Is Your Horse ‘Grass Affected’?
Have you ever wondered why your normally calm, sensible horse suddenly seems to become a completely different horse?
Perhaps they become spooky, anxious, reactive or difficult to handle. They may constantly search for grass, struggle to stand still or suddenly become difficult to ride.
Other horses show more physical signs. They may become stiff, short-striding, footy, drag their toes or seem reluctant to move freely.
At Greenpet, we use the term ‘Grass Affected’ to describe horses whose pasture or diet appears to be adversely affecting their behaviour, health or overall wellbeing.
How Does a Horse Become ‘Grass Affected’?
Some horses cope well with lush pasture, while others are much more sensitive to changes in grass.
Spring and autumn can be particularly challenging, when changing weather and rapid pasture growth can result in higher levels of sugar and other non-structural carbohydrates (NSC).
The type of pasture also matters. Improved pasture, heavily fertilised grass (including harrowing/spreading manure) and certain grass species may be particularly unsuitable for sensitive horses.
Other feeds can add to the problem, including molasses, lucerne, grains, soy-based feeds and some high-potassium ingredients.
The combination of rich pasture and concentrated feed can be especially problematic for a horse that is already struggling to cope.
Behaviour Can Be the First Sign
A horse doesn't always look unwell when they first become grass affected.
Instead, their personality may change.
You may notice that your horse becomes:
- Spooky or unusually reactive
- Nervous, tense or anxious
- Difficult to catch
- Constantly focused on eating grass
- Reluctant to stand still
- Irritable or grumpy
- Difficult to concentrate
- More reactive under saddle
- More likely to rush, buck or spook
Owners will often say, “He's just not himself.”
This is worth paying attention to, particularly if the change coincides with a change in pasture or diet.
Physical Signs Can Follow
As well as behavioural changes, some horses develop physical signs.
These may include:
- Stiffness or muscle tension
- Short or choppy strides
- Dragging the toes
- Reluctance to move forward
- Foot sore or sensitivity on hard ground
- Difficulty turning
- Changes in posture
- Reduced willingness to exercise
- Weight gain or a cresty neck
Some of these signs can have many causes, including pain, hoof problems, injury or arthritis, so they should not automatically be blamed on grass.
However, when physical changes occur alongside a change in pasture or diet, it is worth investigating what the horse is eating.
Why Can Grass Affect the Feet?
Horses that are sensitive to high-sugar pasture can develop metabolic changes that increase their risk of laminitis.
Laminitis is painful and can affect the way a horse stands and moves. Early signs may be subtle, with the horse becoming footy, stiff, short-striding or reluctant to move before obvious lameness develops.
This is why it is important not to wait until a horse has severe foot pain before looking at their diet.
If your horse develops sudden or significant hoof pain, hot feet, strong digital pulses or is reluctant to move, veterinary attention should be sought promptly.
What Can You Do?
Start by looking at the whole diet.
Ask yourself:
- What type of grass is my horse eating?
- How much pasture are they consuming?
- Has the pasture recently changed?
- What hay are they receiving?
- Are they also receiving grain, molasses, lucerne or other concentrated feeds?
- Has their behaviour changed at the same time?
For a horse that appears sensitive to pasture, temporarily removing grass and feeding suitable hay can help simplify the diet and may make it easier to see whether pasture is contributing to the problem.
Hay can also be tested for NSC, and soaking may be useful when a lower-sugar hay isn't available.
The aim is not simply to reduce food. Horses need plenty of fibre and should have regular access to appropriate forage.
Prevention Is Better Than Cure
Don't wait for your horse to become dangerous, develop laminitis or show other signs before taking notice of subtle changes.
Keep an eye on their behaviour, body condition, movement and feet, particularly when pasture changes in spring and autumn.
If your horse suddenly becomes spooky, difficult, stiff, footy or simply seems unlike themselves, don't automatically assume they are being naughty.
Sometimes the first clue is what is in the paddock.
We've created a Horse Symptom Checklist to help you identify the signs that may indicate your horse isn't coping well with their current diet.
Download the checklist, tick the symptoms that apply to your horse and use it as a starting point to review their diet and pasture.
Look at the whole horse. Look at the whole diet. And don't ignore the early signs.