This protein source is called rumen degradable or rapidly degradable protein. Flash dried blood meal is dried rapidly and has more available lysine and methionine than cooker dried blood meal. Because of its high lysine content and the high cost of drying, blood meal is usually an expensive source of bypass protein. Feeding blood meal separately in a supplement or top-dressed on a ration sometimes causes palatability problems, but mixing it into the total ration has avoided this problem. The value of meat meal varies due to the amount of heat applied in drying and the amount of bone and hair contamination.
Meat meal has the advantage of containing high amounts of phosphorus and fat.
Palatability may be a problem if it is fed separately in a supplement or top-dressed on a ration, but not if it is mixed into the ration. Less research is available on the degradability of fish meal protein, but it appears to be a high bypass protein. Fish meal is high in essential amino acids and B-vitamins. Because of its high lysine content and low availability, the price is usually high. Excess oil in fish meal can lead to rancidity, and inadequate drying may allow molding.