Managing insulin dysregulation in horses: a role for nutraceuticals

(c) Brian Sedgbeer Dreamstime.com

Insulin resistance (IR) and insulin dysregulation (ID) in horses are major risk factors for developing laminitis; a painful and potentially debilitating condition. While some horses are genetically predisposed to IR, diet also plays a critical role in its development. Because of this, there's growing interest in whether specific dietary strategies, including the use of nutraceuticals, can help reduce the risk.

A recent study led by Caroline Loos and her colleagues at the University of Kentucky's Gluck Equine Research Center, and published in the journal Animals,  explored whether supplementing the diet with a specific combination of nutrients could help improve insulin regulation in horses that are prone to IR. 

The trial involved 16 mature horses with a known history of insulin dysregulation. The horses were split into two groups:

• One group received a nutraceutical supplement containing omega-3 fatty acids, glutamine, vitamin E, and active yeast.
• The other group received a placebo.

Both supplements were given once daily for four weeks. During the study, horses were kept on dry lots, had free access to grass hay, and were also fed a grain concentrate twice daily (providing 0.5 g of starch per kg of body weight per meal).

To assess the horses’ insulin regulation, each underwent a Combined Glucose–Insulin Tolerance Test (CGIT) at the start and end of the trial. The CGIT is a diagnostic test commonly used in equine medicine to evaluate how effectively a horse’s body clears glucose from the bloodstream in response to insulin. During the test, horses receive a bolus (injection) of glucose and insulin, and blood samples are collected over a 150-minute period to track how quickly glucose and insulin levels return to baseline. The faster the return to normal, the better the horse’s insulin sensitivity.

After four weeks of supplementation, horses receiving the nutraceutical showed notable improvements:

• 61% faster glucose clearance compared to the placebo group.
• Shorter time for blood glucose levels to return to normal.
• Lower insulin levels at 75 minutes post-test, indicating reduced hyperinsulinemia.
• Glucose concentrations were also lower at 45 minutes post-test in the supplemented group.

In contrast, horses in the placebo group still had elevated insulin levels 150 minutes after the test, suggesting poorer insulin regulation.

These findings suggest that prophylactic use of specific nutraceuticals may help improve insulin sensitivity and reduce the risk of insulin-associated laminitis, particularly in horses consuming high-starch diets. By supporting faster glucose clearance and lowering insulin levels, this approach may offer a valuable management tool for horses at risk of ID or IR.

While more research is needed to confirm long-term benefits, this study highlights the potential of targeted dietary supplementation in supporting metabolic health in horses.

 

For more details, see:

 

Loos, Caroline, Annette Castelein, Eric Vanzant, Emma Adam, and Kyle R. McLeod. 

Nutraceutical Supplement Mitigates Insulin Resistance in Horses with a History of Insulin Dysregulation During a Challenge with a High-Starch Diet

Animals (2024) 14, no. 23: 3385. 

https://doi.org/10.3390/ani14233385

Effect of gut supplement on cribbing

Cribbing, also known as crib-biting or wind-sucking, involves the horse grasping a solid object with its incisor teeth, arching its neck, and swallowing air, resulting in a distinct grunting or gulping sound.

Research has linked cribbing to lower gastric pH in adult horses and gastric ulceration in foals. To address this concern, various supplements have been developed to neutralize acid and promote normal stomach activity in horses.

 

A randomised crossover study conducted by researchers from the University of Florida and the University of Costa Rica investigated the impact of a gastrointestinal support supplement on both cribbing and non-cribbing horses. 

 

A full report of the work conducted by Ana M. Arias-Esquivel and colleagues at the. Institute of Food and Agricultural Sciences (IFAS) Equine Sciences Center in Ocala, Florida, is published in the Journal of Equine Veterinary Science.  

 

The study, involved eight adult horses, with four showing cribbing behaviour matched with four non-cribbing horses of similar age and sex. These horses grazed on a Bermuda grass paddock during the day and were housed in individual box stalls overnight with visibility to other horses.

 

The researchers randomly assigned the horses to receive either the gut health supplement or a placebo of alfalfa / timothy hay pellets. Both the supplement and placebo were mixed with a concentrate feed and fed to the horses twice daily. The study spanned a 74-day period, including 14 days of acclimation, two 21-day feeding trials, and a 14-day washout period.

 

Throughout the study, various assessments such as blood samples, gastric endoscopy, video recordings, faecal samples, and behavioural observations were conducted to gather comprehensive data on the horses' response to the supplement or placebo.

 

The researchers found that the addition of a gastrointestinal support supplement had minimal impact on various factors, including concentrations of serum cortisol and gastrin, faecal and gastric pH, crib-bite counts, and the duration of cribbing bouts, according to the researchers.

 

Levels of cortisol, an indicator of stress in horses, showed no significant differences between the two treatments (supplement vs placebo) or among horses exhibiting cribbing behavior. Interestingly, among cribbing horses, those given the supplement exhibited more severe squamous (upper stomach) ulcers compared to horses receiving the placebo. Both faecal and stomach pH were simiilaracross horses and treatments, and 

 

Non-cribbing horses did not display cribbing behaviour throughout the study.

 

Notably, for all cribbing horses, cribbing behaviour was most frequent around feeding time. However, the number of bites per cribbing bout and the duration of cribbing bouts were similar between the supplemented and placebo groups. 

 

In summary, the researchers did not observe significant changes in gut physiology or cribbing behaviour among horses receiving the gut health supplement. 

They conclude: “The findings challenge some prevailing assumptions and emphasize the need for comprehensive, longitudinal research in this field.”

 

 

For more details, see:

 

Ana M. Arias-Esquivel, Ana C. Cerqueira de Melo Vasco, Jill Lance, Lori K Warren, Luis A Rodriguez-Campos, Megan C. Lee, Christina N. Rodriguez, Carissa L Wickens,

Investigating the gastrointestinal physiology of mature horses with and without a history of cribbing behavior in response to feeding a digestive support supplement,

Journal of Equine Veterinary Science (2024) vol 132, 104964

 

https://doi.org/10.1016/j.jevs.2023.104964

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.

Horses Inside Out Conference

 There’s still time to get tickets for the Horses Inside Out Annual Conference. 

 Back this year at the Holywell Conference Center in Loughborough, it will be held on Saturday 18^th and Sunday 19^th February.  If you can’t be there in person, you can still attend virtually.

 

An array of expert speakers has been lined up for what promises to be an inspiring meeting. 

Topics to be covered include bitting, nutrition, training the equine brain, rider psychology, hindlimb lameness, hoof care, dental disease and more.

 

For all the details, go to: 

 

https://www.horsesinsideout.com/annual-conference-2023

Do ponies avoid salt in drinking water?

 Ponies accept drinking water containing low levels of salt and this could potentially be used to help rehydration, according to a recent study.

 Horses lose heat by sweating and in doing so lose sodium as well as water. Sodium plays an important role in numerous functions throughout the body. An increase in plasma sodium concentration is a trigger for thirst.

 

Horse sweat contains high levels of sodium (Na). Excessive sweating may result in the loss of so much sodium that the plasma sodium concentration does not increase enough to trigger drinking. So heavily sweating horses may not voluntarily drink enough water to replenish their body fluids.

 

Could dilute saline solutions be used as drinking water to help combat sodium loss and dehydration? 

 

A study in Germany by Nick Enke and colleagues assessed whether Shetland ponies would notice and tolerate different salt (NaCl) concentrations in their drinking water.

 

Six non-pregnant and non-lactating mares were enrolled in the study, which consisted of three phases. In the first phase only fresh water was provided, as a control. In the second phase, a pairwise-preference test, ponies were given a choice between fresh water and one of six different saline solutions. Finally, the ponies were offered a choice of fresh water and five different NaCl concentrations at the same time.

 

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

 

The researchers report that during the pairwise test, the ponies did not distinguish between fresh water and 0.25% NaCl-water, but demonstrated a clear preference for water containing 0.5%NaCl. Ponies consistently avoided NaCl concentrations above 0.75%. During the free-choice test, the ponies showed a pronounced preference of fresh over saline water. 

 

They noted that sodium intake from a salt lick was not reduced in response to higher sodium intakes in the water. 

 

They conclude: “The ponies exhibited a remarkable sensory discrimination capacity to detect different NaCl concentrations in their drinking water. The acceptance of solutions with low NaCl levels (0.25/0.5%) without adverse effects demonstrates potential as rehydration solution for voluntary intake.”

 

 

For more details, see:

 

Sensitivity of ponies to sodium in the drinking water

Nick Enke, Lea Brinkmann, Karl-Heinz Südekum, Ernst Tholen, Martina Gerken

Anim Sci J (2022);  93(1):e13697.

https://doi.org/10.1111/asj.13697

App to help monitor equine body condition

 A new Equine Body Condition Scoring app has been produced by scientists at the University of
Glasgow.

Obesity in equines is not a new problem. However, the increasing number of obese horses and ponies, predominantly in the leisure industry, has now become a globally recognised welfare concern.  

 

Carrying excess weight contributes to various problems: it increases the stress on the horse’s skeletal system, can limit reproductive performance, adversely affect athletic performance and may lead to an increased risk of laminitis, osteoarthritis, heat intolerance and certain types of colic. 

The Equi-BCS app was developed by Katie Williams, an equine nutritionist, as part of her PhD research at the University.

The app lets owners record and share their horse’s weight data, which should make it easier for professionals to help horse owners keep their horse’s weight on track. This feature also supports horses that are not holding their weight, so health issues can be spotted early.

Ms Williams said: “One of the toughest challenges for any horse owner is keeping weight off their horse, and previous studies have shown that horse owners tend to underestimate their horse’s body condition score.

“To succeed, a collaborative approach is required including vets, nutritionists and farriers working together with horse owners.”

The app contains detailed images and instructions to help horse owners score their horse accurately and photos can be uploaded and stored so that horse owners can remind themselves of how their horse has looked in the past.

Research in human weight tracking apps has shown that frequency of use correlates with greater success and so an important feature of the app is that it will notify users when they are due to assess their horse again.

Ms Williams added: “It is incredible how quickly a horse can change and so monitoring regularly, ideally every two weeks, is key. Receiving a reminder will provide the prompt that many people need to ensure they take time to assess their horse and either make adjustments to the ration, or seek advice from their vet or nutritionist.”

The Equi-BCS app can be downloaded for free from Apple’s app store or Google Play

Brush up on your nutrition and laminitis knowledge with free webinar

Horse owners can take advantage of a series of free nutrition-themed webinars, thanks to SPILLERS™.

The first webinar, to be held on 20th January 2022 at 8pm (GMT), will be hosted by SPILLERS™ nutritionist Gina Burgoyne, and is entitiled “Tips for winter weight gain.” It will cover forage, calories, fibre and oil diets and practical advice.

 

On Thursday 10th February, 8pm, Gina Burgoyne will present a webinar on “Tips for horses prone to gastric ulcers.” The discussion will cover: who is at risk; what to look out for; how nutrition plays a role; and forage.

 

The third webinar, on Thursday 3rd March, 8pm, “Managing your laminitic horse” will be hosted by Isabel Harker and Sarah Nelson. Topics will include: who is at risk; symptoms; how nutrition plays a role; body condition; and grazing tips.

“Whether you have a horse or a pony, and whether you are looking for safe weight gain, weight loss or a maintenance diet these webinars are for you,” said Clare Barfoot RNutr, Marketing and Research and Development Director at Mars Horsecare UK, home of the SPILLERS brand. 

“The webinars incorporate answers to many of the questions we receive via our Care-Line, together with the latest in equine nutrition science, making them highly relevant for every level of horse owner. And the best news is they are free and accessible to all.”

The webinars will be hosted on Microsoft Teams. Each session is free of charge and will last for approximately one hour. 

 

If you would like to join, sign up at:

 

https://www.spillers-feeds.com/webinars

 

 A link to join the webinar will then be emailed to you the day before the session.

Value of strip grazing (and chance to win a strip grazing kit)

 Strip grazing can play a useful part in controlling horses’ weight a recent study has shown.

Strip grazing refers to reducing the amount of grass available by sectioning off a smaller area of the paddock using electric fencing. The fence is moved daily to provide gradual access to fresh grazing. A back fence may also be used which can be moved by the same amount to keep the overall grazing area the same size.

 

Restricting grass intake is an essential part of many weight management programmes, and the latest research on strip grazing shows that it can be an effective solution. For many horses and ponies, grass is the main source of calories in the diet and is also one of the hardest for owners to control. A 250kg pony living out at grass may consume enough energy (calories) to fuel a 500kg racehorse – equivalent to more than half a bag of conditioning cubes every day.

 

The study, comparing three restricted grazing practices for equine bodyweight management during the United Kingdom grass growing season, was conducted by Annette Longland in collaboration with SPILLERS via the WALTHAM Equine Studies Group.

 

Three groups of four ponies were turned out into individual paddocks that had been measured at the start of the study to provide 1.5% of the ponies’ bodyweight (dry matter) in grass, for 28 days. 

 

The ponies were assigned to one of three grazing practices: 

·       after a two-day adaptation period ponies were given access to the whole paddock with no restrictions; 

·       a lead fence was placed across the width of the paddock and after a two-day adaptation period, it was moved 1/26th of the remaining paddock length daily to allow access to fresh grass; 

·       after a two-day adaptation period a lead fence and a ‘back fence’ were moved by 1/26th of the remaining length every day.

 

Ponies with access to the whole paddock showed a significant increase in body condition score, but ponies in either of the strip grazed groups did not. The strip grazed ponies gained significantly less weight than ponies in the total allowance group, regardless of whether a back fence was used. In fact, strip grazing without a back fence was no less effective than strip grazing with a back fence, even though the grazing area got larger every day.

 

The WALTHAM Equine Studies Group, who provide the science behind the SPILLERS brand, have now published 100 research papers relating to obesity, laminitis, equine metabolic syndrome (EMS) and weight management. To celebrate, SPILLERS is giving one lucky horse owner the chance to win a strip grazing kit, including energiser, fencing tape and posts. The competition is running on the SPILLERS Facebook page from 21-28 June.

 

 

For more details, see:

 

Longland, AC, Barfoot, C, Harris, PA. 

Strip-grazing: Reduces pony dry matter intakes and changes in bodyweight and morphometrics. 

Equine Vet J. 2021; 00: 1– 8.

https://doi.org/10.1111/evj.13416

 

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/

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

Barley straw as an aid to weight loss

Feeding a mixture of barley straw and hay is a safe and cost-effective way of promoting weight loss in grazing ponies over winter, according to recent research. 

Obesity is a widespread problem in pleasure horses and ponies. In the past, it was accepted that horses and ponies would lose weight over the winter and then gain weight in the spring when grazing quality improved. Nowadays, however, horses are fed to maintain condition over the winter, and, at the same time, they may be doing less work. 

Obese horses and ponies are at higher risk of laminitis; but shedding that weight is often quite a challenge.

A study conducted by Dr Miranda Dosi and colleagues at the University of Edinburgh Royal School of Veterinary Studies and the Redwings horse sanctuary in Norfolk UK, looked at whether feeding a mixture of straw and hay could be used for reducing weight in grazing ponies over the winter. 

A report of the work is published in the Veterinary Record.

The study involved native type ponies maintained in groups at grass over winter. They were fed supplementary roughage – either hay alone, or an equal mixture of hay and barley straw.

The research team weighed the horses regularly during the four-month long study.

They found that, over the study period, all animals in the hay/straw-fed group lost weight. In the hay only group, three horses lost weight, but overall, horses in that group gained weight. 

One concern of feeding straw is that it might lead to digestive problems such as impaction. However, in this study, there were no reports of colic in either group. Neither were there any reports of laminitis. 

An advantage of the higher fibre barley straw is that it may prolong the time spent eating and may reduce behavioural problems such as aggression.

The researchers conclude “straw is a cost-effective and low-energy roughage, which may be a useful alternative to hay alone when trying to induce weight loss in grazing equids over winter.”

For more details, see:

Inducing weight loss in native ponies: is straw a viable alternative to hay?

Dosi MCM, Kirton R, Hallsworth S, Keen JA, Morgan RA.

Vet Rec. (2020)

doi: 10.1136/vr.105793