Grass frosts, cold snaps and fructans!

Managing horses and ponies in Autumn—especially after cold snaps and frosts requires a careful grazing plan to help prevent any unwanted health issues.

Grass has one purpose, that is to make sugars for growth. However, when grass becomes compromised, anything causing this process to slow or stop will cause grass to stress and store sugar for survival.

Changes in weather patterns is a common problem coinciding with changes in seasons resulting in overnight cold snaps and grass frosts.

Grass becomes stressed with sudden bouts of warm then cold snaps which reduce growth. Grass protects itself for survival by storing sugars in the lower leaves, then once warm again uses these sugars for growth.

These storage sugars are known as fructans. They are commonly found in cool season grasses in autumn and are problematic for all grazing horses and ponies.

The problem with these fructan sugars is horses cannot digest these. The fructans therefore pass through the small intestine (undigested) and ferment in the hindgut, which can lead to health issues and some serious such as:

Grass frosts, cold snaps and fructans can cause:

  • Laminitis

  • Hindgut acidosis (runny manure)

  • Colic

  • Digestive upsets

When fructan levels rise:

  • Cool nights and sunny days: During sunny days, grasses photosynthesize and store sugars. Cold nights below 5 degrees Celsius stop grass growth, so sugars build up rather than being used.

  • Frosts: After a frost, grasses can be particularly high in fructans the next morning. As temperatures warm up the grass will use these fructans for growth.

  • Over grazing: New growth can be high in sugar. Fructan sugars are stored in the lower part of the grass so it is important to not graze to ground level during cool season periods.

Horses and ponies most susceptible to rises in fructan sugars:

  • Ponies and native breeds

  • Overweight horses

  • Insulin-resistant or metabolic horses

  • Horses with a history of laminitis

  • Horses with a history of colic
  • Sensitive horses or ponies or those that have gut issues

Grass frosts, cold snaps and fructans – 6 top tips to manage your horse:

Avoid pasture after frosts.

  • DO NOT allow grazing in early morning after a frost. Feed hay in place of pasture.

  • Wait until late morning or afternoon when the sun has warmed the grass, allowing sugar levels to decrease slightly before grazing.

Restrict Grazing 

  • Grass for shorter periods, with the remainder as hay offered.

  • Avoid turning hungry horses onto stressed pasture—offer hay first to reduce gorging.

  • For ponies or metabolically sensitive horses, muzzles may reduce intake while still allowing turnout and movement. Ensure grass is at least 10 cm in length if using a muzzle.

Feed Plenty of hay 

  • Feed hay, preferably last seasons with lower sugar levels or ensure at least a few months old to age before using.

  • Soak hay in cold water for 30–60 minutes can reduce sugar levels; be aware this will also leach some nutrients so be sure to feed extra vitamins and minerals.

  • Feed a combination of hay and barley straw to provide chew time, fullness, while eating less grass to keep your horse or pony happy.
Feed supplements to support
  • Consider adding Digest easi PLUS to your feeding regime to support digestive health and also reduce mycotoxins that are also common in stressed pastures. The dual effect will support your grazing horse  Toxin binder for horses | Digest Easi
  • Consider using a vitamin and mineral supplement such as Optimin that tops up nutrient shortfalls where horses are restricted on pasture  Opti-Min | Best Horse minerals | Vitamins
Monitor Body Condition

  • Keep an eye on weight, body score and watch for the development of any fatty deposits.

  • Autumn is a great time to allow slight weight loss in easy keepers before winter.

Pasture and Feed Management

  • Rotate pastures to avoid overgrazing.

  • Avoid grain-based or high-sugar feeds when grass is already providing enough sugar. Avoiding grain will lessen the likelihood of digestive upsets.

🧪 When to Be Extra Cautious

  • The day and days following a hard frost

  • After rainfall following a drought (sugar surge in regrowth)

  • Horses with Equine Metabolic Syndrome (EMS) or PPID (Cushing’s)

  • Horses with a history of colic and laminitis