pony tested. It’s also advisable to contact your nutrition advisor to ensure you provide the best diet to manage your individual.”

 

Another valuable initial observation from the study was the significant difference in total adiponectin concentrations between ponies of different body shapes. The middle-heavy body shape was associated with higher total adiponectin concentrations than both other shapes, suggesting this fat accumulation pattern may be less detrimental in ponies. This is similar to research in humans that has shown increased thigh fat or a ‘pear’ shape may be protective against insulin resistance compared to increased visceral fat or ‘apple’ shape. However, more work is needed to investigate these initial findings.

 

Barnabé  concludes that body condition scoring and other morphometric measures of obesity do not reliably reflect circulating total adiponectin concentrations and should not be used to assess metabolic risk factors for EMS or endocrinopathic laminitis in ponies. 

 

“Basal hyperinsulinaemia and hypoadiponectinaemia may be highly prevalent in lean native-breed ponies and circulating concentrations of both these hormones should be measured in animals with predisposing factors, regardless of BCS.”

 

She added: “Understanding the modifiable factors that are associated with total adiponectin concentrations may help to identify targets for preventive or therapeutic intervention, with the goal of reducing the development of endocrinopathic laminitis in at-risk horses and ponies.” 

 

For more details, see:

 

Relationships between total adiponectin concentrations and obesity in native-breed ponies in England

Marine A. Barnabé, Jonathan Elliott, Patricia A. Harris, Nicola J. Menzies-Gow

 Equine Veterinary journal (2023)

https://doi.org/10.1111/evj.14013

Signs of anthelmintic resistance in tapeworms?

Horses frequently carry tapeworm infections, particularly Anoplocephala perfoliata. While these parasites can be linked to colic, most infected horses generally tolerate them well and show no adverse signs.. 

Tapeworms are commonly found in horses grazing on pasture because the intermediate host, an oribatid mite, resides in the pasture environment. In contrast, tapeworms are seldom observed in horses in dry and arid conditions.

 

Two drugs, praziquantel and pyrantel, are commonly employed for tapeworm control and are generally acknowledged as effective in managing these parasites.

 

While the issue of anthelmintic resistance has garnered widespread attention concerning roundworms, it has not received as much consideration in relation to tapeworms. Anthelmintic resistance in equine tapeworms, as in other parasites, poses a significant challenge in the management of horse health. 

 

In contrast to roundworms, which can be easily diagnosed and assessed through a faecal egg count, tapeworms present a greater challenge as they excrete eggs sporadically. This erratic pattern not only complicates diagnosis but also poses challenges in evaluating the response to treatment and identifying anthelmintic resistance.

 

In a report from North America, Martin K. Nielsen, affiliated with the M.H. Gluck Equine Research Center in the Department of Veterinary Science at the University of Kentucky in Lexington, USA, sheds light on an apparent treatment failure involving praziquantel and pyrantel pamoate against tapeworms. The report relates to animals on a Thoroughbred stud farm in Central Kentucky in 2023. The findings have been published in the "International Journal for Parasitology: Drugs and Drug Resistance."

 

Fifty-six young horses were initially dewormed using a combination of ivermectin and praziquantel, followed by a treatment with pyrantel pamoate. The effectiveness of the deworming was assessed by checking the number of parasite eggs in their faeces on the day of treatment and again 14 days later.

 

Two groups of female horses, consisting of 39 and 45 individuals, were also given the ivermectin/praziquantel treatment, and their faeces were examined before and after treatment.

 

In the yearlings, the overall effectiveness against tapeworms, measured by FECR levels, was 23.5% for praziquantel and 50.9% for pyrantel pamoate. 

 

Praziquantel successfully removed tapeworm eggs in three out of 17 yearlings, but five other yearlings changed from having no tapeworm eggs to having them after treatment. 

 

Unfortunately, pyrantel pamoate did not eliminate tapeworm eggs in any of the 14 yearlings that tested positive for tapeworms.

 

Among the tested mares, nine out of 84 were found to have tapeworm eggs, and after praziquantel treatment, seven of them still tested positive for tapeworm eggs.

 

The results also showed that the ivermectin and pyrantel pamoate treatment was not very effective against roundworm (strongylid)  parasites in the young horses. The average reduction in the number of parasite eggs in their faeces was 75.6% or less, and the upper limit of the 95% credible interval was below 90% in all cases.

 

Nielsen highlights that the results differ significantly from the initial field efficacy studies conducted for both active compounds, raising concerns about the potential development of anthelmintic resistance.

 

He suggests the need for continued research and advancements in parasite management strategies to develop more sustainable approaches in addressing equine tapeworm infections.

 

 

 

For more details, see:

.

Apparent treatment failure of praziquantel and pyrantel pamoate against anoplocephalid tapeworms

M K Nielsen 

Int J Parasitol Drugs Drug Resist. 2023 Aug:22:96-101.

 doi: 10.1016/j.ijpddr.2023.06.002

New source for EAS research

 The landscape of equine research changed in October when American publisher Fran Jurga unveiled the Equine Assisted Services Research Report at the 2023 Professional Association of Therapeutic Horsemanship International (PATH Intl.) Conference in Charlotte, North Carolina, USA.

Equine-assisted services (EAS) encompass a range of therapeutic and educational interventions that involve interactions between individuals and horses. These programs use the unique qualities of horses to promote physical, emotional, social, and cognitive well-being.

 

The new digital publication, accessible on smartphones, tablets, and computers, compiles details on and links to peer-reviewed equine research under the “EAS” banner, including both animal and human sciences. 

“Equine assisted services must incorporate aspects of equine and veterinary science to serve the horse as a key participant, but also include diverse human elements from medical practice, social work, kinematics, occupational therapy, experiential learning, psychotherapy, and beyond,” Fran said.

“The recognizable peaks of veterinary medicine, equine behavior, and animal science still dominate equine research,” Fran said. “But now peer-reviewed journals are also documenting equine assisted articles, which delve into therapeutic/adaptive riding, equine-assisted psychotherapy, hippotherapy, equine-assisted learning, human-horse interaction, and veterinary social work. Take a look inside EASR and you’ll see there’s a lot more to it than hugging horses.”

The mission of the Equine Assisted Services Research Report (EASR) is to inform busy EAS center professionals, degree candidates, educators, medical authorities, and funding agencies, as well as clients and their families, and to publicly chronicle the progress of EAS as the field moves into the future. 

The new publication documents the important EAS mission to bring people and horses together in the most positive way for all involved, and to keep moving forward confidently, with the validation of peer review and graduate/doctoral thesis work to build upon and attract potential students and career practitioners. 

For more details, see:

https://equineassistedresearch.com/

Assisted reproduction in Estonian sport horses

Horse embryo Credit Elina Tsopp

 If all goes according to plan, Estonia is on the brink of a pioneering achievement in the realm o
f horse breeding. The imminent birth of the first foal, conceived through a meticulously planned process, marks a significant milestone for the country. 

This innovative method (Ovum Pick-Up and Intracytoplasmic Sperm Injection (OPU-ICSI)) involves extracting an ovum (egg) from one mare, using the OPU procedure, and inseminating it using the Intracytoplasmic Sperm Injection (ICSI) technique, where a single sperm is injected directly into the egg. The embryo is then grown in the laboratory and subsequently transferred to another mare.

Ghent University in Belgium and a few private enterprises already provide an in vitro production service for horse embryos. This service has now been introduced at the University of Life Sciences in collaboration with Luunja Stables and Perila Stables, explained the initiative's leader, Elina Tsopp, a junior researcher in breeding and biotechnology at the University.

The mare, impregnated with an ICSI embryo, is located at Luunja Stables. The embryo transfer was carried out by veterinarian Ulrika Tuppits. “Trials were conducted simultaneously in both stables. The fact that pregnancy was first achieved at Luunja Stable was simply a matter of luck."

 

The trials began two years ago, and according to Tsopp, the easiest way to explain the procedure is that it is very complicated. 

 

"The ovum needs to be injected with one sperm, that is, a single spermatozoon," explained Tsopp. Considering the size of the cells this in itself is already a delicate procedure. But this still does not guarantee the successful fertilization of the ovum. Everything depends on the quality of the cells collected with the OPU procedure, the transport conditions, the quality of the sperm and several other factors, said Tsopp.

The OPU-ICSI technique is in high demand among horse breeders. “Such biotechnology helps to produce offspring from mares involved in top-level sports without disrupting their athletic careers. Furthermore, the OPU-ICSI technique allows obtaining offspring from mares 

that otherwise could not produce offspring or to use the sperm of very valuable stallions more efficiently," explained Tsopp. It's no secret that in equestrian circles, in vitro fertilization is a very hot topic. Nowadays, in addition to selling horses and foals, embryos are also being sold.

Their athletic careers may not give sport horse mares the opportunity for a traditional pregnancy, yet all stables still want to have offspring from the best horses. Now, in addition to embryo transfer, there is also the possibility of obtaining offspring from the best mares through the OPU-ICSI technique: during a quick procedure, oocytes are retrieved from the ovaries, and the horse can go straight back to sport after a rest day. The embryos are taken to the laboratory for fertilization, and the fertilized cells grow in the incubator for 7-10 days until they are ready for transplantation or freezing.

Another significant reason for using biotechnology is the high cost of semen from top stallions. A straw of semen from some stallions can cost 30,000 euros or more. Artificial insemination of a mare often requires two or three straws, and a successful pregnancy is not guaranteed. However, by using the ICSI technique, it is possible to fertilize hundreds of eggs in laboratory conditions with a single straw of semen, providing the best genetic combinations for hundreds of offspring.

Up to 20 eggs can be obtained from one mare at a time using the OPU method, which involves aspirating follicles with a long needle and a vacuum pump. The breeding season for horses falls between spring and autumn, but the OPU method allows for the retrieval of eggs throughout the winter as well. 

 

The first test tube foal in Estonia is due to be born in August 2024.

Free tendon research articles from the EVJ

  

Horse with acute injury to left fore
superficial digital flexor tendon.
(Roger Smith) 

Horses are unfortunately prone to tendon and ligament injuries in the lower limb, and finding a universal treatment remains elusive. Nevertheless, significant scientific progress has been made in this area.

 

In the new virtual issue of the Equine Veterinary Journal (EVJ), guest editor Roger Smith has chosen 13 articles on the subject. 

 

There have been major advances in tendon and ligament disease research during the past 30 years. The 13 papers published in this new EVJ collection have been selected from the past five years to show progress in three key areas: pathophysiology – understanding why injuries occur and how they heal; progress in regenerative medicine; uncommon tendon and ligament injuries.

 

Tendon and ligament disease of the distal limb and the factors affecting treatment are complex, with variation in the severity of injury and variability in outcome between similarly affected horses. Understanding of the pathogenesis and improved diagnostic and predictive tools should enable the development of more effective treatments in the future.

 

• Microdamage in the equine superficial digital flexor tendon provides a review of what is currently known about tendon pathophysiology as well as the effect of ageing and the response to injury.
• Modelling the effect of race surface and racehorse limb parameters on in silico fetlock motion and propensity for injury provides further evidence of how mechanical loading can adversely influence the palmar tendons and ligaments.
• Ultrasound tissue characterisation of the superficial digital flexor tendons in juvenile Thoroughbred racehorses during early race training suggests that there are short-term changes with the onset of training, although it is not possible to know, at this stage, whether these changes have any relationship to the risk of injury.
• The use of sonoelastography to assess the recovery of stiffness after equine superficial digital flexor tendon injuries: A preliminary prospective longitudinal study of the healing process. This study potentially presents another way to monitor tendon healing and predict outcomes.
• Ultrasonographic-based predictive factors influencing successful return to racing after superficial digital flexor tendon injuries in flat racehorses: A retrospective cohort study in 469 Thoroughbred racehorses in Hong Kong: This work confirms that lesion size was predictive of outcome.
• Effect of circadian rhythm, age, training and acute lameness on serum concentrations of cartilage oligomeric matrix protein (COMP) neo-epitope in horses. This study provides important information to establish a clinically useful blood assay for tendon and ligament injury in the future.
• Retrospective analysis of local injection site adverse reactions associated with 230 allogenic administrations of bone marrow-derived mesenchymal stem cells in 164 horses. This work reports the highest frequency of reactions for synovial cavities and the injection of collateral ligaments of the distal interphalangeal joint.
• Ultrasound-guided injection of the cranial tibial artery for stem cell administration in horses reports an alternative delivery of stem cells via the cranial tibial artery to hindlimb structures where intralesional treatment is not possible.
• Extracellular vesicles from equine mesenchymal stem cells decrease inflammation markers in chondrocytes in vitro investigates how MSCs potentially act.
• Retrospective analysis of oblique and straight distal sesamoidean ligament desmitis in 52 horses includes a technique for optimising ultrasonography for imaging oblique DSL injuries.
• Magnetic resonance imaging and histopathological evaluation of equine oblique sesamoidean ligaments raises the question of whether many of these ligament injuries are being missed in practice.
• Magnetic resonance imaging following regional limb perfusion of gadolinium contrast medium in 26 horses considers how this method may enhance the identification of pathology within the foot.
• Chondrosesamoidean ligament enthesopathy: Prevalence and findings in a population of lame horses imaged with positron emission tomography. This study looks at how this new diagnostic technique may identify a new soft tissue injury within the foot.

 

“The field of tendon research is generating a healthy amount of quality research to counter the commonly held belief that there is nothing better than a double helping of God and time,” said Roger Smith. “Bit by bit we are moving closer to the holy grail of ideally preventing, or successfully treating, these injuries.”

 

“This collection provides an essential educational insight into the significant progress that has been made in tendon and ligament disease research over the past five years,” said Professor Celia Marr, Editor of the EVJ. “By giving veterinary practitioners the opportunity to understand the science and the variables behind why a specific treatment may work is a fundamental step towards the ultimate goal of reliable treatment success.” 

 

The virtual issue can be found at 

https://onlinelibrary.wiley.com/doi/toc/10.1001/(ISSN)2042-3306.tendoninjury 

and will be free to view until 27 February 2024.

Research highlights limitations of non-contact infrared thermometers

According to a recent study conducted by the Department of Large Animal Clinical Sciences at Texas A&M University in College Station, TX, non-contact infrared thermometers may not serve as a viable alternative to rectal thermometry for detecting fever in horses.

 Body temperature is a crucial vital sign used for assessing health and is important for monitoring horse health and implementing biosecurity measures within groups of horses. While rectal temperature remains the gold standard for accuracy, its use can be met with resistance from horses, posing potential danger for the operator.

 

Non-contact infrared thermometers have been considered as an alternative, providing quick and convenient temperature readings without direct contact. However, these thermometers offer a rapid assessment of surface temperature, and their readings may not closely reflect the core body temperature compared to rectal thermometers. Environmental conditions and the presence of a thick hair coat can further influence their accuracy.

 

The research, conducted by Leslie Easterwood and Noah D. Cohen from the Department of Large Animal Clinical Sciences at Texas A&M University, involved a comparison of rectal temperatures with recordings obtained using a non-contact infrared thermometer in 142 Quarter Horse horses and 34 Quarter Horse foals. Measurements from the non-contact infrared thermometer were collected from the forehead or neck, while rectal temperatures were recorded separately for each horse and foal.

 

The study revealed that the readings obtained by the non-contact infrared thermometer demonstrated good reliability in terms of measurement repeatability. However, these readings did not align well with rectal temperatures. Notably, there was a substantial negative bias, with adult horses displaying non-contact infrared thermometer readings nearly 2°F lower than rectal temperatures. This difference was more pronounced in foals, where the average difference exceeded 3°F.

 

In conclusion, the researchers assert that the substantial and inconsistent bias observed with the non-contact infrared thermometer indicates that these devices may not be a suitable substitute for rectal thermometry when aiming to obtain valid estimates of core body temperature in horses.

 

 

For more details see:

Agreement of Temperatures Measured Using a Non-Contact Infrared Thermometer With a Rectal Digital Thermometer in Horses,

Leslie Easterwood, Noah D. Cohen

Journal of Equine Veterinary Science,(2023) Vol 123,104243,

https://doi.org/10.1016/j.jevs.2023.104243

Effect of different hay feeders on behaviour

 Horses, being continuous grazers, have a natural inclination to feed steadily. Feral and wild horses may spend about 16 hours per day grazing. 

Allowing domesticated horses free access to roughage aligns with their natural feeding behaviour, representing a potentially optimal approach for horse health and welfare.

However, there are instances where restricting their food intake becomes necessary for management or health reasons. Nevertheless, such restrictions may impact their welfare and behaviour.

 

Implementing tools like hay-nets/bags and slow-feeders may prove helpful in decreasing food waste, extending the time horses spend consuming roughage, and potentially reducing undesirable behaviours.

 

The introduction of automatic hay boxes, providing scheduled feeding times throughout the day, contributes to minimising food waste. Despite this advantage, timed feeding through these devices may lead to abnormal behaviours in horses due to limited access to roughage.

 

A recent study evaluated the impact of three different hay feeders and the availability of roughage on horse behaviours in dry feed lots. The goal was to identify improved feeding techniques that could optimize feeding management, diminish abnormal behaviours, and improve the overall welfare conditions of horses in equine establishments.

 

Fifteen healthy thoroughbred cross horses from the Polo Club at Colorado State University participated in the research, employing a 3x3 Latin square design. The study comprised three groups, each consisting of five horses, with each group undergoing 15 days of one of the three treatments: free choice hay, slow feeder, or box feeder. At the conclusion of each treatment period, the horses underwent weighing, and blood samples were collected to monitor cortisol levels. Behaviour was  monitored throughout the final day of each treatment session.

 

The research, funded by Morris Animal Foundation, is published in Journal of Equine Veterinary Science.

 

Lead author, Jéssica Carvalho Seabra, said “Taking care of horses means more than just giving them a place to stay, food and water. It means giving them an environment where they can do things that are part of their natural behaviour like grazing.”

 

The researchers found that horses using automatic boxes and slow feeders consumed less and exhibited slower weight gain, indicating effective regulation of food intake. 

 

Horses with the freedom to choose when to eat had the highest hay utilization and weight gain rates, suggesting that this approach might not be optimal for overweight horses.

Horses with access to free choice feeding or a slow feeder spent more than half their day doing natural activities such as foraging. 

 

In contrast, horses using box feeders spent only about a quarter of their day eating, leading to increased time spent standing, sniffing the ground, and consuming their own faeces.

Furthermore, horses using the box feeder displayed more signs of aggression. During the study, the researchers noticed that horses became more aggressive as the feeders' size decreased and access to the food became more difficult. To address this issue, researchers recommend ensuring adequate space for each horse to eat without feeling crowded, especially when providing a limited amount of food.

 

"Selecting the right feeding technique can extend the time horses engage in natural behaviours, reducing the incidence of chronic stress and potentially curbing the emergence of abnormal and stereotypic behaviours in the long run," Carvalho Seabra said.

 

For more details, see:

 

Jéssica Carvalho Seabra, Tanja Hess, Marcos Martinez do Vale, Katherinne Maria Spercoski, Ryan Brooks, João Ricardo Dittrich,

Effects of Different Hay Feeders, Availability of Roughage on Abnormal Behaviors and Cortisol Circadian Rhythm in Horses Kept in Dry Lots,

Journal of Equine Veterinary Science (2023) Vol 130, 104911,

https://doi.org/10.1016/j.jevs.2023.104911.

Prevalence of laminitis in Norwegian ponies

New research highlights the problem of laminitis in the Norwegian Nordlandshest/Lyngshest pony breed.

Ponies, in general, are prone to laminitis and field observations suggest Norwegian breeds are no exception

 A recent study by Sigrid Lykkjen, Ingrid Hunter Holmøy from the Faculty of Veterinary Medicine at the Norwegian University of Life Sciences, and Linda Koldal Stenbakk from the Forus Hesteklinikk, sheds light on the prevalence and risk factors associated with laminitis within this pony breed. A full report of the study is published in Acta Veterinaria Scandinavica

 

The Nordland or Lyngshest, native to Norway, is typically small to medium-sized, standing at 12 to 14 hands (48 to 56 inches or 122 to 142 cm) at the withers. With a compact and muscular build, these ponies are well-suited for tasks in challenging mountainous terrains, commonly employed in riding, driving, and therapeutic riding programs.

 

The study aimed to assess the prevalence and risk factors for laminitis in the Norwegian Nordlandshest/Lyngshest pony breed. To address the question, the research team used questionnaires distributed among members of the Norwegian Nordlandshest/Lyngshest breed association..

 

Analysis revealed age, sex, and regional adiposity as notable risk factors for laminitis. Moreover, the level of exercise and outdoor housing was significantly correlated with a reduced prevalence of laminitis.

 

For horses over nine years old, the lifetime prevalence of laminitis approached 20%. However, the overall lifetime prevalence across the entire population was comparatively lower. The researchers attributed this lower prevalence to the study's inclusion of a substantial number of young animals (24% aged five years or less), suggesting their contribution to the overall lower incidence of laminitis.

 

In conclusion, the researchers emphasize that laminitis poses a considerable welfare challenge within the Nordlandshest/Lyngshest pony breed.

 

“The identified risk factors, namely age, sex, and regional adiposity, underscore the importance of heightened diagnosis and monitoring of EMS/insulin dysregulation in the breed. Additionally, the findings highlight the necessity for enhanced owner education and awareness of strategies aimed at reducing the risk of laminitis.”

 

For more details, see:

 

Prevalence and risk factors for laminitis within the Norwegian pony breed Nordlandshest/Lyngshest

Sigrid Lykkjen, Linda Koldal Stenbakk & Ingrid Hunter Holmøy 

Acta Veterinaria Scandinavica (2023) vol 65, Article number: 22 

Revealing the silent reservoir: Horses and the potential threat of Leishmaniosis

 Leishmaniasis, a zoonotic disease capable of transmission from animals to humans, has long
been acknowledged as a significant public health concern. The World Health Organisation reports that over one billion people reside in areas endemic to leishmaniasis, placing them at risk of infection. The disease manifests in three distinct syndromes in humans: cutaneous, mucocutaneous, and visceral. Annually, there are approximately 30,000 new cases of visceral leishmaniasis and over one million new cases of the cutaneous form. Remarkably, leishmaniasis ranks as the second leading parasitic cause of death worldwide, following malaria.

The causative agent of leishmaniasis is an intracellular protozoan parasite known as Leishmania spp., transmitted through sandflies. Traditionally, dogs have been identified as the primary reservoir, but recent research suggests the involvement of other species in the transmission cycle. 

 

Infected horses may exhibit signs of cutaneous leishmaniasis, manifesting as nodules on various body parts such as the head, ear, scrotum, legs, and neck. These lesions, which can be singular or multiple, often present with ulceration. However, some horses may carry the infection without displaying any visible signs, potentially serving as silent reservoir hosts

 

As our understanding of the dynamics of leishmaniasis transmission expands, it becomes increasingly important to consider a variety of animal species, including horses, in efforts to mitigate the impact of this disease on both animal and human populations.

 

Researchers from the Veterinary Faculty at Universidad Cardenal Herrera-CEU Valencia, Spain, conducted a study aimed at elucidating the potential role horses may play in the transmission of leishmaniosis, a parasitic disease. Lola Martínez-Sáez and her colleagues undertook an analysis of the prevalence and factors associated with L. infantum infection in seemingly healthy horses. A full report of the work is published in the online journal Animals.

 

The team gathered epidemiological data and serum samples from 167 apparently healthy horses in the Valencia region of eastern Spain. They used an enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR) to assess the presence of L. infantum during two distinct periods: December 2022 to January 2023 and May 2023 to June 2023.

 

The results revealed that 27.5% of apparently healthy horses tested positive for anti-leishmania antibodies, and infection was confirmed through real-time PCR. Interestingly, horses with a calm temperament and those residing outdoors exhibited a higher prevalence of infection.

 

Additionally, the study unveiled a seasonal variation in equine Leishmania spp. infections, with a notable spike during the spring months, aligning with higher average temperatures. This observation underscores the significant influence of climate on the prevalence of leishmaniosis, raising concerns about the potential impact of climate change on the disease's future trajectory.

 

From a One Health perspective, the researchers emphasize the need for a holistic approach to combat leishmaniosis. Given the close contact between horses and humans, horses may act as silent reservoirs, facilitating parasite transmission. As a result, the study advocates for the incorporation of preventive measures for horses, such as regular use of repellents, to control the spread of leishmaniosis across species.

 

For more details, see:

 

Prevalence and Factors Related to Leishmania infantum Infection in Healthy Horses (Equus caballus) from Eastern Spain. 

Martínez-Sáez L, Dulac Q, Montaner-Angoiti E, Marín-García PJ, Llobat L. 

Animals. 2023; 13(18):2889. 

https://doi.org/10.3390/ani13182889

Discussing colic

The latest edition of the Fresh Scoop podcast from Morris Animal Foundation covers colic in
horses. Join Drs. Kelly Diehl and Sharanne Raidal as they discuss the subject, including types of colic, clinical signs, diagnostics, treatments and ongoing research. 

 

For more details, go to:

 

https://www.morrisanimalfoundation.org/article/episode-62-understanding-colic-horses

 

Or, you can download the podcast from all the usual places

Link between feral horses and peatland carbon emissions studied

(c) Constantin Stanciu Dreamstime.com

Feral horse populations in the Australian Alps pose a threat to Sphagnum peatlands, according to recent
research. 

Peatlands serve as highly efficient natural carbon capture and storage ecosystems, surpassing the capabilities of rainforests. Despite covering just 3% of the Earth's land surface, they house approximately 30% of the world's soil carbon—twice the amount stored in all the planet's forests combined.

 

In the Australian Alps, peatlands are characterised by carbon-rich peat soil within mossy wetlands formed from partially decomposed plants in swampy conditions. These ecosystems excel in capturing carbon in live moss layers and storing it in soils for long periods, sometimes spanning thousands of years.

 

However, when peatlands, particularly those rich in Sphagnum moss like those in the Australian Alps, are degraded, they can switch from carbon sinks to carbon sources. The disturbance may release more carbon into the atmosphere as greenhouse gases than they capture.

 

The precise connection between this degradation and the carbon cycling of peatlands remains unclear. A study conducted by researchers from RMIT University in Australia sought to address this knowledge gap. A full report of the work is published in the Journal of Environmental Management.

 

Sarah Treby, and Samantha P. Grover conducted a multi-site comparison of CO2 and methane fluxes from Australian peatlands. The investigation focused on 12 alpine and subalpine Sphagnum moss-dominated bogs in Kosciuszko National Park, New South Wales. Over a seven-day period in March 2022, the researchers sampled seven sites with feral horses present and five without.

 

Using a portable greenhouse gas analyser and transparent chambers to measure peatland carbon dioxide (CO2) emissions, they revealed a correlation between the presence of feral horses and increased carbon loss.

 

Their findings showed significantly higher emissions at sites degraded by feral horses compared to horse-free sites.

 

Sites with horses exhibited carbon emissions to the atmosphere, while sites without horses showed carbon removal from the atmosphere. Notably, net carbon emission was 91% higher in bare soil areas than in Sphagnum-covered areas.

 

Sites with feral horses also displayed higher soil bulk density, temperature, electrical conductivity (EC), and water pH, EC, and turbidity compared to sites without horses. 

 

The findings suggested that excluding feral horses from peatland areas could mitigate carbon loss to the atmosphere and improve overall site condition, peat soil quality, and water quality.

 

 

For more details, see: 

Carbon emissions from Australian Sphagnum peatlands increase with feral horse (Equus caballus) presence

Sarah Treby, Samantha P. Grover

Journal of Environmental Management (2023) Vol 347, 119034

https://doi.org/10.1016/j.jenvman.2023.119034

Benefit of lighting in trailers?

(c) Oleksii Yaremenko Dreamstime.com

 Loading horses into trailers can be challenging and potentially dangerous, especially with young horses. Could lighting in the trailer help make the process less stressful?

Claire Neveux and others investigated how lighting inside a trailer can affect the horse's experience, especially during loading and when the trailer is stationary. They found that having consistent and bright LED lighting inside the trailer can make a difference.

In their study, they used a specially designed trailer with adjustable LED lights. They tested this setup with twenty young trotter horses who were relatively new to travelling and loading. They had them load into the trailer multiple times, (“Loading Phase”). After loading, the horses remained in the stationary trailer for two minutes with the experimenter. (“Stationary phase”).

 

The research team used varying lighting conditions in the trailer, which included different levels of brightness and temperature, such as warm white light (3000K), neutral white light (4500K), and cold white light (6300K) generated by LED lighting. To evaluate how these distinct lighting conditions influenced the horses' reactions, the research team closely monitored the horses' behaviour and documented their heart rates.

 

Among their findings were that horses expressed fewer stress-related behaviours and loaded faster when there was a high light level inside the trailer.

 

In addition, heart rate recovered more quickly when horses were loaded and kept under artificial white light LED lighting in a stationary trailer.

 

However, they stress that many factors, including the horse’s environment, its personality and past experience affect the horses’ response to loading in a trailer. 

 

A full report of the work is published in Applied Animal Behaviour Science.

 

 

For more details, see: 

 

Effects of different LED lighting conditions on young horses during trailer loading and stationary confinement

Claire Neveux, Marion Ferard, Emmanuel Melac, Nicolas Pousset

Applied Animal Behaviour Science (2023) Vol 261, 105885

https://doi.org/10.1016/j.applanim.2023.105885

Careful use of anthelminitcs can help limit resistance

 Recent research suggests that employing selective treatment regimens can significantly reduce the
development of anthelmintic resistance. This is particularly relevant in the context of parasites such as the cyathostomins (small redworms), which are among the most common internal parasites of horses. These parasites have developed resistance to various deworming drugs over the years due to their widespread and indiscriminate use.

In Sweden, a country known for its controlled approach to anthelmintic use, a study was conducted to investigate the presence of resistance to ivermectin, a commonly used deworming medication. The research found no evidence of resistance to ivermectin in cyathostomes in Sweden.

 

ML resistance has been observed in cyathostomins worldwide. However, the current situation in Sweden is unclear. Routine anthelmintic treatment of horses without prior diagnostic tests is rare in Sweden, since anthelmintic drugs were restricted to being available on prescription only in 2007. What effect would this have had on the development of ML resistance in the country?

 

To assess the effectiveness of deworming treatments, two common tests are used: the faecal egg count reduction test (FECRT) and the egg reappearance period (ERP) after treatment. FECRT evaluates whether a dewormer successfully reduces the number of internal parasite eggs in the horse's faeces. Samples are taken before treatment and around 10 to 14 days after deworming, and the two egg counts are compared. A high reduction percentage indicates that the dewormer is effective, while a low reduction percentage suggests potential resistance.

 

As internal parasites develop resistance to dewormers, the egg reappearance period (ERP) shortens, meaning that eggs reappear in the faeces more quickly after treatment.

 

A study led by Ylva Hedberg Alm and her colleagues aimed to assess FECRTs and ERPs following ivermectin (IVM) treatment in Swedish horses. Sixteen equestrian establishments, each with at least six horses excreting a minimum of 150 eggs per gram of faeces (EPG) during screening, were included in the study. FECRTs and ERPs were evaluated in faecal samples before and after IVM treatment (200 µg/kg) and for eight weeks afterward.

 

The questionnaire responses revealed that 69% of establishments administered anthelmintic treatments based on faecal diagnostics. All establishments achieved a high FECRT, exceeding 99.0%, and ERPs ranged from six to over eight weeks. Notably, younger horses were found to excrete cyathostomin eggs earlier after treatment than older horses.

 

The researchers also observed that riding schools, stud farms, and those not segregating summer and winter paddocks had shorter egg reappearance periods.

 

In conclusion, this study in Swedish equestrian facilities employing selective anthelmintic treatment revealed that the establishments maintained longer ERPs and showed no confirmed resistance to ivermectin. These findings support the use of selective deworming strategies as a means of reducing the risk of anthelmintic resistance in horses. The full report is available in Veterinary Parasitology.

 

For more details, see:

 

Retained efficacy of ivermectin against cyathostomins in Swedish horse establishments practicing selective anthelmintic treatment

Ylva Hedberg Alm, Eva Osterman Lind, Frida Martin, Rebecca Lindfors, Nina Roepstorff, Ulf Hedenström, Isabelle Fredriksson, Peter Halvarsson, Eva Tydén

Veterinary Parasitology (2023) Vol 322, 110007

 

https://doi.org/10.1016/j.vetpar.2023.110007

Survey on Behavioural Challenges in Horses

(c) Kseniya Abramova Dreamstime.com

 Is your horse facing behavioural issues? How do you handle these challenges? Whether you're
a horse owner, rider, or work closely with horses, Dr. Orla Doherty would welcome your valuable input.

Dr. Doherty is conducting a research survey to gather insights on how problem behaviours in horses impact riders, handlers, and individuals involved in equine care, as well as the strategies employed to address these issues. Any additional perspectives or knowledge you can provide on this subject will be greatly appreciated. 

A veterinary surgeon, Dr. Doherty graduated from University College Dublin in 1992 and earned a Master's Degree in Animal Behaviour and Welfare from Edinburgh University in 1993. Her commitment to animal welfare led to the establishment of the Animal Behaviour Clinic in Ireland in 1994, where she has been actively addressing behaviour-related concerns in animals across the nation.

 

The survey results will be made publicly available. 

 

To take part, go to:

https://www.surveymonkey.com/r/International_Survey_on_Problem_Behaviours_in_Horses

Grants available for behavioural research

 Morris Animal Foundation has announced a fresh call for research proposals with the goal of enhancing the well-being of horses by advancing our understanding of behavioural health and welfare. The Foundation is particularly keen on projects related to cognition, learning, stereotypies, separation anxiety, horses' affiliative behaviour towards humans, the impact of equine temperament on their welfare, and equine psychopharmacology. Please note that proposals solely focused on behavioural measurements for non-behavioural conditions will not be considered. 

This initiative has been made possible thanks to a generous donation from Dr. Wendy Koch, a veterinarian who has been a steadfast supporter of the Foundation for over three decades. Dr. Koch embarked on her career in animal welfare with the federal government back in 1990 and achieved board certification in animal welfare in 2016. Her deep interest in equine behaviour and welfare research prompted her to champion funding in these important areas.

 

Researchers interested in this opportunity should submit their proposals by 4:59 p.m. ET on December 13, 2023. 

 

For details on how to apply, see the Foundation's Grants page at:

 

https://www.morrisanimalfoundation.org/apply

Breed differences in ACTH concentrations

 Plasma adrenocorticotropic hormone (ACTH) concentration is commonly measured to diagnose pituitary pars intermedia dysfunction (PPID), also known as equine Cushing’s disease. Several intrinsic and extrinsic factors affect ACTH concentrations, including breed. 

Researchers at the University of Melbourne and the University of Queensland, in Australia, conducted a study to prospectively compare plasma ACTH concentrations among different breeds of mature horses and ponies. 

Dr Nicholas Bamford and colleagues aimed to shed light on how plasma adrenocorticotropic hormone concentrations, a crucial indicator for diagnosing pituitary pars intermedia dysfunction in horses, varied across different horse breeds. 

 

The breed groups under scrutiny were Thoroughbred horses, Shetland ponies, and ponies of non-Shetland breeds. 

 

The health of the animals involved was carefully monitored to ensure they showed no signs of illness, lameness, or clinical signs associated with PPID.

 

Blood samples were collected twice a year, around the autumn and spring equinoxes, to capture any seasonal variations. The ACTH levels were measured using a chemiluminescent immunoassay, a common diagnostic tool. 

 

The results revealed that pony breeds, particularly Shetland ponies, exhibited notably higher ACTH concentrations compared to Thoroughbred horses during the autumn season. 

In spring, no differences were identified among the three breed groups.

 

This observation is significant, especially when diagnosing PPID and interpreting ACTH levels accurately.

 

The findings emphasise the importance of considering the specific breed of a horse when interpreting ACTH levels, especially during the autumn months. 

 

Understanding breed-related differences in ACTH concentrations is essential for a more precise assessment of a horse's health and can guide appropriate healthcare and management decisions.

 

For more details, see:

 

Investigation of breed differences in plasma adrenocorticotropic hormone concentrations among healthy horses and ponies

N.J. Bamford, A.J. Stewart, C.M. El-Hage, F.R. Bertin, S.R. Bailey 

The Veterinary Journal (2023) Vol 296–297, 105995

https://doi.org/10.1016/j.tvjl.2023.105995