05/12/2024
THE LOW DOWN ON SHORT VS LONG GRASS FOR HORSES🌱🌿
Equine nutrition has progressed in leaps and bounds these past few years. I am pleasantly surprised at how quickly things are moving in the right direction.
That said, I still hear people talk about how they want their horse to lose weight so they put it in a paddock with, ‘nothing in it’. The ‘nothing’ they refer to is usually very short, stressed grass of one or two species, with a decent spread of w**ds popping up for good measure.
Understanding the effects of grazing on short grass versus longer grass is crucial for any horse, but particularly for those with endocrine issues or a history of laminitis (usually caused by endocrine issues).
Somewhat ironically, these horses are often the ones who are purposely put on short, overgrazed grasses with the objective of keeping weight off.
🌱There are many reasons why short grasses cause issues:
⚫️ Short grass is constantly trying to grow. Therefore it will store its sugars and starches (Non-Structural Carbohydrates or NSCs) to prepare for improved growing conditions. Growing conditions won’t improve as your horse will continually keep eating it down, but the sugars will stay there.
⚫️ Because NCSs are predominantly at the base of the plant, each mouthful has a high NSC:fibre ratio. Typically the sugars are lower, and fibre higher, towards the top of the grasses, so the longer the grass, the less sugar and higher in fibre it is. A high fibre, low sugar diet is what a horse’s gastrointestinal system is designed to eat.
⚫️ The higher the grass’s fibre content, the lower the NSC intake will be.
⚫️ Eating longer grass means the horse has to chew more. This not only slows down their intake, but increases saliva production. Saliva helps to buffer stomach acid and helps to prevent ulcers and other gastrointestinal issues.
⚫️ A healthy (non-metabolic) horse eats until they have a specific amount of fibre in their stomach. Eating grass with a high-sugar and low fibre ratio means a horse consumes a lot of high-sugar grass before it feels satiated. This is why you might see horses with ad-lib hay standing around in the shade more than you will see horses with short grass doing the same. Horses with access to high-fibre hay can go and eat, then rest. Horses that need to eat all day to feel full will rest less.
⚫️ Because a horse’s front teeth (incisors) work so well, they can eat enough to stay fat on grasses that are 3cm - 4cm. Ponies can do the same on grasses that are even shorter (1cm - 2cm).
⚫️ Grasses grown specifically for lawns have their growth points very close to the ground so the plant can cope with being kept constantly short. These grasses have been selected specifically for this. Overgrazing results in only the 'lawn' type grasses surviving - so the result is a monoculture; just one or two species of grass. In addition, lawn type grasses are typically not ideal grasses for your horses to be eating a lot of.
⚫️ Horses are more likely to pick up sand while grazing short grass than they are on longer grass.
🌿 Property owners who want to take care of their paddocks should also keep in mind that:
⚫️ Short grass plants have short root systems that cannot 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 (not to mention less carbon sequestration).
⚫️ Short, sparsely grassed areas in a paddock quickly turn to mud in wet weather and become dusty very quickly in dry weather. Both lead to soil erosion.
Short grass plants are not as able to outcompete certain w**ds as longer grasses are.
🌱 How long is short?
Clients need to fill in a form to get a diet consultation and I ask for a description of their pasture as part of the process (both written and photographic). I was once astonished at the difference between what they tell me the grass is like, and what it is actually like.
A lot of owners describe grass that’s around 3cms long as, ‘heaps of really good grass’. Because of this misunderstanding of what good grass is, they then don’t offer any additional hay. I end up having a lot of discussions with clients about grass. Sometimes we chat more about pasture and hay than the diet itself which is understandable as grass is complicated!
Short grass is generally shorter than 5cm (2.5 inches). However you need to look at the average height across your pasture as you will (hopefully!) have several species of grass available to your horses. There may also be areas they use as toilets which they won’t eat unless they’re almost starving. While 5cms is pretty short, in reality, on many horse properties, the grasses are as short as 1 or 2 cm.
Many horse owners think a paddock full of grass that is 5 cm long would be regarded as too long. At 5 cm, 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; at less than 5 cm it becomes stressed.
🌿 Why is longer grass better for horses?
⚫️ Longer grasses are healthier and typically not stressed (so they have less NSCs).
Taller pasture plants have a higher fibre-to-sugar ratio than short grass. As mentioned above, this is ideal for a healthy gastrointestinal tract.
⚫️ Longer grass typically allows for more biodiversity (i.e. less monoculture).
⚫️ Longer grasses have a longer and thicker root system. This results in more healthy nutrients being brought up from deeper layers in the soil.
⚫️ Longer/thicker roots equal better soil protection which means less mud or dust. Obviously this is good for the ground and for your horse (less mud is better for a slew of reasons), but it also means plants may be able to be grazed in wetter conditions for a longer period of time.
⚫️ Longer grass shades out and outcompetes many w**d species.
⚫️ When the roots are longer the plant can ‘trades' some sugars for other nutrients such as amino acids. When the grass is short and stressed, it hangs onto excess sugars.
⚫️ The horse has to eat from the top; this means they need to eat the higher fibre, lower sugar part before it can get to the higher sugar part of the plant (at the bottom of the plant).
⚫️ The horse has to chew more, creating saliva to buffer stomach acid.
⚫️ Horses walk more when grazing longer, more diverse pastures as they seek out different plants.
⚫️ Longer grasses mean horses are essentially also browsing, not just grazing, this variety of eating postures is good for them biomechanically.
⚫️ Horses pick up their feet more if they live in paddocks with longer grasses, this is also good for them biomechanically.
🌿 Why is longer grass better for your property?
⚫️ Longer grasses shade the soil in hot, dry conditions. This keeps it cooler and reduces evaporation. This, plus the increase in soil organic matter, helps hold water in the soil for longer. This means your grass can keep growing even when it hasn’t rained in a while.
⚫️ Longer grasses provide a habitat for insects, small mammals/reptiles, and ground-nesting birds.
⚫️ With their longer/thicker root systems, taller grasses sequester more carbon than short grasses and even faster than trees! This is improved when the plants are repeatedly grazed and then allowed to regrow (as part of a rotational grazing system), as it effectively pumps carbon into the soil.
⚫️ Taller pasture plants keep the soil warmer in cold weather.
🌿 How long is long?
In a rotational grazing system of land management, the grass is regarded as tall enough to resume grazing when it is approximately 15cm, or just before it goes to seed. When the grass plants have been grazed down to an average height of 5 cm, horses should be removed and the grass given the chance to rest and recuperate.
Won’t free access to long grass make my horse fat/ter?
This answer to this question requires a whole other very long article and is dependent on many other factors. However, provided you do it sensibly, then in my experience, no.
Of course you can’t just let your horse have free access to endless lush, early spring grass, especially if you have high sugar grass species such as rye. If however, you have grasses that are lower in sugars such as fog, and/or you wait until it’s a little drier then your horse is less likely to gain weight, AND it’s a whole lot better for your horse’s gut AND also for the pasture itself.
If your horse has had their grazing restricted to overgrazed, short grasses for a long time (particularly if they also haven’t had access to hay) then you need to make a slow transition to longer grasses. If you suddenly give them access to long, lush grass then they are very likely to gorge and then they will gain weight.
🌱 What about horses on agistment?
Having a horse on agistment makes things more difficult, but not impossible. Ask your agistment owner if you can rig up some temporary fencing (i.e. pigtails and tape) within your paddock to rest part of it, or set up a track system so you can have longer grasses. Setting up a track next to your existing permanent fencing also encourages more incidental movement and means you can restrict grazing at the height of spring and then allow your horse onto the longer grasses when it’s safe to do so. I suggest approaching them from a ‘paddock/pasture preservation’ point of view and use all the above reasons as to why it will be better for their land, as well as for your horse.
*credit to the Equiculture website which was used as a resource for this article
