No, Calsorb Forte provides salt.

Also, because Calsorb Forte contains amino acids and a range of minerals, it has a distinctive taste. Salt blocks are usually just salt + molasses and (like us) horses have a preference for salt and sugar – and will select them over something more nutritious. When using Calsorb Forte no other salt licks or blocks should be provided, except on veterinary advice.

Feeding more than the needed amount is never better, although with magnesium the deficiencies are often so sizeable it's difficult to overdo it. 

Magnesium absorption from feeds varies from 40-60%. Magnesium in EzyMAG+ is 70% absorbed. Studies in magnesium toxicity have not been done but the upper limit of intake is thought to be 8g/kg of feed – so a 400kg horse eating 10kg of feed per day, the upper limit would be 80g per day. 

Signs of a magnesium deficiency or an increased requirement for magnesium, include nervousness and behavioural issues, and muscle problems through to tying-up. 

Magnesium deficiency also causes mineralisation of the aorta with changes in the wall of the artery occurring within 30 days on a deficient diet. Muscle weakness and muscle tetany have also been reported in horses with magnesium deficiency. 

EzyMAG+ can be fed with Bone Formula Forte. Additional supplementation should only be necessary on veterinary or nutritionist advice.  It is total daily intake that counts – so a diet analysis is the best way to determine if all requirements are met. 

Horses don’t need that much chelated calcium and it would be wasteful and expensive. And we wouldn’t be able to include the trace elements if we just provided calcium. Also horses need some inorganic calcium to bind to the oxalates in the gut. This stops the oxalates from being absorbed into the blood and damaging the kidneys. 

The really important thing to keep in mind is that we are not endeavouring to perfectly balance the mineral content of the entire diet – we are just attending to the oxalate problem and supplying trace elements.

The major minerals like phosphorus, potassium and magnesium are provided by the hay, pasture, chaff and hard feed. Because every horse has a different diet, it would be impossible to make one mineral supplement that would balance and match every diet! Generally we can use published values for the mineral levels in different feeds – but if you want to be very precise you need to analyse your particular hay and/or pasture. Also bear in mind that mineral levels in hay and pasture change with the stage of growth, time of year and soil type. Your state department of agriculture or local agronomists can assist with these analyses.

The major source of the macro-minerals like phosphorus, potassium, sodium, chloride and magnesium is the pasture/hay/hard feed. Most vitamins are covered by pasture – if only on hay, they will likely need extra vitamin A, C, E and K – however this is mostly for performance/hard working horses.

It is the trace elements that are usually deficient.  No other trace element supplement should be needed for horses on Bone Formula Forte except on veterinary advice.

MgSO4 is used intravenously as a sedative and muscle relaxant during anaesthesia. There is no evidence that dietary magnesium has these effects. 
 

Supplements and feeds with added vitamin E use α-tocopherol.
Naturally-occurring vitamin E (the form of 2R4R8R or triple-R) has an activity of 1.36iu/mg whereas the synthetic form has 1iu/mg. This means that more α-tocopherol (synthetic) needs to be fed to get the same level of activity.

Signs of a magnesium deficiency or an increased requirement for magnesium, include nervousness and behavioural issues, and muscle problems through to tying-up. 

Magnesium deficiency also causes mineralisation of the aorta with changes in the wall of the artery occurring within 30 days on a deficient diet. Muscle weakness and muscle tetany have also been reported in horses with magnesium deficiency. 

All horses need correct intakes – but especially young, growing, pregnant, exercising horses and those that have had surgery or been sick or injured as well as horses suffering from veterinary conditions such as tying-up, laminitis, Cushing’s or metabolic syndrome.

Oils = fatty acids. Fatty acids interact with oxygen when exposed to air, or used in the body. This process, called peroxidation, results in the production of ‘oxidants’ as the fatty acids become ‘oxidised’, so it is often recommended that additional antioxidants be added to the diet, to mop-up the extra oxidants. (When fats and oils smell rancid it is a sign that they have been exposed to air and the oil has become oxidised by oxygen). 

Oxidants are the by-product of reactions in the body that use oxygen – similar to the toxic waste products produced by energy generation in power stations.
The body has an oxidant defence system to protect its cells from oxidant damage – oxidants are also known as reactive oxygen species (ROS). The system includes vitamin C which is a water-soluble anti-oxidant (bit like the navy!) and vitamin E, which works in fatty tissues in the body. 

We can measure the amount of oxidative stress in the body by measuring markers in the blood. These markers are elevated after exercise (which causes increased oxygen usage and therefore more ROS produced) and in horses with low vitamin E levels and high oil intakes – indicating that horses with increased oxidant loads need more vitamin E, even when only moderate levels of oils are fed.

The general rule-of-thumb for the prevention of peroxidative damage is to provide a minimum of 100 IU of vitamin E per 100 ml of vegetable oil.

There is a very strong association between magnesium and the body's ability to use insulin properly. Magnesium-deficient diets can induce insulin-resistance (which prevents the muscles and liver from taking up sugars and they are diverted to fat for storage). Magnesium-rich diets have been found to be protective in many cases of insulin-resistance.

Magnesium is needed for optimal muscle contraction, the utilisation of glucose and to sustain the high oxygen consumption necessary for athletic performance. Research indicates that magnesium facilitates oxygen delivery to working muscle tissue – so there is an increased need for magnesium by horses in work that need high starch-sugar feeds. Magnesium levels can be depleted by antibiotics and other pharmaceuticals too. And because the amount of magnesium in the blood does not necessarily correlate with the amount stored in the body, a magnesium deficiency can be difficult to pinpoint. 

Most B-vitamins are involved in the production of energy to maintain life processes – i.e. ATP, DNA processing, amino acid processing, and protein building – all absolutely necessary for life. The effects on growth and performance of subclinical deficiency are difficult to detect or diagnose, so provision of correct intake is important. 

It has recently been recognised that although production of B-vitamins in the gut is enough to meet the needs of ruminants, this is not so in the horse. Gut bacteria in horses do produce B-vitamins, but the production and absorption or both may be insufficient under some circumstances. Published figures (NRC) has been found to be inadequate and a doubling of intake is recommended for exercising horses.

Dietary levels of thiamine (vitamin B1) are good in fresh hay and grains, but fall to 50% after 6 months in storage, almost zero after 2 years. In hot, humid weather, levels fall even faster.

Providing extra thiamine has been shown to improve appetite and energy metabolism and decrease nervousness. The trouble with thiamine deficiency is that the effects are reduced growth rate and performance ability – both of which are subclinical and difficult to identify – but certainly a 10% in either means growth or performance will not be optimal or ideal.

Pyridoxine (vitamin B6) is needed by horses for muscle strength, protein synthesis (i.e. new cell and tissue building), energy and red blood cell production. Requirements are increased in young, growing pregnant and exercising horses. It is produced in the gut – but not well-absorbed. Levels in feeds reduce with feed storage. Current recommendations for B6 are 5 times higher than levels published 10 years ago (NRC). 

You would need to feed 1 ½ kg of brewer’s yeast each day to meet thiamine (B1) requirements and 2kg per day to meet pyridoxine (B6) requirements.