Hay for Horses

Understanding Different Types of Hay for Horses

Hay and fresh grass are both essential forage sources for horses, but they differ in their nutritional composition due to processing and storage methods. These differences can significantly impact a horse’s diet, particularly for those with conditions like laminitis. This article examines common types of hay, their nutritional profiles, and considerations for feeding specific horses.

Types of Hay for Horses

1. Grass Hay

Grass hay is the best substitute for pasture during drought, dry summers or for horses in stables, yards or kept on overgrazed paddocks.

– Meadow Hay is widely used in southern states and is made from various combinations of naturalised grasses and sometimes native grass and legume species. It varies widely in nutritional value, often providing moderate protein and energy.

– Ryegrass Hay is a palatable, nutrient-dense feed with moderate to high protein (12–18%) and energy levels. However, its high ethanol-soluble carbohydrate (ESC) and starch content makes it unsuitable for laminitic horses. In some regions, ryegrass may contain endophytes, which can cause health issues like ryegrass staggers.

– Rhodes Grass Hay is typically low in ESC and starch, making it a safe option for horses prone to laminitis, insulin resistance, or equine metabolic syndrome (EMS). Rhodes grass has a moderate protein content (8–12%) and high fibre, promoting digestive health. Rhodes hay is one of the most common types of grass hay available in northern states.

– Teff Hay has become a popular choice for metabolic or overweight horses.  It is frequently low in sugars and starch, has moderate protein and typically is high in fibre. However, like many warm-season grasses, it can contain moderate to high levels of oxalates, which may interfere with calcium absorption and contribute to conditions like nutritional secondary hyperparathyroidism (NSH) or “big head disease” if fed long-term without calcium supplementation. While it is palatable and digestible for most horses, testing for oxalate content and balancing the diet with calcium supplements is crucial when using Teff hay as a primary forage source.

– Jarra Hay is grown in the Northern Territory (NT) and is popular for its palatability with moderate protein (8–12%) and energy content. Jarra hay is low in oxalates, unlike many other tropical grasses such as Humidicola or Buffel grass. However, its nutrient levels can vary depending on maturity at harvest, so testing is recommended to ensure it meets the horse’s dietary needs.

2. Cereal Hay

–  Oaten or barley hay is made from green oats/barley harvested before the grain matures. Cereal hays are commonly used in Australia but should not be the sole forage source for horses without grazing. They are highly palatable and provide moderate energy and protein (5-10%) but are often high in carbohydrates, unsuitable for metabolic horses. Quality can vary widely depending on plant maturity and seed fill at harvest.

– Straw is made from the dry stems of a mature cereal crop (wheat, oats, barley or rice) cut and baled after the grain has been harvested. It is high in fibre but low in protein (2-5%) and energy. Straw is sometimes recommended for weight loss, used to substitute up to 50% of hay intake but its sugar and starch content can vary, so testing is recommended before feeding.

3. Legume Hay

Legume hays are richer in protein and energy than grass hays, making them ideal for topping up the diets of performance horses, growing foals, and lactating mares.

– Lucerne Hay is the most popular legume hay fed to Australian horses. It is nutrient-dense with high quality protein (16–25%) and calcium levels. It is usually low in ESC and starch, making it a suitable source of quality protein for horses with metabolic issues. Whilst beneficial in many horse diets, lucerne should be limited to 20% of the total daily intake. For horses with a sensitive gut, lucerne’s richness can lead to digestive upset even in small quantities.

– Clover Hay has a high protein content (15–20%) and is often baled as a ryegrass and clover mix for cattle. Clover hay can be too rich for horses and some contains phytoestrogens or mycotoxin producing endophyte fungi. It should only be used strategically in small quantities to boost protein and calcium levels.

The Importance of Feed Testing Hay for Horses

The nutritional value of hay is influenced by plant species, maturity at harvest, and growing conditions. Key nutrients to test for include:

• Digestible Energy (DE (horse)) is a value given in MJ/kg, an indicator of the amount of ‘fuel’ the hay contains. Younger, leafier and cool-season pasture hays (such as ryegrass) are higher in energy than hay from mature (stalkier) plants and warm-season species.
• Water Soluble Carbohydrates (WSC) include simple sugars (monosaccharides such as glucose and fructose; and disaccharides such as sucrose and maltose), short-chain polysaccharides (oligosaccharides and fructooligosaccharides), and fructans. Ethanol Soluble Carbohydrates (ESC) measures only simple sugars and short-chain polysaccharides. Starch is a carbohydrate made up of complex polysaccharides which are digested in the foregut. Hay high in ESC and Starch increase the risk of laminitis through their influence on blood insulin levels.
• Crude Fibre (CF%) is an indicator of the total amount of indigestible fibre in the hay. This is fermented by microbes and is an important component of gut health. Acid Detergent Fibre (ADF) measures cellulose and lignin levels whilst Neutral Detergent Fibre (NDF) measures cellulose, hemicellulose and lignin. Hay made from more mature plants is usually stalkier, and higher in indigestible fibre.
• Protein (CP%) supports muscle development, body maintenance and overall health. While high quality protein is essential for young, growing horses, broodmares and horses in intense work, excess protein can lead to unnecessary nitrogen excretion, which stresses the kidneys. Lucerne is considered a quality protein source for horses because it is rich in the amino acids that horses are commonly lacking.
• Mineral level analysis of hay, especially when it forms a dominant part of the diet, ensures supplement requirements can be accurately calculated. Your nutritionist will be delighted if you can provide an analysis of the macrominerals: calcium, phosphorous, magnesium, sodium, chloride, potassium and key trace or microminerals: iron, copper, zinc, selenium, iodine and manganese. Click here to access our expert diet analysis service.

Feed Central provides affordable feed testing through EquiAnalytical to Australian horse owners.

Grass hay tends to have the highest fibre content, whilst cereals are high in sugars and lucerne is high in protein.

There can be significant differences in hay feed values which cannot be detected without feed testing.

Plant Maturity at Harvest

The maturity of plants at the time of harvest is a significant factor affecting hay quality.

Leafy Hay (Early-Maturity)

   – Plants harvested at an earlier stage of growth retain more leaves than stems, which are richer in nutrients.

   – Early-maturity hay has higher protein and digestibility but lower fibre, making it more energy-dense.

Mature Hay (Late-Maturity)

   – Plants allowed to grow to full maturity have more stems and seed heads. This results in lower protein but higher fibre. The energy content depends on the amount of filled seed heads (grain) and remaining leaf.

   – Mature hay is often coarser and less digestible but may be better for horses requiring low-calorie diets, such as those at risk of laminitis, provided the carbohydrate levels are in the safe range.

Choosing Safe Hay for Laminitis-Prone Horses

Metabolic dysregulation (insulin resistance) is the primary cause of laminitis, which is triggered a spike in blood insulin caused by eating food high in sugar and starch.  Forage for horses prone to laminitis requires constant, detailed attention to sugar and starch levels.

1. Ideally, choose hay which has been analysed and has a combined ESC + Starch value of less than 10%.
2. Avoid high production grasses such as ryegrass and do not feed cereal (oaten, barley, wheaten) hay.
3. If carbohydrate levels of hay are unknown, soak in warm water for 30 minutes or cold water for 60 minutes to remove soluble sugars. Drain and discard soak water before feeding. Soaking hay can reduce water soluble carbohydrates by up to 30%.

Rhodes grass and teff hays generally have lower carbohydrate levels than cereal hays. Some meadow hay can be suitable, although this varies based on species, growing conditions, and harvest timing (hay cut in the late afternoon is higher in energy than early morning cuts).

Forages for laminitis-prone horses should contain no more than 10% combined value of ESC plus starch. Testing each batch of hay is strongly recommended as levels can vary widely. Even lucerne hay, which is usually safely below the 10% level can occasionally be slightly too high. Some grass hay can test inside the safe level, but many harvests will be too high in carbohydrates to be fed to horses with metabolic conditions.

Factors to Consider When Buying Hay for Horses

1. Nutrient Analysis – where possible buy in bulk and test hay to ensure it meets the specific nutritional needs of your horse. Some large hay sellers provide test results for each batch of hay.
2. Visual and Physical Inspection – look for some green colour (indicating freshness) and a sweet smell. Avoid hay with mould, dust, or foreign objects.
3. Horse-Specific Needs – match hay type to your horse’s workload, age, health condition, and metabolic status, taking into consideration the nutrient balance of the rest of the diet (pasture, hard feed and supplements).

Conclusion: Hay for Horses

Hay is a cornerstone of equine diets, providing essential fibre and nutrients when horses lack fresh pasture. However, its nutritional value varies widely, and careful selection is key to meeting a horse’s specific needs. Compared to fresh grass, hay contains lower levels of water, vitamins and omega-3 fatty acids as these are lost during drying and storage, making supplementation essential. The mineral content of hay is similar to that of the fresh grass from which it was made.

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By considering the interplay between hay type, nutrient content, and horse health, owners can make informed decisions that promote optimal wellbeing and performance.