Nutrition CPD April 2018

63
Irish Draught horse

Supplementing the performance equine diet

By Kate Hore RNutr(Animal), senior nutritionist at NAF.

Competing to a high standard takes a lot out of equine athletes, so we must provide them with the nutritional tools for recovery.

As the competition season really gets underway, it’s important we can advise our customers on how to get the best from their horses, and ensure they recover quickly and efficiently ready for the next competition. 

Supplementing for performance

The performance diet should stick as closely to the natural equine diet as possible. We increasingly understand the potentially detrimental effects of small, starchy bucket feeds, particularly with respect to issues such as Equine Gastric Ulcer Syndrome and excitability, both of which are very relevant to the performance horse. 

Therefore we should be advising our customers to keep their horses on a high fibre, low concentrate diet. The challenges of the high forage diet for performance are firstly to ensure that all micronutrient requirements are met, and secondly that sufficient energy for performance is provided. 

Grazing and forage alone may be micronutrient deficient, particularly when that forage is preserved, for example in hay or haylage. In the UK common grazing deficiencies include copper, zinc and selenium. Alternatively it may be that natural levels are lost during forage preservation. Vitamin E is a classic example of an essential nutrient for performance present in fresh pasture, but lost by processing. 

We should also consider annual fluctuations, ie. nutrients such as magnesium may be low in the spring, while vitamin levels drop later in the season. 

When we also consider the increased requirement for performance, we can see that supplementing is advised in order to ensure that all the elements required for fine tuning the equine diet are present. For example, if we consider vitamin E, the requirement doubles from 500 I.U. [international units] per day at rest, to 1000 I.U. per day for elite performance (500kg horse).

Supplementary multi-vitamins are available as powders, liquids or concentrated pellets, each of which have their benefits for horse owners. For busy competition yards, we often find a liquid product with a measured pump dispenser, is a quick and easy way to make sure everyone gets their quota accurately when feeding a yard of horses. 

The forage diet alone may fail to provide sufficient energy for the demands of performance. However, we don’t need to go back to feeding starchy cereals. 

Oil provides a concentrated source of energy which is readily metabolised by the horse. The energy from oil is free of starch, slow release, ideal for maintaining stamina right through a competition, and less likely to cause those explosive releases of energy sometimes associated with other sources. 

The energy from oil is more concentrated than that from cereals, which is very useful for elite horses where poor appetite can be an issue. The high oil diet also provides significantly lower levels of waste heat, which is particularly important if competing in warm or humid conditions to avoid heat stress. For example, if you needed to supply an additional 10MJ of useable energy to your horse, the following shows how that would be metabolised dependent on source.

It’s recommended that plant based oils can be fed for performance up to a level of 1ml/kg BW [bodyweight]. It’s important to introduce the high oil diet gradually, building up over several weeks, to allow the horse’s metabolism to gradually adjust. 

If feeding a high oil diet, the requirement for vitamin E, as an antioxidant, also increases, and it’s recommended to supplement at 1-1.5 I.U. of vitamin E per 1ml of additional oil fed. 

Supplementing for recovery

Competing to a high standard takes a lot out of our equine athletes, and if we want to keep them sound and strong, and get them back to work quickly, it’s essential that we provide our horses with the nutritional tools for recovery. 

Perhaps the most well-known of nutrients lost during exercise is the electrolyte group. These essential body ions are involved in many metabolic pathways including muscle and nerve function, maintaining the acid-base balance of all cell functions and are vital for healthy hydration in hard working horses. 

The principle electrolytes for horses are sodium, potassium and chloride and, to a lesser extent, magnesium and calcium. The most important is sodium, as this is commonly deficient in the forage based diet, so it’s important that we allow free access to a salt lick (sodium chloride) on a daily basis. 

Large amounts of electrolytes are lost through sweating. For example, a horse working hard may lose up to 25% of his total body chloride alone in just a couple of hours, so it’s essential that electrolytes are replaced in order to avoid both short and long term problems. Upgrading that salt lick to a broad spectrum electrolyte supplement for hard work and competition will ensure that these essential nutrients have been replaced. 

Of course sweat doesn’t just lose electrolytes. We must ensure that the water which has also been lost is replenished concurrently, or you risk further dehydrating the horse rather than rehydrating. The best way to ensure adequate water is taken, is to either feed the electrolytes in a nice wet, sloppy feed, or train the horse to take them dissolved in water. For those travelling regularly, training the horse to take their electrolytes in water can help overcome any differences in water taste around the country – something horses can be surprisingly sensitive to.

One of the other effects of hard work on the system is that of oxidative stress. Oxidative stress occurs when the antioxidant defences within the system are overcome by a build-up of Reactive Oxygen Species (ROS) or free radicals. 

There may be a number of reasons for the escalation but, specific to performance horses, ROS will build as a by-product of oxygen metabolism during exercise. The harder the athlete works, the more oxidative stress will build. In human athletes, the condition of ‘over-training’ is increasingly associated with oxidative stress. Over-training is also recognised by trainers, as a horse going ‘sour’ or ‘off-form’. 

When considering antioxidants it’s advised to look beyond a straight vitamin E product, or similar. It’s understood that feeding a combination of antioxidants will be more effective than any one on its own as they often have slightly differing, and complementary, roles during the ROS scavenging process. 

Look for natural antioxidants such as turmeric, rosehip and omicha berries, as they retain their complex of phytochemicals rather than being over-purified. For owners and managers of hard working horses, it’s recommended to feed a short course of concentrated antioxidants following intense exercise to facilitate a return to full training as soon as possible. 

In conclusion, by ensuring that we’re advising our customers both how to prepare equine athletes for the season ahead, and how to counteract the stresses of competition, we can keep our horses sound and strong throughout the coming season. 

About the author: Kate Hore is a Registered Animal Nutritionist and has been with NAF for more than 20 years, where she specialises in fine tuning equine diets through supplementary nutrition.