By Dr Derek Cuddeford
The standard, conventional winter forage for horses has always been hay. This is because relatively simple equipment was required for its production; grass was cut and simply left to dry. In the outer isles of Scotland it was hung on fences to speed the process and in Ireland, and other countries like Iceland, it was/is built into “haycocks” on wooden frames again, to accelerate the drying process. The whole essence of the process of haymaking is to dry or “cure” the grass to the extent that it will store safely(<14% water). Of course, the vagaries of the British climate make it very difficult to achieve satisfactory field curing; at least five continuous days of sunny, windy weather are required to “make” good hay. Various technological advances have since been made. These include “conditioning” the grass when it is cut, a process which crushes/bruises the grass stems and novel ways of physically handling the grass. However, if it rains, conditioned grass loses more nutrients via leaching than untreated grass so, it can also be a risky process heavily dependent on dry weather. It is apparent that because hay is the end result of a drying process then it will have to be stored undercover, usually in a barn. Few stables have covered winter storage facilities to hold enough hay to see them over the winter so it is often necessary to buy as needed.
The question is, what hay should I buy? Generally it acts as a source of energy, poor quality protein, a few vitamins and some minerals. Unfortunately it is often a source of mould spores and dust causing allergic responses in horses culminating in respiratory disease (typically COPD), large veterinary bills and an unusable horse! I would prefer that this type of hay be disposed of since our horses depend on their lung function to be able to exercise and as such there will always be a risk in using such material as a feed for horses. The ideal hay would be green in colour (indicating rapid drying), smell sweet, no dust visible when shaken in a sun ray, be leafy (young stage of growth) and soft when “scrunched” in the hands.
To counteract the problem of low hygiene hays (unfortunately they are ubiquitous) one can minimise risk in a number of ways. It is possible to partially overcome the mould problem by soaking hay but some essential soluble nutrients will be lost on the way. The benefits of soaking hay are two-fold: occupational therapy for the staff together with some free body building! Conventionally soaking requires that hay is thoroughly wetted (not soaked for hours!!) and this need only take 5 minutes. Only provide enough hay that will be eaten in about a 3 hour period so that it does not have time to dry out. Always feed the hay outside rather than in a limited air space thereby reducing the risk of inhalation of any foreign particles; any spores disturbed as the horse eats will be blown away! Feeding in closed mangers or deep buckets will increase the risk of inhalation due to the small air space in which the horse is putting its muzzle and the fact that any spores etc cannot ‘escape’. If the material is shaken out in a hay-rack prior to the horse having access another opportunity then exists for potentially damaging material to be lost to the environment. Also, outside feeding means that any rain will help keep the hay damp; provide shelter for the horse but not the hay, unusual I know but extremely practical. Also remember that the horse is used to eating wet feed since grass contains at least 80% water and that many horses ‘hay dip’-they mostly prefer wet feed so there is nothing odd about damping hay for horses! This approach applies to all hay of dubious hygienic quality but in fact, you can also damp good hay if you like. If you think about this in practical terms it seems crackers as one goes to such trouble and expense to dry the grass to make hay and then store it. You then remove it from store and make it wet again…………
An alternative to hay is silage. Originally, fresh long grass was stored in sealed silage clamps before specialist forage harvesters were developed which harvested and chopped the fresh grass; the latter could be stored in tower or clamp silos. The need to produce silage of consistent high quality provided the stimulus for the development of sophisticated equipment and silage additives which, when used correctly, guarantee that quality silage will be made irrespective of plant sugar content, grass species, weather etc. Thus, nowadays, “wet” grass can be conserved as high quality silage with minimal dependency on the weather. It should be pointed out at this stage that hay is an unnatural feed for herbivores because it is dried out grass. These animals have evolved to consume succulent material and thus, silage represents a nutritious, wholesome (mould-free), more natural alternative to grass that can be cheaply stored in large quantities. However it can present significant handling difficulties. Depending on where you live it may surprise you to know that quite a few horse owners feed silage to their horses and some even allow their animals to self-feed like cattle!
Some years ago there was an evolution in farm technology whereby round, square, large and small bales of fairly wet (~50%) grass could be baled, wrapped in airtight plastic film and stored outside. Initially these bales were used for feeding to ruminants and frequently the wrapping became damaged (rats, etc) and the bale contents degraded. These ruminant products evolved into those that were suitable for feeding to horses and were called haylages. Essentially, the only difference between haylage and silage is that the former is drier. Both depend on the same fermentation processes to make a quality product and can be produced using basically the same equipment and techniques. Silage is generally more acidic (pH 3.8-4.2) than haylage (pH 4.5-5.4) because it is conserved at a higher moisture (~75%) than haylage (~40-60%); dryness limits the extent of the fermentation. However, there has been a trend to produce drier and drier (<30% water) haylages and in these materials there is very little fermentation and, as a result, there is very little of the natural preservative lactic acid to ensure stability. The latter depends on the product remaining anaerobic.Thus, the manufacture of haylage for horses can benefit from all the technological advances made on behalf of farm animals and ultimately, our horses have been the beneficiaries of these advances. The great advantage of these wrapped products is that they could be stored outside because they are weatherproof.
Nowadays, haylages are produced in different sizes ranging from ~20/25kg bags to 25/30kg wrapped mini-bales and up to 300kg wrapped square (mini-Hesstons) or round bales. To ensure a satisfactory fermentation, the grass is wilted quickly to 50/60% dryness (dry matter-DM) then wrapped using a minimum of six layers of wrap with a 50% overlap. This will ensure that the grass will remain anaerobic, lactic acid is produced and the grass is preserved. A little air under the wrap allows yeasts to grow until all the surface air is used up. These harmless moulds (remember, yeasts are used in expensive horse probiotics!) appear as white flecks or small colonies (1-2mm in diameter) on the grass surface.
In response to the huge demand by horse owners for haylage more and more people are producing it. Many farmers are diversifying their business and looking for alternative income streams and haylage production is a winner for them as they have the technology and expertise. However, you must be sure that your supplier is following best practice. What may do for a cow may not be good enough for a horse! For example, preparation of the grassland prior to grass growth is very important. Moles should be destroyed, molehills levelled and the pasture harrowed and rolled. Exclusion of soil is most important because certain soil-borne organisms such as Listeria can be harmful to horses and also, soil reduces palatability and feed value. When the grass is cut with a mower/conditioner a high stubble should be left (again, this reduces the risk of soil contamination) and the grass wilted quickly. When it is time to bale, use a baler with integral chopper, inoculant (see below) should be introduced, the chopped grass rolled tightly and then the bale should also be wrapped tightly as described above. Wrapped bales can be stored outside in a dry sheltered area but wrap integrity must be maintained. The latter is achieved by netting to avoid wind damage and by establishing baiting points to control rodent populations.
Inoculants work in terms of ensuring haylage quality. They have the benefit that they work equally well in small volumes of grass such as those produced in mini-bales and other wrapped bales (big bales). They contain natural strains of bacteria isolated originally from forage such as Lactobacillus plantarum (strain MTD/1), Serratia rubidaea and Bacillus subtilis; the former can be applied at 1 million/ gram of grass and the latter two are applied together at the same rate. It is apparent that huge numbers of microorganisms are added into a wrapped bale of grass. They improve the fermentation and thus nutritive value and palatability as well as reducing waste and variability between bales; the net result is highly palatable, good quality haylage.
In conclusion, the horse owner has a limited choice of forage (hay or haylage) but an unlimited choice of products! Frankly, hay is unreliable, alfalfa/lucerne/dehydrated grass are far too expensive in the UK to use as complete forages and straws are too poor quality to be even considered. Thus, haylage is the forage of choice as it can be stacked outside, the packaging is incredibly strong, it is easily transportable, horses love it and less labour is involved in its usage.