Big Head or Oxalate Poisoning in Horses

I am interested in the subject of Big Head on the Sunshine Coast. I have found a mix of 2 parts DCP to 1 part Calcium Carbonate suits the area I am located in for the prevention of big head for horses grazing pastures containing sub tropical species of grasses that cause oxalate poisoning.
If anyone has any other information on treatment, correct balance of Ca to Phosphorus ratio, feeds affecting the balance, like bran, pollard, rice bran which are high in Phosphorus, lucerne which is high in calcium, and how to calculate rations when feeding with these products I would be grateful.

I plan to compile all the information I source on my health page http://www.awebsite.com.au/Horse_Health.html

Thanks for your contributions......Niki