Wednesday, May 1, 2013

Grass grazing — essential for the horse

by Natalija Aleksandrova

Through the course of its evolution, the horse digestive system changed to one best suitable for digesting grass. It gave to the modern horse means by which it can extract energy needed for life from all forms of the grass nature offers through the seasons. For this the horse got necessary gut flora and fauna, and its caecum considerably expanded. Being still quite primitive and much less efficient than in ruminants, equid's digestive system, combined with high rates of voluntary food intake, gave a great advantage to horses comparing to ruminants in feeding on coarse grasslands, characterized by high fiber and low protein content.

If the horse is provided with all other essential needs, when provided with unlimited access to grazing the whole year-round and unrestricted movement day and night, its body is able to utilize grass in the most beneficial way during each season. Spring grasses give a boost to horses during their mating season, helps them to gain weight and energy back coming out of winter, to fill for a lack of nutrients after the winter season, as well as provides extra energy to foals which is needed for their proper growth and development. Fat deposits are stored in horses' bodies during summer and autumn grazing, which is then used during the winter.

When the horse is allowed its natural grazing habits the whole year-round, it is never abruptly exposed to a new type of food, what could affect negatively its metabolism. Spring pastures have a mix of both new growth green plants and the previous year's dried ones, so the animal goes through a gradual transition to the food that is richer in nutrients. As new grass stops growing in autumn, the horse gradually converts to eating more fibrous dried plants, which has its benefits in the horses body during the colder weather. Also, despite popular believes, dry winter grasses still may be high in sugars and other nutrients, they are not the same as straw, which is a byproduct of agricultural business.

The fermentation process of insoluble plant fibers in the hind gut creates heat in the horse body. Dried mature grasses and the branches of bushes and trees have higher insoluble fiber contents than that of fresh green plants. It is more natural for the horse to eat green grass in the summer, when it is hot, because less heat is produced during fermentation of the soluble fibers the grass contains, and thus the animal doesn't have to struggle to rid his body of excess internal heat. It is beneficial for the horse to eat dry plants that are rich in the insoluble fiber in cold weather. The fiber is digested slowly and the heat is sustained for a longer time in the body, helping the animal to stay warm during the winter.

Restricting an access to grazing through reducing a time a horse spends in a pasture, may bring only a bigger mess to the horse's metabolism, and thus only opposite to the 'thinning' or 'laminitis preventing' effects. Studies showed that, when a horse knows that her time in a pasture will be limited, she is able to consume up to 3 times bigger amount of grass in a given time as normally (P.D.Siciliano). It means, if a horse is let to the pasture for 4 hours, she is able to consume an amount of grass which normally she would eat in 12 hours, in other words, approximately a half of her normal day/night amount.

In general, it is very incorrect to say 'grass is bad for the horse', because grass has been the most natural food for the horse ever since it evolved into a free-ranging, primarily grazing, plains dweller. We need to learn and consider all the effects that humans cause when manipulating the horses' lifestyle and their pastures in order to prevent situations where grass turns into a 'danger'. Such as, limiting a horses' access to food, changing the chemistry inside the horse's stomach which makes it unable to properly absorb all the nutrients from the grasses, providing horses with over-fertilized mono-species pastures manipulated especially to suit cattle who have a very different metabolism, or restricting horses in the free movement which damages their metabolism, etc.

Domestic horses kept naturally. Grazing in a natural not fertilized pasture. Beginning of spring. Latvia:

The same horses later in the spring, a few days in between these two shots:

Domestic horses kept naturally. Spring grazing in not fertilized pasture. Poland:

Przewaski wild horses in Ukraine. Summer grazing:

Konik Polski wild horses. Latvia and Poland. Summer grazing:

Domestic horses kept naturally. Summer grazing in a natural not fertilized pasture. Latvia:

Domestic horses kept naturally. Summer grazing in a natural not fertilized pasture. Norway:

Konik Polski wild horses grazing in autumn. Poland:

Domestic horses kept naturally. Winter grazing in a natural not fertilized pasture. Poland:

Continue reading to "Restricted grazing — does it bring the desired effect in horses"? >>

Photos © author, B. Bratny, Z. Wroblewsky