Alfalfa: what do the latest studies reveal?
By Dr Katie Williams, technical and product development manager at Dengie.
Alfalfa (Medicago sativa), also known as lucerne, has been cultivated as fodder for horses for over 2,000 years. It originated from Iran before spreading across the world as Persians, Greeks and Romans expanded their empires, taking their horses and their feed with them.
Alfalfa is a highly nutritious forage crop and so it’s probably no surprise that more than 250 million tons is now grown globally every year. Due to its value as a sustainable, plant-based source of protein in particular, there has been a resurgence in the number of studies being carried out exploring its benefits for humans and animals.
Why is alfalfa so abundant in protein?
Alfalfa belongs to the legume family – the same as peas, beans and clover – and has a complex root system which runs deep into the soil accessing water and nutrients from deep into the earth. That abundant root network is also where rhizobia are found and they fix nitrogen from the atmosphere and convert it into a form the alfalfa plant can utilise and incorporate into its own tissue. The animal that eats the alfalfa plant then gets the benefit of that quality protein.
To put this into context, a pure alfalfa, chopped fibre feed, supplies around twice the amount of lysine found in average grass hay and just two Stubbs scoops (around 800g) can deliver around 20% of the lysine requirement for a 500kgs horse in light work. As alfalfa pellets are heavier, just one scoop provides an impressive 45% of requirements for the same horse.
The amino acid levels provided by alfalfa frequently exceeds many supplements marketed as muscle building or for improved top line. Feeding just 2-3 scoops of a chopped alfalfa or 1kg of alfalfa pellets daily will deliver higher levels of most amino acids than many muscle supplements based on whey or pea protein and one mug a day of alfalfa pellets will supply greater levels of many amino acids than the recommended amount of spirulina-based muscle supplements, including around three times the lysine content.
Unsurprisingly, alfalfa is much more cost-effective to feed than supplements and also provides valuable fibre too.
So can more alfalfa be fed to performance horses?
Researchers at the Lab to Field research centre in Dijon, France believe so. In work funded by the French government and published in Frontiers in Physiology, they found that Standardbred 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 horses were monitored over an 8-week period rather than just in a one-off standardised exercise test (SET). The replacement of a significant proportion of oats with alfalfa had no detrimental effects on muscle tone; an increase in muscle size (specifically the gluteus medius) was seen in both groups so a predominantly forage diet did not seem to compromise muscle development. There was no compromise on performance either and in fact, energy metabolism was altered in such a way as to potentially improve performance and recovery according to the authors (Martin et al., 2023).
Alfalfa and gastric health – what’s the latest?
The RSPCA’s ‘Horse Sense’ report published in 2025 highlights various factors contributing to an “equine crisis”. One of the issues listed was gastric ulcers and whether you agree with the findings of the study or not, the fact it is being highlighted means it is an issue that needs to be taken seriously in the context of equine welfare.
Studies back in the early 2000s (Nadeua et al, 2000; Lybbert et al, 2007) showed that alfalfa was more beneficial for horses with ulcers compared to grass forages because the abundance of minerals such as calcium meant that alfalfa acts as a buffer to acidity in the stomach.
More recently, Julliand et al (2025) set out to explore just how effective a buffer alfalfa is by carrying out a lab experiment where they measured the amount of acid needed to decrease the pH down to 4; pH 4 is recognised as the level below which damage to the squamous tissue in the stomach occurs. Significantly larger quantities of hydrochloric acid were required to decrease the pH of alfalfa; 3-5 times more than wheat bran which was used for comparison.
This finding backs up another study that used a combination of alfalfa, sugar beet and cereal fibre fed alongside the existing ration, which found a reduction in recurrence of gastric ulcers. Again, the authors attribute the findings to the abundance of calcium and therefore buffering in the ingredients (Menzies-Gow and Shurlock, 2024).
The Lab to Field research group has also demonstrated clinical success in a real-world situation. Standardbred horses in race training were 47.7 times more likely to recover from Equine Gastric Glandular Disease (EGGD) if fed alfalfa pellets as part of their ration compared to those on concentrate only rations (Julliand et al., 2023).
What about the format of the alfalfa?
The increased chew time from adding a chopped fibre to the bucket feed has long been recognised. The recent trend for mashes is counter-productive when it comes to saliva production and therefore promoting the horse’s own mechanism for regulating acidity levels in the stomach.
The amount of saliva produced when a horse chews is related to the amount of force the horse needs to apply (Vervuert, 2012). So more fibrous materials help to increase saliva production and therefore more natural buffering in the digestive tract than softer ones. Whilst mashes and pelleted fibres contribute fibre, they don’t require as much chewing and so do not generate as much saliva.
This phenomenon is supported by a recent study that found unmolassed sugar beet pulp mash resulted in a greater drop in pH (increase in acidity) in the horse’s mouth than other feed materials including alfalfa and haylage, which the authors suggest could be related to the fact it requires less chewing (Daniels et al, 2024). Whilst the level of acidity returned to normal within 15 minutes and so doesn’t represent a cause for concern in the context of dental health, it demonstrates the importance of chewing for saliva production which has benefits further along the digestive tract in the stomach. So the recent trend for feeding mashes rather than chopped fibre may well ultimately prove to be detrimental for gastric health.
Quality matters
A key point from these studies is that the quality of fibre matters. Alfalfa and sugar beet both contain higher proportions of digestible fibre such as pectin and hemi-cellulose, rather than indigestible fibrous elements such as lignin. This means they aren’t sitting in the gut for so long and are being digested and utilised as an energy source by the horse more easily.
The nutritional content of alfalfa is at its highest when the plant material is still young and so conserving alfalfa before it matures is key. This is commonly done to produce chopped and pelleted fibres in the UK and Europe in contrast to countries such as the USA where alfalfa is allowed to mature and so is more commonly fed as hay.
The drying techniques used to conserve chopped or pelleted alfalfa also mean they have an exceptional hygienic quality. Symoens at al (2025) compared alfalfa pellets with steamed hay in horses diagnosed with Severe Equine Asthma (SEA).
They were fed either steamed hay or alfalfa pellets for 4 weeks, at approximately 2% of their bodyweight per day. Although both forms of forage lead to a significant improvement in clinical signs, feeding alfalfa pellets lead to a greater improvement of lung function and tracheal mucus which was sustained in contrast to the steamed hay. With alfalfa pellets there was significant improvement in lung function after 1 week and close to normalisation after 4 weeks.
This is significant as the authors report that normalisation is not always achieved even with a longer period of 6–12 weeks. The horses on steamed hay did not sustain their improvement which was unexpected.
So these recent studies demonstrate how alfalfa is an important source of nutrition and has other benefits for equine health. Utilising ingredients like alfalfa, that are both sympathetic to the horse’s digestive system and have benefits for biodiversity, soil structure etc, clearly makes sense in an age when equine welfare and sustainability are key issues for our industry
References
- Daniels SP, Whiteside EJ, Martin S,Moore-Colyer MJS, Harris P. Straight from the horse's mouth: The effect of different feedstuffs on oral pH in horses and ponies. J Equine Vet Sci. 2024 Nov;142:105181. doi: 10.1016/j.jevs.2024.105181. Epub 2024 Sep 4. PMID: 39241897.
- Julliand, S., Julliand, V. and Grimm, P. (2025) Biochemical composition of feed ingredients influences equine gastric ecosystem activity in vitro. Animal Feed Science and Technology
- Martin A, Lepers R, Vasseur M, Jullian S. (2023) Effect of high-starch or high-fibre diets on the energy metabolism and physical performance of horses during an 8-week training period. Front Physiol.
- Symoens A, Westerfeld R, Vives BM, André V, Moulon L, Collomb M, et al. Steamed hay and alfalfa pellets for the management of severe equine asthma. Equine Vet J. 2025;57(3):756–65. https://doi.org/10.1111/evj.14209
