Haylage for horses

The difficulties in making hay of a good hygienic quality have prompted many producers to turn to making haylage. Haylage is grass or other plant material that is cut, wilted in the sun until a specific dry matter is reached, then baled and wrapped in several layers of plastic or sealed in a plastic bag, excluding air.

Haylage for horses should have a dry matter of over 55% (and no more than 75%), protein of less than 12%, crude fibre of around 30% or more, and a pH of around 6. Ideally, haylage with a dry matter of 65-75% and fibre of 35-40% is best for horses because it can be fed in high quantities.

Producing good haylage requires a high level of expertise form the manufacturer. The naturally occurring bacteria on the grass ferment water soluble carbohydrates in the forage, producing short chain fatty acids, which preserve the grass as long as it remains air-free. The manufacturing process ensures a dust-free product with little or no mould spores, which makes a more suitable feed for stabled horses than hay. Haylage is an ideal feed for performance horses, because it is hygienically superior to hay; therefore supporting respiratory health, and because it is often has a higher nutritive value than hay, meaning less compound feed will be necessary.

How to feed haylage

Haylage does not 'keep' like hay, and after a bale is opened, it will last several days before it goes off. Ponies and horses at maintenance can be fed haylage, but a relatively low nutrient version should be chosen so that plenty can be fed. Early versions of haylage were over-nutritious for horses, and too low in fibre. The high energy and protein content meant that people fed too little in order to avoid weight gain, therefore their horses became fibre-deficient. Haylage should be fed in greater quantities than hay, because more of its weight is water; therefore less is fibre. The dry matter should be taken into account when planning the feed quantity, and if such a quantity would oversupply protein and energy, either a less nutritious haylage should be sourced, or a less nutritious forage such as stalky hay or straw should be mixed in (soaked first if necessary for horses with respiratory challenges).

Haylage can be a safe feed for laminitis-prone horses and ponies, but a high dry matter, high fibre, low protein haylage with low residual sugars should be selected. The horse must be monitored carefully for weight gain, and if the haylage has to be restricted to avoid weight gain, another forage such as straw or long-soaked hay should be offered alongside to fulfill the horse’s forage requirements.

Safety of haylage

Haylage should never be made from hay that has been rained on and after several days drying is still too wet to bale. Such material is not suitable for baling for haylage, primarily because it will have lost much of its water-soluble carbohydrate content, therefore may not undergo sufficient fermentation. The safety of haylage for horses depends on a good fermentation. A variety of microbes are normally present on grass, and more may be added in the form of a ‘fermentation additive’ during the haylage-making process. In well-made haylage there is a large proliferation of bacteria that produce lactic acid by fermenting water-soluble carbohydrates. A good haylage contains a high proportion of lactic acid compared to butyric or acetic acid.

Some clostridia bacteria are present on grass, but most come from soil contamination in the cut grass. If these proliferate, they can cause botulism in the horse eating the haylage. Clostridia require a lot of moisture and will not proliferate in haylage with a dry matter over 50%. They also require a relatively high pH of 7 to 7.4, and pH of around 4 is required to inhibit their growth. Horse haylage is rarely as acidic as this due to the restricted fermentation compared to silage, but providing it is dry and is not contaminated with soil, the risk of botulism is very low. Clostridia bacteria produce butyric acid, so haylages with high butyric acid contents, and specifically those with higher butyric than lactic acid contents must be avoided.

You can read more about the risk of botulism in forages in the Equine Nutrition Learning Centre

Good fermentation also depends on the haylage being well packed with as little air as possible in the bale, so the wrapping should be tight around the grass, and the grass inside the bale well compacted.

Some manufacturers make large (300-400 kg) bales of haylage, then after the fermentation process has taken place, repackage them into smaller more easily handled bags, of around 20kg. Haylage made in this way is perfectly safe for horses and is often of a more consistent quality due to a better fermentation in the large bale than could be obtained in a small, wrapped 30kg bale. However, the repackaging process should be carried out with care, with the large bales opened and exposed to the air for as short a time as possible.

Punctured bales of haylage should not be fed because they will have started to deteriorate as a result of the entry of air. Haylages are particularly susceptible to moulding after opening or when a bale is punctured and the resulting mould and mycotoxins it produces may be dangerous to horses and the people handling the product. A small amount of white creamy substance on the haylage will not harm the horse eating it – it is simply an overgrowth of yeast. If a wrapped bale (rather than a repackaged bagged bale) from one batch smells or looks significantly different to the others, it should not be fed because this could indicate a poor fermentation. Never feed mouldy or ‘off’ haylage. Good suppliers will replace bad bales with no question, because you cannot tell before opening, and because bad haylage can be very harmful to horses. Bales that contain soil should never be fed due to the risk of contamination with unwanted bacteria including botulism, and such bales should be returned to the manufacturer to alert them to the soil problem.

Look for the following in good haylage for horses:

·         High dry matter (DM) 55% plus (but no higher than 75%) and high fibre of over 30%

·         Low pH of 6 or below

·         Higher lactic acid than butyric or acetic acid; the lower the latter two and the higher the first, the better

·         Low ammonia; ideally less than 10g/kg total nitrogen

·         No soil contamination

·         No punctures or holes in wrap or bag

·         Supplier who is willing to replace any spoiled bales

·         Enough plastic wrapping/tough enough bags that they require a knife to open (not just your hands)

·         No sour/ammonical or ‘off’ smell

·         No heating up as soon as the bale is opened

·         Reject any bale that contains an animal carcass or part of e.g. a bird’s wing (risk of botulism)