Range of estimated requirements per day
15000-60000iu
Function
Vision, cell division, reproduction, resistance to disease, bone remodelling
Effect of Excess
Bone decalcification, internal haemorrhage, poor skin condition, increased heart
rate and reduced absorption of Vitamin E
Effect of Deficiency
Night blindness, anorexia, poor growth, impaired conception, respiratory infections
and weakness
Inter-related Micronutrients
Vitamin D, Vitamin E
Range of estimated requirements per day
5000-10000iu
Function
Controls absorption, transport and deposition of calcium and phosphorus
Effect of Excess
Hypercalcaemia, calcification of tissues and bone abnormalities
Effect of Deficiency
Bone disorders, decreased bone density, loss of condition, appetite and weight
Inter-related Micronutrients
Phosphorus, Calcium, Vitamin A, Vitamin D
Range of estimated requirements per day
750-4000iu
Function
Antioxidant to prevent cell damage by free radicals, hormone production, maintenance
of muscle tone and increased exercise endurance, optimum immune response
Effect of Excess
Unlikely, although levels 20 times greater than requirement may interfere with
absorption of other fat soluble vitamins
Effect of Deficiency
Nutritional muscular dystrophy (white muscle disease), marginal deficiencies
may cause muscle lesions (myopathies and 'tying-up'), reduced stamina, poor
disease resistance and immune response
Inter-related Micronutrients
Selenium, Vitamin A
Range of estimated requirements per day
3-10mg
Function
Factors involved in blood coagulation are all Vitamin K dependent
Effect of Excess
Unlikely, although renal colic, blood in urine and electrolyte abnormalities
may be induced by administration of excessive quantities
Effect of Deficiency
Reduced coagulation of the blood, spontaneous haemorrhage of blood vessels.
Stored in the liver in only very small quantities - daily supply required
Range of estimated requirements per day
10 grams minimum required to raise plasma levels
Function
Essential for the formation and maintenance of intercellular skeletal tissues
and stimulates immune response mechanisms
Effect of Excess
Not reported Although synthesized by the horse in tissues, supply may not meet
requirements in neonatal foals, aged horses and horses exposed to environmental
or physiological stress.
Effect of Deficiency
Deficiency may compromise collagen formation and immune response
Range of estimated requirements per day
50-500mg
Function
Feed conversion, energy metabolism, appetite, production of red blood cells
Effect of Excess
Excesses are generally excreted within 24 - 48 hours Unthriftyness, reduced
appetite, anaemia, nervousness and compromised muscle function.
Effect of Deficiency
Although produced as a result of bacterial activity in the hind gut, horses
in hard work or on high grain/low forage diets will benefit from a daily intake
of these vitamins
Range of estimated requirements per day
125-230mg
Function
Release of energy from absorbed and stored carbohydrates and fats, activity
of the nervous system
Effect of Excess
No apparent harmful effects
Effect of Deficiency
Reduced availability of energy, muscle weakness and fatigue, weight loss and
hyper-excitability
Range of estimated requirements per day
350-500mcg
Function
Metabolism of proteins, starch and fats
Effect of Excess
No apparent harmful effects
Effect of Deficiency
Reduced appetite and growth rate
Inter-related Micronutrients
Vitamin A, Folic Acid, Iron, Copper
Range of estimated requirements per day
50-120mg
Function
Essential for cell formation and function, regeneration of blood cells
Effect of Excess
No apparent harmful effects
Effect of Deficiency
In other species: anaemia, reduced growth rate, loss of appetite, scouring and
susceptibility to infection
Range of estimated requirements per day
3-15mg
Function
Supports development and maintenance of strong hooves
Effect of Excess
No apparent harmful effects
Effect of Deficiency
Poor strength and conformation of the hooves which will tend to crumble and
crack at the lower edges
Range of estimated requirements per day
3-10mg
Function
Synthesis of thyroid hormones, supports immune response
Effect of Excess
Iodine toxic goitre, alopecia (n.b. beware overfeeding seaweed)
Effect of Deficiency
Weak foals and abnormal oestrous
Range of estimated requirements per day
1-3mg
Function
Detoxification of peroxides toxic to cell membranes - relationship with Vitamin
E
Effect of Excess
Low levels of toxicity may cause alopecia and cracking of the hooves around
the coronary band
Effect of Deficiency
White muscle disease, impaired function of cardiac and skeletal muscle
Inter-related Micronutrients
Vitamin E
Range of estimated requirements per day
150-270mg
Function
Mobilisation of iron stores, red blood cell formation, bone maturation, maintenance
of elastic and connective tissues, efficient muscular function at the cellular
level
Effect of Excess
No apparent effect, however, excess may interfere with absorption of other
trace minerals
Effect of Deficiency
Increased incidence of bone disease, rupture of uterine artery in aged mares,
anaemia and reduced muscular function
Inter-related Micronutrients
Zinc, Iron, Calcium
Range of estimated requirements per day
450-810mg
Function
Enzyme functions, maturation of cartilage and bone
Effect of Excess
May interfere with copper metabolism although toxicity is unlikely
Effect of Deficiency
Reduced growth rate and increased incidence of metabolic bone disease
Inter-related Micronutrients
Calcium, Copper, Iron
Range of estimated requirements per day
500-650mg
Function
Lipid and carbohydrate metabolism and formation of cartilage
Effect of Excess
May interfere with absorption of other trace minerals
Effect of Deficiency
Associated with abnormal cartilage development and limb abnormalities
Inter-related Micronutrients
Copper, Zinc
Range of estimated requirements per day
500-650mg
Function
Necessary for formation of haemoglobin
Effect of Excess
Reduce absorption of copper and other trace minerals
Effect of Deficiency
Unlikely, as equine feedstuffs contain high levels
Inter-related Micronutrients
Copper, Zinc, Folic Acid
Range of estimated requirements per day
25g (min) to at least 1.8 x level of phosphorus
Function
Formation and maintenance of integrity of bone, contraction of skeletal and
cardiac muscle, hormonal secretion, blood clotting and nerve function
Effect of Excess
Possible osteochondrosis although as long as phosphorus is adequate calcium
has been fed at more than 5 times the required level without detrimental effects
Effect of Deficiency
Developmental orthopaedic disease, bone demineralisation, sore shins, fracturing,
insidious shifting lameness, poor muscle function. Ca:P ratio minimum 1.8:1
Inter-related Micronutrients
Phosphorus, Zinc, Iodine
Range of estimated requirements per day
15-30g
Function
Skeletal growth, normal blood chemistry and muscle and nerve tissue, feed metabolism
and energy transfer
Effect of Excess
Reduced rate of calcium absorption leading to chronic calcium deficiency,
poor integrity of bone, shifting lameness
Effect of Deficiency
Developmental orthopaedic disease, retarded growth rate and/or bone strength,
reduced feed utilisation, reduced fertility
Inter-related Micronutrients
Vitamin D, Calcium
Range of estimated requirements per day
10-30g
Function
Constituent of bone, activator of many enzymes, essential to muscle and nerve
function
Effect of Excess
May interfere with calcium metabolism
Effect of Deficiency
Compromised muscle function, nervousness, muscle tremors, mineralisation of
cardiac tissue, reduced immune response
Inter-related Micronutrients
Calcium, Phosphorus
Range of estimated requirements per day
10-50g
Function
Maintenance of acid base balance, nerve and muscle function, protein synthesis
and carbohydrate metabolism
Effect of Excess
Excess dietary potassium is readily excreted when water intake is adequate
Effect of Deficiency
Muscular weakness and stiffness, heart abnormalities, intracellular acidosis,
nervous disorders, decreased growth rate and appetite
Inter-related Micronutrients
Sodium, Chloride
Salt(sodium and chloride) (Mineral)
Range of estimated requirements per day
25-90g
Function
Major electrolytes involved in acid base balance, vital role in muscle contraction
Effect of Excess
Unlikely that horses will willingly consume toxic amounts, although excessive
salt intake may result in excessive water intake, excessive urine excretion
and digestive disturbances
Effect of Deficiency
Compromised muscle function/fatigue, loss of appetite, decreased feed utilisation,
milk production and growth, reduced immune response
Inter-related Micronutrients
Potassium, Chloride, Calcium