Nutrition CPD October 2016


Supplementing the equine diet

By Kate Hore RNutr(Animal), senior nutritionist with NAF

Any bucket feeds should also be based on short chop fibre and split between multiple feed times to mimic grazing.
Horses and ponies evolved as trickle grazers which means, as most of us know, they love to eat all the time! 

Around 16 to 18 hours grazing per day is normal for horses allowed free access to pasture. This habit of eating for hours isn’t greediness, but a natural adaptation which allows horses to effectively digest tough, fibrous plants, and extract their required energy, fibre and nutrients from that.

As horse owners, and advisors, this means that if we want to keep our horses and ponies happy and healthy we should be basing their diet predominantly on forage, ie. grazing, hay or haylage. 

Natural diets, high in fibre and low in starch, have been shown to improve behaviour and reduce the risk of a number of common health issues such as Equine Gastric Ulcer Syndrome (EGUS) and laminitis. Ideally, any bucket feeds should also be based on short chop fibre and split between multiple feed times to mimic grazing. 

Balancing the diet

The only real issue with this natural diet is that it can be lacking in nutrients required for health and vitality, particularly the micronutrients – vitamins, minerals and trace elements. It’s a fair question to ask - why, if it’s so natural, is the forage diet not meeting our horses’ dietary requirements? 

There are a number of reasons as to why this might be. Firstly, grazing for the modern horse lacks the variety of the shrubs, herbs, legumes and trees available to natural horses. Studies have shown wild horses graze a huge number of species, and will even select different herbs and grazing dependent on the time of year. 

Conversely, modern grazing usually only contains one or two species of grass and, perhaps, a legume. So it’s important to put back some of the variety in the diet. Secondly, areas of soil deficiency for certain nutrients are common in the UK. This deficiency will be passed to the grazing and also to the forage harvested in that area. Therefore, again, it’s important to balance up those deficiencies. This is where supplements are advised.

Broad spectrum supplements contain the required vitamins, minerals and trace elements, and are available as powders, liquids or pellets; the choice of which is usually personal preference. 

A good quality product will be designed to balance what is naturally provided in a high fibre diet, rather than, for example, providing 100% of RDI (Recommended Daily Intake) for all nutrients - which rather implies the horse shouldn’t eat anything else at all! 

Remember, over-supplying just means the horse works harder to excrete excesses, or runs the risk of stores building within the system. So look for a balancing product to suit that horse, their age, work load and body condition score. For working equines, and where maintaining condition is important, supplements will usually include gut support. The harder the horse works, the harder the gut works – and keeping the gut happy and healthy is the secret to keeping the horse happy and healthy. 

That gut support may be live probiotic yeast, such as Saccharomyces cerevisiae for the hind-gut microflora; prebiotic sugars, which support the role of the probiotics; natural antacids, such as calcium carbonate, or herbal gut support from plants including mint, ginger and psyllium. 

Brewer’s Yeast is also commonly included and is an inactive form of Saccharomyces cerevisiae, meaning the yeast is killed off so doesn’t have a probiotic action, but it’s a useful source of B vitamins, and is considered to support gut health as a prebiotic. 

Both probiotic yeast and brewer’s yeast commonly appear together in products, and can cause confusion when reading the label, so it’s worth understanding the difference. 

The live probiotic will be listed as Saccharomyces cerevisiae in the Additives section of the label, and will have a ‘cfu’ (colony forming unit) figure telling you the inclusion rate of the yeast. Brewer’s yeast may be listed as ‘Saccharomyces cerevisiae (inactive)’ and will be under Composition, as it’s classed as a feed material rather than additive. This explains how ‘Saccharomyces cerevisiae’ may appear twice on a label from very different ingredients. 

The final combination of gut support used in a product will depend both on the manufacturer, and the type of horse the product is designed for. 

Feed balancers, which are concentrated, nutrient rich feeds typically fed at between 100g – 500g per day, are really just an extension of this. Balancers usually include gut support alongside vitamins and minerals for health and vitality, so are a form of broad spectrum supplement, generally fed as pellets. 


Once the diet is balanced, supplements can then be considered which go beyond simply diet balancing to target various areas of health specifically. The term ‘nutraceutical’ is a fairly new one, but simply means using nutrition as a therapy tool. 

This is nothing new, herbal veterinary formulae can be found recorded in the pyramids of ancient Egypt. And increasingly, ‘old wives tales’ are being validated through scientific research. 

We all know the power of plants, whether we think we do or not. For example, would you casually chew on some deadly nightshade, or let your horse graze ragwort? So if we know certain plants can be powerfully harmful, it’s not a big leap to understand that others can be powerfully beneficial. 

The science of supplements is putting the right combination of those plants and natural ingredients together to support health. Nutraceutical supplements can cover all areas from a simple biotin and zinc blend for hooves, through technical combinations of glycosaminoglycans (GAGs) for joint health, to innovative herbal antioxidant complexes to flush out oxidative stress.

Legal classification

All supplements are legally classed as complementary feed and, as such, come under EU feed law, which prevents any medical claims being made. 

While this is a good thing in preventing unsubstantiated claims, it does mean manufacturers are restricted in how they market their supplements, particularly for the targeted nutraceuticals. So if you’re unclear as to whether a supplement is appropriate for a particular horse or not, discuss it with the manufacturer who should be happy to advise. 

In conclusion, supplements can basically be split into two groups – those designed to balance the diet, whether covering deficiencies or replacing what has been lost through work, and those designed to be used in a targeted way for specific health support.