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.