Written by Briony Witherow MSc RNutr. FHEA
When grass growth tails off and turnout is limited, many horses move onto conserved forage only (hay or haylage). That’s when vitamin E deserves a second look. Vitamin E is a key antioxidant for muscle and immune function, helping to protect cells from everyday oxidative stress that can rise with training, illness/injury, or higher-oil rations. Fresh grass is normally the biggest contributor of vitamin E in the diet; dried forages contain much less, so winter can quietly create a gap.
Why it matters
Antioxidants “mop up” free radicals produced during normal metabolism and periods of stress or exercise. They tend to work best in combination (vitamin E alongside vitamin C, selenium and other antioxidant compounds), supporting recovery and overall resilience.
Who’s most at risk in winter?
- Horses with little/no access to fresh grass (stabled or on bare paddocks).
- Horses in moderate–hard work, where oxidative demand is higher.
- Diets with added oil (e.g., vegetable/linseed oil) without matching antioxidant support.
How much vitamin E?
Use bodyweight and workload to check your ration:
- At rest/light work: aim for 1–2 IU/kg BW/day (e.g., 600–1200 IU for a 600 kg horse).
- Moderate–hard work: typically 2000–4000 IU/day.
- If adding straight oil: add 100–150 IU vitamin E for every extra 100 ml oil fed.
Use these figures to help you review whether your current ration is likely to be meeting requirements and whether you need a top-up through winter.
Practical winter checks
- Audit the ration: total up the IU of vitamin E from all feeds/supplements. Compare to the targets above.
- Match to workload and management: conserved forage-only diets commonly run short; training, travel and cold weather can add to oxidative load.
- Think “antioxidant team”, not solo: combining vitamin E with other antioxidants offers synergistic benefits.
Simple ways to close the gap
If your calculation shows a shortfall, consider adding a dedicated vitamin E source through winter. From your range:
- Premier E – 50 g provides ~3000 IU vitamin E alongside complementary antioxidants; a good option for harder work or oil-supplemented diets.
- Selenavite E – 50 g provides ~2000 IU vitamin E alongside complementary antioxidants
Final notes
- Many “general” feeds include some vitamin E, but don’t assume it covers winter needs on hay/haylage alone—especially for working horses or those on added oil.
- Aim for consistent daily intake rather than occasional high doses; review after a few weeks and adjust to workload and season.
By building a small winter vitamin-E check into your routine, you’ll keep muscle function, immunity and recovery on track when grass is scarce and oxidative demands can creep up.
