About the Processing of Blood

by Eben van Tonder

13 June 2021


These are notes about the processing of blood for human and animal consumption.

“Blood is a highly perishable product and must be processed as soon as possible after slaughter. Blood meal can be prepared by a small-scale operation. Blood meal is hydroscopic and needs to be dried to less than 10-12% moisture and stored in a dry place in order for it not to deteriorate.” (feedipedia)  The right terms is actually Hygroscopic which is a “phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance’s molecules, adsorbing substances can become physically changed, e.g., changing in volume, boiling point, viscosity or some other physical characteristic or property of the substance.”

Suggested action: bind blood and collagen in a ratio of 1:10 or 1:20.

“There are different ways to prepare blood meal: solar drying, oven drying, drum drying, flash drying, spray drying. The drying method is important because there is an inverse relationship between the amount of heat applied and protein digestibility. Particularly, lysine content and lysine availability decrease when the amount of heat increases (Batterham et al., 1986). Overcooked blood meals are darker, due to the destruction of the haemoglobin, and less palatable.” (feedipedia)

Composition of Blood

Bovine blood is made up of

Water 80.9%
Typical Make-up of Bovine Blood (Alencar, 1983)

Blood composition is similar to meat composition except for the iron (36.3 mg/100 g of blood), which is ∼10 times the concentration in meat (Wismer-Pedersen, 1979; Alencar, 1983)


Blood can be coagulated to aid in the removal of water by adding 1% unslaked or 3% slaked lime. However, this method of water removal increases the amount of dry matter losses by 10-15%, which includes many of the minerals. 

In some situations, blood needs to be stored prior to being processed and dried. Raw blood can be stabilized and stored for one week by adding 0.7% sulphuric acid or an equivalent amount of another acid. A method for preparing blood meal by adding 3% sulphuric acid and storing for 72 h before sun-drying has been described (Divakaran, 1987; Divakaran et al., 1988).

Suggested action: Sodium citrate is used as an anticoagulant in the collection of slaughterhouse blood.

After bleeding warm blood is only stable for approximately eight hours. Without refrigeration, fresh whole blood must be processed and dried shortly after bleeding. Even with the addition of sodium citrate, animal byproduct producers reduce whole blood degradation, bacterial contamination and further clotting by chilling stored blood with stirring prior to inspection and further downstream processing. This is important if blood must be transported to another facility. Chilled whole blood held at 2-3o C is stable for approximately 120 hours which facilitates off-site processing (Labudde Group, 2017; Sjoberg, 2017). (Sodium Citrate)

Sodium oxalate may also be used as an anticoagulant, but it is considered poisonous and may not be appropriate for application to soil as a soil amendment (Ockerman and Hansen, 2000). (Sodium Citrate)

Anhydrous Citric Acid is a tricarboxylic acid found in citrus fruits. Citric acid is used as an excipient in pharmaceutical preparations due to its antioxidant properties. It maintains stability of active ingredients and is used as a preservative. It is also used as an acidulant to control pH and acts as an anticoagulant by chelating calcium in blood. (Pub Chem)

Anticoagulent, generally in solution with glucose, to prevent clotting of blood intended for transfusion. (Pub Chem)

To prevent clotting of fresh beef blood, at 0.2%, with or without water; not more than 2 parts water to 1 part citric acid shall be used; to incr effectiveness of antioxidants in frozen, fresh pork sausage and freeze-dried meats, at 0.01% in combination with antioxidants. (Pub Chem)

Your ideal blood pH is between 7.35 and 7.45, which is slightly alkaline.

Blood is often prescribed in anemia. In its usual form it has a bad taste and odor, and a as made according to my preferred examples herein given, appear much like malted milk. Salt, malt, cocoa, chocolate or vanilla or other desirable flavors or condiments may be added if desired or introduced in the process of manufacture. Such a product may be consumed a tablespoonful, more or less, in a glass of warm water or milk as a palatable food of exceptional medicinal value. The combined proteins are in an especially assimilable form.

Other Processing Methods

Fermentation of Blood Meal with Bacillus amyloliquefaciens as Broiler Feeding. See https://scialert.net/fulltext/?doi=ajava.2016.840.846

Nutritional attributes 

Blood meal contains mostly protein (about 90-95% DM) and small amounts of fat (less than 1% DM) and ash (less than 5% DM), though non-industrial blood meals may include other materials and thus be richer in ash. Unlike other animal protein sources, blood meal has a poor amino acid balance. Its lysine content is relatively high (7-10% DM) which makes it an excellent supplementary protein to use with plant-derived feed ingredients that are low in lysine. However, its isoleucine content is very low (about 1% DM), so diets for monogastric animals must be formulated to contain enough isoleucine for the level of performance desired (Piepenbrink et al., 1998Maiga et al., 1996). Pepsin digestibility has been shown to be a good test for assessing the availability of the protein fraction of blood meal (Hegedüs et al., 1989). Blood meal is rich in iron (more than 1500 mg/kg DM). Leucine contents ranging from 5.1% for hemp to 13.5% for corn protein, compared to 9.0% for milk, 7.0% for egg, and 7.6% for muscle protein. (Gorissen, 2018)

Blood meal is generally unpalatable, particularly if overcooked, so care needs to be taken to not add more than 5 to 6% blood meal to a ration, especially if high feed consumption and performance are desired. Often an adaptation period is required to get animals used to eating blood meal. Potential constraints 

For safety reasons, blood must be heated to be used in animal feeding: a minimal temperature of 100°C for 15 min is necessary in order to destroy potentials pathogens (salmonella, mycotoxins, prions) (Göhl, 1982). It is recommended to avoid feeding a species with blood meal from the same species.

In the European Union, blood meal has been banned from feeding to animals since 2000 (Council Decision 2000/766/EC), though since 2006 blood products from non-ruminants are now authorized for use in aquaculture (Médale et al., 2009).Ruminants 

Blood meal is valuable for ruminants due to its high protein content and rumen-resistant amino acids. Rumen undegradable protein is up to 78% in blood meal and increases with the heating temperature used in its processing. Blood meal contains more essential amino acids than soybean meal (Klemesrud et al., 2000Piepenbrink et al., 1998), but it is deficient in sulphur-containing amino acids (Klemesrud et al., 2000) and isoleucine (Maiga et al., 1996). It should be supplemented with other protein sources (Maiga et al., 1996).


In steers and in calves, 3% dietary inclusion of blood meal increased daily weight gain, dry matter intake and energy intake (Knaus et al., 1998Tartari et al., 1989). In dairy cows, it improved milk production and milk protein yield (Schor et al., 2001).


In sheep, blood meal can be used as a by-pass protein (Kamalak et al., 2005), which allows a reduction in the overall dietary protein content of the diet (from 16-18% to 13%) (Antongiovanni et al., 1998). The nutritional status of pregnant ewes fed at or near maintenance while consuming low-quality roughages was enhanced by supplementation with additional crude protein in the form of blood meal (Hoaglund et al., 1992).Pigs 

Blood meal is a good source of protein in pigs. Recommended dietary levels vary from 4% of DM (Cunha, 1977Wahlstrom et al., 1977) to 6-8% of DM (Seerley, 1991 cited by Lewis et al., 2001).


During post-weaning phase I (day 0-14), dry skimmed milk can be replaced by animal by-products, such as porcine blood meal, porcine plasma, extracted meat protein, bovine plasma protein, spray-dried blood meal or soybean protein concentrate. Spray-dried porcine plasma (SDPP) is superior to every other protein sources (Hansen et al., 1991Tokach et al., 1991Rantanen et al., 1994). Recommended inclusion rate is 7.5% spray-dried plasma (Bergstrom et al., 1994Owen et al., 1994). However, spray-dried blood meal at 2.5% of the dietary DM could replace 67% of spray-dried plasma from day 7 to 14 (Kats et al., 1992bDritz et al., 1993).

During post-weaning phase II (day 14-28), spray-dried blood meal will be preferred to SDPP or fish by-products as it increases both animal performance (Tokach et al., 1991) and economic performance (Kats et al., 1992aDritz et al., 1992). Inclusion rates should be no more than 2-2.5% of DM (Kats et al., 1992aKats et al., 1992b).

During post-weaning phase III (day 28-42), spray-dried blood meal can be included at 2-2.5% of DM and supplemented with 0.4-0.44% methionine (Owen et al., 1993).

Growing pigs

In growing pigs, blood meal can partially replace soybean meal in maize-soybean based diets: it is then included at 3 to 4% of DM (flash dried blood meal) or at 6% (Ilori et al., 1984Rerat et al., 1975). It can supplement cottonseed meal to counterbalance the negative effects of gossypol in pig diets (Fombad et al., 2004).

Feeding growing pigs with fermented blood meal (dried or not) in combination with molasses allows the same feed intake, growth and feed conversion efficiency as soybean meal. Utilization of N is also high (M’ncene et al., 1999King’ori et al., 1998). A 10% fermented blood meal inclusion in pig diets is recommended (Tuitoek et al., 1992).Poultry 

Blood meal can be used successfully in poultry diets.


For broilers, blood meal is a good protein source. It can replace 50 to 100% of fish meal (Rao et al., 2009Seifdavati et al., 2008Nabizadeh et al., 2005), 50% of soybean meal (Onyimonyi et al., 2007Tyus et al., 2008), and also copra meal or groundnut meal (Donkoh et al., 2001Donkoh et al., 1999) resulting in improved performance and greater profit. The amounts of blood meal are equivalent to 3 to 9% of the dietary DM (Tabinda Khawaja et al., 2007Matserushka, 1996Quarantelli et al., 1987).

Blood meal has a high tryptophan digestibility coefficient which is valuable as tryptophan is the third limiting amino acid in broilers (Ravindran et al., 2006). It is necessary to supplement blood meal with lysine and isoleucine (Elamin et al., 1990Tyus et al., 2008) to ensure better animal performance.

Laying hens

In laying hens, blood meal is as palatable as other rendered animal products. Sun-dried blood meal given at 4.5% of the diet has a positive effect on layer performance (feed intake, live-weight gain, egg weight and yolk colour) (Donkoh et al., 2001). Blood meal improves Fe content in yolks (Revell et al., 2009). One case of cannibalism related to blood meal feeding has been reported (Atteh et al., 1993).

Fermented cattle blood gives comparable egg production to fish meal when these products are used to replace soybean meal. However, rendered animal products can cause undesirable flavour in eggs and it is not recommended that they fully replace soybean meal in layers diets (Tuitoek et al., 1994).

Nutritional Tables – see https://www.feedipedia.org/node/221


Gorissen, S., Crombag, J., Senden, J., Waterval, W., Bierau, J., Verdijk, L. B., & van Loon, L. (2018). Protein content and amino acid composition of commercially available plant-based protein isolatesAmino acids50(12), 1685–1695. https://doi.org/10.1007/s00726-018-2640-5

Sodium Citrate

Pub Chem

Patented Aug. 5, 1941 PROTEIN COMPOSITION OF MATTER Lloyd A. Hall, Chicago