Healthy Horses – Healthy Land (part 2)

overgrazed paddock

Jane and Stuart Myers

When you watch your horse (or pony) graze pasture you are correct in thinking that this is the most natural situation for your horse. Millions of years of evolution have created this symbiotic relationship between grazing animals (your horse) and pasture plants.

However two factors, the domestication of the horse and the selective breeding and production of grass species has created an imbalance in this once harmonious relationship. There are two real issues of concern for the modern horse owner. The first being how the nutritional changes associated with the new grasses have detrimentally affected the horse.

The second being the pressures we put on our land by confining our horses on relatively small areas of pasture causing overgrazing and degradation.

Horses are natural grazers, browsers and foragers that naturally eat a diet of low energy, high fibre plants such as grasses, along with some leaves, bushes herbs, succulents etc. As explained in the last article, their whole physiology has evolved to enable them to do this as efficiently as possible.

Good healthy pasture is a horse’s natural diet and has many benefits. It provides the essential roughage that a horse requires. It is a relatively cheap form of feed. It allows them to carry out natural behaviours such as walking whilst grazing (these two actions are physiologically linked), browsing and foraging. It allows them to clear their airways while their head is down in the grazing position. It is also an excellent feed source for most horses.

Grazing on the Correct Grass

Many grass species that horses graze upon in a domestic situation have been selectively bred to be more productive, but not for horses, mainly for sheep and cattle. Recent studies have shown that some improved Ryegrasses for example, can contain up to 600 times the amount of sugars in them than their naturally occurring unaltered relatives. This is fine for the cattle industry that wants to put weight on their beef cattle or produce gallons of milk from their dairy cows, but it is deadly for most horses.

When you consider that these sugars, such as fructans and starches, have been closely linked to conditions such as Laminitis, Cushing’s Disease and Equine Metabolic Syndrome, you can see how these highly developed grasses area concern for most horse owners.

What we have to ensure is that our horses are grazing on the correct types of grasses. Unimproved, old fashioned species, native or naturalised, are all types of grasses we should be encouraging in our pastures for horses. In order to encourage these types of grasses we must manage our pasture. This usually entails reducing our grazing pressure as many of these species, particularly the native grasses do not cope well with being overgrazed.

Grass and other pasture plants have, however, evolved alongside grazing animals and actually thrive on being grazed… but just the correct amount!   

In fact some studies suggest that there are chemicals within the animals saliva that may actually stimulate grass growth.

Grazing animals (in a natural setting) move across a landscape biting plants and trampling the rest with their hooves or feet. The pasture plants are put under a large amount of pressure but for a relatively short period of time, then the animals move on and the pasture usually gets time to rest and recuperate. This intense grazing followed by a period of rest stimulates the plants to start re-growing. The animals also leave small indentations on the land with their hooves into which some of their manure drops (along with the seeds of the plants that they have consumed in the last few days). Some of these seeds are able to germinate and start life afresh. In the natural situation various species of animals graze and browse the plants. As they each favour different plants (with some cross overs) the plants get chance to rest and recuperate as the animals only return periodically to the same areas.

So, pasture plants thrive on being grazed intensively then being given rest period, it is this process that you should try to replicate on your property to produce healthy grass and to avoid overgrazing. The grazing system that you should implement on your property to maximize efficient grazing practices is rotational grazing. There are other systems that can be used alongside rotational grazing to ‘fine tune’ your grazing practices but rotational grazing is the main one that you should use. 

Rotational grazing

All land managers should use this system so that pasture gets a period without any grazing pressure (remember you are aiming to copy what happens to pasture and grazing animals in the natural situation). Having several smaller areas rather than one large paddock allows the use of paddock rotation. These smaller areas can be created with temporary electric fencing if necessary. Horses can then be moved around the property as a herd. You need to learn how to assess the pasture and decide when it is time to move the horses on to the next paddock.

Horses should be allowed to graze a designated paddock (as part of your rotational grazing system) when the plants have reached an average height of around 15cm to 20cm. When they have grazed the paddock down to an average height of around 5cm to 8cm they should be moved to the next paddock.

When pasture is between 5cm’s and 20cm’s it is generally in the elongation stage. This is when it is best able to cope with grazing pressure. When pasture is shorter than this it is in the vegetative stage and is usually unable to cope with grazing pressure and re-growing at the same time. Pasture plants need a certain amount of leaf content to make use of sunlight and moisture from rain and dew. If they are continuously grazed when too short they eventually die out. Short grass plants also have higher sugar levels (per mouthful) as they store sugar, waiting for the right conditions to re-grow (a rest from grazing along with some rain and sunshine). Therefore very short grass can actually be more dangerous for fat and laminitic horses to graze.

When the pasture plants reach the reproductive stage (generally longer than 20cm) they stop growing and set seed. If your pasture gets to this length it is a good idea to slash (mow) the paddock. This puts seeds and organic matter back onto the soil and kick starts the plants into growing again.

Once the horses have been moved on to the next paddock pasture maintenance such as slashing (mowing) and pasture harrowing can be carried out.

By adopting a rotational grazing system and encouraging or cultivating grass species that are less sugar dense we can provide a pasture for our horses that is as close to natural and is safer for our horses to graze. We are then providing a healthier, more ‘natural’ lifestyle for our horses, which has many additional benefits to horses health (and ours!)

Jane and Stuart