Western Morning News

Grass has formed and integral part of the horse's diet for centuries. In their natural state horses may spend two thirds of the day grazing and can consume up to 10 per cent of their body weight in the form of fresh grass.

Browsing to find the most palatable swards, horses are trickle-feeders, eating small quantities of grass almost continuously throughout the day. This grazing behavior is sympathetic to the horse's digestive system, having a relatively small stomach and well-developed hindgut.

Our domestication of horses over the years has, however, imposed a very different regime by restricting access to grazing or other forage, housing in stables and meal-feeding. Most of these changes in management have been introduced either for our convenience, or to help meet the nutritional challenge that faces the modern competitive horse.

Grass is the most natural part of a horse's diet but does it have a role to play for the competitive dressage horse? Putting grazing in the spotlight, we can uncover some of the benefits as well as problems with 'Dr Green'.

Allowing competitive horses access to grazing has many benefits including the provision of energy, which makes a significant contribution towards paying the daily 'energy bill'. In practical terms, access to reasonable grazing on a daily basis can reduce the quantity of hard feed required by half. If grazing is not available and cereal-based concentrates are over-fed in an attempt to maintain condition, digestive upsets, loose droppings or poor feed utilization may result leading to reduced performance.

An adequate forage intake (including hay/haylage) and increased access to grazing will reduce the reliance on cereal based concentrate feeds and so help to avoid some of these potential problems. As well as nutritional benefits, the competitive horse may also gain a psychological advantage from regular access to grazing. A horse which spends a large part of his day either working, or restricted to a 12' by 12' stable, will surely realise the benefit of at least a couple of hours in a grass paddock, having the freedom to relax and 'let off steam'.

Recent evidence suggests that the incidence of 'stable vices' or stereotypical behaviour such as cribbing, weaving and box-walking is lower in horses which have more free time outside of the stable and have more opportunity for social contact. Other factors such as the availability of forage/fiber and the amount of concentrate fed also appears to influence the incidence of these and other stable vices such as wood-chewing.

Prominent dressage rider Lulu McAlpine maintains and successfully competes her string of horses from a largely grass-based diet. I asked Lulu about her horses and how she felt they responded to their very natural management regime. 'My horses live out all of the year around without rugs. I feel that they are much happier and relaxed as a resul4 and in my opinion are more likely to perform consistently well in the dressage arena in this respect. Even when the horses are working hard, I find that they only require a small amount of additional feed to maintain condition, yet they have plenty of energy for the work I ask of them. All of my horses are fed Dengie Alfa-A and Naked Oats and have free access to a Saracen mineralised feed block. Having competed and seen the benefits of such a natural regime, I would find it very difficult to revert to a more conventional regime of predominantly stabling my horses,' says Lulu.

Up-and-coming rider Hannah Esberger is also a firm believer in allowing horses daily access to grazing. 'We only have a small amount of grazing on our yard, but I like to ensure that each of my horses is turned out as regularly as possible," says Hannah. Hannah maintains that Fernando, whom she partners in the 2000 Dressage Squad, is more relaxed in the summer when he is turned out more regularly. In Hannah's case the grazing probably doesn't contribute much nutritionally, but allows the horses to have a 'run and a buck' as well as giving them a change of scenery. All of Hannah's horses are fed Dengie Alfa-A and small quantities of Naked Oats when required, as well as NAF Pink Powder, a broad-spectrum vitamin and mineral supplement.

So why is grass known as 'Dr Green'? Most of us will have noticed that horses and ponies thrive on good pasture and that even the leanest animal will quickly improve condition given good grazing. Grass contains varying quantities of fibre and water-soluble carbohydrates or 'sugars', which provide the horse with two different sources of energy. Fibre is digested mainly in the hindgut and the energy produced is released slowly over a sustained period. Some of the water-soluble carbohydrates found in grass are digested in the small intestine and some, particularly 'Fructans', reach the hindgut where they are fermented by the resident bacteria. The 'sugar' digested in the small intestine provides more energy more quickly than that produced from fibre. In the spring, the grass has a higher feed value and provides more of this 'instance type of energy, which can often lead to the characteristic over-exuberance seen in horses at grass at this time of the year.

The energy or feed value of grazing is influenced by the relative quantities of fibre, 'sugar' and protein present which in turn is influenced by many different factors including:

- Species of grass - Modern pastures often have a high inclusion of ryegrass species, which have a higher potential feed value due to their increased water-soluble carbohydrate content.

- Stage of growth - As grass matures, the protein content drops and it becomes more fibrous and less digestible, giving it a lower feed value. Grass, which is either topped or grazed, will not go to seed and so will retain more of its feed value for longer.

- Environmental conditions - Any factor which increases the rate of grass growth, such as an increase in light and temperature or the application of fertiliser, will increase the availability of grass, providing that there is an adequate supply of water.

Generally speaking, early sea-son lush grazing tends to contain higher levels of water-soluble carbohydrates and protein, and lower levels of fibre, giving it a higher feed value. In contrast mid to late season grass is often more fibrous and lower in protein and water-soluble carbohydrate, giving it a lower feed value.
A potential downside to grazing competitive horses is over-consumption of grass. With unrestricted lush grazing, even an active horse can become over-weight which may have a negative effect on performance. Like-wise, 'free access' to this type of lush pasture can also in some circumstances lead to digestive or other problems.
When horses or ponies consume a large quantity of grass, with a high water-soluble carbohydrate content within a relatively short period of time, more of the sugar' is fermented rapidly in the hindgut producing an accumulation of acid. The 'useful' bacteria in the hindgut can't cope with this increase in acidity and so a proportion die, producing harmful endotoxins. This scenario can lead to digestive disturbances such as fermentative colic or even laminitis. Remember that laminitis is not confined to fat ponies. If practical, shared grazing with other animals such as cattle and sheep can help to modify grass intake, as well as improving the pasture through reducing the parasite load and grazing off areas of rough.

Although your grazing will make a significant contribution towards your horse's vitamin and mineral requirements, it's unlikely that all his requirements for work will be met if grass is the sole source of nutrition. Additionally, the trace mineral content of your grazing e.g. copper, selenium, manganese and zinc levels, will be influenced by the prevailing soil type in your surrounding area.

Soil type can influence the ability of soil particles to 'hold on' to trace minerals, thus affecting their availability to the growing plant. If you are relying on your grazing to make a significant contribution to your horse's nutrient intake, it is useful to be aware of any localised trace mineral deficiencies in the soil. You may be able to glean some information from local farmers or can alternatively have a soil and herbage analysis carried out on your own land.

Feeding supplementary concentrates such as a coarse mix or cube, or the addition of a vitamin and mineral supplement such as Dengie Optimum or Classic will provide some 'insurance' against fluctuations in the vitamin and trace mineral content of both grass and other forage sources. Alternatively, a mineralised feed block e.g. Dengie Main Ring 'Keep Block' or Forage Balancer Bucket is ideal for supplementing grazing, providing an additional source of energy as well as a steady supply of vitamins, minerals and trace elements. By Dr Green