Study finds widespread contaminants in horse feed across the EU

 A recent study by the University of Veterinary Medicine, Vienna, has found that contaminants posing potential health risks are widespread in commercially available horse feeds across the EU.

While the equine feed market offers a wide range of products tailored to different nutritional needs, feedstuffs can also carry contaminants such as fungal and bacterial toxins. Limited knowledge of how frequently such contamination occurs prompted researchers to investigate exposure levels and their possible health implications.

The study analysed 108 horse feed samples from EU suppliers, spanning hay, processed roughage, grains, and supplementary feeds. Each sample was screened for more than 1,200 compounds, including mycotoxins, phytoestrogens, pesticides, and veterinary drug residues, using liquid chromatography tandem mass spectrometry.

Findings showed contamination was highly prevalent: 107 of 108 samples (99%) contained fungal metabolites, with fusarium toxins the most common. Bacterial metabolites were detected in 16% of samples, and veterinary drug residues in a further 16%, though concentrations were generally low. 

Processed roughage products, particularly those containing lucerne (alfalfa), had significantly higher concentrations of phytoestrogens and plant toxins compared with hay. Grain-based mueslis and mashes were more likely to contain pesticide and veterinary medication residues. Notably, monensin (an anti-coccidial drug used in poultry feed) and colchicine, both highly toxic to horses, were detected in 10–20% of samples, though at levels considered too low to pose an acute health risk.

The authors conclude that the findings highlight the complexity of biotoxins and chemical residues in equine feeds and emphasise the need for stronger regulation and routine testing to safeguard equine health and welfare.

For more details see: 

L.M. Kwaß, R. Khiaosa-ard, Q. Zebeli, M. Sulyok, V. Milojevic, B.U. Metzler-Zebeli,

Exposure of horses to biotoxins, phytoestrogens, and pesticides from different feed materials and supplementary feeds,

Journal of Equine Veterinary Science,(2025) Vol 151,105632,

https://doi.org/10.1016/j.jevs.2025.105632

Impact of environmental exposure and captivity on gut microbial diversity

Petrą Kaczensky Wikipedia CC-BY-SA3.0

Over thousands of years, hosts and their resident microbiota have evolved complex interactions, with microbial communities adapting to the physiological and dietary conditions of their hosts. 

In addition to these evolutionary relationships, genetic factors play a crucial role in shaping microbial colonisation and immune responses. Domestication significantly influences microbiome composition through changes in diet, habitat, and human-driven selection pressures. The external environment also contributes to microbial diversity, as hosts acquire microbes from soil, water, and food sources. 

A study conducted by Victor Hugo Jarquín-Díaz and colleagues, and published in Scientific Reports, explored the contribution of environmental microbiota from freshwater sources to the gastrointestinal microbiomes of wild khulans (Equus hemionus hemionus). 

 The study also compared the faecal microbial diversity of wild khulans to that of captive khulans in Europe and two other equid species—Przewalski’s horses and domestic horses—in Mongolia. By examining these populations, the researchers sought to understand the extent to which environmental exposure and captivity shape equid gut microbiota. 

They used PacBio sequencing (a DNA sequencing technique widely used for microbial genomics) and the LotuS pipeline for 16S rRNA gene sequencing, enabling a detailed analysis of microbial communities. The research team measured alpha diversity (species richness and evenness within a sample) and beta diversity (differences between samples) and conducted differential abundance analysis to identify microbial differences between groups. 

Their findings showed minimal microbial exchange between wild khulans and their water sources, suggesting that freshwater sources have little impact on their gut microbiomes. They point out that this finding also indicates that khulans contribute little to waterborne microbial contamination, despite regular interactions with these water sources. 

 Comparisons revealed that wild khulans have a more diverse and richer gut microbiome than captive khulans. The researchers suggest that this is an adaptation to the harsh nutritional conditions of the Gobi Desert, where wild khulans must digest a wide range of fibrous, low-quality forage. In contrast, captive khulans have reduced microbial diversity, likely due to changes in diet, lower exposure to environmental microbes, and possible antibiotic use. 

They conclude that their findings demonstrate limited microbial sharing between khulans and the waterholes they drink from, challenging the hypothesis that these act as a source of their gut bacteria or that khulans shape the water microbiome through their exudates. Captive khulans exhibit lower microbial diversity compared to their wild counterpart. However, captivity appears to be less of an influence than species differences – as the faecal biomes of captive and wild khulans are more like each other than they are to those of domestic horses and Przewalski’s horses. 

For more details, see: 

 Jarquín-Díaz, V.H., Dayaram, A., Soilemetzidou, E.S. et al. 

 Unraveling the distinctive gut microbiome of khulans (Equus hemionus hemionus) in comparison to their drinking water and closely related equids. 

 Sci Rep (2025)15, 2767 (2025). 

 https://doi.org/10.1038/s41598-025-87216-z

Survey on SGLT2 Inhibitor Use in Horses with EMS or PPID

(c) Brian Sedgbeer Dreamstime.com

Have you used an SGLT2 inhibitor (one of the          "-flozin" drugs) to treat your horse? If so, the Equine
Cushing's and Insulin Resistance Group (ECIR) invites you to contribute to an important research initiative.

Sodium-glucose cotransporter 2 inhibitors (SGLT2i), such as ertugliflozin and canagliflozin, are increasingly used to manage equine metabolic syndrome (EMS), particularly in horses with laminitis that has not responded to dietary changes. These drugs have shown potential benefits, including reducing serum insulin levels, aiding weight loss, and improving laminitis associated with hyperinsulinemia.

However, concerns have arisen about possible side effects, such as elevated serum triglycerides and liver enzyme levels, lethargy, and increased drinking and urination.

Dr. Kellon of the ECIR Group has created a survey to investigate factors that may influence the outcomes of SGLT2 inhibitor use in horses. This includes individual horse characteristics, comorbidities, and dietary factors that may contribute to or mitigate adverse effects.

If you are an owner, veterinarian, or caretaker of a horse receiving one of these drugs—such as canagliflozin, ertugliflozin, or dapagliflozin—you are encouraged to participate in the survey. Your insights will help enhance understanding and improve the management of metabolic disorders in horses and ponies.

The survey can be found here www.surveymonkey.com/r/YM5JD9G 

 

See also:

Eleanor M. Kellon, V.M.D. (Equine Nutritional Solutions) 

www.drkellon.com

 

Equine Cushing's and Insulin Resistance Group Inc.

www.ecirhorse.org

Equine feed manufacturer announces free webinar series

 

 The SPILLERS™ Brand has announced a new series of free nutrition webinars designed to
elevate horse owners’ understanding of equine nutrition and wellbeing. 

 

The four webinars, to be held over the winter months, promise to provide valuable insights from nutrition, veterinary and welfare experts. 

 

The first webinar Forage fundamentals will be held on 24th October 2024, led by equine nutrition expert, Sarah Nelson. She will explore the role of forage in the horse’s diet, covering essential topics such as the different types of forage, their nutritional value, and how to choose the most suitable type and amount of forage for different horses and ponies. 

 

“This webinar is the perfect opportunity for horse owners to deepen their understanding of forage management and in turn, be better placed to support their horse’s digestive health and wellbeing,” said Sarah Nelson.

 

The first webinar will be followed by: 

 

Stabling horses: Can we do it better? – 21st November 2024, with Isabel Harker, head of the SPILLERS Care-Line team, and Sarah Hallsworth, Equine Behaviour Manager at Redwings Horse Sanctuary

Caring for the senior horse – 16th January 2025, with SPILLERS Nutritionist and Product Manager, Sarah Nelson, and Professor Pat Harris, a leading authority on veterinary clinical nutrition and senior horse nutrition.

Spring into action: Effective strategies to help your horse shed the pounds – 27th February 2025, with SPILLERS Nutrition Advisor, Isabel Harker, and Nicky Jarvis, Head of Veterinary and Care at Redwings Horse Sanctuary. 

 

To register visit: https://www.spillers-feeds.com/webinars

Do haynets affect tooth wear in horses?

(c) Nigel Baker Dreamstime.com

Using haynets to feed horses has several benefits, including reducing hay waste and slowing down consumption. 

However, there are potential downsides, such as the risk of injury and unnatural feeding positions. When individual haynets are hung too high, horses may eat with their heads raised, which may lead to muscle discomfort and long-term problems. This position also increases the chance of inhaling dust or hay particles, which may cause respiratory issues.Do haynets also influence tooth wear.?

 

Michelle DeBoer and colleagues conducted a study to compare horse body weight and condition, hay consumption, tooth wear, and dental conditions between horses fed with or without hay nets. 

 

The work was presented at the Equine Science Society Symposium 2023, and a report is published in the Journal of Equine Veterinary Science.

 

Thirteen adult geldings were recruited for the cross-over study and divided into two groups.

 

They were housed in adjacent dry lots with access to shelter and water. Both groups were fed round hay bales in feeders, with one group of six horses receiving hay wrapped in hay nets, while the other five horses were given hay without nets.

 

The study spanned two years, with the two groups switching halfway through: the five horses that initially had their hay wrapped switched to unwrapped hay, while the six horses moved to wrapped hay.

 

The researchers tracked hay consumption and monitored dental health, including incisor length, dental abnormalities, and conditions. They also recorded horse body weight and body condition scores annually—before, during, and after the study.

 

Results showed that horses eating unwrapped hay consumed more and had higher body weight (BW) and body condition scores (BCS). No significant differences were found in incisor length, incisor bevels, or dental abnormalities.

 

The researchers concluded that hay nets do not negatively affect dental health but can reduce hay consumption and help manage horse body weight and condition.

 

 

 

For more details, see:

 

M. DeBoer, L. Keener, J. Layeux-Parks, O. Schueller, L. Johnson, K. Martinson,

Effect of hay nets on horse bodyweight, body condition score, hay usage, and dental health in mature adult horses,

Journal of Equine Veterinary Science,(2024) Vol 136,105051

 

https://doi.org/10.1016/j.jevs.2024.105051

Effect of diet on strongyle infection and gut microbiome

Recent research from France suggests that the first step in controlling intestinal worm infections inanimals should be providing them with diets that maintain a healthy gut ecosystem. 

Horses’ intestines can harbour many different worms, some of which can cause severe disease. It's concerning that some of these worms are becoming resistant to deworming medications. This resistance has emerged through factors such as incorrect dosing or frequent use of the same medications.

 

It's clear that we need to adopt a more sustainable approach to managing equine  intestinal parasites.

 

To address this challenge, scientists are exploring different methods, including dietary changes. These diets might enhance the body's defences, regulate gut bacteria, or directly combat parasites. For example, certain foods containing plant compounds might hinder worm reproduction in the body.

 

A study by Noémie Laroche and colleagues, at Lab to Field, Dijon, and the University of Bourgogne Franche-Comté, investigated how diet affects strongyle infection in horses, focusing on immune-mediated, microbiota-mediated, or direct deworming mechanisms. The work is reported in PLos ONE.

 

They studied twelve adult French Trotter geldings naturally infected with strongyles. These horses were divided into two groups and fed either a high-fibre or high-starch diet, along with supplements containing polyphenol-rich pellets from dehydrated sainfoin or control pellets made from sunflower and hay.

 

The study revealed that horses on a high-starch diet had higher strongyle egg excretion compared to those on a high-fibre diet. However, adding sainfoin to the high-starch diet reduced egg excretion. What’s more, sainfoin supplementation decreased larval motility, regardless of the diet.

 

Moreover, the high-starch diet was associated with lower faecal bacterial diversity, changes in faecal microbiota structure, lower faecal pH, reduced blood acetate levels, and lower haematocrit compared to the high-fibre diet.

 

Overall, these findings suggest that dietary changes can be an alternative strategy for managing helminth infections. 

 

The study highlights the importance of considering broader ecological mechanisms in parasite management strategies. The researchers emphasize that eradicating helminth infections entirely is unrealistic and could have negative effects. 

 

They write: “… pursuing a goal of eradicating helminth infection (zero infection) is not only illusionary but also likely to produce more negative effects than benefits. Mammals have coevolved with helminths during millions of years, and in most cases, the infection does not produce severe symptoms.’

 

“We therefore suggest that a safer strategy to control helminth infection would be to improve host tolerance to the infection rather than pursuing a hopeless, environmentally toxic, strategy of drug-based eradication.”

 

For more details, see:

 

Laroche N, Grimm P, Julliand S, Sorci G (2024) 

Diet modulates strongyle infection and microbiota in the large intestine of horses. PLoS ONE 19(4): e0301920. 

https://doi.org/10.1371/journal.pone.0301920

Strip grazing delivers more consistent nutrients than free grazing

(c) Sarah Shephard

A recent study has revealed that strip grazing can provide horses with a more consistent nutrient supply
compared to unrestricted grazing once rapid spring grass growth subsides. This finding adds further insight into the potential effectiveness of strip grazing as a tool for managing weight in horses.

The research, conducted by Dr. Annette Longland from Equine Livestock and Nutrition Services in collaboration with the WALTHAM™ Equine Studies Group and the SPILLERS brand, builds upon previous work by the same team. Earlier research* demonstrated that strip grazing could effectively restrict grass intake to aid in managing the body weight of pastured ponies, although the underlying reasons were not fully understood. This follow-up research highlights the benefits of consistent nutrient intake achievable through strip grazing.

 

In this study, twelve ponies were individually grazed in long, narrow paddocks specifically designed to provide herbage equivalent to 1.5% (dry matter) of the ponies’ body weight per day over a 28-day period from late June to late July, once the rapid growth phase of spring grass had finished.

 

For the first two days, all ponies were grazed on freshly mown "start paddocks" before being allocated to one of three grazing regimes for the duration of the study: unrestricted grazing (total allowance; TA group), or one of two strip grazing methods. In the first strip grazing method, a lead fence was positioned across the width of the paddock and moved daily to allow access to fresh grass. The second strip grazing method involved both a lead and a rear fence, with the rear fence moved the same distance daily as the lead fence.

 

Weekly evaluations were conducted to assess pasture nutrient levels and estimated digestibility.

 

The results showed that strip grazing provided herbage of more consistent nutritional quality throughout the trial compared to when ponies had unrestricted access to the same amount of original herbage. The findings also reiterated the potential value of strip-grazing as an effective tool for weight management.

 

Throughout the study, the start paddocks remained leafy and green, while the nutritional value of the remaining grass declined as it matured, consistent with typical trends for mixed-species pastures in the UK. Notably, strip grazing prevented the aggressive selective grazing observed in the total allowance (TA) group, where ponies consumed the more nutritious herbage early on, leaving less nutritious herbage for the latter part of the study period.

 

As a result, the calculated digestible energy intakes of the TA ponies in weeks one and two exceeded requirements by 42 % vs. 8 % by the strip-grazed ponies. Over the course of the study, the TA ponies gained three-four times more weight than their strip-grazed counterparts, with over 70% of the TA ponies’ weight gain occurring in the first two weeks. In contrast, strip grazed ponies gained significantly less weight overall at a more consistent rate.

 

“This study gives us some important practical take home messages regarding weight management and potentially the management of associated disorders such as insulin dysregulation and laminitis,” said Sarah Nelson, Product Manager at Mars Horsecare, home of the SPILLERS brand. 

 

“Strip grazing in this study prevented rapid weight gains by providing gradual access to fresh pasture of decreasing nutrient value and preventing aggressive selective grazing. This work shows how strip grazing, if carried out appropriately, can be an effective weight management tool especially once the very rapid, spring growth is over. However, it is important to remember that even strip grazing on high non-structural carbohydrate (NSC) containing pastures may not be suitable for some laminitis prone equids, especially those that are at high risk or at certain times of year.” 

 

For more details, see:

 

Longland, AC, Barfoot, C, Harris, PA. Strip grazing: 

Changes in biomass, nutrient content and digestibility of temperate, midsummer pasture by strip-grazed or ‘free’-grazing ponies, over 4 weeks.

Journal of Equine Veterinary Science (2023) Vol 131, 104957

https://doi.org/10.1016/j.jevs.2023.104957

 

*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

 

(Edited press release)

Palatabilty of hemp

 As feed expenses escalate in the horse industry and hemp becomes more accessible,
researchers are examining hemp as a potential substitute for horse feed. 

 A recent American study examined the palatability and acceptability of hempseed meal pellets, comparing them to other commonly used horse feed options.

 

Ryon W. Springer and co-workers conducted the research at the Tarleton State University Equine Center, Stephenville, Texas. A full report is published in the Journal of Equine Veterinary Science.

 

During an initial experiment, horses were provided with soybean meal pellets (SBM), rice bran pellets (RBP), or beet pulp pellets (BPP) in one bucket (500 g) and hempseed meal (HSM) in a second bucket (500 g) twice daily for three days. The feeding regimen involved rotating the treatments so that each group of horses received every type of feed during the trial. Horses had a 10-minute window for eating during each feeding session. 

 

Horses consumed significantly more hempseed meal pellets compared to soybean meal pellets and beet pulp pellets. The quantities of HSM  and RBP consumed were similar. A gradual increase in hempseed meal consumption was observed as the study progressed.

In a subsequent experiment, six geldings were presented with 1 kg of hempseed meal pellets over two 5-minute intervals, separated by 1 hour each day. Coastal Bermudagrass hay (1kg) was provided between these offerings. The results revealed that horses exhibited increased consumption of hempseed meal pellets on days 5 and 6 in contrast to days 1 to 3. 

 

Notably, the consumption of HSM pellets did not show any correlation with hay intake.

 

The researchers conclude that HSM may be similar in palatability to RBP and more palatable than SBM and BPP. Consumption of HSM increases over time but is not impacted by hay consumption. They suggest that hempseed meal may serve as an acceptable replacement to more common feedstuffs in equine rations.

 

For more details, see:

 

Ryon W. Springer, A. Cheyenne Mason, Teighlor D. Cross, Kimberly A. Guay, Randel H. Raub, Kimberly B. Wellmann, Trinette N. Jones,

Assessment of the Palatability and Acceptability of Hempseed Meal Pellets in Horses Compared to Mainstream Feedstuffs,

Journal of Equine Veterinary Science, (2023) vol 131, 104929,

https://doi.org/10.1016/j.jevs.2023.104929

Insulin Dysregulation: not limited to overweight ponies

  

Body condition score alone does not reliably predict the risk of a pony developing laminitis
according to recent research. 

 

The study, by Edd Knowles, Post-doctoral researcher at the Royal Veterinary College (RVC) and Internal Medicine Specialist at Bell Equine Veterinary Clinic. with colleagues at the RVC, and Pat Harris of the Waltham Equine Studies Group, is published in the Equine Veterinary Journal.

 

The findings show that insulin dysregulation (ID), which is linked to an increased risk of laminitis, may occur in ponies across a wide range of body conditions, ages and levels of exercise, not just in those that are overweight. The study also showed that ID was less common in ponies that undertook more exercise, including low-intensity activities.

 

Insulin is a hormone produced by the pancreas. The release of insulin is the signal for cells, largely in muscle and liver tissue to absorb glucose (sugar) from the blood. Insulin dysregulation (ID) is a term that includes a high basal or ‘resting’ insulin (in the blood), an exaggerated insulin response to consuming starch and/ or sugar and tissue insulin resistance (a failure of cells to respond to insulin). 

 

An association between ID and laminitis is well-established, and early detection of ID is likely to be useful in helping to prevent the disease.

 

In this study, the concentration of insulin was measured in the blood of ponies before and sixty minutes after they were given, orally, a sugar syrup (an oral sugar test (OST)). 

 

A total of 1763 OSTs were taken from 367 non-laminitic ponies over four years. The ponies were visited and tested in the Spring and Autumn unless they developed laminitis. Various physical parameters were recorded at the time of each OST including weight, height, body length, neck length, heart girth, belly girth, body condition score and cresty neck score. Owners/carers were asked to complete a questionnaire concerning the specific characteristics, diet, management, duration and intensity of exercise and health for each pony at each visit. 

 

The study concluded that associations between InsulinT60 and physical and owner-reported variables were limited. Season, owner-reported and physical features only explained 10%– 27% of the differences in InsulinT60 risk status in the study population.

 

The findings support previous work that suggested body condition scoring alone was not sufficient to determine insulin dysregulation (ID) status and emphasises the value of using an oral sugar test to screen for ID status.

 

Lead author Edd Knowles stated: “Our work has shown that while physical and owner-reported features can be used to identify ponies with a higher risk of ID, veterinarians should not limit testing for ID to ponies in which these risk factors are present. Doing so would miss identifying ponies at moderate to high risk of laminitis.” 

 

The study also indicates that relatively small increments in equine exercise routines may be beneficial. 18% of samples from ponies that were reported to do no trotting exercise were in the high-risk InsulinT60 category compared with only 9% of samples from those reported to undertake 1–2 h of trotting per week. 

 

This finding supports earlier research, on the benefits of low intensity exercise, conducted in collaboration with the WALTHAM® Equine Studies Group, which provides the science behind SPILLERS®,

 

“This work confirms that while body condition is a useful indicator, we can’t simply assume that ponies with obvious physically apparent attributes such as excess weight are the only group likely to have ID,” said Sarah Nelson, Product Manager at Mars Horsecare, home of the SPILLERS brand. 

 

“We must consider multiple variables when targeting ponies for ID screening, in order not to miss those potentially at increased risk of laminitis, who may have a ‘healthy’ body condition score.” 

 

“The association with even low-level exercise is also an important practical management message for horse owners” she added.

 

For more details, see:

 

EJ Knowles, PA Harris, J Elliott, Y-M Chang, NJ Menzies-Gow.

Factors associated with insulin responses to oral sugars in a mixed-breed cohort of ponies. Equine Vet J. 2023.

https://doi.org/10.1111/evj.13983

Need for vitamin D supplementation

 Stabled, non-grazing Thoroughbred racehorses should receive vitamin D supplementation to
maintain an adequate vitamin D status, according to recent research. 

Vitamin D is an essential nutrient for horses, as it is for many other animals and humans. It plays a crucial role in maintaining overall health and well-being by regulating various physiological processes. The primary function of vitamin D is to help the body absorb and utilize calcium and phosphorus, which are vital for strong bones, teeth, and proper muscle function.

 

Unlike some animals that can synthesize vitamin D in response to UV radiation on their skin, horses have little or no ability to produce vitamin D this way. Consequently, they rely heavily on dietary sources to obtain an adequate supply of the vitamin. Horses primarily obtain vitamin D from their diet, including fresh forage like pasture grasses and certain types of hay, which naturally contain vitamin D. Additionally, commercial horse feeds and supplements may be fortified with vitamin D to ensure the animals receive enough.

 

What effect does limited grazing have on vitamin D status in horses?

 

In a study conducted by Miranda Dosi and colleagues, the vitamin D status of racehorses in training from both Hong Kong (HK) and the United Kingdom was assessed. A full report is published in the journal Animals. The main objective was to investigate whether the management practices and athletic activity of these horses made them more susceptible to having low vitamin D status, and to determine if appropriate dietary vitamin D supplementation could help mitigate this risk.

 

The study encompassed 101 Thoroughbred horses in training, 79 of which were from Hong Kong (HK) and 22 from the United Kingdom (UK). The HK horses did not have access to grazing and received minimal sunlight exposure, usually less than 30 minutes daily, during training and in-hand walking. In contrast, the UK horses had the opportunity to graze for at least an hour each day.

 

The research team assessed the serum concentrations of three active forms of vitamin D, namely 25-hydroxyvitamin D2 (25OHD2), 25-hydroxyvitamin D3 (25OHD3), and total 25-hydroxyvitamin D (total 25OHD). 

 

Forty-one of the HK horses were sampled twice to investigate the impact of their duration in HK on their vitamin D status. By taking samples at two different time points, the researchers could assess how the length of time the horses spent in HK influenced their vitamin D levels.

 

According to the research findings, the HK horses had notably lower serum concentrations of total 25OHD and 25OHD2 compared to the horses from the UK. Additionally, 15 out of 79 HK horse sera showed undetectable levels of 25OHD2. The researchers also found that the serum concentrations of 25OHD2 decreased with the length of time the horses had spent in Hong Kong.

 

Furthermore, the research team observed an inverse relationship between 25OHD2 and 25OHD3 in the study subjects. This finding suggests that oral D3 supplementation might have a negative impact on the serum concentrations of 25OHD2. In other words, increasing the intake of vitamin D3 through oral supplements could potentially lead to a reduction in the levels of 25OHD2 in the blood. They suggest that this highlights the need for further investigation and consideration when administering vitamin D3 supplements to the horses.

 

For more details, see:

 

Thoroughbred Racehorses in Hong Kong Require Vitamin D Supplementation to Mitigate the Risk of Low Vitamin D Status

Miranda C.M. Dosi, Chris M. Riggs, Jessica May, Adele Lee, Eugenio Cillan-Garcia, Joe Pagan, and Bruce C. McGorum. 

Animals (2023) 13, no. 13: 2145. 

https://doi.org/10.3390/ani13132145

Study of ertugliflozin in management of hyperinsulinaemia and laminitis

 A recent report suggests that a drug used to treat type 2 diabetes in people could be effective in reducing insulin levels in horses and ponies with equine metabolic syndrome. 

Hyperinsulinaemia, characterised by abnormally high insulin levels in the bloodstream, is a primary contributor to most cases of laminitis. The exact mechanism by which elevated insulin levels lead to laminitis is still not fully understood.

 

Managing insulin dysregulation can be challenging, with diet and exercise (unless laminitis is already present) being the primary strategies. Unfortunately, these methods may not always yield satisfactory results.

 

Currently, there are no approved medications specifically designed to address this issue. 

 

However, sodium-glucose cotransporter 2 inhibitors (SGLT2i), a class of drugs commonly employed in the treatment of type 2 diabetes in humans, show promise in reducing insulin concentrations in horses by promoting the excretion of glucose through urine.

 

Studies have demonstrated that these drugs can limit the increase in insulin levels after meals and prevent diet-induced laminitis. One such drug in this class is ertugliflozin, which some veterinarians have been using off-label to manage laminitis associated with hyperinsulinaemia.

 

A study conducted by Tania Sundra from Avon Ridge Equine Veterinary Services, in Western Australia, along with Erin Kelty and David Rendle, reviewed the clinical records of 51 horses that received ertugliflozin for the treatment of hyperinsulinaemia. The findings of this study are published in Equine Veterinary Education.

 

According to the authors, horse owners were informed about potential side effects such as loss of appetite, colic, increased drinking and urination, lethargy, or changes in behaviour, and were instructed to report any unusual signs or events immediately.

 

All horses had already been placed on a restricted diet. The diet and management for each horse remained consistent during the treatment period, allowing for a comparison of pre- and post-treatment results. Similarly, the timing of testing in relation to feeding was kept consistent for each horse.

 

After 30 days of treatment with ertugliflozin, the authors report a significant reduction in insulin levels, with the median dropping from >300 μu/ml to 43 μu/ml. This reduction was accompanied by a significant improvement in lameness, as indicated by Modified Obel lameness scores, which decreased from a median of 10/12 to 1/12.

 

During the treatment, there was an increase in serum triglyceride concentrations (from 0.6 mmol/L before treatment to 1.4 mmol/L after treatment). However, none of the horses developed clinical signs of hyperlipaemia.

 

Owners reported that 10 horses experienced increased drinking and urination while undergoing treatment with ertugliflozin, but no other adverse effects were noticed.

 

The authors suggest that ertugliflozin could potentially reduce insulin levels in horses and ponies affected by equine metabolic syndrome. Moreover, they propose that its use might speed up the recovery from laminitis that is linked to hyperinsulinaemia.

 

 

For more details, see:

 

Preliminary observations on the use of ertugliflozin in the management of hyperinsulinaemia and laminitis in 51 horses: A case series.

Tania Sundra, Erin Kelty, David Rendle

Equine Veterinary Education (2023) Vol 35, Pp 311-320

https://doi.org/10.1111/eve.13738  

Steaming hay can lead to protein deficiency

 Hay can be treated with steam to reduce the horse’s exposure to inhaled allergens that cause
respiratory disease. Steaming kills potentially harmful microorganisms and binds fungal spores and dust particles to the hay making them less likely to be inhaled 

However, new research shows that steam treatment can have an adverse effect on the digestibility of protein in the hay. 

 

A team of scientists from Martin Luther University Halle-Wittenberg (MLU) has discovered that steam treatment causes a chemical reaction that damages the proteins in the hay and makes them harder for horses to digest. This can lead to signs of nutrient deficiency in the animals and, for example, impair growth or muscle development. A report of the work is published in the journal Animals.

 

Professor Annette Zeyner from the Institute of Agricultural and Nutritional Sciences at MLU explains: “Many horses suffer from lung problems such as equine asthma. The steaming process virtually eliminates all of the living microorganisms and particles in the hay that could be inhaled during feeding and damage the lungs. In theory, the end result is a very good forage," 

 

However, her team discovered that the treatment also has its disadvantages as the steam damages the proteins in the hay. 

 

"A high proportion of the proteins, and the crucial amino acids contained in them, can no longer be digested by the small intestine - in other words the horse lacks these proteins as a result of the steam treatment. However, some of these protein components are essential for horses and they cannot be absorbed in the large intestine," Zeyner continues. 

 

The researchers demonstrated this by examining various hay samples collected from central Germany. In the steamed hay, they found an increased number of products that are generated by the Maillard reaction, an indication that the proteins in the hay have been damaged. This is a reaction that also takes place when food is cooked, baked or fried and is responsible for browning or the development of flavours. 

 

"Proteins are composed of amino acids. The steaming damages them and they form new complexes with sugars in the hay," explains the first author of the study, Caroline Pisch, from MLU. This makes them difficult for horses to digest. According to the researchers’ analyses, the treatment reduced the amount of protein that can be absorbed by the small intestine by almost half. The pre-caecal digestibility of the essential amino acid lysine was over 50% lower after steam treatment.

 

According to Zeyner, this can lead to an undersupply of essential amino acids from the feed, which can be a problem for growing horses or lactating mares; young horses need proteins to grow, and mares need them to produce milk. To make matters worse, protein deficiency causes very unspecific symptoms in the affected animals. These include impaired muscle development and a dull or shaggy coat with so-called "hunger hair" - long isolated hairs in the horse’s coat. 

 

She suggests that horse owners can counteract this risk by enriching the animals’ diet with protein-rich single feedstuffs such as yeast and soybean meal or high-quality protein-rich compound feeds. 

 

The report concludes: “steamed hay is still a proper and sometimes the only possible roughage for horses suffering from respiratory diseases such as equine asthma. Essentially, horse diets based on steamed hay should be balanced accordingly."

 

For more details, see:

 

Effect of Hay Steaming on the Estimated Precaecal Digestibility of Crude Protein and Selected Amino Acids in Horses

Caroline Pisch, Monika Wensch-Dorendorf, Uwe Schwarzenbolz, Thomas Henle, Jörg Michael Greef, and Annette Zeyner. 

Animals(2022) 12, no. 22: 3092. 

https://doi.org/10.3390/ani12223092

UK senior horses survey findings

Owners and carers of senior horses and ponies responded in their thousands to a survey,
organised by feed company Spillers.  

More than 12,000 participants completed the survey, displaying their loyalty to, and care for their precious equine oldies.

 

The survey revealed that 32.7% of respondents’ horses were 25 years old or more and that 65.6% of owners considered their horses became “senior” at 20+ years. The results will help the feed company understand more about supporting the growing sector of senior horses nutritionally, to help them live longer healthier lives.

 

The survey showed that the participants are faithful to their seniors with 58% having owned their senior for 11+ years and 5.7% having owned their oldie for more than 26 years. 99.3% intended to keep their senior horse for the rest of their life.

 

Senior horses were also shown to be predominantly healthy and active: 78% were considered to be in good condition, with 10% of the remainder being classified as overweight and 12% as underweight.

 

A total of 25.8% of seniors included in the survey had no known clinical issues or health-related problems. However, 44% showed signs of stiffness or arthritis. 15.2% were recorded as having Pars Pituitary Intermedia Dysfunction (PPID – “Cushings disease”), while dental issues were experienced by 15.2% of senior horses.

 

In terms of exercise 62.8% were still in ridden work but 72.9% of these were in light work or slowing down.

 

A diet designed specifically for older horses was fed to 37.2% of respondents’ horses were eating a senior specific feed and of these 53.7% had opted for a senior mash.

 

“Congratulations to all the owners and carers of senior horses as well as the equine industry as a whole for playing their part in helping our treasured senior horses and ponies grow old gracefully,” said Claire Dyett Marketing Manager for SPILLERS.

 

“It’s a real achievement that our seniors are ageing later and staying healthy and active in their older years. While almost a third are recorded as having PPID or dental issues, this is perhaps to be expected because horses are living longer. That more than a third of the respondents are opting for a senior specific feed, predominantly a mash, indicates that nutrition choices are helping to support health as horses age and encounter metabolic and dental problems. The results will help us in our perpetual mission to make the world a better place for horses.”

Can you help with a senior horse survey?

 If your horse or pony is 15 years or over, the team at the SPILLERS feed company is urging you to spare five minutes to participate in their senior horse survey. The results will help them learn more about the specific needs of older horses and every participant will have the chance to win free feed.

Traditionally, senior horses and ponies were classed as being 15 years or over, but perspectives are changing. Management and care continue to improve, and around 40% of horses and ponies in the UK now sit in this 15+ category. 

 

“If you own or care for a horse or pony who is 15 years or over, we would be very grateful if you could spare five minutes to participate in our survey,” said SPILLERS Product Manager Sarah Nelson. “The results will help us to help more senior horses nutritionally, in the very best ways we can.” 

 

If you would like access to the survey results, just add your email address at the end of the survey. If you submit your email address, you’ll also be added to a prize draw for your chance to win a £50 SPILLERS Feed voucher.

 

The survey is set up with one horse or pony in mind. If you own more than one horse or pony of 15 years or over, they ask you to complete a survey for each horse. Every completion will provide an additional entry into the prize draw.

 

Click here to complete the survey https://www.smartsurvey.co.uk/s/Seniorsurvey/

Free nutrition webinars

For a second year, MARS EQUESTRIAN™ are sponsoring a series of virtual educational webinars covering nutrition
research, nutritional advice, and the latest in laboratory diagnostics and medical imaging. All will be available free of charge. 

Published times, dates and topics are as follows: 

 

• 10AM EDT, October 22, 2022 – Keeping the performance horse healthy and active. “The focus of this first webinar is keeping the performance horse healthy and active. The updates on our core research, diagnostic tools and nutritional recommendations will focus on the specific needs of working horses.”

• 10AM EDT, October 29, 2022 – Keeping the gastrointestinal tract healthy. “The focus of this, the second webinar, is feeding specifically for the gastro-intestinal tract, as well as diagnosing problems and our research behind key nutritional recommendations.”

• 10AM EDT, November 5, 2022 – Keeping the performance horse mobile and active. “The focus of this, the third webinar, is keeping the performance horse mobile and fit. Techniques for measuring fitness, imaging and diagnosing lameness as well as relevant nutritional recommendations will be discussed.”

 

Each webinar session must be registered for individually. For those who are unable to attend the live event, recordings will be available afterwards, as are recordings of last year’s webinars, covering obesity, the senior horse and laminitis.

 

For more information, go to:

 

 https://web.antechdiagnostics.com/equinewebinarseries

Strip grazing reduces eating but not moving, new study shows

Studies have already shown that strip grazing is an effective way of restricting grass intake in ponies.

Now, new work indicates the added benefit that eating less doesn’t automatically mean moving less.

Restricting grass intake is an essential part of many weight management programmes. Having shown in a previous study that strip grazed ponies gain significantly less weight than ponies with free access to restricted grazing over a 28-day period, SPILLERS and their research collaborators set out to discover whether eating less as a result of strip grazing also means moving less in the field. 

To evaluate the effects on ‘activity levels’ of ponies strip grazing individually, behavioural data from the previous study was analysed. In addition, a second study was evaluated, that had been carried out in collaboration with the Royal Veterinary College, to look at the effects of strip grazing on the behaviour of ponies turned out in groups.

In the second study 10 ponies were randomly assigned to one of two adjacent paddocks. Both paddocks were the same size, had been managed in the same way and subjectively had the same amount of very limited grazing available. Paddock B was divided into seven strips (using electric fencing) with ponies given access to one additional fresh strip of grazing every day; ponies in paddock A had access to the entire paddock for the duration of the study.

In both studies, behaviour and activity levels were assessed on several occasions using a combination of direct observation and activity monitors attached to the poll strap of the ponies’ headcollars. 

The research team found no significant difference in the over-all time strip grazed ponies spent grazing, standing, or moving regardless of whether a back fence was used or if they were turned out individually or as a group.

“The results of both studies showed that the strip grazed ponies moved just as much as the unrestricted ponies,” said Clare Barfoot RNutr, Marketing and Research and Development Director at Mars Horsecare UK, home of the SPILLERS brand. “Similar amounts of time were spent grazing, standing and locomoting (which included walking, trotting and cantering) within the different groups and encouragingly, performance of behaviours related to stress and frustration were low in both studies too.”

“While we were unsurprised to see that the strip grazed ponies preferred to graze the newly accessible grass and spent most time grazing in the four hours after the fence had been moved, we believe this finding could be useful when deciding if and how those prone to laminitis should have access to grass.”

The researchers are now looking into the effects of strip grazing on the water-soluble carbohydrate (WSC) or ‘sugar’ content of the grass as well as pasture recovery.

For more details, see:

The effect of strip grazing on physical activity and behaviour in ponies.
A Cameron, A Longland, T Pfau, S Pinnegar, I Brackston, J Hockenhull,  PA Harris, NJ Menzies-Gow. (2021).
Journal of Equine Veterinary Science, (2022) 110, 103745. 
https://doi.org/10.1016/j.jevs.2021.103745

Wild parsnip and photo-dermatitis

Wild parsnip has been implicated as a cause of photodermatitis in horses.

 

Clinicians at the Freie Universität Berlin in Germany investigated a series of cases in which horses showed signs of inflammation of unpigmented skin.

 

Judith Winter and colleagues examined nine horses from stables in Berlin and Brandenburg, Germany, which showed variable degrees of erythema, scaling, crusting and necrosis of unpigmented skin on the head and prepuce. Most horses also showed signs of eye involvement: including conjunctivitis, photophobia and blepharitis (inflammation of the eyelids).

 

The clinicians found that, although the horses came from three separate yards, all stables were provided with hay from the same supplier.

 

Analysis of the hay showed that it contained large amounts of wild parsnip plants, including seeds and roots.

 

Wild parsnip (Pastinaca sativa) is widespread in Europe. It contains photodynamic pigments, known as furocoumarins. Contact with parts of the plant that contain the toxins, followed by exposure to sunlight, may cause photodermatitis, keratoconjunctivitis and uveitis. It is thought that lesions can occur due to both systemic uptake and direct topical contact.

 

Horses were treated with systemic anti-inflammatory medication as necessary, combined with topical treatment. They were protected from sunlight by being kept in a dark environment or by being treated with sunscreen and facemasks. Depending on the severity of the signs, treatment lasted from 6–30 days

 

Full details of the cases are published in BMC Veterinary Research. 

 

 

For more details, see: 

 

Photodermatitis and ocular changes in nine horses after ingestion of wild parsnip (pastinaca sativa)

JC Winter, K Thieme, JC Eule, E-M Saliu, O Kershaw, H Gehlen (2022).

BMC Vet Res 18, 80 

https://doi.org/10.1186/s12917-022-03162-2