We are what we eat - are our horses too?

Modern day feeding regimes and substances are responsible for many of the problems experienced in performance horses. Find out how our ideas on feeding have evolved against the horse's natural physiology and anatomy. This superb article questions the status-quo and will make you think! If 'we are what we eat' - are our horses too?

The horse is beautifully evolved for its function, which is to survive on a high fibre diet, and lead a reasonably stress free existence, grazing for up to 18 hours a day and occasionally having to run away from a predator. Contrast this with the management and feeding practices of the modern Sports Horse, which may be out of its stable for as little as an hour a day, has to undergo periods of traveling and competition and tends to be fed large meals of high starch grains stuck together with molasses or corn syrup. Although our management and feeding practices have evolved over the thousands of years that we have kept horses, the horse is still at the same stage of anatomical evolution as when we tamed him.

What the horse would like us to serve up for him! So it is important that when we think about the management and feeding practices that we use to keep our sport horse fit and healthy we must not loose sight of what he is and how he has evolved. If we had sat down and designed the horse I am sure that we would have kept the beautiful exterior and the fantastic spirit but would have surely found a better less troublesome way to power him. But we didn't and so we are stuck to finding ways to manage and feed him that will avoid the common problems.

The basics of digestion

At every stage of the digestive system the horse demonstrates that he has evolved to consume a near constant diet of tough high fibre material. This is fine if we are keeping the horse at maintenance level, although when we require a higher workload from him, the problems in supplying the correct energy source become apparent.

A horse's digestive system is designed to cope with tough forages!Starting off at the beginning of the digestive system - the lips have adapted to be strong and mobile in order to cope with tough forages. In our way of feeding the horse, we have virtually eliminated the need for the lips to be involved in the selection process of which types of grasses and vegetation to consume. The mistake we make is to turn our horses out into paddocks which commonly contain very little variation in vegetation. Following the same theme, we also present him with a hay net full of hay which has been perfectly manicured and selected, then finally (and worst of all) we place a meal of starchy, sugary concentrates in front of him, which he devours in no time at all.

Once this starchy, sugary feed is inside the mouth, saliva is incorporated into the food particles and acts as lubrication for the food to slide down the esophagus, reducing the risk of choke. It also acts as a buffer to the acid produced inside the stomach. The buffering action is due to the concentration of sodium chloride and bicarbonate present, and is relative to the amount of saliva produced. The release of saliva by the salivary glands is related to the amount of chewing that goes on, so by feeding a meal that is easily chewed and rapidly swallowed, (such as one full of grains and sugar) there result is that not much saliva produced. In turn, this reduces the buffering actions of the saliva and initiates problems at an early stage of digestion. Feeding a high fibre diet will combat this problem. Fibrous feeds take longer to chew and as a result, saliva production increases and the benefits are restored.

Teeth issues

Fuelling the competition horse is a challenge!The act of chewing will of course have an influence on the wearing down of the teeth. If the horse is continually presented with concentrates that do not need to be chewed for any decent length of time, then we see problems will occur in dentition. Horses' teeth have evolved to be essential in the grinding down of fibrous materials, and are perfectly suited to continual wearing down through 16-18 hours grazing per day. With fibre based feeds that take longer to chew, the teeth are exposed to the adequate wearing time that they have evolved for.

When talking about dentition and problems associated teeth problems, one of the points that is often overlooked is the position the food is eaten at. We have a habit of presenting our horses with feed at head height - whether it is a meal fed from a manger, or hay tied on the wall in a hay net. It may seem as though we are making our horses' lives easier, although, coming back to the evolutionary side of it, the horse has always grazed from the ground and there are mechanisms in place that benefit from mimicking the horses' natural feeding behaviour. Placing the food at head height causes incorrect wearing of the teeth, and hooks will begin to appear on the molars due to the unnatural positioning of the head during feeding. Not only are the teeth affected, but the musculature in the neck also becomes adapted to this upright posture, causing abnormal development of the muscle tissue. For these reasons, it is advised that the horse is fed off the ground, which allows the horse to ingest the food in the most natural way.

Meal sizes

Additional oil in the horse's feed is probabably the best energy boosterSo, after the feed has been chewed, incorporated with saliva and swallowed, it enters the stomach. The stomach has evolved to hold a small capacity of food; this adaptation has occurred in order to cope with a small, continual supply of forage on an almost constant basis (due to grazing habits). We now tend to feed large meals that the gastrointestinal tract simply can't cope with. Ideally, this bulk would be spread out between 5 or 6 small meals per day, although due to work and time constraints, there are very few horse owners who can manage this level of dedication. So the main problems with this large meal approach, are that there are high amounts of energy that enter the gastrointestinal tract ready for digestion. Once the stomach has done its part, and the feed is pushed through to the small intestine, this results in an empty stomach until the next meal is provided. This large amount of time between emptying and filling again means that the horse is more susceptible to developing problems such as gastric ulcers.

As mentioned before, the stomach has adapted to withstand a continual amount of forage and fibre, and so the acidic gastric juices produced are usually in constant utilization and will not typically cause harm to the stomach wall, since they are mopped up by the fibre passing through. However, given the 'meal' feeding regime that we subject our horses to, it is not surprising that ulcers develop in response to gastric juices which the empty stomach wall is exposed to. On top of this, add our previously discussed issue of limited the salivary buffering action, and feeding grains is really starting to look like a bad idea.

Absorbing nutrients

And so to the small intestine. When the feed reaches this part of the digestive system, this is where the digestion and absorption of nutrients takes place. Enzymes work to break down the different components of the feed - peptidases break down the proteins, lipase breaks down fats (with the help of bile) and amylase in the pancreatic juice breaks down starches. The presence of amylase in the pancreatic juices is relatively low (at around 5-6% of that in the pig) which suggests that the horse has not evolved to cope with the break down of a large amount of starches.

Again, this organ has evolved to be relatively small, and the rate of passage through the small intestine is typically 30cm per minute. This reiterates the fact that the horse is suited to a little food, often. If this were not the case, then rate of digestion would be slower in order to increase digestion and absorption, and the capacity of the digestive organs would be larger. Another anatomical feature that rejects the concept of large meals, is the fact that the horse secretes a continual flow of bile. This is because the horse does not have a gall bladder. The evolutionary adaptation of a continual secretion of bile helps to create an optimum environment in the intestine in order for the enzymes to function correctly. If the horse had evolved to eat the meals that we provide, then there would be no need for this constant flow of bile into the small intestine.

The dangers of acid

Calmness is essential in the ring!The site in which the fibrous, insoluble carbohydrates found in forages become broken down is in the large intestine. The main function of the large intestine is to digest fibres that are too tough for any enzymatic degradation. In order to do this, there is a population of microbes present, which work best at an optimum pH of 6.5, and are sensitive to any changes in environment. Fermentation of these insoluble carbohydrates (cellulose and hemi cellulose), are converted to volatile fatty acids as a form of energy.

If there were any soluble, easily digestible carbohydrates to enter the large intestine (such as ones contained in cereals, grains and sugar), then these would result in extremely rapid fermentation, creating a large burst of energy for the horse and an acidic environment in the large intestine due to the copious amounts of volatile fatty acids produced, along with lactic acid. This acidic environment means the optimum pH is altered, and the microbes begin to die off, releasing toxins into the blood stream. This is where problems such as laminitis can initiate. Feeding a meal that consists predominantly of grain, cereals and sugar, means the capacity of the small intestine can get overloaded, and the overflow of these food stuffs pass into the large intestine, where these problems begin.

Fuelling the competition horse

So now we have been through the different components of the digestive system, we can discuss the best way to feed the competition horse. As competition horses are constantly subjected to periods of training, competing and then a reduction in work, there is often more uncertainty regarding what type of feed must be given during these times. Energy requirements will obviously change throughout the year depending on the amount of work done, and this is where the idea of starches comes to play when more energy is required. As mentioned before, this is not always to most suitable form of energy to give any horse.

Feeding large amounts of cereals and grains can be very problematic - not only are cereals a form of carbohydrate which is totally unsuitable in terms of what the horses' digestive system requires, but it is also the reason as to why so many of these animals are "fizzy" (Bishop, 2003). This seems to the most problematic myth of all, as owners are baffled as to why they have a horse with such behavioural problems. Horses are biologically designed to digest carbohydrates in the form of forage and fibre, and it is not until we start interfering and adding foreign food stuffs to the diet that things start to go wrong.

Energy

If you are looking for an energy source without all the problems that are attached to cereals, then the addition of vegetable oil will be more beneficial then high starch feeds, however if the ration of oil exceeds 22% then a suppression of microbial fermentation has been reported (National Research Council, 2007). There are many different types of oil that can be used as a "non heating form" of energy, all of which have a great many advantages over some cereals and grains. Oils contain up to 2 and a half times more energy than cereals of the same weight. A wonderful benefit to adding linseed oil into the ration is that it contains one of the highest levels of omega 3. This is particularly beneficial to horses on a training programme or taking part in competitions that induce an inflammatory response, as omega 3 has anti inflammatory properties.

Hydration

Fibre is absolutely essential in the horse's diet, and although supplementary hay is regarded as a necessity, sometimes forage is not considered as being of such importance in the concentrate meals we give. As mentioned earlier, there are many health mechanisms that rely on the diet and most are beneficially influenced by the addition of plenty of fibre in the diet. Since the competition horse loses a considerable amount of water through exercise, every measure should be taken in order ensure the horse doesn't get dehydrated. Fibre can help with this concept as it assists in retaining water in the gut, similar to the action of a sponge.

Protein

This is no fun at all and what food you put into the horse's mouth is often to blame, yet the easiest thing to control!Another common opinion is that when a horse (or human) begins a high training regime, the requirement for protein dramatically increases due to the fact that the muscle fibres need building and rebuilding. According to years of research, this is not necessarily true (Jackson, 2003). Undoubtedly there is a fundamental role for protein in the horses' diet - synthesis of proteinaceous structures in the body, synthesis of enzymes, hormones and blood proteins amongst other things - although owners who simply feeding a lot of protein will not benefit the horse in any way unless all aspects are present. These aspects are known as amino acids which are the building blocks in which the horse can develop new structures around the body. There are around 22 different amino acids and all are required to be present in the body before the complex interactions can begin. So, feeding high quality proteins with high amino acid profiles is very different from feeding ones with only a few amino acids present (Bishop, 2003).

The golden rule

Feeding the competition horse is a challenge for any owner as there are so many different aspects to consider. The horse needs to be kept at a constant weight with balanced energy and nutrients, in relation to exercise done. However, this is an ongoing battle, as there are so many variables that are affecting all facets of the horses' life and environment. All this makes the task of balancing the requirements seem incredibly daunting and complex. The golden rule is, remember the competition horse has evolved to eat like a horse!

We are what we eat - are our horses too?

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