Yeah... All porcelain contain some bone ash but content may vary depending upon if it is soft or hard or china type, Mostly in Bone china has the highest content
bone ash is made by burning the bones of all animals
Ash Content is usually expressed in % Ash Content & is calculated as follows: % Ash Content = (Sample wt. after drying @ 500-550 Deg C - for 3 Hrs) x 100 (Initial Sample wt. dried @ 105 Deg.C - for 3 Hrs.)
Ash content is determined by calcination and deionized water is not necessary.
because bone ash is considered as unauspecious
To evaluate the insoluble content of a substance.
The amount of ash produced during combustion relative to the amount of fuel fed into the wood pellet stove. Ash content is one indicator of quality for wood pellet fuel. Ash content for wood pellets should be between one and three percent. 

As far as I know, the type of animal doesn't matter, I would guess that the bones used are byproducts from meat packing plants or slaughterhouses, and would therefore be bones from whatever type of animal is most frequently consumed in the area that the porcelain is being made.
Bone china is made out of clay, not bones. Actually, bone china is made out of clay AND bone ash, which is the white ash produced from the burning of bones in open air. I would assume any type of bone could be used.
Fixed Carbon by Difference = 100 - (Volatile Content + Ash Content + Moisture Content)
0.01 g
When the filter paper is burned some 'ash' will be left behind.