Magnesium Oxide - heavy or light?

[marianne]

The chemist in France always gets in 'light' magnesium oxide when I order it. Does anyone know what the different between the light and heavy versions is, and which one SHOULD I be ordering for my horse?

Thank you!

[june]

I've upped another magnesium thread for you.

There is a post on there from Jackie taylor which says "The main disadvantage of this material, and the reason it is so cheap I suspect, is that it is very 'light' magnesium oxide, ie heated for much less time than 'heavy' which I stock. This means that it is much more fluffy, and so you will have to feed a lot more volume to get an equivalent amount of magnesium into your horse. This will mean 6 x 15ml tablespoons full for some horses to start with, more for the level some trimmers are wanting fed, and that is an awful lot of white powder to ask a horse to eat."

[Catrin]

This is off Jackie A Taylor's product information list. She stocks two types and the Pure Magnesium Oxide is the one I chose for long term use to replace local grass and haylage deficiency. If you try a search, you will see that she explained the difference in a recent thread - in the last month, I think.

Pure Magnesium Oxide
Magnesium is critical for metabolic, nervous and muscular function, yet low in many diets.
Our pure magnesium oxide is a consistant, high grade, fine white powder for optimum absorption, so should allow lower feeding levels, with far lower contamination levels than standard feed grade product. Recommended as superior for horses with slow metabolism, laminitics, for building hoof structure and soundness and longterm use (Only15p a day maintenance for a full sized horse).
Magnesium Oxide £15.00 1kg

Magnesium Oxide (CalMag)
CalMag is a feed grade product offered for short term use.
Magnesium Oxide (CalMag) £4.00 1kg
Magnesium Oxide (CalMag) £13.00 4kg

[fin]

Heavy magnesium oxide is heated to a much greater temperture than light mag ox, which is why it's more dense. So I guess if you were to want to feed 10g of Mag Ox, the heavy Mag Ox would be less volumewise. Not sure how much, but the light Mag Ox I have is 40ml volume to 10g weight, which is quite a bit of white powder.

It's ok to use if your horse will happily eat it though

[anon]

It may be that the light Mag Ox is more available to the horse (smaller particles, easier to absorb)

[marianne]

Thanks folks, looks like I'll be contacting Jackie then :-)

[wendyihts]

My chemist here in Samatan got the heavy MgOx in for me Marianne. It was 26 euros a kilo, I seem to remember. So it's definitely available here in France. I've got some tubs here if you want me to look up the label for you so you can ask your chemist direct.

[marianne]

Ta Wendy, I'll call my chemist first. It's strange they always ordered one rather than the other!

[fin]

I wondered that about light Mag Ox, anon. The one advantage I have found with having to feed about 80ml of the stuff is that I can split in into three feeds without it being too fiddly to measure. I know a lot of dairy farmers try to make sure their cows get several small doses of mag per day rather than one large one, which is suposed to increase magnesium uptake.

I haven't read anything to confirm or deny that, but it sounds reasonable and plausible enough to be worth trying, doesn't it?