Equis ISSN 2398-2977

Nutrition: vitamins

Contributor(s): Derek Cuddeford, Zoe Davies, David Frape, Deborah Lucas, Katie Williams (nee Lugsden)

Introduction

  • Vitamins are organic substances required in very small quantities for the maintenance of tissues and metabolic systems.

Sources

  • Diet.
  • Tissue synthesis (vitamin C (ascorbic acid), vitamin A from ß-carotene).
  • Skin synthesis as a reaction to ultraviolet light (vitamin D3).
  • Alternative metabolic pathways (substitution of methionine and other sources of methyl groups for choline).
  • Large intestinal micro-organisms (K and some B complex vitamins).

Requirements

  • Amounts reported as 'requirements' generally represent the level below which clinical signs of deficiency may occur.
  • In some cases, eg vitamins E and B complex, increased supplementation may be beneficial.
  • Depends on:
    • Age: foals' rapid growth increases the requirement for vitamins A   Vitamin A  , D   Vitamin D3  , B   Vitamin B1   complex and K. In very young foals the poorly developed large intestine is not a reliable source.
    • Parasitism: intestinal parasites may increase vitamin requirements.
    • Reproductive status: requirements are greater for lactating mares   Nutrition: brood mare  but tend to be eating more anyway, so vitamins per unit of feed are not affected.
    • Work levels: decreased appetite of horses in heavy work   Nutrition: work    →   increased requirement for certain B vitamins   Vitamin B1  .
    • Latitude: horses with dark skin, heavy coats, those kept indoors or in northern latitudes all have increased requirements for vitamin D   Vitamin D3  .
    • Disease: horses with rhabdomyolysis syndrome   Muscle: myopathy - exertional rhabdomyolysis  (azoturia/tying-up) may benefit from increased levels of vitamin E   Vitamin E   to protect muscle tissues.

Fat soluble vitamins

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Water soluble vitamins

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Further Reading

Publications

Refereed papers
  • Recent references fromPubMedpublished during the last 12 months.
  • Hintz H F (1992) EdClinical nutrition. Vet Clin North Am6, (2).
  • Roneus B O et al(1986)Vitamin E requirements of adult Standardbred horses evaluated by tissue depletion and repletion. Equine Vet J18(1), 50-58PubMed.

Other sources of information

  • Frape D (2004)Equine Nutrition and Feeding.3rd edn. Blackwell Publishing Ltd, Oxford, England. ISBN: 1405105984.


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