An endoscopic examination aka gastroscopy is the only way to definitively diagnose ulcers but the following symptoms may be indicative of ulcers and mean you should be discussing the situation with your vet:

• Recurrent mild colic that seems to resolve without veterinary intervention
• Reluctance to go forward when ridden particularly if this is not normal for this horse
• Limited appetite
• Starts eating bucket feed and stops
• Poor condition and weight loss
• Starting or worsening of wind-sucking and/or cribbing
• Biting when being girthed

The squamous mucosa or tissue is about one-third of the horse’s stomach. It doesn’t have any built-in protection against the acid produced in the glandular region but instead relies on the almost continuous trickle of fibre and saliva entering the stomach to act as a physical barrier to the acidity and to buffer the acidity respectively. This is one of the key reasons why low fibre diets are so detrimental to gastric health. When the horse is exercised the stomach is compressed and if there is little or no fibre present, the acidic juices in the stomach can splash around and are in closer contact with the squamous mucosa. This increases the risk of ulceration occurring. In addition, feeding cereals which are high in starch, increases the level of acidity in the stomach which compounds the problem.

Feeding forage to appetite is the simple answer assuming the horse isn’t overweight. Horses will typically consume between 2 and 2.5% of bodyweight per day as forage when fed to appetite. Ponies may consume more so it is important to watch for weight gain as a result. In fact, the challenge of feeding enough forage to reduce the risk of ulcers without promoting weight gain was a key issue for many of the 650 horse owners that participated in a survey about managing good doers in 2021.

Clearly in many cases we do have to limit our horses’ access to grass to manage their weight and so what do we replace it with to find that balance between reducing ulcer risk but maintaining digestive health? Grass hay or haylage can still be too much for some good doers especially if fed to appetite and so restricting the amount fed is often necessary.

The increasing frequency with which ulcers is being diagnosed may account for why the recommendations for minimal dry matter intake tend to increase in more recent studies. Rendle et al (2020) cite 1.5% of the horse’s bodyweight on a dry matter basis which is the level most equine nutritionists would work to for the long term management of good doers. The veterinary perspective in some cases may be to restrict intake to below 1.5% in the acute scenario to deal with significant obesity, hyperinsulinaemia and acute laminitis but the aim should always be to return to 1.5% of bodyweight for the long term health of the horse. There are other potential health issues aside from EGUS to consider too. It has been shown in trials in mice for example, that a low fibre diet increases the permeability of the gut – a phenomenon known as leaky-gut syndrome. When fibre is fermented in the hind gut, one of the volatile fatty acids produced is butyrate and this is the energy used by the colonocytes (gut cells) themselves. Insufficient fibre and therefore butyrate, can compromise the health of the cells creating bigger gaps between them which allows contents of the gut that shouldn’t pass through, to do so. Therefore, the better strategy for feeding to maintain gut health without promoting excessive weight gain is to feed a lower calorie forage so that more can be fed.

The concern about using a true haylage for horses with ulcers is that the fermentation process used to conserve the forage produces acids and feeding a forage with increased acidity levels would not be helpful in trying to manage EGUS. However, a more accurate description of many so-called haylages would be ‘wrapped hay’ as they are often very dry which has meant that little or no fermentation has occurred. This means the levels of acidity are no different to a normal hay which can be seen in table 2. A possible benefit of using wrapped hay is that it may well have been harvested earlier and so is likely to be more digestible meaning that the horse is likely to do better on it. Forages containing more moisture and cut earlier are often more palatable which is useful for poorer doers who may not have a big appetite. For poor doers, feeding forage to appetite is ideal as there is no reason to restrict them.

Table 2 – A comparison of different forages (data from Dengie analysis records and Muller and Uden (2007))

UK pastures and forages produced from them, lack a number of key trace minerals including zinc, copper and selenium and so even horses and ponies at rest or in light work, benefit from a source of these essential nutrients. They are important for many different functions such as energy breakdown and utilisation and as part of the body’s antioxidant defence system. Topping up these nutrients by adding a broad-spectrum vitamin and mineral supplement or balancer helps to ensure a balanced diet is supplied.

Feeding a double handful of a chopped fibre feed in the 20-25 minutes before exercising is also recommended to help prevent ‘acid splash’ in the squamous region of the horse’s stomach. The fibre ensures the stomach isn’t empty and suppresses the movement of the acidic contents when the horse moves. If a horse has been eating grass or forage then this performs the same function.

For poorer doers and those in harder levels of work, forage may not be sufficient to keep them in an acceptable condition and so the bucket feed is an important part of the ration. There are a range of feeds with the BETA approval mark for horses and ponies prone to EGUS which range in ingredients and type. This is an independent assessment of the suitability of a product for those prone to EGUS. Part of the approval process involves the Veterinary Medicines Directorate – a government agency responsible for ensuring medicines are safe and efficacious as well as ensuring false claims aren’t attributed to products such as feeds and supplements. Choosing an approved product means you can be sure companies are not making claims about products they can’t substantiate.

Alfalfa has really deep roots – about 3 to 4 metres – and the calcium at this depth in the soil is more available for absorption. This means that alfalfa plants can take up more calcium than grass – chopped alfalfa contains between 30 and 50% more calcium than grass forages. Early studies suggest that omeprazole is reducing calcium absorption in the horse as is seen in humans and in Swanhall et al’s (2018) study, they recommend using bio-available calcium sources in the diet to help counteract this effect. Plant based sources of calcium such as alfalfa are much easier for the horse to absorb than inorganic sources such as limestone flour.

Researchers suggest adding around 200grams, which is about half a Stubbs scoop, when cereals are fed to help counteract the increases in acidity generated by the starch.  In many cases, high quality fibre sources can be used to provide the horse with sufficient energy for the work they are doing reducing the need to feed cereals and thereby reducing starch intake. This has been demonstrated in a recent study by Martin et al (2023) who showed that horses in training fed a third of their total ration as alfalfa with just 7% oats performed comparably with those fed 33% oats (the remainder of the diet was hay). The replacement of oats with alfalfa had no detrimental effects on performance or muscle tone and in fact, altered energy metabolism in such a way as to potentially improve performance and recovery.

Like other plants alfalfa makes sugar when photosynthesising but it stores any surplus sugar as starch in its roots – the part that horses don’t eat! Grass plants tend to store sugar as fructan in leaves and the stem which is why they supply the horse with more sugar.

There has been a study published that has caused confusion about the use of alfalfa. It explored the incidence of ulcers in foals and used the weaning process to induce ulcers. The researchers then compared groups fed alfalfa chaff or alfalfa pellets or hay. Foals were fed 3kgs (7.5 Stubbs scoops) of alfalfa chaff (way more than is typically used or what would typically be recommended for foals), 2.7kgs of oats and 0.25kgs of soybean meal. It’s also important to note that the alfalfa chaff used was 40% lower in calcium than the alfalfa pellets used. Evidence of EGGD was found in foals fed alfalfa chaff but not in those fed alfalfa pellets or hay but none showed any clinical signs. It is important to reiterate the link between stress and EGGD; those foals might well have had EGGD regardless of what they were fed – as evidence from other studies suggests. The same research group have recently published another study comparing grass and alfalfa hay in adult horses and found no issues with feeding alfalfa (Bauerlein et al, 2020)