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Feeding Horses in the Drought

Scone Equine Hospital - Thursday, December 31, 2020
Feeding Horses in the Drought

Although there have been pockets of moderate rainfall along the eastern states, unfortunately drought conditions still dominate most areas and even with rain, recovery of feed growing areas will take time. It is too common a situation to have horses on bare, dusty and dry paddocks with very limited grass coverage. Even new short green pasture after any rain will have limited nutritional value. Supplementary feeding is vital to provide a balanced diet in an attempt to keep the horse’s digestive function normal. This article hopes to remind horse owners of suitable alternatives while waiting for that elusive change in rainfall patterns.

Why it’s important to fill up their belly

One of the most significant and obvious issues facing horses in a drought is the lack of forage from pasture. Generally, the minimum amount of forage required to maintain healthy gut function is 1.5% of the horse’s body weight. For example, a 500kg horse should have at least 7.5kg dry matter (i.e. the weight with all the water removed) of roughage per day. Horses with less than this are at risk of losing condition as well as colic, diarrhoea and stomach ulcers.

Gut Health 

The fibre within grass, hay and other forage aids the passage of food through the digestive tract as well as providing bulk weight in the intestines. A full intestinal tract reduces the possibility of part of the intestine being able to displace or twist and therefore help to prevent serious or possibly fatal colic.

Gut Bacteria

In the horse, bacteria in the hind gut transforms the fibre in feed into energy to be used by the horse’s metabolism to maintain weight as well as growth and performance.A constant and consistent supply of forage is very important in maintaining the optimum amount and type of bacteria within the gut. If this balance is upset, harmful organisms can over grow and cause problems such as colic and diarrhoea.

Stomach Ulcers 

Stomach (or “Gastric”) ulcers are caused by too much acid within the horse’s stomach. Forage helps to reduce this firstly as a physical barrier in the stomach and protecting the susceptible stomach wall layers from acid, and secondly by increasing the time the horse chews, stimulating saliva and therefore reducing the acidity within the stomach. Stomach ulcers can again lead to colic but also poor performance, weight loss and diarrhoea.

Nutrients and Vitamins 

Roughage supplies minerals as well as stimulating hindgut bacteria to produce important vitamins such as B1, B2, B3, B5, B6, K as well as Biotin.

Mental Health 

If horses can’t graze it is unnatural and can lead to behavioural changes. Lack of grazing can lead to horses chewing on other materials such as fences, trees or stables and can result in undesirable behaviours such as fence walking, crib biting and weaving.

Different Types of Hay

In these drought conditions, the physical bulk of the forage is the most important as different concentrates can be used to supplement energy and nutrition. The main factors affecting choice that many horse owners are struggling with are cost and availability. The best replacement for pasture is free choice grassy hay, ideally with additional lucerne or cereal hay to further balance the diet. The grass type and weed level is also important to consider. For example, silver grass is not as good as ryegrass. Where nothing else is available, lower quality grassy hay or even straw may suffice, though this must not be the only source of forage or nutrients.

Bulk buying or large bales will help reduce the cost of hay, however, it is vital to try to make sure it is free of mould, not overly dusty, and free of sticks and thawns that may cause injury to the digestive tract if swallowed. Slow feeder hay nets and large free access bales help hay last longer and mimics natural grazing behaviour. Feeding bulk forage intermittently leads to higher risks of digestive problems and colic compared to some hay offered constantly.

Alternative sources of feed

Sourcing adequate quality and quantity of hay is difficult for many horse and property owners with many media reports of hay being transported across the country. Consequently, alternative sources of forage may need to be fed alongside a reduced ration of hay such as:


Most commonly chopped lucerne and cereal hay or a mixture of the two. Straw chaff has minimal nutrients and may increase the risk of impaction colic if it is the main part of feed due to the high levels of indigestible fibre. 

Silage and Haylage 

This is a possible alternative to hay, though it is important to ensure the silage is not mouldy. There are health risks associated with feeding silage, as bacteria such as botulism can grow in anaerobic conditions of a fermented feed. Avoid silage that is dry, dark brown/green or has a putrid odour.     

Hay Cubes and Pellets 

These are made from high quality forage and can help maintain nutritional requirements. It is a good, consistent product with the protein, fat and fibre levels printed on the bag. However, it does not promote natural grazing behaviour.


Beet pulp or lupin hulls, soybeans, almonds and sunflowers have relatively high levels of digestive fibre and energy, therefore can sometimes be used to replace chaff as a source of additional fibre. The disadvantage of this source is they can be costly. Super-fibres must be soaked before feeding. Do not feed rice hulls or oat hulls as they can increase the risk of impaction colic.

Bran and Pollard 

Wheat bran, wheat pollard and rice bran are best fed in pelleted feed but can be given separately. These feeds are traditional “bulking” feeds. They have low levels of fibre and calcium but are high in phosphorus. Bran is more useful when adding volume and fibre but pollard has a better energy content. If there is a lot of bran or pollard in the diet then calcium should be supplemented. Rice bran is high in fat and easily digested fibre so makes a safe and palatable choice for horses that need to gain weight.


Commercial Feeds 

These feeds have a mix of pellets, vitamin and mineral premix as well as chaff or low starch pelleted feed containing hulls. These are useful alternatives if local chaff supplies are restricted. The best options are those with a fibre content of 10-15%. Horses are only able to digest a low level of starch, so concentrates must be kept below 0.5% body weight if using this feed.


If options are severely limited, straw may be fed with additional vitamin/mineral and energy supplements. The high level of indigestible fibre means it should be fed with caution as it may predispose to impaction colic.

Type of Forage Positives Negatives Tips and tricks
Hay Best alternative to pasture Sourcing difficulties Variable quality




Grass hay quality may differ - check the source well. Avoid mouldy/dusty hay Avoid canola hay and those with high lignin content.
Chaff Made from good quality hay Increases “chew-time” Local supplies may dwindle Avoid straw chaff
Silage/Haylage Similar nutrients to hay Good water content Risk of disease if soiled/mouldy Feed with care
Hay cubes/pellets High quality forage Expensive Reduced “chew-time”  
Super-fibres Good levels digestible fibre Expensive Soak before feeding
Bran/Pollard Fairly cheap and easy to use Relatively lower levels of digestible fibre If using in bulk must use calcium supplement.
Commercial Feeds Easy to source Good quality fibre Quite Expensive Higher in starch Choose those with 10-15% fibre content Concentrates must be 0.5% bodyweight
Straw Cheap Increased “chew-time” High levels indigestible fibre Feed with other forage sources and increase water intake

What to avoid

High carbohydrate sources such as bread or grains (wheat/sorghum) have very high carbohydrate and low fibre so are not a good alternative source of roughage. These feeds can increase the likelihood of colic and laminitis. 

Canola hay or sugar cane bagasse should not be fed to horses as they have very high levels of lignin and horse’s digestive tract will struggle to digest them like ruminants.

Cattle feed and poultry feed may contain ionophores (such as additives to aid rumen digestion) that are toxic to horses. 

Don’t forget water!

Many of these alternative sources of feed compared to a natural pasture have a much lower water content, so it is even more important horses have free access to water and the quality is checked regularly. Extra water may be required where dams and creeks have dried up or are low and stagnant.

If using different feed sources always change the diet gradually over at least a week and monitor your horse closely during this time. Do not hesitate to contact your veterinarian if your horse is losing condition or showing any signs of disease such as colic, diarrhoea or laminitis. Remember to ensure horse’s feet, teeth and worming programme are not forgotten to ensure they can maintain themselves as best as they can during times of drought feeding. Although drought brings considerable difficulties in managing horses, it does require some resourcefulness to maintain an adequate feeding programme. Remember, there is always advice that can be sought from local veterinary practices or Local Lands Services offices in your area.

Written by Dr. David O’Meara