Why Do Horses Often Seem More Spooky or Fresh in Cold Weather?

How Gut Health Plays a Role

As temperatures drop and winter settles in, many horse owners notice a curious change: horses that seemed calm and predictable through autumn suddenly become lively, playful or “fresh” in the colder months. It can be entertaining to watch a horse buck and play in frosty fields, but this shift in behaviour can also make them more unpredictable under saddle or in hand.

Understanding this change and the role that management, nutrition and gut health play in it can help you support your horse’s wellbeing throughout the winter months.

The Winter Behaviour Shift: Not Just Energy

It’s a common belief that cold weather makes horses more energetic, but research suggests the reality is more nuanced. In truly cold conditions, many horses actually conserve energy by reducing activity, huddling for warmth and seeking shelter. Wild horses in northern climates, for example, have been observed slowing their movements and lowering metabolic rate to preserve energy during harsher months.

So why do domesticated horses seem more vigorous?

The answer often lies in changes in routine, environment and feeding, rather than the cold itself.

Routine Changes and Residual Energy

In winter, turnout and training routines frequently change. Icy or muddy ground can limit outdoor movement and horses may spend more time stabled than they do in warmer months. This reduction in physical activity can lead to pent-up energy - the same energy that once went into regular movement now shows up as spirited behaviour when the opportunity arises. 

Shorter daylight hours also influence behaviour. Circadian rhythms affect hormones and activity patterns, meaning horses can adjust how and when they feel alert or active as seasons change.

Nutrition, Carbohydrates and Behaviour

Feeding plays a significant role in how horses behave - and not just in winter.

Carbohydrate-rich feeds such as grain or molasses-based mixes can cause rapid changes in blood sugar and hormone levels. These fluctuations can make some horses feel “spicy”, excitable or more reactive under saddle.

In cold weather, owners often increase concentrates to meet the horse’s perceived higher energy needs. However, this can be counterproductive if the diet becomes high in simple carbohydrates without a solid base of forage - the foundation of a horse’s natural digestive health. Horses keep warm by digesting forage and so the best way to help them maintain condition through winter is by increasing their fibre and forage intake – not by increasing their bucket feeds. 

The Hindgut and Behaviour: Why Gut Health Matters

Horses are hindgut fermenters, meaning much of their digestive activity happens in the large intestine (the hindgut). Here, microbes break down fibrous plant material and produce volatile fatty acids - a major energy source for horses. This microbial community also influences immune function, digestion efficiency, nutrient absorption and even behaviour.

When a horse’s diet shifts - for instance, more concentrates and less forage - the delicate balance of these microbial populations can be disrupted. This reduction in hindgut microbiome diversity can lead to inconsistent fermentation, digestive discomfort and behavioural changes, particularly in horses already sensitive or prone to excitability. 

Forage is not just food - it is the driving force behind stable microbial fermentation and consistent digestive function. In winter, when grass is scarce and turnout time is limited, ensuring horses have access to high-quality, digestible fibre is critical.

The Gut–Brain Axis: How Digestion Affects Temperament

Emerging research in mammals points to a strong connection between the gut and the brain - the so-called gut–brain axis. In horses, while research is ongoing, there is growing recognition that digestive comfort and microbial balance can influence stress responses, mood and overall temperament.

A stable hindgut with diverse microbial populations helps:

• aid digestive comfort
• maintain regular behaviour
• reduce physiological stress responses
• prevent spikes in excitability
• support immune function

In winter, when feeding, exercise and routines are less stable, this connection becomes particularly important.

Practical Steps to Support Behaviour Through Winter

1. Forage First

Make forage the cornerstone of the winter diet. Horses should receive fibre steadily throughout the day - this keeps the hindgut working and supports microbial diversity. Slow-feed nets, hay cubes or chaff (for those that struggle with long stem forage) can help extend eating time and mimic natural grazing.

2. Balance Carbohydrates

Avoid sudden increases in high-starch or high-sugar feeds unless they are genuinely required for body condition. Instead, prioritise fibre and low sugar/starch sources to reduce sugar spikes that can promote excitability. Remember also that horses don’t eat percentages and that the grams of sugar and starch per feed/day are more relevant than the % on the feed bag (particularly with supplements where the daily feeding rate is often very small).

3. Maintain Movement

Even if outdoor turnout is limited by weather, regular exercise - in the arena, on a horse walker or even through hand walking - helps both physical health and gut motility. Movement encourages healthy digestive flow and can help moderate behaviour.

4. Mind the Microbiome

A diverse hindgut microbiome thrives on variety and continuous fibre. Providing different types of high-quality fibre and avoiding abrupt dietary changes can help sustain microbial balance.

5. Routine and Enrichment

Stable routines offer predictability that can help reduce behavioural stress. Enrichment - such as safe toys or puzzle feeders - can also occupy horses mentally when turnout is limited.

Feeding to Support Winter Digestion

As equine nutrition experts often recommend, horses require extra attention to diet and digestive health in winter. In winter care guidance, forage is highlighted not only as an energy source but as a way to keep the digestive system functioning and behavioural needs met, especially when grass is sparse. 

Providing sufficient forage also keeps the hindgut microbiome active — a critical part of maintaining digestive comfort that influences behaviour and overall wellbeing.

A Holistic Winter Strategy

Horses that seem frisky in cold weather are often responding to a complex mix of environmental shifts, dietary changes, routine disruptions and internal physiological dynamics. A burst of energy is rarely about the temperature alone.

By focusing on gut health, maintaining a forage-rich diet with plenty of prebiotic fibre diversity (easily provided in a supplement such as Equell Gut Food), preventing abrupt nutritional changes and supporting regular movement - especially when winter limits turnout - you can help ensure that your horse stays balanced and comfortable, not energetic at the wrong moments!

Understanding how digestion, microbes and metabolism interact gives you a foundation for winter management that supports both physical and psychological wellbeing - so your horse remains confident, calm and ready to work regardless of the season.

Sources:

Brinkmann, L, Gerken, M., and Riek, A. (2011). Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus). Journal of Experimental Biology 215; 1061-1066.

Heleski, CR, and Murtazashvili, I. (2010) Daytime shelter-seeking behavior in domestic horses. Journal of Veterinary Behavior 5; 276-282

Mejdell, CM and Bøe, KE. (2005) Responses to climatic variables of horses housed outdoors under Nordic winter conditions. Canadian Journal of Animal Science 85; 301-308.