HAY can be made from permanent meadows (of mixed grass species) or from sewn ‘leys’ of single or mixed species. A ley can be sown for just one year in an arable rotation, or for a number of years. The grass is cut and dried to a maximum of 15% moisture before being baled. It is usually turned (tedded) several times during drying and it takes skill to make good hay.
HAYLAGE can also be made from both meadows and sewn leys and is cut then dried to around 30-45% moisture before being baled then wrapped tightly in several layers (typically 6-8) of plastic wrap. Alternatively small bales can be encased in thick plastic bags. The anaerobic environment this tight wrapping creates coupled with the moisture causes the water-soluble carbohydrates (WSC – sugar and fructan in UK grass) in the grass to ferment, causing a drop in pH and production of volatile fatty acids (VFA). The sweet smell of haylage does not come from sugar; it comes from VFA, and well-made haylage is lower in sugar than the equivalent hay.
Years ago, haylage was more like silage; wetter, more fermented and much more nutritious, and wasn’t suitable for leisure horses and ponies. Farmers have adjusted the way they make haylage nowadays, to provide a drier, less rich, more suitable forage for horses. Both hay and haylage can vary in nutrient content, and quite widely in WSC content (from around 5% up to 25%) although the highest WSC forage would tend to be hay, and the lowest would tend to be branded haylage e.g. Horsehage, which is well-fermented.
Nowadays, no assumptions can be made about both hay and haylage, because both can vary so widely, from around 7.8-10MJ digestible energy (DE) per kilo (to around 11MJ in haylage) and 7-12% crude protein dry matter.
Benefits and disadvantages
Both forages have their own pros and cons. The primary benefit of haylage over hay is that it is more hygienic from an air quality point of view. UK-made hay contains dust and mould spores, whereas well-made haylage contains very little of either. UK-made hay should ideally be steamed or soaked for 10 minutes before being fed to stabled horses and must always be soaked or steamed for horses with RAO (used to be called COPD) whether its fed in the stable or the field.
Haylage tends to be more nutritious than hay, and more palatable, so when it’s fed ad lib it could supply more nutrients. This might be why a horse might become more energetic on it. However, not necessarily because some haylage may actually be lower in nutrients than early cut hay!
Hay is usually more suitable for good doers and laminitics since it can be soaked for 10-12 hours to reduce calories and WSC, BUT some hay will not be low enough in WSC for sensitive laminitics even after soaking. Haylage can be suitable in terms of WSC content (under 10% dry matter, DM) but it is usually too high in calories for laminitics and good doers. Some owners do soak haylage but there is no research to prove the safety of soaking for every different type of haylage.
Haylage needs to be fed by volume, not weight since it contains more moisture than hay. If you feed the same weight of haylage as hay, you’ll be feeding less forage, less bulk and less fibre.
Keeps once bale is open
Some can be low in nutrients, ideal for good doers
A wider choice of types is often available locally
More hygienic (very low in dust and mould spores)
Can be stored outside
Some can be more nutritious than hay
Some is guaranteed low in WSC
Contains dust and mould spores
Needs to be soaked for horses with RAO and ideally for all stabled horses
May be too high in WSC for sensitive horses and ponies
Must be stored inside or under cover
Most needs to be used within days of opening to avoid moulding
Most is too nutritious for good doers and laminitics
Risk of wrapper puncture and subsequent wastage
Choose forage carefully…
Whether you decide on hay or haylage for your horse, choose your forage carefully:
Whichever type of conserved forage you choose, always change from one sort and from one batch to another gradually. Horses are at higher risk of colic from immediate changes of forage, than changes in hard (bucket) feed.
Don’t assume that you cannot feed hay or haylage to an individual. Hay and haylage vary considerably so assess each type before making decisions for your horse. Consider having the forage analysed, if you have a consistent supply, although bear in mind this is only a guide. Equi-Analytical in the US offer an excellent forage analysis service. The answer to whether hay or haylage is best is ‘it depends on your horse and your situation’.