Nutrition CPD November 2018

57

Understanding forage

By Clare Barfoot RNutr, research and development manager at Spillers. 

Forage should make up the majority of the horse’s diet. However, with the UK’s swelteringly hot, dry summer following hard on the heels of a cold, wet winter, some of your customers may be struggling to find a healthy source of forage over this coming winter.

But horse owners don’t need to panic if there is a winter hay shortage, because there are plenty of forage alternatives to choose from. 

You can be a big help to your customers if you have the facts and figures about fibre and forage at your fingertips and it could help boost sales too. 

Forage: the key facts

Fibre provided by forage is the mainstay for equine digestive health. It is made up of structural carbohydrate and it is this that horses need to keep their gut and the microbes that colonise it happy.

Every horse or pony should have a minimum fibre intake of 15g/kg bodyweight (dry matter) per day, which is approximately. 9kg of hay or 10.5kg of haylage for a 500kg horse. Ideally horses should be fed fibre ad lib, unless on a specific restricted diet.

Why horses need fibre

Horses are herbivores, meaning they have evolved to digest a vegetarian herbaceous diet. The horse has formed a very special symbiotic relationship with the microbes that live in its hindgut. The job of these microorganisms is to ferment and break down fibre to produce volatile fatty acids, which are used as a form of energy for the horse. 

If a horse doesn’t receive enough fibre there are many negative consequences including an increased risk of gastric ulcers, colic and weight loss. Mental wellbeing can also be affected if horses are unable to forage and chew for around 16-18 hours a day as they have evolved to do.

Hay and haylage

Whether your customers choose hay or haylage, the golden rule is to go for the best quality they can. Poor quality forage may contribute to weight loss, respiratory problems and even colic. 

The nutritional differences can vary just as much between hays as between haylage and hay. The main consideration is how much to feed; a few years ago most horse owners believed that haylage was nutritionally richer than hay and should be fed in lesser quantities. In fact haylage contains more water than hay (at least double the amount!) so it’s useful to remind your customers that they actually need to feed more haylage (approximately 20-50% more by weight) to provide the same level of fibre and nutrition. 

The main advantage of haylage is that it is damp. This means any mould spores that are naturally present will swell up and be less likely to travel deep down into the sensitive areas of the lungs where they could contribute to conditions such as recurrent airway obstruction (RAO). Haylage is, however, best avoided for horses prone to laminitis or tying up.

Advising your customers on how to choose hay or haylage

For hay…..
• It should smell sweet and pleasant; any musty or mouldy smells should be treated with suspicion.
• The colour can vary from light yellowy green through to bright green. It is often perceived that the greener the hay the higher in protein it is but you can’t really tell without analysis.
• It shouldn’t be damp to the touch; if it is it may not have been dried properly and may be at more risk at going mouldy.
• Look for any visible signs of mould.

For haylage…
• Haylage should be well wrapped with at least six layers of plastic. Don’t buy it if there are holes in the plastic film as air will be allowed to enter and start the growth of yeasts and moulds.
• Again haylage should smell sweet and often slightly fermented but not too acidic like silage.
• Make sure there is no obvious soil contamination, as this can increase the risk of botulism.

Looking out for seniors

Seniors often need some extra special care and should all be treated as individuals. It’s helpful for your customers if you can signpost your senior-suitable feeds, especially those that have been veterinary approved, to give added reassurance.

A mash may be more appropriate for those with dental issues, for fussy types a mix may be more suitable or for good doers a balancer and a short chopped low calorie fibre may be the best option. The overriding priority should be to tailor the diet to individual needs.

Alternative forage options

As yet, the extent of any potential shortage of winter forage is unclear, although it’s likely that quantity and quality may be reduced and prices may go up accordingly. But your customers don’t need to worry because you can supply them with numerous hay and haylage alternatives that can replace or extend their winter forage supply.

Straw: Good quality straw is particularly useful for good doers and overweight horses to decrease the energy density of hay. The type of straw is less important than the hygienic quality, although oat and barley straw are used more commonly than wheat. Straw shouldn’t be used as the sole forage source though as the protein content is very low and the fibre can be particularly indigestible, which can contribute to impaction colic in susceptible horses. Up to 30% replacement is acceptable.

Chopped dried grass: Dried grass differs from hay because it is harvested earlier and is dried artificially rather than in the field. It is much greener in colour than hay and is often higher in protein and energy. It’s ideal for poor doers and veterans but shouldn’t be used to completely replace forage and should be avoided for laminitics and good doers. 

Grass nuts: Harvested and dried in a similar way to chopped dried grass, nuts are pelleted rather than chopped. The protein content is higher than hay and the fibre content is lower so they provide more energy per kilo. They not suitable as a complete hay replacement but can be useful for poor doers and veterans. The high water soluble carbohydrate (WSC) levels make them largely unsuitable for those prone to laminitis. 

Sugar beet: Soaked sugar beet is a palatable way to add fibre into your horse’s diet. It can’t be used to completely replace hay because it’s 80% water once soaked and doesn’t require much chewing – which is physically and psychologically important for horses. But, there is some evidence that feeding sugar beet can increase the digestibility of hay.

Short chopped fibres: These can be a useful option. Some contain vitamins and minerals in addition to chopped straw, grass and alfalfa. Likely to be particularly useful this winter are products that can completely replace hay due to their similar levels of protein, fibre and energy. Often these products are also suitable for laminitics and good doers.

Soakable fibre products: Often these can partially replace hay due to their high fibre and low sugar and starch content. Advise your customers to choose products that have protein levels of 8-10%, which is similar to hay. 

High fibre cubes: These are a versatile and palatable way of providing additional fibre to the daily ration as a complete compound feed, as a partial forage replacer or as healthy fibrous treats in a snack ball.

Forage alone is not enough

Research has shown that horses on a hay-only diet may not digest some nutrients as effectively as those fed diets that include fortified feeds and could benefit from dietary supplementation.

A pertinent study published last year by Waltham, which provides the science underpinning the Spillers brand, in collaboration with Michigan State University, discovered that feeding a hay-only diet resulted in reduced digestibility of many micro and macro minerals (such as calcium, magnesium, copper and zinc). 

An ideal way to balance a forage-based diet, especially for good doers that don’t require extra calories, is to add a balancer to the diet. This will provide the horse with all the additional nutrients he needs to stay healthy.