Animal Nutrition: Proteins, Fats, Vitamins, and Energy in Feedstuffs

Proteins

Compounds made up of long chains of amino acids that serve as components of muscle, enzymes, hormones.

Amino Acid

The building block of a protein, containing an amino (NH2) group and a carboxyl (COOH) group attached to a carbon skeleton.

Essential Amino Acids

Amino acids that cannot be synthesized by the animal and must be supplied in the diet.

Non-Essential Amino Acids

Amino acids that can be synthesized by the animal's body and do not need to be supplied in the diet.

Ruminants

Animals with a digestive tract that has four compartments, allowing microbial organisms to synthesize amino acids.

Microbial Protein

Protein produced by microorganisms in the digestive tract of ruminants that can meet part of the animal's protein needs.

First Limiting Amino Acid

The amino acid present in the least amount relative to an animal's requirement, which limits protein synthesis.

Hemoglobin

A protein that contains the mineral iron and transports oxygen in the blood.

Sulfur-Containing Amino Acids

Amino acids that include sulfur in their structure and can serve as a source of sulfur for the animal.

Protein Quality

A measure of the amino acid composition and digestibility of a protein source, determining its usefulness in the diet.

Fats (Lipids)

Organic compounds that are insoluble in water and provide concentrated energy and essential fatty acids.

Fatty Acid

A chain of carbon atoms ranging from 2 to 24 carbons, linked to a glycerol molecule to form fats.

Glycerol Backbone

The molecule to which fatty acids are attached to form fats.

Saturated Fatty Acid

A fatty acid in which all carbon bonds are taken up by hydrogen, containing no double bonds.

Unsaturated Fatty Acid

A fatty acid that has one or more double bonds because not all carbon bonds are filled with hydrogen.

Gross Energy

The total amount of energy in a feed, measured by completely burning it in a bomb calorimeter.

Digestible Energy

Gross energy minus the energy lost in feces; represents energy actually digested.

Metabolizable Energy

Digestible energy minus the energy lost in urine and intestinal gases; a more accurate measure of usable energy.

Net Energy

The most accurate energy measure; metabolizable energy minus heat lost during metabolic processes, representing energy available for maintenance and production.

Bomb Calorimeter

A device used to measure the gross energy of a feed by combustion.

Metabolism Trial

An advanced experiment to measure total nutrient and energy intake vs. all losses (feces, urine, gas, heat).

Ration Formulation

The process of matching an animal's nutrient and energy requirements with the nutrient composition of feedstuffs.

Animal-Animal Bond

A mutual interaction, affection, or communication between animals.

Neoteny

A feature of behavior often interpreted through human interaction.

Dry Matter

The portion of feed remaining after all moisture is removed.

Ash

The total mineral content of a feed ingredient, determined by burning off all organic matter.

Crude Protein

An estimate of total protein in feed, calculated by measuring nitrogen content and multiplying by 6.25.

Kjeldahl Procedure

A chemical method used to determine nitrogen in feed, which is then used to estimate crude protein.

Ether Extract

A chemical procedure that extracts fat from feed using diethyl ether, isolating the lipid content.

Crude Fiber

The portion of carbohydrates in feed made up of cellulose, hemicellulose, and lignin, simulating digestion in the stomach and small intestine.

Nitrogen-Free Extract

A calculated carbohydrate fraction representing readily available sugars and starches, derived by subtracting other measured components from 100%.

Feeding Trials

Experiments that determine if animals will eat a feedstuff and how they perform on it, without explaining why the results occur.

Lactation Trial

A feeding trial designed to evaluate feed effects on milk production.

Digestion Trials

Experiments to determine how much of a feedstuff is digested and absorbed by the animal by analyzing nutrient content in feed vs. feces.

Digestion Coefficient

The percentage of nutrients from feed that disappear in the digestive tract, inferred as being digested and absorbed.

Percent Digestibility

Another term for digestion coefficient, representing the proportion of nutrients digested.

Metabolism Trials

Advanced digestion trials that measure total nutrient intake and all nutrient losses, including urine, feces, and other excretions.

Calorie

A basic unit of energy used in nutrition.

Kilocalorie (kcal)

1,000 calories, commonly used in human nutrition.

Megacalorie (Mcal)

1,000 kilocalories, commonly used in livestock nutrition due to large energy needs.

Fats (Solids)

Fat sources that are solid at room temperature, usually containing saturated or longer chain fatty acids.

Oils

Fat sources that are liquid at room temperature, typically containing shorter chain or unsaturated fatty acids.

Fat-Soluble Vitamins

Vitamins A, D, E, and K, which require fat for absorption and transport because they are insoluble in water.

Palatability

The acceptability or flavor of feed; fats improve the palatability of animal feed.

Fat Pads

Deposits of fat that cushion and protect vital organs such as the kidneys, heart, and pelvis.

Vitamins

Organic compounds required in very small amounts that help enzymes perform their functions, supporting many chemical reactions in the body.

Catalytic Function

The role of vitamins in helping enzymes carry out metabolic reactions.

Water-Soluble Vitamins

Vitamins C and B-complex; absorbed directly into the bloodstream, not stored in the body, and excreted in urine when consumed in excess.

Lipoproteins

Compounds made of proteins with lipids attached that transport fat-soluble vitamins through the bloodstream.

Minerals

Inorganic, crystalline elements in the diet that cannot be synthesized or decomposed by chemical reactions.

Proximate Analysis

A laboratory process used to determine nutrient levels in feed by burning it to measure mineral (ash) content.

Macro Minerals

Minerals required in large amounts, such as calcium and phosphorus.

Micro Minerals

Minerals required in very small amounts, such as selenium and copper.

Osmotic Pressure Regulation

A function of minerals that helps maintain fluid balance and proper cell function in the body.

Nutrition

The study of how the body uses nutrients from feeds to sustain life, growth, reproduction, and productive functions.

Balanced Ration

A diet that contains all required nutrients for an animal in the correct proportions.

Feedstuffs

The nutritionist's term for feed ingredients used to formulate animal diets.

Maintenance

Nutritional needs required to sustain life processes without supporting productive functions such as growth or lactation.

Work

Any productive function of an animal, including growth, lactation, reproduction, or physical labor.

Lactation

The production of milk, one of the most nutritionally demanding processes.

Gestation

The period of pregnancy where nutrients are required to support fetal development.

Published Data

Reference information on nutrient requirements of animals and nutrient composition of feedstuffs, often from the National Research Council.

Feed Label

Information on a feed bag that lists species, nutrient composition (guaranteed analysis), and feed ingredients.

Energy

Not a nutrient itself but a required function provided by the breakdown of carbohydrates, fats, and proteins.

Carbohydrates

Organic compounds composed of carbon, hydrogen, and oxygen that serve as the primary energy source for animals.

Monosaccharide

The simplest form of carbohydrate, containing five or six carbon atoms; also called a simple sugar.

Pentose

A monosaccharide with five carbons.

Hexose

A monosaccharide with six carbons.

Glucose

The primary building block of plant material and the most common monosaccharide in animal diets.

Glycogen

The stored form of carbohydrates in animals for future energy use.

Disaccharide

A carbohydrate composed of two monosaccharides linked together; examples include sucrose and lactose.

Polysaccharide

A carbohydrate composed of many monosaccharide units linked together; examples include starch and cellulose.

Starch

A digestible polysaccharide found in grains, seeds, tubers, and roots.

Cellulose

A polysaccharide found in stems, stalks, and leaves of plants; indigestible by animals without microbial help.