Forage is vital for any horse or pony and should form the main building blocks of their diet, but the options available can be mind boggling. Understanding the benefits and shortfalls of each forage type can help owners make an informed decision on the best option for their equine friend. 

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Why is forage so important for horses and ponies? 

After water, fibre is the most important component of a horse’s diet. Fibrous forages such as haylage, hay or grass should form the largest percentage of a horse’s intake, providing them with essential fibre and nutrients, and supporting their gut function.

Horses are hindgut fermenters. This means bacteria in their caecum and colon (parts of the large intestine) work to digest fibrous carbohydrates such as cellulose, converting the fibre into usable energy through the process of fermentation. Provision of sufficient forage supports gut function, while also prolonging eating time; which is important for horses’ mental well-being as they are adapted to spend much of the day eating (14-20 hours!). Insufficient forage provision can lead to boredom and anxiety. And it may lead to the development of behaviours that mimic foraging or represent an oral occupation such as wind sucking. Alongside these benefits, the grinding motion of chewing wears down the enamel of horses teeth, which continually erupts throughout the horses life, helping to prevent painful overgrowths. 

What type of forage is best?

There is no one-size-fits-all rule to forage, and selecting the most appropriate option can be a tricky task. There are several factors to consider, including the size, type and body condition score of the animal, their activity levels, what other food sources they have access to and any particular health concerns such as Equine Metabolic Syndrome (EMS) or dental disease. 

Hay vs haylage

A basic understanding of the nutritional values of each forage type is important when deciding what a particular horse is to be fed. Determining the dry matter content of the forage is one of the most important nutritional elements to help decide what and how much should be fed. The dry matter content of a forage, simply put, is what is left when all of the water has been removed. This means that drier forages such as straw and hay contain higher dry matter percentages than moister forages such as grass and haylage.

Hay is generally 85% dry matter or above, whereas haylage is usually between 50 and 70% dry matter. This means that by weight, all else being equal, more haylage must be fed to provide the horse with the same amount of dry matter, and therefore fibre. For example, a 500kg horse that needs to consume 10kg forage on a dry matter basis daily would require 11.8kg of hay as fed assuming it was 85% dry matter and 16.7kg of haylage as fed assuming it was 60% dry matter in order to provide this.

However – haylage has increased digestibility, so the digestible energy (DE) content of haylage is generally higher than that of hay. This means it may be more appropriate for horses in work, young horses, or those needing to maintain or gain weight. The DE content is the amount of energy in the feed, minus the amount lost in the horse’s faeces. So essentially, DE is the amount of energy available to the horse. 

Similarly, the amount of protein required in growing, pregnant, lactating or heavy exercising horses is increased; so forages higher in protein e.g. haylage or alfalfa may be more appropriate. 

Non-Structural Carbohydrate

Finally, the non-structural carbohydrate (NSC) content of the forage should be taken into account. I.e. the simple sugars and starches contained in the forage. Enzymes in the stomach and small intestines break these starches down into glucose, which is an essential energy source for working horses. The amount of required NSC varies by many factors; such as lifestyle, age, gender, body condition, fitness level, metabolism, and current health complications. Generally speaking, horses with higher energy demands require higher NSC levels. And those with lower or those with metabolic issues such as obesity and Equine Metabolic Syndrome (EMS) require lower. 

What is the difference between hay and haylage?

The main difference between these two forages lies in the conservation methods used when grass is cut. Hay is usually cut from more mature grass, and left to dry before being baled. This prevents the hay from spoiling. Haylage however, is usually cut earlier and left to wilt for a shorter period of time before being wrapped in several layers of plastic to exclude oxygen, which prevents the haylage from spoiling. Because haylage contains more water, and oxygen is excluded, some fermentation occurs. This fermentation uses up the sugars in the haylage and converts them to volatile fatty acids; meaning haylage is usually lower in sugar than hay. That being said, the nutritional differences between the two primarily comes from the grass type and age of maturity when harvested, rather than the conservation methods. This makes forage analysis vital when accurately determining the nutritional value of a particular forage. 

As a rule of thumb, haylage is usually (but not always!) higher in protein, less dusty, more digestible, lower in sugar, higher in calories and moister than hay. However, haylage is also generally pricier, more prone to spoilage making it difficult to store and cannot be easily soaked like hay. 

How much should I feed?

Horses should consume at least 1.5-2.5% of their bodyweight in dry matter of good quality forage per 24 hours to meet their daily fibre requirements. And they should ideally have access to it day and night. The actual amount fed depends on the forage used, and the individual requirements of the horse.

Overweight horses and ponies should be fed no more than 1.5% of their bodyweight in dry matter over a 24 hour period. Methods to make this ration last over a 24 hour period (especially for greedy horses and ponies!) include small hole or double netted hay nets, trickle feeders, grazing muzzles (for horses and ponies at grass). Or splitting the ration into several small portions and dividing them across the day. 

And what about soaking?

Soaking is generally used to alter the physical and or nutritional factors of forages to suit a horse’s needs. It can reduce respirable particle concentrations of dust and mould in the forage, which can be beneficial in preventing or improving airway disease such as recurrent airway obstruction (RAO). Some horse owners also soak their hay to reduce the concentration of sugars, or nonstructural carbohydrates (NSC), in the forage. Horses that require a low-sugar diet, such as those with laminitis or insulin resistance, might benefit from soaked hay. 

It is important to remember that alongside sugars, other nutrients such as crude protein, calcium and magnesium concentrations also reduce when forage is soaked, meaning these nutrients may need to be replaced elsewhere in the horse’s diet. 

The length of time forage needs to be soaked for has been the topic of much debate. It generally depends on what is aiming to be achieved. For example, soaking hay for 10 minutes can significantly reduce the concentration of respirable particles in the hay, and a longer period of soaking may not alter this dramatically. Soaking length does however affect the sugar concentration in the forage. Generally, the longer the soak, the lower the sugar content. 

However, longer is not always better

A longer soak reduces the dry matter content of the hay; may increase the microbial load of the hay; and in warmer conditions, may allow the fermentation process to begin. As a rule of thumb, 2 hours is generally sufficient to reduce the sugar content to a degree without compromising the dry matter content and allowing fermentation to begin. However, this may not provide a sufficient drop in sugar content for some horses. In the UK in cooler conditions, soaking overnight is generally acceptable and often a more practical solution for many owners.

The volume of water used should also be considered as the more water used, the greater the leaching of sugars into the water. Some researchers have advocated 10 parts water to 1 part hay but this simply isn’t practical for everyone. The general principle is to use as much water as is practical, whilst also taking into consideration the fact that water is a very precious resource.

So, can my horse just eat grass?

In horses or ponies where laminitis or metabolic issues are not a concern, well managed pasture can provide a complete nutrient and energy dense food source that needs little supplementation. As with other forages, animals with additional needs may need further energy sources to meet their nutritional requirements. 

Throughout the grazing season, the nutritional content of grass changes as the grass grows and ages. But in the spring, grass may contain more energy than the average competition feed, and up to twice the protein! 

Due to the differing vitamin and mineral content of grass, it is usually advisable to provide all horses and ponies with a vitamin and mineral balancer to avoid deficiencies. 

Can I feed my horse silage?

Silage is a forage commonly used to feed cattle and other livestock in the UK. And it is produced by fermenting fresh or ‘wet’ grass; meaning it has a much lower dry matter percentage (around 30%) than hay or haylage. If preserved properly, silage may be suitable as a feedstuff for horses. But due to the risks of improper fermentation leading to the proliferation of mould and bacterial toxins, as well as the large quantities needed to provide horses with an adequate dry matter intake, many owners choose to avoid it. 

Can I feed my fat pony straw? 

Straw is usually made up of the remaining stalks when grain heads, such as wheat or oat, have been harvested. This means it is less nutrient dense than hay or haylage. Used carefully, straw can be a valuable source of forage which can be used to dilute more nutrient dense forages such as hay to reduce calorie consumption and maximise chew time in good doers. Maximising chew time not only prevents boredom, but also increases saliva production which is beneficial to gastric health. Previous studies have suggested the use of straw may be linked to the development of gastric ulcers. But more recent research has shown that feeding 50% wheat straw as part of the ration showed no increased risk of gastric ulcers.

Owners are often also concerned about the risk of impaction colic caused by straw consumption. Straw has a higher lignin content and lower digestibility than hay or haylage. And when fed solely straw, horses may be at an increased risk of impaction colic. However, when fed in moderation alongside other forages such as hay, and when introduced gradually, straw can provide a safe and useful source of low calorie forage. 

What if my horse can’t chew?

Equine dental disease is a significant problem in the UK. Recent studies found that up to 70% of UK horses have undiagnosed dental problems. Chewing is important in increasing the availability of nutrients. As well as promoting bicarbonate containing saliva production which buffers stomach acid and promotes gastric health. 

In geriatric horses with significant dental wear, or those suffering from dental disease, chewing can be difficult, making adequate forage provision tricky. Chopped forages such as chaff mixes or alfalfa, and soaked fibre nuts or sugar beet can help to meet these animal’s needs. 

Some of the first signs of difficulties chewing include ‘quidding’ (dropping partially chewed forage from the mouth); reluctance to eat; and episodes of choke. Thorough dental examinations, ideally under sedation, should be carried by a fully qualified Equine Dental Technician (EDT) or vet at least annually. This will ensure any dental issues are picked up and treated appropriately. 

Summary

As with people, every horse or pony has differing energy requirements, and their diet should reflect this. As forage makes up the largest proportion of the horse’s diet, it is important to select the most appropriate option for the individual animal.

Understanding the basic elements of the nutritional content of each forage can help to determine what your horse’s requirements are. The nutritional value of a forage comes primarily from the grass used rather than the different conservation methods; making forage analysis a useful tool when calculating an animal’s forage requirement. Practical elements such as ease of storage, price and longevity should also be considered when deciding which option to feed. 

Generally, modifications to the diet, quantities fed and methods of feeding can be made to account for various different forage options and usually more than one option may be suitable for most animals. As always, you should contact your vet for advice on which option is best for your horse or pony. 

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