Crude fibre is an essential part of every horse’s diet and should make up at least 50% of the daily ration. It looks after the health of the digestive tract: it improves gut motility, keeps the intestinal microflora at the right level, reduces the risk of colic and helps prevent ulcers. Feeds high in fibre give horses a feeling of fullness, which has a positive effect on how they feel. They also help wear the teeth down properly, and digesting them is one way horses produce heat, which is particularly worth remembering in winter. The main source of fibre in the horse’s diet is hay.
Horse feeding guidelines recommend that the daily hay ration should be at least 1-2 kg per 100 kg of body weight, so this feed deserves a close look. The safest approach would be to take samples and send them to a laboratory for analysis, but that is expensive. Fortunately, we can assess hay quality ourselves by sight, smell and touch. What should good hay be like? Above all it should have a pleasant, slightly sweet smell, a green or green-yellow colour, feel dry to the touch, and be free of sand and dust. Hay turns yellow when it lies in the field for too long, while darkening, together with high moisture and an unpleasant smell, can mean that it is starting to rot. One of the best indicators of the value of a forage is the cutting date. As hay matures, its fibre content rises and its digestibility falls, while protein and phosphorus decline. The best hay for horses comes from a first cut taken at the start of grass flowering, because it is richest in nutrients. It should, however, contain at least 20% crude fibre. The presence of seed heads usually means the crop was harvested late. Hay should also be made up of several grass species (timothy, brome) with some herbs and a smaller share of legumes such as lucerne or clover, which are high in protein. Hay with a larger share of legumes is better suited to lactating mares, foals and performance horses. Interestingly, because of its high calcium content, this kind of forage works well for horses with ulcers, as it reduces acidity.
Storing hay is just as important as its quality. It should be kept in a dry place, out of direct sunlight, which reduces the carotene content. Moulding is another process that lowers hay quality, so the moisture content of this feed should not exceed 20%. However well hay is stored, its nutritional value and palatability decline, and the dust, mites and fungi that build up in it increase the risk of allergy. For that reason it is better to avoid using hay that is more than a year old.
Finally, a very important point. Under no circumstances should horses be fed fresh hay! The fermentation period, or “sweating”, can last for up to 8 weeks. Hay that has not finished sweating can cause bloat, colic and even laminitis.