Cool feeding for hot horses

Does your horse "fizz up" when certain feeds are added to its diet? Feeding hot horses can feel like a challenge, but there's a growing number of cool energy feeds that are formulated to avoid spikes of rapid energy.

As a starting point it's important to stress that every horse is an individual and a feed that one horse accepts without issue may trigger a behavioural change in another.

Having said that, there are certain ingredients that are more likely to provoke a ‘feisty’ response from your horse. Avoiding these and identifying alternatives may provide you with the best opportunity to add the desired condition whilst steering clear of unwanted behaviour.

The 4 Sources of Energy

Whilst the mere mention of the word ‘energy’ can strike fear into the hearts of many nervous horse owners, the reality is that without energy a horse cannot function, move, breathe or survive at all.

In simple terms, if a horse utilizes more energy than it takes in through feed or pasture then it will lose condition. If it consumes more energy than it uses, then it will gain weight. It is therefore necessary for us to either provide more energy to a horse that requires condition or reduce its output. The actual source of energy is the key to how behaviour will be affected.

How to feed a horse calm feed
(image above: Excitable behaviour can make a great photo in the pasture, but be problematic under saddle.)

This leads us to the primary sources of energy that we can feed a horse.


Whether it is pasture, hay, chaff, or a superfibre such as beet pulp or lupin hulls, fibre remains the most essential source of energy in the diet. The ‘heating’ potential of fibre can vary wildly as anyone with a spring flush of clover will attest to. Cereal hays such as Oaten and Wheaten as well as cool season grass hays such as rye/clover can be extremely high in sugar and provoke an excited response. Lucerne is generally lower in sugar yet excellent for conditioning, however some horses may also react negatively to this higher protein option.

Generally the safest sources of fibre from a behavioural point of view (that also provide excellent conditioning) are soluble fibres such as unmolassed beet, as well as products based on lupin hulls. In addition it is recommended that ‘fizzy’ horses be provided with a base hay that is lower in sugar such as Rhodes Grass, Teff or indeed Barley straw.


Starch is a non structural carbohydrate and is primarily sourced from cereal grains such as oats, corn, barley and wheat. Once consumed, the longer chain glucose molecules are transformed into available sugars and as such are the energy source of choice for high performance horses (including horses that race, event, jump or are involved in any high level equestrian pursuits).

Starch provides rapid energy. For horses prone to ‘fizzy’ behaviour it is likely to make matters worse and so is generally not the energy source of choice for sensitive horses. In particular, oats and corn are more likely to be problematic from a behavioural point of view, however there may be instances where a highly digested form of barley (eg EXTRU-BARLEY®) may provide the conditioning benefits of carbohydrates without excessive fizz.

Again this will be very much an individual response but particularly in the case of thoroughbreds the application of some extruded barley is worth a try.

Extru-Barley horse feed digestible barley


Protein is essential for life itself. More specifically the amino acids that are the building blocks of protein are essential in the repair and redefining of muscle and topline. It follows that any desire to add healthy condition must include protein. Aside from pasture and legume hays such as lucerne, protein is also readily provided through ingredients such as soyabean meal, lupins, tick beans and sunflower seeds. All of these sources are high in protein and relatively low in starch, which means they generally provide a lower ‘fizz’ type of energy.

However, whilst protein is an important element in topline conditioning it should not be wholly relied upon as a singular energy source as it is both expensive and can provoke ‘deamination’ which sees excessive amino acids transformed into ammonia. Such a scenario can be of concern to a stabled horse in particular.


Fat is the most dense of all energy sources yet is generally found to be the least ‘heating’ from a behavioural point of view. Oils are highly efficient with 100ml’s providing as much energy as 250-300 grams of oats and also have the added benefit of improving coat quality. Oils are effectively ‘starch sparing’ as they diminish the dependence on carbohydrates as an energy source.

Fats/Oils are often referred to as ‘slow release’ as they can be utilized aerobically and are devoid of the quick acting sugars that can impact glycemic index so intensely.

Oil (eg HYGAIN® RBO®, HYGAIN® PERFORMA 3®) should always be a significant part of any diet that seeks to add condition and stamina with minimal excitability.

RBO and Performa 3

 HYGAIN® RBO® Equine Performance Oil is a unique blend of pure rice bran oil, omega essential fatty acids and natural antioxidants formulated for all equines.

HYGAIN® PERFORMA 3® is a rich, natural source of Omega 3, 6 & 9 fatty acids. By combining Omega 3 rich vegetable and fish oils with added garlic, PERFORMA 3® contains high levels of usable EPA and DHA's.


Which weight gain feeds should I avoid feeding my hot, fizzy horse?

The first type of energy that we should attempt to avoid is one that is high in either starch or sugar. Feeds coated in excessive molasses or those containing oats or corn should be avoided. Although barley is a cereal grain containing starch, a small amount of correctly processed barley (e.g. steam extruded or micronised) may be suitable for thoroughbreds in poor condition. However the horse's response will be very much a case by case basis.

How to put weight on your horse (the smart way!)

With knowledge of potential energy sources we can look at practical ways to formulate a diet that adds condition with minimal ‘fizz’.

As with any diet we always start with fibre, be it pasture, hay or chaff. The more a horse can rely on fibre the better, and so a combination of a low sugar pasture along with approximately 1.5 to 2% of the horse’s bodyweight in a low sugar hay is an ideal base.

We should then endeavour to maximise feed efficiency by providing at least 2 feeds per day consisting again of an efficient low sugar fibre source and then a balanced blend of fat, protein and ‘cooler’ carbohydrates.

An appropriate premixed feed with full micro nutrient profile will also avoid the need to add more supplements on top.

Horses eating roughage calm feed

(image above: The importance of fibre. Always start with fibre.)

Tips when looking for a cool feed for weight gain

Firstly, let’s consider that each horse is different. What works for keeping one horse “cool headed” will not necessarily work for another. Horses also have varying tolerance levels for starch. One horse may tolerate a medium level of starch (between 10-20%) whilst another horse may be better suited to a low starch feed (<10%).

Keep in mind that starch and sugar levels also contribute to condition. It follows that a transition from a high starch feed to a low starch feed may result in a drop in condition.

Look for a feed that is lower in starch, but high in fat and fibre so that condition is maintained or added.

The best of both worlds – Premixes that add weight with “cool energy”

Tailoring your own feed ingredients is one option. Another option is to select a premix that is specifically formulated to provide cool energy, condition and balanced nutrition. Such mixes are subject to comprehensive analysis to ensure they provide everything your horse needs. The benefit of a premix is that it provides the convenience of a “ready to feed” blend and the confidence that the mix is consistent from one bag to the next. A premix is likely to also offer a saving on time and money compared to the “do it yourself” option.

Quality is still very important when choosing a premix. Between manufacturers there are varying degrees of quality assurance, production methods, processing and ingredients. Mitavite® are proud of their commitment to high quality and modern processing methods.

(Image above: Cool premixes)


The key to slow, steady weight gain

Adding weight should be done in a way that avoids shocking the horse’s system. A sudden influx of calorie rich feeds can upset the digestive system and further compromise a horse’s condition. Gradually increase any new feed and opt for smaller, more frequent meals in preference to one big dinner.

It can be tempting to chase a rapid result by shovelling weight-gain feed into a horse, but a slow, steady approach aligned with the manufacturer’s recommended feeding rate is the best way to safely add condition.

If it’s not the feed...what else can make a horse hot and fizzy?

Whilst energy dense feed is an obvious trigger for behavioural change, it’s important to consider other factors and the overall “big picture.”


Check if your horse’s paddock has had a seasonal change to its pasture. Flushes of sugar-rich green grass in Spring and Autumn are notorious for bringing on hyperactivity and “naughtiness.” Grass can hold a surprising amount of sugar and is often overlooked as a suspect when it comes to identifying behaviour causes.

Rich clover pasture high energy

Pasture can also be mycotoxin affected, meaning your horse is ingesting microscopic toxic fungi. Such toxins can have an effect on behaviour (amongst other systemic issues.) A broad-spectrum toxin binder such as Safeguard EQ® may be beneficial in resolving this problem.

Think about the effect of any recent changes to herd dynamics. Does your horse have a new friend that he may be focusing on instead of his work? Perhaps the removal of a friend has placed your horse under a period of stress. Both situations tend to resolve given time and/or training.

Consider your horse’s living conditions. If your horse is stabled, then its excitable behaviour could be the result of inactivity. Give your horse more to occupy its mind and body with increased access to exercise. Even fairly short periods of turnout or in-hand walking for 30 minutes can make a difference to the horse’s physiological and psychological wellbeing.

Nutritional imbalance:

A diet deficient in Magnesium or B Vitamin (Thiamine) can make a horse nervous, anxious or spooky. Whilst it's uncommon for a diet to be lacking in Magnesium or Thiamine, it’s not a difficult fix and is achieved through feed or supplement.

The individual horse:

Take a closer look at the type of negative behaviour your horse is exhibiting and rule out other causes such as pain. It’s important to remember that a horse has limited ways in which to communicate, so jogging, spooking, bucking and rearing may be an indicator of pain instead of simply excess energy.

Natural disposition and workload

Let’s not forget that horses are individuals. If you are basing a new horse’s diet on one that worked for another horse, then you could be setting yourself up for a real eye-opener. What one horse tolerates (e.g. grain) can be completely the wrong fit for another horse. Horses vary in their ability to digest starch and therefore have different blood sugar reactions from one individual to the next.

If you have reduced your horse’s workload but not adjusted its feed, then it may have an excess of energy. Excess energy can be expressed under saddle, on the ground, or in the paddock.

On the other side of this equation are horses that lack condition and have an undersupply of energy. Their deficiency leaves them lethargic, which may be mistaken for a quiet disposition. When such horses have their diets balanced then it stands to reason that more energy will make them feel more “energetic.” In such cases it’s important to re-evaluate the horse’s baseline for normal behaviour and apply training and/or further exercise as appropriate.

Is your horse spooky, anxious or nervous? This is a great time to check in with your equine nutritionist and make sure your horse’s diet is still the right fit. You can access a free diet analysis and advice through Nutrikey. Click here to book a time to talk.