Supplement is the term generally used to mean a feed that is given on top of the normal daily ration in relatively small quantities of grams per day. Legally, supplements are classed as either complementary feeding stuffs, straights, or mineral feeding stuffs, depending on their composition.
Hundreds of supplements are available to horse owners, which can make things confusing, but there are specific categories to which they belong which can help to clarify whether or not your horse will benefit from a supplement.
The most useful but perhaps underused supplements are broad spectrum vitamin and mineral products, which balance a forage-only diet, or one that contains less than the full recommended amount of compound feed. Two other widely used and useful essential nutrient supplements are electrolyte salts and a combination of vitamin E and selenium, two important antioxidants. Most other supplements are targeted at specific problems e.g. joint or hoof health, and often contain a mixture of essential nutrients, nutraceuticals, herbs, and other active ingredients. Nutraceuticals are not essential nutrients, but are substances that have an effect in the body, and include glucosamine, creatine, MSM, and antacids.
Probiotics and prebiotics are supplements that boost the health of the beneficial micro-organisms in the horse’s gut, and include yeast (both live and deactivated), oligosaccharides (soluble fibres made up of many sugar units), and live beneficial bacteria. These supplements may also contain other gut-boosting ingredients such as digestive enzymes, herbs and/or clays.
Herbal supplements can be very effective and many modern medicines have been developed from substances in plants. A great deal of research investigating the effectiveness of herbs has been published so herbs are not to be dismissed.
It’s a myth that supplements containing ‘base’ material are of poorer quality or somehow less useful than ‘pure’ ingredients. A base such as ground alfalfa, grain or limestone flour may actually make the supplement more palatable, safer to feed by diluting an ingredient that could be harmful if overfed, or to round the daily amount up to a whole scoopful, making it easier to feed.
The legally required analytical declarations on supplements are in percentages, so calculating the actual dose of an active ingredient per day can depend on a little maths, unless the manufacturer has declared the active ingredients in a daily dose. For example, a supplement that has a protein content of 25% and is fed at a rate of 40 g per day only supplies 10 g of protein, so is not a good source of protein. Some manufacturers are very helpful with clear information on their products and/or their website.
The key to using supplements effectively is to use them in a targeted manner for an individual horse. First and foremost, the horse’s diet must be balanced for all the essential nutrients and it is pointless adding any health-promoting or therapeutic supplement if the basic diet is not balanced. After that, specific therapeutic supplements can be of great value to horses.