Nicola Tyler B.Sc. (Hons), Nutrition Director, TopSpec Equine

Horses are generally on box rest for one of three reasons. The first is that they are ill or recovering from illness or accident. Secondly they may be on box rest because they cannot be turned out or exercised, usually because of the weather. Finally they may be having a day off work and without turnout.
The way that horses should be fed during these days on box rest varies with the circumstances but has a profound effect on the horses future health and ability to perform.
What are the needs of a horse on box-rest?
Vitamins and minerals.
It is easy to understand that a horse will continue to need his vitamins and minerals during box rest as it is well understood that these micronutrients play a vital role in a horses metabolism. It is not surprising that on our helpline we often hear people say Ive been told just to give my horse hay and a supplement.
But what about protein?
Protein is found everywhere in the horses body. It is needed for the maintenance of healthy tissue and it plays a major role in the development and function of the musculo-skeletal system. Enzymes, which control the metabolism of the horse, are composed almost entirely of protein as are most hormones.
Many people do not realise the importance of protein for tissue repair. A damaged muscle or tendon, for example, cannot be repaired without feeding the horse the high quality protein needed for that purpose.
What other problems can be caused by too little protein in the diet? These problems are caused by either too little quantity or too low a quality of protein or a combination of both. They include loss of appetite and condition; poor coat and hoof quality; slower growth and development rates in youngstock; and in broodmares a reduction in fertility, milk production and size of foal at birth. In addition, there is an increased risk of developmental orthopaedic disease (e.g. contracted tendons) when the ratio of protein to energy is too low in youngstock feeds. The balance between energy and protein in feeds is important for different classes of horses because if there is insufficient protein in the diet then the energy cannot be properly utilised and is wasted.
How do we measure the quality of protein?
The level of protein declared on a feed label (e.g. 13% on a typical competition horse cube), is the crude protein level. Not all of this protein can be digested by the horse. The amount which can be digested is called, not surprisingly, the digestible crude protein level and some protein sources are more digestible than others, for example soya is highly digestible.
Proteins are made up of chains of amino acids linked together. There are approximately twenty five amino acids found in horse feeds and the order in which they are linked together creates thousands of different proteins. Ten of these amino acids cannot be made by the horse and are therefore considered essential in his diet. It is the level and availability of these essential amino acids in a particular source of protein which is the other important way in which we measure the quality of protein. Dried skimmed milk is one of the highest quality protein sources used in horse feeds but it is only used rarely post BSE and then in small amounts and only in certain feeds. This is also because adult horses cannot digest lactose, the sugar in milk. Of the plant protein sources used, soya is by far the best.
When a horse is on box-rest, for whatever reason, his needs for protein, minerals and vitamins need to be considered when deciding upon a ration.
What about energy or calories?
It is widely understood by horse-owners that when their horses are on box rest their feed should be cut down. What is not understood is quite what nutrients to reduce and what nutrients to keep feeding. What usually needs reducing when horses are on box rest is the amount of calories in their diet so that they do not become over weight, over-excitable or risk problems such as tying-up once work can recommence.
Calories come in many forms of course and it is rarely a good idea to reduce forage intake except when a horse needs to lose weight and even then every effort should be made to feed hay of a lower nutritional value, for example late-cut meadow hay rather than early cut ryegrass hay, before limiting forage intake. Hay can also be soaked for six to twelve hours in fresh, clean water before feeding. This leaches out soluble carbohydrates (mainly sugars and starches) to reduce the nutritional/calorific value of hay and is another method of maintaining optimal forage intake, allowing the micro-organisms in the hind-gut to function normally.
The calories that do need to be severely reduced during box rest are those that are derived from sugar and starch, which means cutting out cereals, molassed mixes and most cubes.
What products should be fed during box rest?
A horse on box rest needs a small feed which contains ample high-quality protein and high levels of vitamins and minerals but very little sugar and starch. A cereal-grain-free feed balancer, low in sugar and starch, which combines protein and micronutrients in a small amount of feed, would be ideal. Mixing it with an unmolassed low sugar/starch chop will help to stretch mealtimes and reduce boredom.
But we can be more precise than that. A fit horse with a short term injury can retain its fitness quite well, even without turnout, for three weeks. For horses like this a top-specification feed balancer formulated for hard work fed twice a day with a Stubbs scoop of unmolassed alfalfa chop will provide nutritional support to speed recovery and allow the horse to return to work with minimum disruption.
Similarly a horse recovering from a major operation will respond to the high level of nutritional support in such a diet even if the feed needs to be softened. If feed needs to be given in liquid form then the same feed balancer can be mixed with grass/alfalfa/straw-free high-fibre cubes and then soaked in cool water until the desired consistency is achieved.
Horses in light work or retired, however, will usually have their needs amply met by a standard feed balancer designed for leisure horses fed twice a day mixed with a Stubbs scoop of unmolassed alfalfa/straw chop. For those horses in this group which are overweight they must still receive the feeds described but attention will need to be paid to the type of hay offered and whether it needs soaking.
Hard working horses having a day off should be turned out if at all possible but if they cannot go out their hard feed should not be changed for one day but must be reduced. If they were being fed a feed balancer, chop and cubes/mix/cereals then they should receive just the feed balancer and chop on their day off. If they are being fed just a compound feed then this should be reduced by at least 75% but of course the horse will have his intake of important vitamins and minerals severely reduced.
There are of course many specific circumstances when nutritional advice can be tailored to the horse or pony concerned. For example a pony on box-rest recovering from laminitis would usually be advised to feed a pelleted multi-supplement or feed balancer containing a therapeutic hoof supplement. A horse with a soft-tissue injury that needs maximum nutritional support to speed recovery would usually be advised to feed a top-specification feed balancer even if he was not in hard work.
What if the horse is bored?
Products such as unmolassed alfalfa/straw chops are ideal low sugar/starch boredom breakers and so are a small number of high-fibre cubes fed in a snack ball.
What if the horse needs to gain weight?
Where a little weight gain is required unmolassed sugar beet pulp or unmolassed alfalfa chops are also low sugar/starch products. Products to avoid are high in sugars and starch because not only to they risk digestive disturbance in a confined horse but also they often promote excitable behaviour.
What additional products might help?
There are many cases where the use of a pure, protected yeast to help maintain optimal conditions in the hindgut would be justified. The use of mannan oligosaccharides (MOS) to mop up pathogens throughout the horses gut may also be helpful. A top-specification feed balancer may contain these products but they may need to be purchased separately if not.
For those horses and ponies that find confinement very stressful despite a considered diet then the use of a daily in-feed calmer is a good idea. Finally for those horses that are so sick that they have lost their appetite adding a daily in-feed appetizer, or in extreme circumstances syringing it in, has proved very beneficial in many cases.
Nicola Tyler B.Sc. (Hons), Nutrition Director,TopSpec Equine Limited. Triple-Award-Winning, Free, Advice Line: 01845-565030


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