Understanding Forage

There are many factors to consider when choosing a suitable conserved forage for your horse. Not all owners are able to source their own forage, due to stabling on a livery yard. However, it is still beneficial to gather information about your forage, to determine the suitability for your horse and how it may affect the rest of their diet.

Hay vs Haylage

Hay and haylage are both conserved forages fed to horses in the UK. Hay is dried before baling resulting in a dry matter content between 85-95%, whereas haylage is sealed in a plastic wrap at a lower dry matter, often between 55-85%. Well made haylage is typically lower in dust than hay, making it a great option for horses with respiratory issues. It is a common misconception that haylage is always higher in energy than hay, but this is not always the case, with plant maturity being the biggest factor determining nutritional quality, rather than conservation method. If the same grass species is harvested under the same conditions, at the same plant maturity, the nutritional value is likely to be comparable whether it is conserved as hay or haylage. Often, haylage is harvested slightly earlier than hay, in which case you could expect a slightly higher digestible energy and crude protein content, but this is not always the case.

Well made haylage typically has a good hygienic quality, however haylage wrapped at too high dry matter can increase the risk of mould and bacteria accumulation, due to the coarser stems leaving air pockets within the bale and shifting the environment from anaerobic (without oxygen) to aerobic (with oxygen). Coarse stems can also protrude through the plastic wrap, causing similar issues. Once opened, a bale of haylage should be used within 5-7 days to preserve hygienic quality, so it is better to opt for smaller bales if only feeding a couple of horses. Alternatively, hay preserved with too high moisture is at greater risk of spoilage, due to accumulation of bacteria and fungi, which consume the hays nutrients and release heat as a byproduct.

Types of Hay and Haylage

Meadow hay comes from established permanent pastures, containing a variety of grass species, and potentially herbs, wildflowers, and clovers. This can provide variety to the horse’s diet but can lack consistency and increases the risk of unwanted plant species being present.

Seed hay is taken from crops of grass specifically grown for hay or haylage making. It often contains only 1-2 specific grass species, most commonly ryegrass or timothy, so may provide a more consistent end product. This may be preferred for horses with specific dietary needs such as a good doer or a horse with metabolic issues, as you can choose a specific hay type to suit your horses needs, and have a more consistent batch.

Common Grass Species Used for UK Hay

• Timothy: high fibre, palatable, tends to be lower in energy and sugar than ryegrass.
• Ryegrass: mostly found on cultivated land. Rapid growth allows for several cuts during the year. Tends to be higher in protein and sugar than timothy.
• Orchard grass: highly palatable, moderate protein and energy.

Effect of Plant Maturity on Nutritional Composition

Although there are natural variations in nutritional quality between plant species, the main factor determining nutritional value is the plant maturity at harvest. Grass cut in the more vegetative state is known as early cut, and is typically more digestible, resulting in a higher energy (calorie), water soluble carbohydrate, and protein content, and lower levels of fibre. As the plant matures and grows taller, the less digestible, fibrous portions of the plant increase to maintain the plant structure, and the nutritional value decreases.

Visually Assessing your Hay Maturity: typically, an earlier cut, less mature hay is softer to the touch and has a higher leaf to stem ratio, whereas a later cut, mature hay tends to have a coarser, stemmy feel, and less leaves. This can be more difficult to determine in haylage due to the higher moisture content giving a naturally softer texture. It is important to note that the only way to accurately assess the nutritional content of hay or haylage is to send a representative sample for nutrient analysis.

Effect of Cutting

Multiple cuts generally occur with more intensively grown grass crops. Depending on environmental conditions, the first cut usually occurs in early May, then left for regrowth for a second cutting in July. Cut number can affect nutritional content but plant maturity is more relevant. The first cut is often left to grow more mature than the second and third cut, resulting in higher fibre, lower energy, sugar and protein levels. Second and third cuts are usually comparable in nutritional value but may depend on environmental conditions during growth and harvest.

Effect of Conditions at Harvest

Weather conditions at harvest can impact the nutritional quality of forage. Prolonged rain can lead to nutrient leaching, decreasing the energy value of the hay, and wet hay being more prone to leaf loss during handling and storage. Conversely, excessive dry or hot periods can increase plant respiration and potential plant cell damage, decreasing the energy content.

Forage safety

If getting hay straight from the field it is safer to wait 6 weeks prior to feeding, as they hay may not yet have reached an optimal dry matter, and microbial activity may still be occurring. The same applies to haylage, allowing 6 weeks for the fermentation process to complete.

Main Takeaways

• Ask your forage provider for as much information as possible about plant species, maturity, length or storage, and whether they have any average nutritional analysis results for the batch.
• Consider sourcing a later cut timothy hay for good-doers or hoses with metabolic issues.
• Hay maturity can be visually assessed, however sending a sample for nutritional analysis is the only way to accurately assess nutrient levels.