Vitamin A (with β-carotene)
What it does
Vitamin A is needed for skin and mucous membranes, for vision and for immune defence. It does not enter the horse as a finished vitamin but as β-carotene from green plant material — the body builds it from there.
Why it matters
Mucous membranes are the first border against pathogens, and their renewal depends on this vitamin. As long as fresh green is on the menu, the ration covers this item by itself.
When it becomes critical
The stable months are the critical stretch: stored hay loses much of its β-carotene, so a gap can open across weeks — showing up as brittle horn, dry membranes and infections that come more often. In the other direction, finished vitamin A turns toxic at high doses; as a standing dose, 1000 IU per kilogram of body weight per day marks the ceiling. With pure β-carotene that risk does not arise.
How much a horse needs
Maintenance: about 15,900 IU a day for a 500 kg horse; for breeding mares and foals the figure is considerably higher. Where pure β-carotene is given, breeding mares receive at least 200 mg daily.
Wird fuer Sehen, Haut, Schleimhaeute und Abwehr gebraucht. Gras und gutes Heu liefern die Vorstufe reichlich — Vitamin A ist der Fall, in dem Zufuettern schneller zu viel wird als zu wenig.
Pferdefütterung (Vervuert/Coenen), 6. Aufl. 2019, Georg Thieme Verlag; Bedarfswerte nach GfE 2014. Obergrenze aus Tab. 6.3, S. 206 (Risiko „mittel"); dreifach unabhaengig am Seitenbild bestaetigt (zwei Lesungen 20.08., dritte am Bild IMG_1406 22.08.).
Cited values
| Type | Value | Unit / context | Source |
|---|---|---|---|
| Requirement | 150 | IE/kg metabolische Koerpermasse und Tag (Erhaltung) | Equine Applied and Clinical Nutrition (Geor/Harris/Coenen) (2013, Tab. 9-2, S. 173) |
| Requirement | 225 | IE/kg metabolische Koerpermasse und Tag (Arbeit) | Equine Applied and Clinical Nutrition (Geor/Harris/Coenen) (2013, Tab. 9-2, S. 173) |
| Requirement | 300 | IE/kg metabolische Koerpermasse und Tag (traechtig) | Equine Applied and Clinical Nutrition (Geor/Harris/Coenen) (2013, Tab. 9-2, S. 173) |
| Requirement | 300 | IE/kg metabolische Koerpermasse und Tag (laktierend) | Equine Applied and Clinical Nutrition (Geor/Harris/Coenen) (2013, Tab. 9-2, S. 173) |
| Requirement | 300 | IE/kg metabolische Koerpermasse und Tag (Wachstum) | Equine Applied and Clinical Nutrition (Geor/Harris/Coenen) (2013, Tab. 9-2, S. 173) |
| Tolerance limit | 16000 | IE/kg Futter-TS | Pferdefütterung (Vervuert/Coenen), 6. Aufl. (2019, Tab. 6.3, S. 206) |
| Maximum per meal | 1000 | IE je kg Koerpermasse und Tag (langfristig nicht ueberschreiten — Vergiftung: raues Haar, Ataxien, Depression) | Pferdefütterung (Vervuert/Coenen), 6. Aufl. (2019, S. 118) |
Careful when comparing: the requirement is given **per day**, the upper limit **per kilogram of feed dry matter**. These are different reference bases and cannot be compared directly. The upper limit is also not a target — it is the amount at which harm begins.
A maximum per meal applies per meal and per kilo of horse — not per kilo of feed. Two small meals can add up to more while each stays below the limit.
“Metabolic body mass” is a calculated figure, not a weight: body weight to the power of 0.75. For 600 kg that is about 121 — the requirement is multiplied by that figure, not by 600. This is why the number looks small when it is not.
Sources
- Quelle der Bedarfswerte und fachlichen Angaben: „Pferdefütterung“, Hrsg. Prof. Dr. Ingrid Vervuert und Prof. Dr. Manfred Coenen, 6. Auflage 2019, Georg Thieme Verlag (begründet von Helmut Meyer); Werte nach GfE 2014.
- Pferdefütterung (Vervuert/Coenen), 6. Aufl. 2019, Georg Thieme Verlag; Bedarfswerte nach GfE 2014. Obergrenze aus Tab. 6.3, S. 206 (Risiko „mittel"); dreifach unabhaengig am Seitenbild bestaetigt (zwei Lesungen 20.08., dritte am Bild IMG_1406 22.08.).