Feeding Horses in Winter: Cold Weather Diet Tips

Feeding Horses in Winter: Adjusting for Cold and Reduced Forage Quality

Winter brings unique nutritional challenges for horse owners. Plummeting temperatures, frozen ground, and declining forage quality all demand changes to your horse's diet. Get it wrong, and you risk weight loss, poor condition, colic, or even metabolic stress. Get it right, and your horse will sail through the coldest months in great health.

This comprehensive guide explains exactly how to adjust your horse's feeding programme when winter hits — covering energy needs, forage strategies, supplementation, hydration, and more.

Why Winter Changes Everything About Feeding

Horses are remarkably well-adapted to cold weather. Their thick winter coats, ability to generate heat through hindgut fermentation, and natural fat reserves all help them cope. But these adaptations depend on one critical factor: adequate nutrition.

When the temperature drops below a horse's lower critical temperature (LCT) — typically around 0°C (32°F) for an unclipped horse with a winter coat, or as high as 10°C (50°F) for a clipped horse — the animal must burn extra calories just to stay warm. At the same time, the forage that forms the backbone of their diet is often at its lowest nutritional value of the year.

This double hit — more calories needed, fewer calories available from pasture — is why winter feeding requires careful attention.

Understanding Increased Energy Requirements

The single biggest dietary adjustment in winter is energy. Horses need more calories to maintain body temperature, and the colder it gets, the more they need.

How Much Extra Energy?

As a general rule, for every 1°C drop below a horse's lower critical temperature, energy requirements increase by approximately 1%. That may sound small, but it adds up fast during a prolonged cold snap.

For example, if the temperature sits at -10°C and your unclipped horse has an LCT of 0°C, that's a 10% increase in energy needs. For a 500 kg horse in moderate work already requiring around 85 MJ of digestible energy per day, that's an extra 8.5 MJ — roughly equivalent to an additional 2-3 kg of good hay.

Factors that raise energy requirements further include:

• Wind and rain — wet, windy conditions dramatically increase heat loss, even more than dry cold
• Clipping — a clipped horse loses its insulating coat and has a much higher LCT
• Thin body condition — horses with a body condition score below 4 (on the 1-9 Henneke scale) have fewer fat reserves to draw on
• Age — older horses often struggle to maintain condition in winter due to reduced digestive efficiency and dental issues
• Young, growing horses — they need energy for both growth and thermoregulation

The Best Source of Winter Calories: Fibre

Here's a crucial point many horse owners miss: fibre is the best fuel for keeping horses warm in winter, not grain.

When a horse digests fibre in its hindgut, the microbial fermentation process generates significant heat — essentially turning your horse into a living furnace. This is called the heat of fermentation or the heat increment of feeding. Concentrates (grain-based feeds) produce far less internal heat during digestion.

This means that increasing hay or other long-stem forage is the most effective and safest way to help your horse stay warm. It also supports gut health and reduces the risk of colic, ulcers, and stereotypic behaviours.

Dealing With Reduced Forage Quality

Winter forage quality is almost always lower than what's available in spring and summer. Whether you're feeding conserved hay, haylage, or relying on any remaining pasture, here's what typically changes:

• Lower digestible energy — mature, late-cut hay has more lignin (indigestible fibre) and less soluble carbohydrate
• Reduced protein content — crude protein in winter hay can drop below 8%, which may not meet the needs of growing, breeding, or hard-working horses
• Lower vitamin levels — vitamins A, E, and D decline significantly in stored hay, especially after several months
• Variable mineral content — depending on soil and region, hay may be deficient in key minerals like zinc, copper, and selenium

Get Your Hay Tested

The single most valuable thing you can do for your horse's winter nutrition is have your hay analysed. A forage analysis will tell you exactly what energy, protein, sugar, starch, and mineral levels your hay provides. Without this information, you're essentially guessing — and guessing can be expensive and harmful.

Once you know what your forage provides, you can identify the gaps and fill them efficiently with the right concentrates, supplements, or complementary forages. Consider analysing your horse's full diet at MyEquiBalance to see exactly where the nutritional gaps lie and how to close them.

Strategies for Improving Winter Forage Intake

1. Feed more hay, more often — Increase total daily forage to at least 2-2.5% of body weight (10-12.5 kg for a 500 kg horse). Feeding little and often keeps the digestive system active and heat production consistent.

1. Offer hay ad libitum if possible — Free-choice hay is ideal for most horses in winter, particularly those that are good doers and won't overeat. Monitor body condition and adjust accordingly.

1. Use slow feeders or small-holed haynets — These extend feeding time, reduce waste, and mimic the horse's natural trickle-feeding behaviour. They also help prevent long gaps between meals, which is critical for gut health.

1. Consider adding a complementary forage — If your hay is particularly poor quality, adding a higher-energy forage like alfalfa (lucerne) chaff, sugar beet pulp, or a high-fibre cube can help bridge the gap. These are all fermented in the hindgut and contribute to that valuable internal heat production.

1. Soak or steam hay if needed — For horses with respiratory issues, steaming hay can reduce dust and mould spores. However, be aware that soaking hay leaches water-soluble carbohydrates and some minerals, so you may need to compensate with additional supplementation.

Adjusting Concentrates and Hard Feed

While fibre should always be the foundation, some horses will need additional concentrates in winter to meet their energy or protein needs — particularly horses in work, breeding stock, youngsters, and veterans.

Tips for Adjusting Hard Feed

• Increase gradually — Any changes to concentrate feeds should be made over 7-14 days to allow the gut microbiome to adapt. Sudden changes are a leading cause of colic and laminitis.
• Choose fibre-based concentrates — Feeds based on sugar beet, alfalfa, and digestible fibre sources are preferable to cereal-heavy feeds. They provide sustained energy without the metabolic risks of high starch.
• Don't over-feed cereals — High-starch diets increase the risk of hindgut acidosis, gastric ulcers, and excitable behaviour. Keep starch intake below 1 g per kg of body weight per meal.
• Consider oil for extra calories — Adding vegetable oil (such as linseed or soya oil) is a calorie-dense way to boost energy intake without increasing meal size or starch load. Start with 50-100 ml per day and build up to a maximum of around 300 ml per day for a 500 kg horse.

Vitamins and Minerals: Filling the Winter Gaps

Winter is the season when vitamin and mineral deficiencies are most likely to occur. Here's what to watch:

Vitamin A

Fresh pasture is rich in beta-carotene (a vitamin A precursor), but levels drop sharply in conserved forage. After six months of storage, hay may have lost most of its vitamin A content. A broad-spectrum vitamin and mineral supplement is the simplest way to address this.

Vitamin E

Like vitamin A, vitamin E degrades rapidly in stored hay. Horses on pasture in summer typically get plenty, but winter-housed horses on hay can become deficient. Vitamin E is critical for immune function and muscle health. Supplementation with natural vitamin E (d-alpha-tocopherol) is recommended for horses without access to fresh grass.

Vitamin D

Horses synthesise vitamin D through sunlight exposure, and during short winter days — especially for stabled horses — levels can drop. Most commercial feeds include vitamin D, but if your horse lives out and eats only hay, a supplement may be warranted.

Key Minerals

The minerals most commonly lacking in UK and Irish forage are zinc, copper, and selenium. Salt (sodium chloride) is also essential year-round and is often overlooked in winter because horses may drink less and owners assume sweat losses are minimal. Always provide a salt lick or add loose salt to feeds — at least 1-2 tablespoons daily for an average horse.

Hydration: The Overlooked Winter Essential

Dehydration is one of the most common — and most dangerous — winter health problems in horses. Cold water is less appealing to drink, and horses on dry hay diets need significantly more water than those eating moisture-rich pasture.

A horse at rest needs a minimum of 25-35 litres of water per day, and this increases with exercise, lactation, or cold stress. Dehydration is a major risk factor for impaction colic, which peaks during winter months.

How to Encourage Winter Water Intake

• Keep water ice-free — Use insulated buckets, heated troughs, or break ice at least twice daily
• Offer lukewarm water — Research shows horses drink up to 40% more when water is between 7-18°C compared to near-freezing water
• Add water to feeds — Soaking hay, sugar beet, or mixing feeds into a mash increases total water intake
• Ensure access at all times — Horses should never have to go more than a few hours without water, especially when eating dry forage
• Monitor intake — If you can, note how much your horse is drinking. A sudden drop in consumption is a red flag

Body Condition Monitoring

Thick winter coats can hide weight loss, so relying on your eyes alone is unreliable during winter. Use hands-on body condition scoring every two weeks, checking key areas:

• Ribs — You should be able to feel them easily but not see them
• Spine and withers — There should be a thin layer of fat cover
• Behind the shoulder — Check for developing hollows
• Croup and tailhead — Fat cover should feel smooth, not bony

Using a weight tape regularly provides a useful trend line, even though the absolute numbers aren't perfectly accurate. The trend matters more than the number.

If your horse is losing condition, increase forage first, then add calorie-dense fibre sources, then consider concentrates. If your horse is gaining excessive weight (common in good doers even in winter), reduce concentrates and consider using lower-energy forage or restricting intake mildly with small-holed haynets.

Special Considerations

Veteran Horses

Older horses often have dental issues that make chewing long-stem hay difficult. Consider providing soaked hay cubes, chopped fibre, or high-fibre mashes. Veterans may also need increased protein (look for feeds with 12-14% crude protein) to maintain muscle mass.

Horses Prone to Laminitis

Winter doesn't eliminate laminitis risk. If feeding extra forage, ensure it's low in water-soluble carbohydrates (below 10% WSC on a dry matter basis, ideally confirmed by forage analysis). Soaking hay for 30-60 minutes in cold water can help reduce sugar content.

Horses Living Out 24/7

Outdoor horses need the most dietary support in winter. Ensure they have constant access to forage, fresh water, and shelter from wind and rain. Their calorie needs will be higher than stabled horses, and they deserve extra monitoring.

Winter Feeding Checklist

• ✅ Increase forage to at least 2% of body weight daily, ideally more
• ✅ Get your hay analysed and balance the diet accordingly
• ✅ Provide a broad-spectrum vitamin and mineral supplement
• ✅ Ensure constant access to ice-free, ideally lukewarm water
• ✅ Add salt to the diet daily
• ✅ Make any feed changes gradually over 7-14 days
• ✅ Body condition score every two weeks using hands-on methods
• ✅ Monitor water intake and manure consistency for signs of dehydration
• ✅ Prioritise fibre over grain for safe, sustained energy
• ✅ Consider oil supplementation for horses needing extra calories

Final Thoughts

Feeding horses well in winter isn't complicated, but it does require awareness and adjustment. The core principle is simple: more fibre, better supplementation, and constant hydration. Your horse's digestive system is a remarkable heat-generating engine — keep it fuelled with quality forage, fill the nutritional gaps with targeted supplements, and keep the water flowing.

By understanding your forage quality, monitoring your horse's condition regularly, and making thoughtful adjustments, you'll help your horse not just survive winter — but thrive through it.