Haylage is a feed preserved biologically by fermentation, or, more simply, by ensiling. In short, compacting the material and wrapping it in film creates anaerobic conditions in the feed. The growth of aerobic organisms is held back and fermentation involving lactic acid takes place, and the pH falls. Acetic acid is also produced in the process, which is a positive thing. It is a different matter if butyric acid bacteria, putrefactive bacteria, moulds or yeasts appear in the material. You may then notice a characteristic smell of acetone, which should prompt you to stop feeding that bale. Where do these unwelcome guests come from? They appear when the plant material used to make the haylage was contaminated, or when the film was damaged after wrapping. Haylage is also an ideal environment for Clostridium botulinum, which can lead to botulism. In that case too the feed changes smell, which is another reason to pay attention to it. Good haylage should smell pleasant 🤤
Despite this complicated and responsible process, haylage is relatively quick to prepare, because it is harvested within 2 days of cutting. That clearly limits losses, especially in poor weather, compared with making hay, which needs at least four days of sunny weather. Tightly wrapped and stored in a dry place, haylage is ready to feed after about 7-8 weeks, and it keeps for 12 months. Storing the ensiled feed is therefore simpler and, if the material was prepared with proper hygiene, you do not have to worry about it spoiling or losing nutritional value, as you do with hay.
How can horses be fed haylage safely? First of all, a transition period is important when a new feed is introduced. Second, an opened bale of haylage is best fed within 24 hours. As haylage bales are often quite large, it suits bigger yards better. An alternative is to buy a steamer, which removes dangerous bacteria and extends the time the feed can be used. For still greater safety, haylage can also be sent for laboratory analysis, which does unfortunately mean extra cost.
Nutritionally, haylage is rich in calories and minerals, and it is also low in sugar. Of course its nutritional value depends on when the plants were cut, just as with hay. Haylage made from young grass contains more nutrients than haylage from late-cut, mature grass that is high in fibre. Early-cut haylage is therefore better for horses with high energy requirements, while late-cut haylage has a nutritional value similar to hay.
Why is haylage worth feeding? Its main advantage is the absence of dust, which greatly reduces the dust in the stable at feeding time and so does not irritate the airways while the horse is eating. It is therefore ideal for horses with respiratory problems. Its taste is also worth remembering: horses eat it more willingly, and it can help when feeding fussy unicorns. 🦄