Comprehensive Overview of Animal Nutrition and Digestion

NUTRITION

The act or process of nourishing or being nourished; specifically, the sum of the processes by which an animal takes in and utilizes food substances.

FEED

Food for farm animals, such as livestock and poultry.

FORAGE

Fresh or preserved plant material that animals graze on, like fresh grass or silage (fermented plants).

ROUGHAGE

Includes older, coarser plants like hay or straw; it's higher in fiber but lower in nutrients, helping animals' digestion by adding bulk to their diet.

DRY FORAGES AND ROUGHAGES

Fibrous plant materials like dried pasture, leaves, stems, and hay, typically having more than 18% crude fiber, which is essential for digestion, particularly in ruminants.

GREEN PASTURES AND FORAGES

Includes fresh plant materials like green pastures, range plants, and other fresh forages, often high in moisture, providing hydration and a natural source of vitamins, minerals, and fiber.

SILAGES

Fermented feeds commonly made from corn, alfalfa, or grass; the fermentation process preserves the forage and enhances its digestibility and nutrient availability.

ENERGY FEEDS

Rich in carbohydrates, such as corn, wheat, barley, and rice, primarily used to provide animals with the energy necessary for daily activities, growth, and production.

PROTEIN FEEDS

Protein-rich ingredients, such as soybean meal, fish meal, meat and bone meal, and milk replacers, used to support growth, muscle development, lactation, and reproduction.

CONCENTRATES

Feeds that are rich in energy and/or protein but low in fiber, such as corn, soybean meal, oats, wheat, molasses, etc.

SUPPLEMENTS

Added to enhance protein quality, especially in feeds lacking specific amino acids.

MINERAL AND VITAMIN SUPPLEMENTS

Fulfill specific nutritional requirements not adequately met by other feeds.

FEED ADDITIVE

An ingredient or combination of ingredients added to the basic mixed feed to fulfill a specific need.

PASTURE

Land where grasses and other plants grow for animals to graze.

FODDER CROPS

Cultivated plant species grown specifically to be used as livestock feed, typically harvested and prepared for stall-fed animals.

DIET

Balanced mix of feedstuffs formulated to provide essential nutrients.

FEEDSTUFF

Any material that can be used as part of an animal's diet to provide nutrients.

FEED INGREDIENT

Specific component within that feed; the building blocks of a feed ration.

NUTRIENT

Substance in the diet that is physiologically useful in cellular, animal and plant metabolism.

FUNCTIONS OF NUTRIENTS

Building and supporting the animal's body structure; promoting health and overall well-being; managing essential functions like growth, cell activity, enzyme production, and temperature regulation; providing energy for immediate use or storing it for later needs.

ESSENTIAL NUTRIENTS

Nutrients that are necessary in the diet as the body cannot produce them in sufficient quantities to meet metabolic requirements.

NON-ESSENTIAL NUTRIENTS

Nutrients that are not required in the diet since the body produces them internally.

NUTRIENT REQUIREMENTS

The least required quantities of nutrients (energy, protein, fat, minerals, and vitamins) needed to fulfill an animal's actual requirement.

NUTRITIVE VALUE

The amount of nutrients contained in a feed that can be utilized by the animal.

RATION

The total daily amount of feed given to an animal.

BALANCED RATION

Ration that provides all the nutrients needed by the animal in the right amount and proportion.

MEALS

Portions of the ration served at specific times (e.g., morning and evening).

CRUDE PROTEIN

Represents the total nitrogen in the diet, including true protein and non-protein nitrogen like urea and ammonia.

PALATABILITY

Refers to how much an animal prefers and is willing to eat a specific feed, which can affect its nutrition and health.

ENSILED

Refers to plant materials preserved through anaerobic fermentation and stored in a silo, bag, bunker, or wrapped bale.

IMPORTANCE OF ANIMAL NUTRITION

Nutrition drives the profitability of production animal enterprises; more than 60% of the variable costs of production in intensive animal production enterprises are feed-related.

COMPOSITION OF ANIMALS

Animals, like their feed, are made up of water, proteins, lipids, carbohydrates, vitamins, and minerals.

Water

Major item in most animal's diet.

Water content of newborn animal

750-800g water per kg body weight.

Water content of mature fat animal

500g water per kg body weight.

Functions of Water

Acts as solvent for nutrient transport and waste excretion.

Sources of Water

Drinking water.

Water Requirement for Beef cattle

22-66 liters/day.

Water Requirement for Dairy cattle

38-110 liters/day.

Water Requirement for Sheep and goats

4-15 liters/day.

Water Requirement for Horses

30-45 liters/day.

Water Requirement for Swine

11-19 liters/day.

Water Requirement for Chickens

0.2-0.4 liters/day.

Water Requirement for Turkeys

0.4-0.6 liters/day.

Factors Affecting Water Intake

High level of protein intake and fats may increase water intake.

Carbohydrates

Neutral chemical compounds containing carbon, hydrogen, and oxygen.

Functions of CHO

Metabolize as source of energy.

Monosaccharides

Simple sugars.

Disaccharides

Made of two monosaccharide units.

Oligosaccharides

Contain 3-10 monosaccharide units.

Polysaccharides

Contain more than 10 monosaccharide units.

Glucose

A key building block in oligosaccharides, polysaccharides, and glucosides.

D-Fructose

A component of sucrose (a disaccharide) and fructans (polysaccharides).

D-Mannose

A key component of glycoproteins.

D-Galactose

Present as a constituent of the disaccharide lactose - milk.

Sucrose

The most abundant disaccharide in plants and the primary form of carbon transport.

Lactose

Produced by the mammary gland.

Maltose

Formed during the hydrolysis of starch and glycogen.

Cellobiose

The fundamental repeating unit of cellulose.

Raffinose

Present in small amounts in sugar beet and accumulates in molasses.

Starch

Acts as a reserve carbohydrate in plants.

Glycogen

The main carbohydrate storage product, playing a crucial role in energy metabolism.

Dextrins

Contribute to the characteristic flavor of bread crust, toast, and partly charred cereal foods.

Cellulose

The fundamental structure of plant cell walls.

Chitin

A major structural component of the exoskeletons of invertebrates.

Hemicellulose

Not digestible by mammals but can be fermented by microbial activity.

Hyaluronic Acid

Essential for joint lubrication, providing cushioning and reducing friction in the synovial fluid.

Chondroitin

Major structural components of cartilage, tendons, and bones, contributing to their strength and elasticity.

Lipid

Insoluble in water but soluble in common organic solvents.

a-linolenic acid

Most abundant fatty acid.

Palmitic acid

Most common saturated acid.

Oleic acid

Most common monosaturated acid.

Lipids

Major energy storage - fats.

Adipose tissue

Fats in obese animals may be contained at ~97%.

Energy yield after oxidation

Fat: 39 MJ/kg DM vs glycogen: 17 MJ/kg DM.

Water content

Fats are anhydrous, glycogen is highly hydrated.

Stored energy source

Fats are six times as effective as glycogen.

Functions of lipids

Improve physical appearance, dietary energy supply, insulation, and vitamin absorption.

Marbling

Interspersion of fat particles in lean meat.

Brown fat

Burning fat releases heat instead of energy.

Glycerides or acylglycerols

Fatty acid esters of glycerol, referred to as neutral fats.

Triacylglycerol or triglyceride

Formed when fatty acids combine with all three alcohol groups.

Simple Triacylglycerols

Contain three identical fatty acid components.

Mixed triacylglycerols

Involve more than one type of fatty acid.

Saturated fatty acids

Have only single carbon-carbon bonds.

Unsaturated fatty acids

Contain carbon-carbon double bonds.

Polyunsaturated fatty acids (PUFA)

Fatty acids with more than one double bond.

Butyric Acid and Caproid Acid

Found in significant amounts in milk fats of ruminants.

Caproic Acid and Caprylic Acid

Present in few oils like palm kernel and coconut.

Essential fatty acids (EFAs)

Linoleic and a-Linolenic Acid contribute to membrane structure and lipid transport.

Hydrolysis

Achieved by boiling fats with alkalis, yielding glycerol and soaps.

Lipolysis

Process of fat breakdown under the influence of enzymes - lipases.

Antioxidants

Vitamin E is a vital naturally occurring antioxidant.

Glycolipids

Compounds consisting of a carbohydrate bound to a lipid by glycosidic linkage.

Galactolipids

Lipids of grasses and clovers that form the major part of dietary fat of ruminants.

Phospholipid

Constituents of the lipoprotein complexes of biological membranes.

Sphingomyelins

Important components of membranes in nervous tissue.

Waxes

Simple non-polar lipids that are water-insoluble and solid at ordinary temperature.

Steroids

Biologically important compounds such as sterols, bile acids, adrenal hormones, and sex hormones.

Phytosterols

Plant