Nutrition CPD November 2015

85

What do horses eat?

Nutrition plays a significant role in equine health and welfare, so it’s difficult not to discuss feeding within any healthcare conversation. For SQPs, therefore, a working knowledge of nutrition means a better service to clients, says Ruth Bishop. 

The dietary options on offer in any store are many and varied. No wonder the choice of product can sometimes be quite overwhelming for consumers. 

The spectrum of feedstuffs is very wide, with intake ranging from many kilos per day to a few grammes. The major categories are as follows -

Of course there’s some blurring of the edges between categories as some products sit between two, for instance mixes containing high proportions of fibre. 

Horses mainly eat forage, in the form of grass, hay or haylage; forages are what horses are designed to eat, and are essential for a healthy horse. Forage is capable of supplying the energy, fibre and protein needs of a horse, especially one at maintenance or light work – although essential micronutrients will in many cases need topping up.

At least 50% of the daily diet should be forage, but in most horses it is significantly greater than this – typically over 80% of the daily diet in many horses kept for leisure purposes. 

Grass

Good pasture contains an even cover of palatable grasses, free from weeds, and provides a rich source of nutrients from energy and protein to vitamins, minerals and plant phytochemicals. 

Horses thrive at grass - physically and mentally – but some do too well, gaining excess weight. A recent survey of predominately outdoor living horses found that over 30% were overweight. 

The amount of nutrition that grass provides varies according to the time of year, the grazing management, the number of horses (or other animals) grazing the land and how long the horse is turned out for. Good grass is generally equivalent to a medium or high energy, high protein feed. It’s at its very richest in spring (and often again in the autumn), when the protein content can be above 20% and the energy content equivalent to that of a racing feed. Actively growing grass can be rich in sugar – as much as 3% of every mouthful, and this together with fructans, a storage form of plant sugar, has been implicated in the incidence of pasture-associated laminitis. 

Poor grazing isn’t as rich, but a horse turned out for several hours a day can still easily receive more from its pasture than it will from most low energy feeds.

Hay

Hay is dried mature grass, normally in the form of either:

• Seed hay - usually perennial ryegrass varieties, timothy or specialist blends of them, grown and sown specially for hay. Seed hay tends to be quite coarse in nature with a relatively low energy and protein content; or 

• Meadow hay - from pasture permanently kept as grass, usually comprised of a more varied mixture of grass species, and tends to be softer and finer with a higher nutritive value than seed hay.

As a general rule of thumb, small bales weigh about 20kg, with large bales weighing 250-350kg depending on size. A slice or section from a small bale typically weighs about 2kg / 4lbs.

The main concern with hay is its hygienic quality: moulds, spores and other dust particles that develop during harvest or storage can cause respiratory irritation and lead to the development of Recurrent Airway Obstruction (RAO) in horses. 

Soaking and steaming Hay

Unless it’s been expertly dried in controlled conditions (there are suppliers who do this), UK hay is likely to contain some mould and dust. Soaking or steaming hay are popular ways of removing any dust, by either removing the particles, or effectively ‘sticking’ them to the grass stalks so that they are consumed rather than inhaled. 

Soaking time

Research has shown that 30 minutes’ soaking is effective. Soaking hay also causes some loss of nutritional value as some soluble sugars and proteins are leached out into the water; more soaking equals less nutritional worth. Owners of laminitis-risk horses can take advantage of this to reduce unwanted sugar contents.

Haylage

Haylage is grass that is baled moist (typically 35-40% moisture) and then bagged or wrapped to keep the air out and moulds from forming. It’s popular with growers because it’s easier to make than hay, and with horse owners because of its low dust and spore content. Plastic packaging means it can be stored outside.

Disadvantages are that quality can be variable between different suppliers. Also portioning can be a challenge, since the bales don’t often break into easy slices. Moisture content can be variable between suppliers, ranging from 20-50%. 

Small haylage bales weigh about 25kg, whereas large wrapped bales can be 180-250kg or greater.

Haylage tips for SQPs

• Up to 50% of haylage can be water, compared with 15% in hay, so it cannot be fed on a weight-for-weight basis with hay; advise feeding about 1½ times the weight of haylage as hay.

• The quality of the airtight seal is essential. Air ingress will allow mould growth in the bales. Small bales may split at the seal, large bales can be punctured by haylage stalks or from bird, rodent or mole damage.

• Quality is all important, so choose a supplier with a good reputation and ask for an analysis of their product. 

• A good rule of thumb is to use a bale within four days of opening (less in summer) as moulds start to grow again immediately the bale is opened.

• Avoid feeding visibly mouldy haylage and “gritty” or soil contaminated material, as there could be a risk of listeriosis.

Forage analysis

Hay and haylage are often thought of as an inert and safe nutritional bases. However because they constitute such a large part of the diet their contribution is worth monitoring especially if the horse competes, is at risk of laminitis, has Cushings disease etc. Energy, protein and sugar contents can vary depending on the grass species, date of cutting and the weather during cutting and baling. Sugar contents can exceed 10% in some forages. Nutritional value can be quantified by a simple test, a service offered by many feed manufacturers.

Ad lib forage feeding

Many owners feed on a free access or ad libitum basis to ensure the horse always has forage available. Actual individual amounts consumed should be monitored though as offering ad lib doesn’t always mean an optimum intake especially where several horses share the forage, or if the quality is variable.

Chaffs and forage replacers

A number of chopped fibre products are marketed as forage replacers. Chops and chaffs that can be added to the hard feed to bulk it up or slow down the rate of eating. There is some evidence to show that horses take longer to eat short chop forages than they do hay or haylage. 

There are also complete fibre feeds available fortified with protein, vitamins and minerals etc., designed as the full compound feed. These aim to fit more closely with the digestive physiology of the horse, and are particularly good for horses or ponies prone to laminitis and digestive issues such as gastric ulcers.

Compound feeds

Compounds are balanced blends of ingredients formulated to meet the requirements of horses when fed in conjunction with forage. A recent survey found 87% of owners feed some form of compound, the majority of which was commercially prepared. 

The market for compound feed is highly fragmented with different products and product forms for every kind of horse or pony (see table below). Balancers are concentrated, nutrient-rich versions of compounds, and the balancer category has itself recently become more fragmented along similar lines to compound feeds.

FeedDescriptionTypical feed rate
Low energy / High fibreCubes and mixes with a high fibre content designed for horses at maintenance, in light work, or
for horses that work well off low energy feeds.
1-4 kg per day
Senior feedsCubes and mixes with additional nutrients for older horses. Some come in low-and high-energy form; some contain joint support ingredients.1-4 kg per day
Feeds for laminiticsUsually in fibre-mix or cube form, low energy, high fibre, low starch and sugar complete feeds. Capable of replacing the total diet of at risk animals.1 -10 kg per day
Competition feedsMedium energy cubes and mixes with higher vitamin and mineral contents designed for the working and competing horse or pony.2-6 kg per day
Conditioning feedsHigher energy and protein feeds designed to put on weight. Some are starch based, but more modern versions are high in fibre and oilto ensure condition is achieved without increased excitability.1-3kg per day
Stud and breeding feedsHigh energy, protein and mineral feeds designed for breeding stock.2-6 kg per day
Racehorse feedsHigh energy cubes and mixes
for horses in training or intense work. Traditional products are starch based, but modern variants use alternative energy sources such as oil and digestible fibre to support digestive health and aid performance.Some companies offer low energy lay off or rest and recuperation variants for horses on the easy list.
5-7 kg per day
Feed BalancersConcentrated nutrient-rich pellets, supplying essential amino acids, vitamins and minerals. Commonly marketed to complement high- forage diets, but also as top-ups to existing diets or when cereals, eg. oats, form a large part of the diet.250g – 1kg

Supplements

Supplements augment the nutrition provided by the main part of the diet. They come in a variety of forms; powders, herb blends, liquids, pastes, pellets, licks - and in a variety of packaging.

Under regulations governing animal feed, supplements are considered “complementary compound feeds” as are cubes, mixes and balancers. However in the horse owner’s eyes, they fulfil a different role, tailoring individual diets to meet specific needs.

Supplements are used regularly, with estimates of their use in 80% of equine diets. 

There are two main categories of supplements:

- Broad-spectrum: providing a broad spectrum of major and trace minerals together with vitamins, these are designed for topping up micronutrient levels where little or no hard feed is fed. There’s some blurring of the edges here between balancers and broad spectrum supplements in terms of the nutrients they supply. Balancers tend to be in pelleted form whereas supplements can be in the form of a powder or a lick.

- Specific: providing an ingredient or mixture of ingredients designed to perform a specific function. These range from daily addition of salt and/or oil to the diet to more targeted support, eg. for joints or hooves.

The top five specific nutritional concerns of horse owners are hoof quality, joint quality, colic, care of the senior horse and laminitis. Behaviour also ranks highly especially related to supplement purchases. Different companies takes different approaches to each functional area, and the following table gives some examples of these.

Medicinal claims for supplements and feeds are not permitted. There is an exception for laminitis, but only in relation to a product’s (low) starch and sugar content. Claims linking laminitis and hoof health are not permitted.

Category
Examples of typical product approaches
Behaviour - Nutrients and herbs associated with calming or modifying behaviour eg. magnesium
- Probiotics – in case behaviour is caused by digestive discomfort
Joint
support
- Support to the cartilage via providing building blocks for cartilage formation e.g. glucosamine, chondroitin sulphate, MSM, collagen
- Increased antioxidant support to combat free radicals in the joint- Substances added to support joint comfort
Hoof- Nutrients to support hoof growth and development - Biotin is research proven but other vitamins, amino acids and trace elements can also be added.
Skin and coat- Oils, particularly sources of omega 3 fatty acids
- Nutrients and herbs that help coat and skin quality
Digestive support- Probiotics in the form of yeast designed to help support a healthy hindgut microflora
- Prebiotics made up of specific carbohydrates that support the growth of beneficial microflora in the gut.

About the author: Ruth Bishop is a director Ruth Bishop Consulting Ltd. She has 25 years’ research and development experience in animal nutrition both in consultancy and commercial roles in major food businesses including Dalgety and Mars. She is a former technical director of Mars Horsecare and works with feed industry trade associations.