ON the sunny days of high summer, all-important forage is being made for the winter and horse owners will be on the lookout for good quality hay to see their charges through the cold days and dark nights when paddocks are bare.

While hay and haylage, the modern version of "treated" hay, is available throughout the year from specialist dealers, many people prefer to buy theirs "off the field". In other words from the field where the crop has been made and before it has been removed for storage.

This way it is usually cheaper, because the farmer hasn't had the labour costs of hauling it and, if you have the room, you can buy enough to feed your horses throughout the winter and won't have to go looking for some more in February when, if the season has been particularly hard, it may be expensive.

Buying the right hay for your animal's needs is something of an art and it's worth taking advice if you're not sure. Hunters and competition horses, for example, do best on what's called "seed hay". This comprises grass that is specifically grown as a crop for hay.

It is generally higher in nutrients and energy than "meadow hay", which is made on fields that are usually grazed by sheep or cattle, but are closed off during the spring to allow the grass to grow until it is long enough to cut for hay.

If you only want to use your horse for light exercise during the winter, meadow hay is perfectly all right, but if you want to hunt or engage in some other more strenuous activity, you will have to increase the volume of your horse's hard feed.

However, the variety of hay you choose should always come second to the quality. Hay has to be free of dust, mould and foreign objects and it needs to meet your horse's nutritional requirements, since a mature horse will eat two to two-and-a-half per cent of its body weight a day - equal to 10 pounds of hay each day for a 1,000 pound horse.

Hay is the most important feed product you will give your horse and makes up the majority of his diet. Most people buy hay on how it looks, smells and feels and when appraising hay keep in mind the following points:

It's what inside that counts so it's a good idea to open one of the bales so you can evaluate the hay inside.

Choose hay that is fine stemmed, green and as leafy as possible and is soft to the touch.

Avoid hay that is over-cured, excessively sun bleached or smells mouldy, musty and dusty.

Examine the leaves, stems and flowers or seed pods to determine the level of maturity.

Select hay that has been harvested when the plants are in early bloom.

Avoid hay that contains significant amounts of weeds and dirt. Examine hay for signs of insect infestation or disease and ask the grower about any potential problems in the region.

Reject bales that seem excessively heavy for their size or feel warm to the touch. When possible, purchase and feed hay within a year of harvest to preserve its nutritional value. Store in a dry, sheltered area out of the rain, snow and sun or cover in the stack to protect it.

Hay provides the required fibre to maintain good digestive tract function and provides most of the nutrients your horse needs.

It is low in salt and may be deficient in one or more minerals so salt and a mineral supplement should always be given with hay.

If nutrient-rich hay is fed to a horse with low nutritional needs, weight gain will occur.

If low nutrient hay is fed to a horse with high nutritional needs then there will be weight loss or poor growth and low milk production.

Including a concentrate in a horse's diet can rectify too little energy that is in the hay. This concentrate may be oats, corn, barley, commercial feed or a fat supplement concentrate - it depends entirely on what is available in your area.

Excess energy is stored as fat and owners of fat horses try and solve the problem by restricting the horse's hay intake. While this may seem the right thing to do, it can lead to problems such as colic or boredom vices, such as wood chewing.

Hay that is too low in protein will need a high protein supplement added to the diet.

And although there are lots of these on the market, it is ultimately cheaper to buy hay with an adequate amount of protein.

Alfalfa hay has a higher protein content than grass hays but it depends partly on the maturity of the forage at the harvest.

If you buy hay which is too high in protein, the horse will simply eliminate the excess in the form of urea which is then excreted in the urine at no detriment to the horse. As a secondary problem of excess protein, the urea is converted into ammonia and can cause irritation to the lungs of horses kept in poorly ventilated stables

Hay with protein levels above the horse's requirements is of no benefit to the horse so try and buy hay that meets, or only slightly exceeds, the protein requirements.

Horses with kidney or liver problems may have difficulty with high protein hay.

If all this sounds tricky, without a doubt the biggest challenge is to find dust-free hay.

Dust in hay can come from mould spores or leaf shatter. Only in rare occasions does dust come from hay which is improperly stored, allowing moisture to enter from the top or from the ground up.

Dust from leaf shatter occurs when the hay is too dry, causing it to be brittle. Mould dust acts as an allergen and can cause inflammation of the respiratory tract in horses.

With repeat exposure, the horse can develop permanent lung damage, commonly known as heaves or chronic obstructive pulmonary disease.

Mouldy, dusty hay simply should not be fed to horses.