All About Rendering
Protein Conversion Terminology
AAFRD: Alberta Agriculture, Food and Rural Development.
Amino acids: a class of nitrogen-containing molecules that are the building blocks from which protein is made in the body.
Animal fat: an aggregate term generally understood to be fat from mammals.
Antioxidant: a compound added to feeds to prevent the oxidative rancidity of fats.
Anvils: raised rectangular solid sheet teeth in some of the reducing size equipment.
APHIS: Animal and Plant Health Inspection Service
Ash: the inorganic mineral elements of animals and plants, determined in a laboratory by burning off the organic matter at a high temperature and weighing the residue (ash).
Available protein: the portion of the crude protein that can be digested by the animal
Balanced ration: a 24-hour feed allowance that provides an animal with appropriate amounts and proportions of all nutrients required for a given level of performance.
Blended: two or more feed ingredients combined; blending does not imply a uniformity of dispersion.
BOD (biochemical oxygen demand): the quantity of oxygen used in the biochemical oxidation of organic matter in a specified time, at a specified temperature, and under specified conditions. Normally five days at 20°C unless otherwise stated. A standard test used is assessing the biodegradable organic matter in municipal wastewater.
BSE: bovine spongiform encephalopathy
By-pass protein or Rumen-degradable protein: portion of ingested protein that is susceptible to digestion by rumen microorganisms; used in the synthesis of microbial protein.
By-products: feed ingredients produced as a result of industrial manufacturing, plant or animal processing.
Cake: residue remaining after pressing seeds, meat or fish to remove oil, fat or other liquid.
Carbohydrate: energy-providing substrate, including starches, sugars, cellulose and hemicellulose. All carbohydrates contain carbon, hydrogen and oxygen, and are usually divided into two fractions: structural (fibre from plant cell wall) and non-structural (sugars and starches from plant cell contents).
Carcass meal: proteinaceous solids.
Centrifuge: machine used radiating force to separate materials of different densities.
Chelated mineral: a compound formed between an organic molecule and a mineral that increases mineral bioavailability to the animal, which can reduce excretion of excess minerals in manure.
Chemical analysis: the use of standard chemical analytical procedures to determine the composition of a feed.
Cleaned: cleared of undesired materials by screens, magnets or forced air.
Clostridium perfringens: an indicator microorganism, which shows the sterilizing effect of rendering procedures.
COD (chemical oxygen demand): a measure of the oxygen-consuming capacity of inorganic and organic matter present in water or wastewater. It is expressed as the amount of oxygen consumed from a chemical oxidant in a specified test. It does not differentiate between stable and unstable organic matter and thus does not necessarily correlate with biochemical oxygen demand.
Complete feed: a thoroughly blended mixture of different feed ingredients formulated to meet specific nutrient requirements that allows for greater efficiency in feeding and provides better control of nutrient intake. A complete feed may or may not include the roughage portion of the ration.
Composting: a natural biological decomposition process that takes place in the presence of oxygen (air).
Cooker: horizontal, steam-jacketed cylinder equipped with a mechanical agitator. Raw material is heated to certain conditions and according to a repetitive cycle.
Continuous cooker: heating equipment used in rendering process, where the raw material through the system is flowing in an essentially constant manner and without cessation or interruption.
Corn distillers' grains: the residual grains or byproduct that contain the nutrients remaining after the starch from corn has been fermented to alcohol. The concentration of these residual nutrients is approximately 3x that found in the original corn.
Cracklings: solid protein material discharged from screw press of rendering process and after removal of liquid fat.
Crude fibre (CF): chemical analysis that involves extraction of a ground feed sample with diethyl ether followed by sequential boiling in dilute acid and dilute base. Residue is then burned in a furnace; CF is calculated as the difference in weight of the sample before and after burning. CF has been replaced by ADF and NDF fibre fractions in ruminant feeds but is still reported for monogastric feeds.
Crude protein: an estimate of the total protein content of a feed determined by analyzing the nitrogen content of the feed and multiplying the result by 6.25. Crude protein includes true protein and other nitrogen-containing substances such as ammonia, amino acids, nitrates.
Crumbles: pelleted feed that has been broken into smaller granular pieces.
Crusher: machine containing blades or knives that grind raw material to uniform size.
D Value: the time in minutes required to destroy 90 percent (or a one-log cycle) of a population of cells at a given reference temperature.
Digestible Energy (Kcal/kg): gross energy of feed intake minus fecal energy.
Digestibility: the percentage of feeding stuff taken into the digestive tract that is absorbed into the body.
Dry matter: the portion of a substance that is not comprised of water. The dry matter content (%) is equal to 100% minus the moisture content (%).
Edible rendering: fats and proteins produced for human consumption which is under the inspection and processing standards established by the US Department of Agriculture, Food and Safety Inspection Service (USDA/FSIS).
Edible tallow: exclusively beef, this product is rendered from fat trimmings and bones taken from further processing at a slaughterhouse. Because of the associated processing and the limits of raw material, the product of light color and low moisture, insolubles, unsaponifiables, and free fatty acids. The tallow may be further refined, polished, and deodorized to become a cooking fat. The pet food industry generally uses the crude product not shipped under seal. This often is referred to as technical tallow.
END: exotic Newcastle disease
Energiewaarde (Kcal/kg): EW 2.59 digest. prot. + 8.63 digest. ether extract + 1.5 percent digest. fiber + 3.03 digest. N-free-extractives.EPAA: Environment Protection Authority of Australia
Enzyme: a complex protein produced by living cells that speeds up chemical reactions without being changed or destroyed itself. Enzymes are added to animal feeds to supplement low enzyme production or to improve utilization of poorer quality feeds.
Essential amino acid: amino acids that must be supplied in the diet, as the animal either cannot synthesize them at all or cannot synthesize them in sufficient quantities to meet its requirements.
Essential fatty acid: fatty acid that cannot be synthesized by an animal from other sources. Linolenic (18:3n3) and linoleic acid (18:2n6) are essential in the diet; these fatty acids are the basis for the omega-3 and omega-6 classes of fatty acids and are building blocks for longer-chain fatty acids. Fatty acid deficiencies are unusual but can affect skin, coat and reproductive performance.
Extracted: fat or oil removed from a feed or byproduct by heat and mechanical pressure (mechanically extracted) or by organic solvent (solvent extracted).
Extruded: feed forced through narrow openings under pressure.
Fat-soluble vitamins: includes vitamins A, D, E and K. Fat-soluble vitamins are stored in body fat reserves. Vitamins A, D and E are supplemented in many livestock rations.
Fatty acid: a major component of fat that is used for energy by the animal. Molecules are composed of carbon and hydrogen in chain-like formation.
FDA: US Food and Drug Administration
Feed efficiency: a ratio describing the amount of feed consumed per unit of production
Feed grade: term to describe the quality of feedstuffs suitable for animal, but not human, consumption.
FFA: free fatty acids
Fines: any materials that pass through a screen whose openings are immediately smaller than the specified minimum particle size.
FMD (foot and mouth disease): a highly infectious viral infection of cattle, pigs, sheep, goats, buffalo and artiodactyls wildlife spies characterized by fever, vesicles (blisters) in the mouth and on the muzzle, teats, and/or feet; and death in young animals. Affected animals may become completely incapacitated or be unable to eat/drink due to pain associated with the vesicles.
Functional feed: a feedstuff specifically used because of its nutrient composition to enhance dietary content and potentially influence the nutrient content in livestock productsGesamthahrstoff (g/kg): Same as TDN but with factor 2.3 for digestible crude fat.
Grax: suspended solid proteins.
Greaves: a high-protein solid which is left following the extraction of tallow from animal by-products during the rendering process with further processing this becomes MBM.
Gross Energy (GE) (Kcal/kg): laboratory analysis that measures the total combustible energy in a feed. It is determined by the amount of heat produced when a feed sample is completely burnt in a bomb calorimeter.
HACCP: hazard analysis critical control point
Hasher: a chopper of materials (a French word).
Heat damage: reduction in nutrient content of a feed because of chemical reactions induced by high temperatures. Maillard reaction refers to loss of amino acid availability as it complexes with carbohydrates.
Heat Increment (Kcal/kg): portion of ME required for the utilization of the remaining net energy for maintenance and production.
HTR: high temperature rendering
Independent rendering plant: obtains its byproduct material from a variety of sources and especially dead animals which are off-site or separate from the plant facility.
Inedible products: fats and proteins produced from dead animals for feeding the animals with certain specifications and for other non-edible uses.
Integrated or dependent rendering plant: Operates in conjunction with a meat slaughterhouse, or poultry processor whose byproduct materials are processed on-site.
International unit (IU): a standard unit of potency of a biological agent (e.g., vitamin, hormone, antibiotic, antitoxin); also called a USP unit in the U.S.
Irradiated: feed treated, prepared or altered by exposure to a specific level and duration of radiation.
Lard or edible grease: fat which is obtained from the pork tissue by the rendering process and its production is very similar to tallow.
LTR: low temperature rendering
Lysine: an essential amino acid for protein synthesis. It is the first limiting amino acid in corn-soybean-based swine diets. Can be added in a synthetic form to diets.
Macro minerals: minerals required in relatively large amounts by livestock. Includes calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), chlorine (CI), sulfur (S) and sodium (Na).
Marine oils: oil extracted from fish or algae, particularly rich in long-chain fatty acids that have health benefits.
MBM (meat and bone meal): meat and bone meal is prepared from the rendering of dead animals or wastes materials associated with slaughtering operations (carcass trimmings, condemned carcasses, condemned livers, inedible offal (lungs) and bones). It is basically dry rendered protein product from mammal tissues with more than 4.4 Percent phosphorus.
Metabolizable Energy (ME) (Kcal/kg): gross energy of food intake minus energy lost in feces, urine and combustible gases. The 'usable' energy of a feed.
Methionine: a sulfur-containing essential amino acid for protein synthesis
Micro-ingredient: a vitamin, mineral, antibiotic, drug or other compound normally required in small amounts and added to diets in milligrams or micrograms.
Micro mineral (trace mineral): minor mineral elements required fed in very small amounts in the ration of animals; includes manganese (Mn), copper (Cu), zinc (Zn), selenium (Se), iron (Fe), cobalt (Co), iodine (I) and fluorine (Fl).
Minerals: inorganic feed elements essential for life.
Near-infrared analysis (NIRA): a laboratory analysis of feeds that uses a specific wavelength of near infrared light to estimate nutrient content of feeds based on computerized calibrations of nutrient composition of feedstuffs; a lower-cost analysis compared with traditional wet chemistry. It is dependent on correct calibration to specific feeds for accurate analysis.
Net Energy (NE) (Kcal/kg): metabolizable energy minus heat increment (HI): NE includes the amount of energy used for maintenance and for production.
Net Energy for Maintenance (Kcal/kg): metabolizable energy minus heat increment (HI) and minus net energy for production (NEp). It is the fraction of NE expended to keep the animal in energy equilibrium.
Net Energy for Production (Kcal/kg): metabolizable energy minus heat increment (HI) minus net energy for maintenance (NEm). The fraction of NE is used for tissue gain and/or work.
Niacin: a water-soluble B vitamin involved in the metabolism of carbohydrates, lipids and proteins. It is essential in monogastric diets but not for ruminants and non-ruminant herbivores. Niacin has a beneficial role in controlling energy use and ketosis in dairy cattle, especially in early lactation.
Offal: all material from the animal’s body cavity processed in a rendering plant.
Omega-3 fatty acid: the family of fatty acids based on the presence of a double bond in the 3rd carbon from the methyl end of the molecule. Linolenic acid (18:n3n) is an essential omega-3 fatty acid because it cannot be synthesized by mammals.
Omega-6 fatty acid: the family of fatty acids based on the presence of a double bond in the 6th carbon from the methyl end of the molecule. Linoleic acid (18:2n6) is an essential omega-6 fatty acid because it cannot be synthesized by mammals.
Palatability: the appeal and acceptability of feedstuffs, including the taste, odour, texture and temperature of the feed.
Particle size: the diameter of granular feed materials (e.g., grains, pellets, mineral particles) and/or the length of roughage fragments. Particle size can affect mixing of feed ingredients and digestion rate.
Percolating pan: a tank with a perforated screen through which the liquid fat drains freely and separates from the tankage.
pH: a scalar measure of acidity or alkalinity. Values range from 0 (most acidic) to 14 (most alkaline or basic). A pH value of 7.0 is neutral (neither acidic nor alkaline).
Polyunsaturated fatty acid: typical structure of vegetable oils that have double bonds in the molecular structure. These oils are characterized by being liquid at room temperature.
Post-rendering process: screening the protein and fat materials, sequential centrifugations for separation of fat and water, drying and milling of protein materials.
Prebiotic: a non-digestible feed ingredient that beneficially affects the animal by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon.
Premix: a uniform mixture of one or more microingredients and a carrier, used to facilitate uniform dispersion of micronutrients into a larger mixture. A mineral premix contains higher fortification of trace minerals and vitamins than a mineral supplement.
Pre-rendering process: size reduction and conveying.
Probiotic: a live microbial feed supplement that beneficially affects the host animal. Claims include reduced early mortality, increased growth rate, improved feed conversion, egg quality and animal health (e.g., prevent disease and/or aid recovery from illness). Lactic acid producing strains (e.g., Lactobacillus and Streptococcus) are common components
Protein: naturally occurring compounds containing nitrogen, carbon, hydrogen and oxygen, and sometimes sulfur or phosphorus. Proteins are made up of complex combinations of amino acids and are essential for animal growth, production and reproduction.
Protein supplement: a feed or mixture of feeds containing 20% or more protein or protein equivalent (e.g., soybean meal, canola meal).
Ration: the 24-hour feed allowance for an individual animal.
Rendering process: a process of using high temperature and pressure to convert whole animal and poultry carcasses or their by-products with no or very low value to safe, nutritional, and economically valuable products. It is a combination of mixing, cooking, pressurizing, fat melting, water evaporation, microbial and enzyme inactivation.
Salmonella: human pathogen that causes gastro-intestinal problems.
Saturated fat: a completely hydrogenated fat, solid at room temperature (e.g., animal tallow).
SBO: specified bovine offal
Scratch: whole, cracked or coarsely cut grain.
Screenings: small, imperfect kernels, broken grains, hulls, weed seeds and other foreign material obtained from the cleaning of grain.
Screw press: machine used to separate fat from tankage continuously by applying the required pressure with a rotating screw.
Scrubber: pollution control device for containing air exhausted from rendering plant with a water solution containing deodorizing chemicals for odor removal.
Sewage: refuse liquids or waste matter carried off by sewers.
Shredded: similar to chopped, except feedstuffs are cut longitudinally rather than cross-wise.
Steamflaked: processing technique for cereals that subjects the grain to steam under atmospheric conditions for usually 15-30 min, before rolling. Heavy roller mills make the grain completely flat and rupture the cells, making the nutrients available more freely to the animal. Increases feed efficiency and rate of gain compared with feeding dry rolled cereals.
Sterilization: sterilization is based on a statistical probability that the number of viable microorganisms will remain below a specified level after heating process (particularly temperature, time and pressure) and is dependent upon the overall heat transfer coefficient (conductive and convective) of cooking materials, which can determine the lethal effect of the heat.
Stick liquor or stick water: the viscous liquid left in the rendering tank after cooking process.
Structural carbohydrates: complex carbohydrates including cellulose, hemicellulose, lignin and pectin that form the plant cell wall; measured in the laboratory as neutral detergent fibre (NDF). Also known as fibre.
Supplement: feed or feed mixtures used to improve the nutritional value of basal feeds. A supplement is rich in one or more of protein, energy, vitamins, minerals or antibiotics, and is combined with other feeds to produce a more complete feed. Often used interchangeably with concentrate.
Sweet feed: a commercial feed sweetened with molasses to improve palatability.
Tallow: the white nearly tasteless solid rendered fat of cattle and sheep which is used chiefly in soap, candles, and lubricants.
Tankage: cooked material remaining after the liquid fat is drained and separated.
Textured: ration containing fine materials in a pelleted form, mixed with coarser ingredients.
Total Digestible Nutrients (%): the energy value of feedstuffs, comparable to digestible energy in accuracy. Digestible protein, percent + dig. fiber percent + dig.nitrogen-free-extract percent plus 2.25 times the content of digestible crude fat.
Total mixed ration (TMR): homogenous mixture of mechanically mixed ration ingredients, including roughages.
Toxicity: the extent to which a substance is poisonous to animals.
Trace minerals (micro mineral): minor mineral elements required fed in very small amounts in the ration of animals; includes manganese (Mn), copper (Cu), zinc (Zn), selenium (Se), iron (Fe), cobalt (Co), iodine (I) and fluorine (Fl).
Tricanter: a vessel used to separate three phases of small solid protein particle, water and fat solutions.
TSE: transmissible spongiform encephalopathy
Unavailable protein: reduction in protein content of feedstuff that is available to the animal because of chemical reactions that occur at high temperatures.
Unsaturated fat: any fat that is not completely hydrogenated. Unsaturated fats are liquid at room temperature (e.g., corn oil, vegetable oil).
USDA: U.S. Department of Agriculture
USEPA: U.S. Environmental Protection Agency
Vitamin: organic compounds that typically function as parts of enzyme systems essential for many metabolic functions.
Wafers: fibrous materials compressed into a form having a cross-section measurement greater than its length. Exact dimensions and bulk density of wafered feeds will vary according to the processing equipment used.
Water-soluble vitamins: sub-class of vitamins that includes B complex vitamins and vitamin C.
Wet chemistry: laboratory methods used to determine nutrient content of feeds directly by chemical means.
Wet rendering: a method of batch rendering in which the raw material is subjected to a temperature of 140°C under high pressure generated either by injecting steam into the cooker, or by allowing the steam from moisture in the raw material to build up.
Yeast: single-cell fungi that improves feed digestion by stimulating microbial activity and stabilizing digestive tract pH. Products packaged as "yeast" consist of cells only; "yeast culture" includes live yeast cells plus growth media.
Yellow grease A or B; no 1, no 3 tallow: these result from the poorer pork and beef sources of raw material. Free fatty acid range up to 35%, and color can be as high as 37 FAC. (FAC is the abbreviation of the Fat Analysis Committee of the AOCS.) Often referred to as feed fats, they come from spent frying oils and animal fats. They may be animal or vegetable. A sample of fat is filtered then compared with standard color slides mounted on a circular aperture. FAC color standard runs from 1-45 using odd numbers divided into five series for grading: 1-9 = Light colored fats 11, 11A, 11B, 11C =Very yellow fats, 13-19 = Dark, reddish fats. 21-29= Greenish fats 31-45= Very dark fats. The different series are somewhat independent so there is no orderly increase in the color from the lowest to the highest numbers, i.e., fats graded 21-29 may actually be lighter than those graded 13-19. The FAC method is used when fats are too dark or green to be read by the lovibond method.
Z value: The temperature increase required to reduce the thermal death time by a factor of 10 (or a one-log cycle).