Blood meal contains

A blood meal is extremely rich in Nitrogen. It contains about 13 - 20% Nitrogen, 1% phosphorous and 0.6% of potassium. It is a dry, inert powder made from blood, used as a high-nitrogen organic fertilizer, non-synthetic and high protein animal feed.
A blood meal is composed of protein mostly, small amounts of fats and ash. It usually comes from cattle or hogs as a slaughterhouse by-product.