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Horses - short grass or long grass?

horse care horses land care Apr 09, 2021
Equiculture short v long grass

Horses - short grass or long grass? That is the question! Traditionally horse owners have been told to keep horses on short grass if they want to manage their weight (and prevent laminitis etc.).

But you need to be aware of the pros and cons of grazing horses on short grass versus longer grass plants.

Short grass:

  • Is usually stressed grass as it is 'behind the eightball', constantly trying to recover/grow. Therefore it will store/hang on to a lot of Non-Structural Carbohydrates (NSCs) (sugars/starches) in preparation for when growing conditions improve.
  • Each mouthful is relatively high in NSC's because sugar/starch is stored at the base of the plant. So each mouthful has a high sugar/fibre ratio.
  • A healthy horse eats until they have a certain volume of fibre in their stomach before they stop. So eating grass with a high sugar and low fibre ratio means they have to consume a lot of high sugar grass before enough fibre is ingested to trigger that 'full enough' feeling and they finish their grazing bout.
  • Horses on short grass are not getting their fibre requirements met, see this article for more information about their fibre requirements
  • Horses have the perfect equipment to eat short grass (two pairs of incisors that meet in the mouth like pair of sharp scissors). Horses can eat their fill (and get/remain fat) on grass plants that are 3cm - 4cm, ponies can do the same on 1cm - 2cm (1 inch = 2.54cm).

 Horses have the perfect equipment to eat short grass (two pairs of incisors that meet in the mouth like pair of sharp scissors).

  • Overgrazing results in only the 'lawn' type grasses surviving - so the result is a monoculture of just one or two types of grass plants. 'Lawn' types grasses have their growth points very low down the plant and can cope with being kept constantly short. In fact, these types of grasses have been selected and bred/developed further for lawns and golf courses etc.
  • Short grass plants have short root systems which are not able to reach far down in the soil for nutrients.
  • A short root system results in much less organic matter in the soil causing soil compaction and poor drainage (and of course less carbon sequestration - important for climate change mitigation).
  • Short, sparsely grassed areas in a paddock quickly turn to mud in wet weather and dry out very quickly (become dusty) in dry weather. Both lead to soil loss.
  • Horses are more likely to pick up sand while grazing short grass (if the soil is sandy).
  • If horses graze short grass for a long time they can wear the front teeth (incisors) abnormally. Especially if the soil is sandy/gritty.
  • Short grass plants are not as able to outcompete certain weeds.

 Overgrazing (to produce short grass) results in only the 'lawn' type grasses surviving - so the result is a monoculture of just one or two types of grass plant.

 How long is short grass?

Short grass is generally shorter than 5cm (2.5 inches), but you need to be looking at the average height across your pasture as you will have several species (unless you have created a monoculture) and possibly 'toilet areas' ('roughs') as well. In reality, on many horse properties, the plants are kept down to 2cm or even 1cm (especially if the owners are trying to restrict their horse's grass intake), but remember, horses have just the right equipment to eat grass no matter how short.

A paddock full of grass that is 5cm long would be regarded as being too long/tall by many horse owners, but think about the fibre content. At 5cm the plant is just about reaching the stage where it has 2 to 3 leaves and it can now start to make a rapid recovery, using its stored sugars/starches for growth, less than 5cm and it becomes stressed.

Long grass:

  • Has a higher fibre to sugar ratio than short grass, this is a good thing.
  • The plants are healthier, not stressed, and are in what is called 'the growth phase'.
  • The horse has to eat the longer fibres before they can get to the higher sugar part of the plant (at the base of the plant).
  • The horse has to chew more - much healthier as this creates saliva to buffer the stomach acid.
  • Longer grass plants result in more biodiversity as a larger variety of plants get to grow, set seed and multiply.
  • Horses walk more when grazing longer more diverse pasture as they seek out different plants.
  • Longer grass equals longer roots, equals more healthy nutrients being brought up from the deeper layers in the soil.
  • When the roots are longer, the plant 'trades' some of its sugars for other nutrients such as amino acids (when the grass is short and stressed it hangs onto these excess sugars).
  • Longer roots equal better soil protection (less or no mud/dust) so plants can be grazed in wetter weather for longer (to a point).
  • Taller plants provide habitat for beneficial insects, small mammals/reptiles, and ground-nesting birds.
  • Taller plants shade out and out-compete many weed species.
  • Taller plants keep the soil warmer in cold weather.
  • Taller plants shade the soil in hot conditions keeping it cool and reducing evaporation. This and the increase in organic matter in the soil help to hold water in the soil for longer - very important in dry conditions.

 Longer grass plants results in biodiversity as a larger variety of plants get to grow, set seed and multiply.

How long is long grass?

In a rotational grazing system of land management grass is regarded as tall enough to resume grazing when it is approximately 15cm (8 inches)  tall (or just before it 'goes to seed'). When the grass plants have been grazed down to an average height of 5cm (2.5 inches) then the animals should be removed and the grass given chance to rest and recuperate. This grazing and resting also creates a healthy root system and vastly increases organic material in the soil.

So you can see how this is very different from how pasture is managed on most horse properties.

Where does this outdated info about short grass come from?

Traditionally, much of the information about grazing horses comes from grazing farm animals such as cattle. Cows are not able to eat very short grass to the same extent as horses because they only have one set of incisors and they use their tongue (by wrapping it around the plant) to graze. So the plant needs to be taller for them.

If you forced a cow to graze short grass plants it would eventually starve. It is often assumed that horses are like cows - but they are not, they have very different teeth and a completely different digestive system!

So, it has always been assumed that if you put a horse on short grass it will lose weight. However, this does not necessarily happen.

If the grass is extremely short to almost nonexistent then most horses will eventually lose or at least maintain weight, BUT at this stage, the grasses are highly stressed land degradation is taking place - which results in soil loss/erosion/compaction, less biodiversity, mud, dust, etc.

We need to give our horses more fibre and less sugar (NSC). The digestive system of a horse relies on a certain volume of feed passing through it, so it is important to make this feed fibre rather than sugar, in human terms that would be more salad and less chocolate.

You cannot treat soil like dirt! This is not sustainable in so many ways:

  • You will lose topsoil (which has taken eons to make).
  • You will grow less viable feed and you will have to buy in more feed.
  • You will have mud for large parts of the year (and compacted, dusty soil for the rest).
  • You will have more weeds etc. etc.

How can you make the switch?

If your horse has been grazing a restricted diet of short grass up to now and you would like to make a change you need to slowly and carefully manage the transition over to grazing longer grass. You cannot just suddenly make the switch as that horse will initially gorge when given 'free rein'.

Make sure you also read this follow up article about how to make the transition if that is what you decide to do:

In most cases, this is best done over winter when there are generally fewer NSCs in the plants.

Of course, you cannot let your horse overeat on long grass, especially until they have learned to self-regulate (some horses will - some won't). Also, some grass types are much higher in sugar than others. But once you know how it is usually possible to manage your horse on longer grass and reap the other benefits listed in this article.

Learn how to manage your land and horses better, in a way that is good for biodiversity, the wider environment, soil health, horse health, and their welfare etc. etc.

Start by signing up here for the free mini-course about Horses, Pasture and Grazing

Jane xxx

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