Spring Grass


Disaster Pasture or What!?


It is well known that spring grass can have a dramatic effect on your horse’s health and behaviour. Understanding the reasons why this happens will help you avoid likely problems.

 Spring grass is full of water –

A common phrase often used in relation to spring grass, is that it is full of water. But water is a good thing right? So why is this an issue?

The horse is a hind-gut, fermenting herbivore that relies extensively on the microbes present in its gastrointestinal tract to be able to process high fibre forages. The microbes are a mix of different organisms that work together to the benefit of the horse. If the feedstuffs the microbes are utilizing change suddenly, from high fibre to low fibre with the complication of high sugar and nitrate levels, there may be too little time for the microbial populations to adjust to the change. Instead, large numbers of them die, while others flourish, setting up a situation where toxins may be absorbed by the horse, resulting in digestive dysfunction, laminitis or possibly colic. A gradual change from one feedstuff to another, reducing the intake of lush grass and providing more hay will all help provide enough time for the microbial populations to adjust.

There are three main forms of roughages: (1) dry roughages such as hay, straw, oaten and grass chaffs, (2) silages such as grass or lucerne, and (3) pastures. Even though hay, silage and pasture are all forms of forages, there are significant differences. Dried hay is approximately 85-90% dry matter (roughage) with a low percentage of moisture, compared to fresh pasture that is 85% moisture with very low levels of dry matter (roughage). Silage sits somewhere in the middle and suitability for feeding to horses can depend of when it was cut. November would be considered early cut and could be problematic. December January would likely have a higher fibre content and be more suitable.  


Then The Sugar Rush!

Seasonal variations in pasture carbohydrates are well documented. Studies show concentrations of NSC (non-structural carbohydrate) concentrations were highest in the spring, lowest in summer, and intermediate in the winter. High NSC grasses bred for fast weight gain and high milk production in dairy cattle, such as rye grass and clover, have crept into our horse pastures, greatly increasing the incidence of NSC related metabolic issues such as Equine Metabolic Syndrome and laminitis compared to the incidence of these problems 30 years ago. Because horses are selective grazers, and are known to find feedstuffs with elevated sugar content highly palatable, restricting grazing of these lush pastures and feeding adlib hay or in the case of horses with laminitis or EMS avoiding grazing altogether may be necessary to avoid serious health complications.    


Lush ryegrass...

Protein levels – Rocket fuel for your horse!

The average horse requires around 10%-12% protein in their diet. Lush spring pasture can have protein levels far in excess of the average horse’s requirements, at around 25% to 30% crude protein or even higher. Even for those horses in harder work, these levels will be counterproductive, especially when combined with "Low GI” feeds that are largely made up of protein, effecting health and performance. Symptoms of excess protein are heavy sweating, thick-windedness, spooking, shying and aggressive grumpy behaviour. 


White clover can be very high in starch, protein and potassium. 

The Double "P” - Problematic Potassium –

High potassium levels in soil and pasture are very problematic for horses. Plants easily uptake potassium instead of other minerals, resulting in high levels relative to other essential minerals such as magnesium, sodium and calcium.  Potassium in levels excess of a horse’s daily requirements may result in spooky, nervous behaviour, heavy or unusual sweating, colic type symptoms including unusual lying down, then getting up for short periods and lying down again. This type of colic is due to low level gut pain and horses MUST be taken off pasture immediately, given oral doses of a chelated magnesium product mixed with a tablespoon of baking soda and seen as soon as possible by a vet. 

We recently had this scary situation happen with a young horse due to eating kikuyu grass that had been affected by frost. This was not impaction colic, rather low level gut pain cause by a chemical reaction in the grass. We removed this horse from pasture for 4 days and he fully recovered with no further problems. We did not graze him back on the kikuyu area. The vet did not really know why this happened but fortunately I did! I have heard about horses that have been euthanized with these exact symptoms. They were never removed from the grass which seems so obvious to me. So sad to be too late to save them. This is a problem caused by grass rather than an internal part of the horse malfunctioning. 

Our case study "Moonie” was suffering with this type of colic prior to coming to our farm. The owner rang me and we got her straight to our place and off the grass. She also was suffering many other grass/mineral imbalance problems. She fully recovered and returned back to the beautiful elegant mover that she naturally was. 

 Loss of Minerals -

There is another serious problem that occurs with excessive protein and potassium levels in pasture. As the horse excretes this excess of potassium and protein, which happens via the kidneys, through urine, in a complex series of electrical charge exchanges, a significant loss of essential minerals occurs. Magnesium and calcium in particular are excreted resulting in dangerously low levels in the animal.

 When combined with the problems already discussed above, the result is a spooky, nervous reactive horse with way too much energy!  A very dangerous combination.  

 Mycotoxin Madness -

Mycotoxins are an invisible and potentially harmful pasture "nasty”. Many people are now familiar with endophyte ryegrass. Endophytes are a type of fungus that attach themselves to the base and seeds of the ryegrass plant. These were bred into ryegrass to protect the plant from insect damage. Unfortunately these endophytes have a very toxic effect on horses and other livestock. Symptoms can be very subtle, ranging from excessive sweating, herd bound behaviour and spookiness to full blown staggers or colic. 

There are also other mycotoxins present in all types of pasture that can affect horses. Warm weather conditions can cause proliferation of mycotoxins throughout the year –including winter.

Toxin Binders have been developed to "catch hold” of ingested mycotoxins before they can pass into the bloodstream, passing harmlessly out in the manure and avoiding toxicity.

Becoming knowledgeable about the types of grasses in your pasture and hay will help you choose the best solutions for any health or behavioural issues that may arise. 

DUWELL Broad Spectrum Toxin Binder has been developed using world leading toxin binder ingredients and gives your horse the best possible cover against mycotoxin ingestion.    


Perennial ryegrass seed heads contain endophyte fungus

 Solutions -

  1. Become knowledgeable about the symptoms of Equine Metabolic Syndrome and Laminitis. Both of these come about from poor diet management.
  2. Understand which grasses are in your pasture and hay.
  3. Avoid grazing horses on lush, short grass. If possible allow grass to grow to at least 200mm in length as grass will then contain more fibre with protein and potassium being more diluted.
  4. Ensure horses consume adequate hay to fulfil daily fibre requirement and further dilute mineral and protein levels.
  5. Feed plenty of plain salt (sodium chloride). Do not rely on salt blocks as some horses need to be trained to eat salt. Salt blocks can also give horses a sore tongue and so they will not uptake required amounts of salt.
  6. Feed bioavailable forms of calcium and magnesium. DUWELL Compete n Grow is ideal.   
  7. Contact us if you are unsure about what to do or seek veterinary advice.