Biodiversity – the key to equine health?

As grazing herbivores, horses are finely tuned to consume a continuous supply of forage, which provides a low protein, high fibre diet.  Ideally, horses should be grazing 16-18 hours per day on high fibre grasses, plants and herbs, creating natural biodiversity within the diet.  Providing forage biodiversity can help support optimum health and nutrition but what exactly is biodiversity, and what are the benefits for you horse? – Lisa Elliot, Msc – our expert nutritionist here at castle horse feeds, explains more:

What is Biodiversity?

Biodiversity simply means ‘biological diversity’ and within grassland it is defined by the levels of species richness within the grasses and plants.

Generally, grasslands with one to nine plants per square metre are considered species poor, those with nine to 15 species per square metre are moderately species rich, and those with 15 to 20 + species per square metre are species rich.

Much of the present UK grazing falls into the first category, generally having a history of agricultural improvement and re seeding with agricultural grass and legumes. They are usually abundant with perennial ryegrass, which is ideal for fattening up cattle but not so ideal for horses, who need a higher level of plant biodiversity for optimum nutrition.

True species rich grassland containing many different grasses, plants, herbs and wildflowers is the healthiest type of grazing for horses but is now one of the UK’s most threatened. Agricultural practices mean that UK grass and meadowland has tragically lost 95% of its biodiversity. This means there are now fewer than 1000 hectares of biodiverse grassland left, representing 0.03% of the total 3.1 million hectares of UK grassland. These remaining species rich grasslands have been given SSSI status (Sites of Special Scientific Interest) and need careful management to maintain and protect their biodiversity.

The Benefits of Biodiversity

Species rich, biodiverse grassland and meadowland containing a variety of grasses, plant species, herbs and wildflowers will provide horses with a wide range of vitamins, minerals and essential antioxidants, helping to optimise health and boost immunity.  Additionally, traditional wild grasses found in species rich grassland are lower in sugar and calories than ryegrass-based grazing, reducing the potential for obesity and laminitis.

Probably the greatest benefit of providing plenty of forage biodiversity in your horse’s diet, is its impact on the microbes in your horse’s hindgut or in other words the hind gut microbiome:

Recent research (Dougal et al. 2013; Costa et al 2012) has indicated that the equine hindgut microbiome contains a diverse range of bacterial species. This diversity is associated with a healthy microbiome, with a loss in diversity being linked to digestive disease and upset.   A diverse diet promotes a diverse microbiome, which in turn promotes a healthy hindgut, and a healthy hindgut = a healthy horse.

Within the hindgut microbiome are different groups of bacteria. One of these, the Firmicutes, are major contributors to a healthy microbiome and are more abundant in healthy horses as opposed to those with compromised hindgut health (Venable et al. 2016).  This beneficial group of bacteria also produce the Volatile Fatty Acid (VFA) butyrate as an end product of fibre digestion.  Butyrate has many benefits for the hindgut because it is a source of food for gut wall cells, promoting gut wall health and integrity, but also supports immunity, tissue repair and is anti-inflammatory.   Firmicutes thrive on a diverse variety of complex fibre, so providing plenty of forage biodiversity within your horse’s diet will help support these beneficial microbes for optimum hindgut health.

Tips for increasing Biodiversity in your horse’s diet

If you are lucky enough to own your own grazing and want to increase biodiversity within your grass, this can be achieved through good management:

  • Avoid fertilisers – reducing fertility in the land will encourage a greater diversity of plant species which have adapted to thrive in nutrient poor soils.
  • By cutting out fertiliser, rye grasses will decrease, and wildflowers will better compete, creating a more diverse grassland.
  • Consider shutting off an area of pasture on a rotational basis from April to November to allow wildflowers and grasses to flower and set seed. This is also beneficial as a standing hay crop for horses over the winter.
  • Avoid grazing grass below 2.5cm as this can cause damage and loss of plant species.
  • Remove droppings regularly to avoid ‘latrine’ areas developing which horses will avoid, putting more grazing pressure on other areas of the field.
  • Droppings that aren’t removed will put nutrients back into the pasture at the detriment of more sensitive plants that may be more beneficial for horses.

Getting your grassland surveyed to see what it already contains is a great idea.  If you would then like more species within it, re-seeding is the best place to start.  Look for a seed mix with a variety of grasses, herbs and wildflowers, to provide high fibre forage.  Good horse friendly grasses include cocksfoot (Dactylis glomerata), red fescue (Festuca rubra), Sheep’s fescue (Festuca ovina) and crested dogtail (Cynosurus cristatus). These grasses are also tougher with robust root systems and can better withstand bad weather and environmental conditions.  Seed should be sown in late autumn through to early spring.  It can take years for plants to become established and to flower, but it is always well worth the wait. Not only will biodiversity in your grazing benefit you and your horses but it will also have a positive impact on wildlife by providing a habitat for birds. butterflies, bees and other animals.

Hedgerows and roadside verges are probably the best places left to find biodiversity and will provide plenty of varied forage. So, take your horse for a wander alongside quieter verges and hedgerows and go browsing! This has the added bonus of increasing the bond between you as you meander along the lanes together.

If your horse is stabled due to grazing restriction or during winter, try and feed a good mixed species meadow hay to inject some more biodiversity into the diet.  A mix of hay and haylage along with chopped meadow grass and various herbs will also add more interest and diversity.  Forage enrichment like this also has the added benefit of helping to reduce stress when stabled, as it enables your horse to satisfy his natural desire to forage and browse.

For more information on creating, restoring and maintaining species rich pasture for horses visit

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