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Feedmark's Gastric Supplement Trial

Feedmark's Gastric Supplement Trial


Equine gastric ulcers are a common issue across all populations of horses from high level performance to youngstock and even retired and non-working horses. Whilst gastric ulcers are by far the most common form of digestive upset in the horse, digestive problems such as Free Faecal Water, Colic and Inflammatory Bowel Disease also affect horses every day.  

Feedmark are continuously investing in new product development to ensure they can provide horse owners with the products and ingredients they want to feed to support their horse’s health. With digestive problems being the most frequently advised on issue, this gastric supplement trial was undertaken with the aim of identifying a supplement which could offer a high level of support for horses suffering from a range of digestive issues.


1. Identifying ingredients proven to support digestive health

With a variety of digestive supplements commercially available to horse owners, feeding a supplement containing ingredients that are proven to work will increase the success rate of the product. Identifying these ingredients can be difficult for horse owners therefore the purpose of this trial was to provide horse owners with a clearer understanding of which ingredients are proven to have a positive effect on digestive health.

The trial supplement contained ingredients which are commonly found in equine digestive supplements as well as ingredients which are unique to this product. Ingredients such as Pectin, Lecithin, Live Yeast and Postbiotics have proven benefits to the digestive health of the horse.

Pectin forms a gel-like substance that binds to bile acids when exposed to an acidic environment (Venner et al., 1999; Ferrucci et al., 2003). When combined, Lecithin and Pectin support the natural protective mucosa of the stomach which is known to become irritated by high concentrate diets, medications, and stress (Lo Feudo et al., 2021; van der Boom, 2022).

Saccharomyces cerevisiae, a live yeast, is an important component of the microbial population and stimulates the cellulolytic activity of bacteria within the hindgut, optimising fibre fermentation (Medina et al., 2002). Saccharomyces cerevisiae also promotes activity of bacteria that utilise lactate (Rossi et al., 1995), and so help to stabilise the hindgut.

Research has shown increased volatile fatty acid production by horses fed a postbiotic, demonstrating a positive outcome on fibre fermentation (Morgan et al., 2007). Bacteria species within the hindgut were also more consistent in horses fed a postbiotic compared to those fed a control diet (Ganda et al., 2022), making it beneficial for keeping the hindgut stable and reducing digestive disturbance. Research has also shown improved immunity in horses fed postbiotics (Trench et al., 2021).

Additional ingredients that offer benefits such as supporting the mucosal lining and buffering stomach acid were also included in this formulation and are commonly seen in widely available digestive supplements for horses.




Providing a total digestive tract supplement that offers a high level of support into a market that contains several established digestive supplements required a product trial to determine the benefits that it could provide to horses who suffer from digestive upsets. Many horse owners will verify the quality of a product based on its efficacy and will only use products when shown positive results.


2.1 Participant recruitment

In March 2024 a request for a Gastric Supplement Feeding Trial was made on the Feedmark Facebook page to establish the interest of participants. Interested horse owners were asked to complete an initial questionnaire to gauge suitability of their horse(s) for the trial.

Sixty-one horses were selected to participate in the trial. Horse details obtained included:

  • Horse Age
  • Horse Weight
  • Workload
  • Horses current diet (feed & forage)
  • History of digestive issues
  • Current symptoms of digestive issues


Following registration, the feeding rate for each horse was calculated and a 30-day supply of the trial gastric supplement was sent out to each participant.


2.2 Trial schedule

Week commencing


11th March

Request for Gastric Supplement Trial participants on Facebook

18th March

Trial participants registered via Google Forms

8th April

Pre-trial questionnaire issued to participants

15th April

Trial supplement sent to participants

29th April

Week 2 questionnaire issued to participants

13th May

Final questionnaire issued. Trial Finished


2.3 Product formulation

One formulation was tested during the trial. It was decided not to use a placebo supplement as the purpose of the trial was to determine the efficacy of a product using a range of horses with different digestive issues.


2.4 Product evaluation

Efficacy of the trial supplement was assessed based on information provided by the trial participants through questionnaires. Horse health questions were asked to gather information on the horses’ digestive issues and associated symptoms and the results were compared from the final, mid-way and pre-trial questionnaires.




Sixty-one horses were selected to participated at the start of the trial, with 49 horses completing the feeding trial. One horse would not eat the trial supplement, another horse was admitted to the vets for issues unrelated to digestion and the results from 10 horses were excluded due to omission of the owners to complete the full set of questionnaires during the trial period.


3.1 Horses

Horses were aged between 3 – 22 years old and weighed between 200 – 750kg. All horses were fed on a high forage, low sugar and starch diet and no changes were made to their diets or feeding regimes prior to or during the trial.

Most horses were in light to medium work prior to and during the trial period. The workload of the horses did not change during the trial period.

Forms response chart. Question title: Horse Workload. Number of responses: 68 responses.








Figure 1. Workload of horses participating in trial


3.2 Digestive history

Participants were asked questions based on their horse’s digestive history, including any history of digestive upset, whether it was diagnosed / confirmed by a vet, any treatment and what symptoms their horse was showing.

Forty eight percent of horses participating in the trial had previously been diagnosed with a digestive issue by a vet and all these horses had received medication in the past to resolve the issue. No horse participating in the trial was currently on any medication or had recently been receiving medication and no horses participating in the trial had ever undergone an operation on their digestive system.


Forms response chart. Question title: Has your horse been diagnosed with a digestive disorder by a vet?. Number of responses: 68 responses.







Figure 2. Number of horses included in the trial that had been formally diagnosed with a digestive problem by a vet.


Gastric Ulcers


Free Faecal Water











Participants were asked to provide details about which digestive issues their horses had been diagnosed with. Most horses had suffered from Gastric Ulcers of varying severity. Some horses had not received an official diagnosis of digestive disorder by a vet but were showing symptoms of digestive upset. Only horses with a confirmed diagnosis are included in the table below.



Table 1. Number of horses with previously diagnosed digestive issues. Some horses suffered with more than one issue.


Over sixty percent of the horses participating in the trial had been suffering from digestive issues for more than 12 months and over thirty percent of the horse owners had tried at least three digestive supplements in the past to try to alleviate the symptoms their horses were showing.

 Forms response chart. Question title: How long has your horse been suffering with digestive issues. Number of responses: 49 responses.

Figure 3. How long the trial horses had been suffering with digestive issues.


3.3 Symptoms

Prior to the trial starting, all participants were asked to select symptoms they were seeing in their horses that are widely considered as indicative of signs of digestive upset. The top three symptoms seen across all the trial horses were girthyness, sensitivity to touch or grooming and behavioural changes.

Forms response chart. Question title: What symptoms does your horse currently display? . Number of responses: 68 responses.

Figure 4. Number of horses showing common symptoms of digestive upset prior to the trial starting.

At the end of the trial period, participants were asked to select the symptoms that their horses were currently showing after being fed the trial supplement for 4 weeks. All symptoms had improved and less horses were showing signs of digestive upset following the trial period.


Forms response chart. Question title: Does your horse still display any of the symptoms they were exhibiting before the trial started?
. Number of responses: 40 responses.

Figure 5. Number of horses showing signs of common symptoms of digestive upset following the trial period.


It was also found the number horses were displaying signs of new symptoms that had not been exhibited before starting the trial supplement.


3.4 Severity of symptoms

All participants were asked to initially gauge the severity of their horses’ symptoms using a 1 – 10 likert scale (1 = not bad, doesn’t affect horse, 10 = very bad). Most horses scored a 5 or 6 with all horses scoring between 3 and 9.

At the end of the trial the participants were asked the same question, and it was found that most of the horses scored between 1 and 3 on the scale, showing that the appearance of their symptoms had improved whilst being fed the trial supplement.




The trial gastric supplement was a commercially available product which had been formulated and produced by Feedmark. During the trial period, the participants were asked to complete questionnaires to provide information which related to the use of the supplement, the palatability and the perceived effects of the supplement when fed to their horses. Owners were asked to rate the symptoms of the digestive issues that their horses were presenting with.

Observations in horses suffering from Equine Gastric Ulcer Syndrome usually include weight loss, poor body condition, and colic. Symptoms specifically associated with squamous ulcers include changes in appetite, slowed eating, and poor performance. Horses suffering with glandular ulcers tend to have less typical symptoms (van den Boom, 2022).

Girthyness was the most common symptom seen with 42 horses (61.8%) having been reported as displaying this symptom. Following the trial period only 15 horses (37.5%) were still displaying signs of girthyness. Initially 39 horses (57.4%) were showing signs of sensitivity to being touched or groomed, this reduced to 14 horses (35%) following the trial period. Prior to the trial, 37 horses (54.4%) were showing signs of behavioural issues associated with digestive discomfort, this reduced to only 3 horses (7.5%) following the trial supplement being fed.

Hay dunking can be a possible sign of gastric ulcers. Eight horses presented with hay dunking behaviours, however following the trial period, only 2 horses were still showing this behaviour.

Horses showing signs of loose droppings and Free Faecal Water Syndrome showed an improvement in their symptoms following the trial period. The pre-trial questionnaire highlighted that 33 horses were suffering from loose droppings and or Free Faecal Water and following the trial only 12 horses were still showing some symptoms of these issues. Horses showing signs of colic went from 10 horses to only 1 horse still presenting with symptoms and only 6 horses were still displaying behaviours of wood chewing with 22 horses initially presenting with this symptom.

Overall, the severity of symptoms seen improved throughout the trial with 33 of the final trial horses were showing none – mild symptoms (1-5) with the rest scoring 6 – 8. Prior to the trial, 61.1% of the horses were scored 6-10 for the symptoms that were displayed. It is likely that the few horses that were scored moderate (6-8) for their symptoms at the end of the trial period had been showing multiple symptoms of digestive upset and a longer period of feeding the supplement would have helped to reduce the severity of the symptoms further.

On a scale of 1 – 5 with 1 being the horse didn’t eat the supplement and 5 being the horse ate it well, 92.9% of horses ate the supplement well with no issues. Only 3 horses were initially unkeen on the supplement with two of them eating well throughout the trial and one horse not eating the supplement and was therefore removed from the trial.  When asked if the participants would continue using this supplement 57.1% said they would and 33.3% said they might but would like to trial the supplement for longer before deciding. In terms of the feeding rate 85.7% of people found the feeding rate to be appropriate for their horse and 100% of people liked the smell of the supplement.




This trial aimed to assess owner reported efficacy of a current formulation used for a digestive supplement commercially available from Feedmark. Efficacy was tested using questionnaires to determine owner assessments of horse health based on common symptoms seen in horses with digestive issues. Results indicate a positive effect of feeding the product on reduction of symptoms seen and perceived effect on horse digestive health. Horses seemed to experience less symptoms and the severity of the symptoms was also lessened whilst being fed the trial supplement.

When fed in conjunction with a suitable feeding regime to manage digestive health, this supplement will support normal digestive function and comfort when fed to horses suffering from common digestive complaints.

Feedmark would like to thank the trial participants and their horses for being part of this trial and for their time in providing feedback.

The trial product used was Ultimate Gastro-Ease® which is available to purchase on Feedmark’s website

Ultimate Gastro-Ease® is a comprehensive digestive supplement which supports the foregut as well as the hindgut. Ultimate Gastro-Ease® contains ingredients which buffer the stomach acid helping to maintain a stable pH as well as protecting the sensitive stomach lining from acid splash. Pre, pro and postbiotics are also included to support hindgut function. Prebiotics provide a food source for the hindgut bacteria; probiotics help to establish a strong population of good hindgut microbes and support fibre fermentation whilst postbiotics further strengthen the gastrointestinal support that this product provides.






Ferrucci, F., Zucca, E., Croci, C., Di Fabio, V. & Ferro, E. (2003). Treatment of gastric ulceration in 10 standardbred racehorses with a pectin-lecithin complex. Veterinary Record, 152: 679-681.

Ganda, E., Chakrabarti, A., Sardi, M., Bobel, J.M., Kozlowicz, B., Norton, S.A., Warren, L.K., & Khafipour, E. (2022). A Postbiotic from Saccharomyces Cerevisiae Fermentation Improves Microbiome Robustness in Young Stress-Challenged Horses in Training. Journal of Animal Science, 100(S3): 292.

Lo Feudo, C.M., Stucchi, L., Conturba, B., Alberti, E., Zucca, E., & Ferrucci, F. (2022). Effects of a nutraceutical supplement in the management of mild equine squamous gastric disease in endurance horses. Vet Record, 189(11): e942.

Medina, M., Girard, I.D., Jacotot, E., & Julliand, V. (2002). Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large intestine of horses fed a high fibre on a high starch diet. Journal of Animal Science, 80: 2600-2609.

Morgan, L.M., Coverdale, J.A., Froetschel, M.A., & Yoon, I. (2007). Effect of Yeast Culture supplementation on Digestibility of Varying Forage Quality in Mature Horses. Journal of Equine Veterinary Science, 27(6): 260-265.

Rossi, F., Cocconcelli, P.S., & Masoero, F. (1995). Effect of Saccharomyces cerevisiae culture on growth and lactate utilisation by the ruminal bacterium Megasaphera elsdenii. Annales of Zoologici, 44: 403-409. 

Trench, M., Bobel, J.M., Bazurto, C., Dolly, J., Hansen, T.L., Kirk, N., Lopez, C., & Warren, L.K. (2021). Dietary Saccharomyces cerevisiae fermentate affects mucosal immunity in young stress-challenged horses in training. Journal of Equine Veterinary Science, 100: 103503.

van der Boom, R. (2022). Equine gastric ulcer syndrome in adult horses. The Veterinary Journal, 283-284: 105830.

Venner, M., Lauffs, S., & Deegen, E. (1999). Treatment of gastric lesions in horses with pectin-lecithin complex. Equine Veterinary Journal, supplement (29): 91-96.

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