We would go to a local slaughter house to get 5 gallon carboy of beef blood filled as we used that to feed our stable fly culture so we could proprigate a healthy egg supply to keep the culture/ colony going. We would heat the blood to 98 degrees F. To keep it we would refrigerate. To prevent it from coagulating we added Trisodium Citrate when the blood was first added. That prevented coagulation. How much is what I am trying to find out.
JW