Kikuyu Pasture: When Summer Rain Changes the Game for Our Hōiho

11 minutes ago

6 min read

Kikuyu can be one of our greatest assets during a Northland summer, but understanding how it responds to changing weather conditions is particularly important for horses prone to laminitis.

Here in Northland, we're pretty familiar with kikuyu. It's hardy, persistent and has an incredible ability to keep growing through the warmer months when many of our other pasture species have slowed down or completely shrivelled up.

For horse owners, this can be a real advantage.

But there's another side to kikuyu that deserves our attention, particularly when those long, hot, dry spells are followed by a decent downpour.

Let's look at why kikuyu can be so beneficial, what changes when the rain arrives and how we can manage our paddocks to better protect our Hōiho.

Why Kikuyu Can Be Such a Valuable Summer Pasture

Kikuyu is a warm-season, C4 grass that thrives in warmer temperatures and can tolerate periods of dry weather remarkably well once established.

Its vigorous growth and spreading root system allow it to persist under conditions where many cool-season pasture species struggle.

For horses, this means a potentially valuable source of forage during summer.

Kikuyu can also have relatively low levels of non-structural carbohydrates (NSC) under certain growing conditions, making it an option worth considering for some horses with insulin dysregulation or a history of laminitis.

However, kikuyu isn't automatically a low-sugar or laminitis-safe pasture. Its nutritional composition changes with growing conditions, maturity, weather and management.

There is also an important nutritional consideration.

Kikuyu and Calcium Availability

Kikuyu contains soluble oxalates, which can bind calcium in the digestive tract and reduce the amount available for absorption.

Over time, horses grazing high-oxalate pasture without adequate available calcium may be at risk of nutritional secondary hyperparathyroidism, sometimes referred to as big head disease.

This is why ensuring adequate calcium and an appropriately balanced mineral intake is particularly important for horses grazing kikuyu.

At Holistic Hōiho, we believe understanding what's growing in your paddock is just as important as understanding what's going into your feed bucket.

What Happens When the Rain Arrives?

Picture this.

We've had weeks of hot, dry weather. Our paddocks have been grazed hard, the kikuyu has slowed down and there's not much fresh growth around.

Then along comes a decent summer downpour.

Within days, the paddocks can begin changing colour. Fresh green shoots appear, and suddenly that tired-looking pasture comes back to life.

But fresh, green grass isn't necessarily the safest grass for every horse.

Rain following drought can trigger rapid pasture growth, particularly when soil temperatures remain warm.

During this period, the nutritional composition of the pasture can change considerably.

Understanding Pasture Sugars

Non-structural carbohydrates include sugars and starches, which are important considerations when managing horses with insulin dysregulation.

Pasture carbohydrate concentrations are influenced by several factors, including:

Sunlight and temperature
Water availability and plant stress
Stage of growth and maturity
Fertiliser and soil nutrient availability
Time of day and seasonal conditions

Following rain, rapidly growing pasture may have a different balance of sugars, starch, protein, fibre and moisture compared with the mature, dry pasture horses were previously grazing.

It's important to understand that rain doesn't automatically cause pasture sugar levels to rise. In fact, rapid growth can sometimes dilute carbohydrate concentrations.

The concern is that we cannot reliably predict the nutritional composition of a fresh flush simply by looking at it.

For horses with insulin dysregulation, changes in pasture intake and carbohydrate consumption can increase the risk of laminitis.

And even where sugar concentrations aren't particularly high, highly palatable new growth may encourage horses to consume more pasture.

This is why a sudden change in grazing conditions deserves some thought.

Why Are Insulin-Resistant Horses More Vulnerable?

Horses with insulin dysregulation can have an exaggerated insulin response to certain dietary carbohydrates.

In susceptible horses, prolonged or excessive insulin concentrations can contribute to endocrinopathic laminitis.

Laminitis affects the sensitive tissues connecting the hoof wall to the pedal bone and can become an extremely painful and serious condition.

Horses with equine metabolic syndrome (EMS), some horses with PPID and those with a previous history of endocrinopathic laminitis may be particularly vulnerable.

While kikuyu can form part of a carefully managed feeding programme, no pasture should be assumed safe for an insulin-dysregulated horse based on grass species alone.

Testing forage and understanding the individual horse's metabolic health provides a much stronger foundation for making feeding decisions.

Practical Ways to Manage Laminitis Risk After Summer Rain

The good news is that there are several practical steps we can take before the rain arrives.

1. Be Careful With Fresh Pasture Access

If your horse is prone to laminitis, don't assume that a paddock is safe simply because the grass is short.

Fresh regrowth can still be readily consumed, and closely grazed paddocks can expose horses to young shoots.

For higher-risk horses, restricting or avoiding pasture access may be necessary, particularly during periods of rapid growth.

A bare paddock, dry lot or appropriately managed track system can provide an alternative to unrestricted grazing.

2. Consider Setting Up a Track System

Track systems are becoming increasingly popular with horse owners, and for good reason.

By creating a designated track around the outside of a paddock, owners can help control access to the central grazing area while encouraging horses to move between feed, water and resting locations.

A well-designed track system can offer several benefits:

Greater control over pasture intake
Opportunities to encourage natural movement
Reduced pressure on certain grazing areas
Flexibility to manage different horses according to their nutritional needs

However, movement should never be encouraged in a horse showing signs of active laminitis. These horses require veterinary assessment, appropriate hoof support and restricted movement during the painful phase.

For horses that are comfortable and sound, a track system can be a useful long-term management tool.

3. Have a Reliable Low-NSC Fibre Source Available

Horses are designed to consume fibre throughout the day, and limiting pasture access should never mean leaving a horse without sufficient forage.

When fresh grazing needs to be restricted, having suitable alternative fibre available becomes particularly important.

Options may include tested low-NSC hay or an appropriate low-NSC fibre feed.

For horses requiring strict carbohydrate management, forage analysis is particularly valuable because hay can vary considerably in sugar and starch content.

It's also important to remember that soaking hay may reduce some water-soluble carbohydrates, but the results can be variable and soaking can cause nutrient losses.

4. Monitor Your Horse Closely

Early recognition of laminitis can make a significant difference.

Some warning signs include:

Increased or bounding digital pulses
Heat in the hooves
Shortened or hesitant steps
Reluctance to turn on firm ground
Shifting weight between feet
Increased time spent lying down
An unusual or rocked-back stance

Not every horse will display the classic laminitis stance.

Some of the earliest signs can be surprisingly subtle.

If you suspect laminitis, contact your veterinarian promptly, remove access to pasture and avoid forcing the horse to walk. Provide a deeply bedded, comfortable area while awaiting veterinary advice.

The Importance of Fibre Beyond Laminitis

Fibre isn't just about filling a hungry horse's stomach.

Adequate forage intake supports normal digestive function, hindgut microbial activity and natural feeding behaviour.

When we restrict grazing, we need to consider how we're replacing that lost forage.

A horse may need fewer calories or less dietary sugar, but it still requires an appropriate amount of fibre.

This is particularly relevant for good-doers and horses with metabolic challenges, where we're trying to balance nutritional requirements without supplying unnecessary energy.

A carefully selected low-NSC fibre source can help bridge the gap between what the horse needs nutritionally and what the pasture can safely provide.

Where Hōiho Super Fibre Fits In

At Holistic Hōiho, one of our goals is to provide practical, cost-effective feeding options suited to New Zealand horses and our local grazing conditions.

Hōiho Super Fibre is a pelleted soy-hull fibre feed with a typical NSC analysis of less than 7%.

It's a useful option when pasture access needs to be restricted or when additional low-NSC fibre is required.

Some of its key features include:

Very low NSC (less than 7% on the stated typical analysis)
High fibre content
Molasses-free formulation
No added mineral component
Suitable for use as part of a carefully balanced feeding programme

Hōiho Super Fibre must be soaked before feeding and introduced gradually.

As it contains no added mineral component, the horse's overall diet must still supply appropriate vitamins and minerals, including adequate available calcium where high-oxalate pastures such as kikuyu are involved.

For horses with insulin dysregulation or a history of laminitis, feeding plans should be developed with appropriate veterinary and nutritional guidance.

Don't Forget the Bigger Picture

Summer pasture management isn't about fearing every flush of green grass.

It's about understanding that our paddocks are constantly changing.

Rainfall, temperature, soil conditions, grazing pressure and pasture maturity all influence what our horses are eating.

Kikuyu can be an incredibly useful forage in Northland, especially through our hotter, drier months. But like any pasture, it has nutritional characteristics that need to be understood and managed.

A little forward planning can go a long way.

Have your alternative fibre ready, consider your grazing arrangements and keep a close eye on those horses that are more metabolically sensitive.

And remember, what works for one Hōiho may not be suitable for another.

Need to Prepare for the Summer Rain?

2 Blakey Road, Maungaturoto📞 0800 769 843

Holistic Hōiho — Made in Aotearoa for Aotearoa.

Disclaimer: This article provides general educational information and is not a substitute for veterinary or individual equine nutritional advice. Horses with suspected laminitis require prompt veterinary attention. Pasture and forage composition can vary, and testing is recommended when managing horses with specific metabolic or nutritional requirements.