Common Terms Used in Animal Feeding and Nutrition Uttam Saha, Program Coordinator, Feed and Environmental Water Laboratory Leticia Sonon, Program Coordinator, Soil, Plant, and Water Laboratory Dennis Hancock, Assistant Professor, Extension Forage Specialist Nicholas Hill, Professor, Crop and Soil Sciences Lawton Stewart, Assistant Professor, Extension Beef Specialist Gary Heusner, Professor, Extension Equine Specialist David E. Kissel, Professor and Director, Agricultural and Environmental Services Laboratories The largest operating cost in a livestock production enterprise is the feed bill. To keep this cost low, one must sup- ply the right amount of feed to the animals. Overfeeding is wasteful. Underfeeding will decrease animal perfor- mance and profitability. Therefore, proper animal feeding and nutrition are crucial to the profitability of the live- stock enterprise. Laboratory analyses of the composition of feed or forage are used to assess their nutritive value (Figure 1). A typi- cal feed analysis includes measurements of some important quality attributes or parameters (e.g., crude protein, fiber, digestibility, etc.) used to define nutritive value. Other parameters are analyzed under some special circum- stances. For example, acid detergent insoluble crude protein (ADICP) is usually only measured if heat damage to the feed is suspected. Feed or Forage Sample Dry Water Removed Organic Matter (Burned) Burn Moisture Free Feed/Dry Matter (Remains) Ash (Remains): Neutral Detergent Extraction Various Minerals and Sand Neutral Detergent Solubles (NDS) Insoluble: Neutral Detergent Fiber (NDF) Acid NDSC: Detergent A. NDSF: Fructans, Glucans, Pectic Substances Extraction B. Sugars, Starches, Organic Acids Soluble: Hemicellulose Insoluble: NPN: Crude Protein Acid Detergent -Urea RUP/DIP Fiber (ADF) -Amino Acids -Cellulose -Amines -Lignin Degradable -Fiber-bound N True Proteins -Heat-damaged N Undegradable Ether Extracts: Esterified Fatty Acids Pigments and Waxes Abbreviations: DIP = Degradable Intake Protein; NDSC = Neutral Detergent Soluble Carbohydrate; NDSF = Neutral Detergent Soluble Fiber; NPN = Non Protein Nitrogen; RUP = Rumen Undegradable Protein. Figure 1. A schematic that describes the partitioning of organic and mineral components in a feed and forage sample. University of Georgia Cooperative Extension Bulletin 1367 3 Common Terms Used in Animal Feeding and Nutrition Many of the parameters included in laboratory reports tion of the protein reacts with carbohydrates (fiber) to are calculated or estimated from measured feed quality form an indigestible complex, rendering it unavailable attributes. For example, digestible energy, total digest- for digestion. This parameter is also reported as acid ible nutrients and intake potential are all estimated detergent insoluble protein (ADIP), acid detergent in- from the concentration of the various fiber components soluble nitrogen (ADIN) or acid detergent fiber protein and the relationship between them. The University of (ADFP). It is expressed as a percent of crude protein. Georgia’s Feed and Environmental Water Laboratory It is an adequate estimate of heat-damaged protein in (FEWL) is located in Athens and dedicated to provid- forage feeds but not in non-forage feeds (Nakamura et ing objective analyses of feeds and forages. This is in al., 1994). line with UGA’s mission as a land-grant university to provide unbiased interpretations, recommendations and Aflatoxins pertinent educational materials to enhance the profit- Fungal or mold growth in or on foods and feed can ability and sustainability of livestock production sys- result in the production of many different types of toxic tems in the state. biochemicals. As a group, these toxic substances are commonly called mycotoxins. The term aflatoxins refers The purpose of this publication is to serve as an educa- to a particular group of mycotoxins produced by some tional reference and resource to those who are interest- species of the genus Aspergillus. There are four major ed in animal feeding and nutrition. Our primary objec- aflatoxins named B1, B2, G1, G2 plus two additional tive is to list the common terms used when discussing metabolic products known as M1 and M2 that are of animal feeding so that one might be better informed significance as direct contaminants of foods and feeds. when consulting with county Extension personnel, feed salesmen, animal nutritionists, veterinarians, feed Fungal (or mold) growth and aflatoxin contamination laboratory managers and other industry professionals. are the consequence of interactions among the fungi, This listing will also be helpful when reading articles the host (foods or feeds) and the environment. On on animal feeding and nutrition, feed analysis reports or a standing crop, aflatoxin contamination of peanuts tags associated with feeds sold in the market. and corn is favored by high temperatures, prolonged drought conditions and high insect activity, while post- Acid Detergent Fiber (ADF) harvest production of aflatoxins on corn and peanuts The fibrous component represents the least digestible is favored by higher water content, warm temperatures fiber portion of forage or other roughage. This highly and high humidity. Forages are generally not analyzed indigestible part of forage includes lignin, cellulose, for aflatoxins but in some situations (e.g., corn or sor- silica and insoluble forms of nitrogen but not hemicel- ghum silage that is at risk) this analysis may be war- lulose. Forages with higher ADF are lower in digestible ranted. energy than forages with lower ADF, which means that as the ADF level increases, digestible energy levels de- The presence of aflatoxins in feeds, forages and foods is crease. During laboratory analysis, ADF is the residue an important anti-quality factor and is associated with remaining after boiling a forage sample in acid deter- various diseases in livestock, domestic animals and hu- gent solution. ADF is often used to calculate digestibil- mans that are broadly termed aflatoxicosis. Aflatoxico- ity, total digestible nutrients (TDN) and/or net energy sis is primarily a hepatic (liver) disease. Liver damage, for lactation (NEl). decreased reproductive performance, reduced milk or egg production, embryonic death, teratogenicity (birth Acid Detergent Insoluble Crude Protein defects), tumors and suppressed immune system func- (ADICP) or Acid Detergent Fiber-Crude Protein tion are caused by aflatoxins even when low levels are (ADFCP) consumed. ADICP (or ADFCP) is the insoluble protein fraction remaining in the acid detergent fiber residue of a feed The FDA’s (Food and Drug Administration) action sample. ADICP escapes ruminal breakdown and rep- level for human food is 20 ppb total aflatoxins, with the resents the portion of the protein that is not degrad- exception of milk, which has an action level of 0.5 ppb able and is therefore unavailable to the animal. It also for aflatoxin M1. The FDA action level for most feeds contains any heat-damaged protein that may result from is also 20 ppb (Table 1). heating during storage or processing. In this case, a por- Common Terms Used in Animal Feeding and Nutrition 4 University of Georgia Cooperative Extension Bulletin 1367 Table 1. FDA action levels for aflatoxins§ Ash Action level The residue containing inorganic mineral elements of Commodity (µg/kg or ppb) a feed sample, determined in a laboratory by burning All products, except milk, designated for 20 the sample at a high temperature (removing the organic humans matter) and weighing the residue (i.e., ash). Milk 0.5 Corn for immature animals and dairy 20 As-fed Basis cattle Feed analyses reports often state results based on the Corn for breeding beef cattle, swine and 100 feed’s natural state (i.e., including water) and/or on mature poultry a dry matter basis. The term “As-fed Basis” is used Corn for finishing swine 200 to alert the reader that the analytical results of a feed Corn for beef cattle 300 sample are based on its natural state including water. Cottonseed meal (as a feed ingredient) 300 That means it is affected by the sample’s moisture level All feedstuff other than corn 20 before drying. This may also be referred to by the terms §According to compliance policy guides 7120.26, 7106.10 “As-is Basis” or “As-received Basis.” When comparing and 7126.33. two or more analyses, it is generally best to utilize the data from the “Dry Matter Basis” rather than the “As- If the level of aflatoxins in forage is higher than the ac- fed Basis” unless you are mixing a ration for feeding. tion level, it may be fed in combination with other feeds containing low levels of or no aflatoxins. Balanced Ration Complete feed formulated to provide a specific ani- Amino Acids mal species and class with appropriate amounts of all A class of nitrogen-containing molecules containing an nutrients required for maintenance and a given level of amine group, a carboxylic acid group and a side chain performance. that varies between different amino acids. Amino acids are the building blocks from which protein is made in Botulism the body. There are 20 known standard amino acids Botulism is a muscle-paralyzing disease caused by forming various proteins. When taken up into the body botulinum toxin, a potent neurotoxin produced mainly in the diet, the 20 standard amino acids are either used by the bacterium Clostridium botulinum and also by a to synthesize proteins and other biomolecules or broken few strains of C. baratii and C. butyricum. Clostridium down into urea and carbon dioxide. Of the 20 standard botulinum is an anaerobic (can only grow under anaero- amino acids, eight are called essential amino acids and bic conditions) bacterium that usually grows when the the other 12 are called non-essential amino acids. Ani- pH of the growing medium is greater than 4.6. mals (including humans) cannot synthesize the essential amino acids from other compounds at the level needed Botulism can result from the ingestion of the toxin or for normal growth, so they must be obtained from food the growth of C. botulinum on anaerobic food/feed (hence they are called essential amino acids).