Animal Nutrition and Growth Concepts

Compensatory Growth

• When animals are underfed and then given a nutritionally adequate diet, they show faster growth compared to animals that were continuously fed.
• This phenomenon is found in both ruminant and non-ruminant animals.

Definitions

• Complete feed - Mixed blend of food ingredients containing all the required nutrients for an animal. It's designed to prevent animals from selecting individual ingredients.

Chitin

• A linear polysaccharide made of repeating units of N-acetyl-D-glucosamine.
• Found in the exoskeletons of crustaceans, insects, and spiders.
• Also found in some fungi, algae, and yeasts.

Collagen

• A fibrous protein found in connective tissues like skin, tendons and bones
• Makes up a significant portion of white fibers in connective tissues.
• Constitutes about 25% of body protein in mammals.
• Boiling collagen in water converts it to gelatin.

Contamination

• The presence of unwanted substances in food that were not intentionally added.

Cholesterol

• A neutral lipid with the formula C27H45OH
• The primary sterol found in higher animals.

Colostral Immunity

• Passive immunity provided to young animals through colostrum.
• Offers protection against various pathogens.
• This immunity can be systemic, absorbed in the first 24–48 hours of life, or localized within the gut later.

Colostrum

• The milk produced before and around the time of birth.
• May differ in consistency and color from milk produced later.

Concentrate

• A general term for any non-forage dietary ingredient, typically for herbivores.
• Includes compound feeds, protein concentrates, and single raw materials.

Coprophagy

• The consumption of feces, often the animal's own feces.
• Provides nutritional benefits like B-complex vitamins and bacterial protein synthesized in the hindgut.

Crude Fiber

• A collective term for complex carbohydrates, mainly cellulose and lignin, that are insoluble in water, dilute acid, and dilute alkali.

Creep Feeding

• Providing supplementary food to nursing animals, mainly used for piglets.
• Can involve giving a single food or a combination of feeds.

Diarrhea

• Major cause is irritation of the intestinal mucosa by infectious or chemical agents.
• Leads to increased intestinal secretions, luminal distension, and increased gut motility.

Digestion

• The breakdown of food components to make them available for absorption.
• Involves mechanical and chemical processes.

Digestible Energy

• The portion of gross energy in food not expelled as fecal energy.

Endogenous Protein

• Non-dietary nitrogen compounds found in the digestive tract.
• Includes enzymes, glycoproteins, mucus, and desquamated intestinal cells.

Energy

• The capacity to do work.
• Exists in various forms, including chemical, mechanical, and heat energy.
• The sun is the primary source of energy on Earth.

Energy Requirements

• In a thermoneutral environment, the animal's total energy requirement is the sum of energy retained in animal products and the associated energy cost of ingestion, digestion, and metabolism.

Enzyme

• A protein (or sometimes more than one protein) that speeds up a specific chemical reaction.
• Requires specific conditions, such as temperature, pH, and substrate concentration.
• Not consumed during reactions.
• Their activity can be reduced by enzyme inhibitors.

Feed

• A source of nutrients for animals and an ingredient of diets.
• Includes pasture, forage crops, grains, seeds, crop residues, and by-products.

Forage

• Vegetable food for grazing or browsing animals.
• Includes both indigenous plants (grasses, forbs, shrubs, trees, lichens, mosses) and cultivated fodder crops.

Gastrointestinal Microflora

• The populations of microorganisms inhabiting the digestive tract of farm animals.
• Host animals and their gut microbes form a mutually beneficial ecological unit.
• Microbial density and diversity vary along the gut, with higher concentrations in the stomach and large intestine.

Glucose

• A central metabolite in animal metabolism.
• A primary fuel source and is stored as glycogen in the liver and muscle.
• The main energy substrate used by the brain.

Glycogenolysis

• The breakdown of glycogen in the liver, kidney, or muscle to glucose-1-phosphate.
• Glucose-1-phosphate is then converted to glucose-6-phosphate, which is a source of metabolic energy.

Glycolysis

• The process of breaking down glucose-6-phosphate to pyruvate in the cytoplasm of cells.

Growth

• The process of an animal developing from a single fertilized cell into an adult.

Haylage

• High dry matter (DM) silage.
• Usually has a DM content of 50% or greater.
• Commonly made in big bales for feeding horses and sometimes sheep.

Hemicelluloses

• Mixtures of various polysaccharides, including xylans, glucomannoglycans, arabinogalactans, arabinans, and arabinoxylans.
• Primarily found in plant secondary cell walls.
• Often associated with lignin.
• Found in grasses, annuals, hardwoods, cereal grains, fruits, and vegetables.

Heat Stress

• When environmental conditions make it difficult for animals to lose heat.
• Body temperature tends to rise.
• Can be caused by high temperatures alone or in combination with high humidity.

Immunity

• The ability of an animal to resist disease, typically resistance to infection.

Joule

• The SI unit of energy.

Ketosis

• A metabolic disease caused by high levels of toxic ketone bodies in the blood.
• Common in dairy cattle, especially those with fatty liver syndrome, during early lactation.
• Occurs when energy demands of milk production exceed energy intake.

Kjeldahl Method

• A procedure used to measure total nitrogen in biological materials.

Legume

• Any plant from the family Leguminosae.
• Includes alfalfa, clover, peas, and beans.

Lehmann System

• A feeding system where animals are given bulky feed freely and a restricted amount of concentrate feed once or twice a day.

Lignin

• An insoluble polyphenolic compound found in plant cell walls.
• Provides rigidity and hydrophobicity to the cell wall.

Mastication

• The act of chewing food to prepare for swallowing.

Macronutrients

• Nutrients required in the largest amounts.
• The six major macronutrients are carbohydrates, lipids, proteins, water, vitamins, and minerals.
• Carbohydrates, lipids, and proteins comprise the majority of food.

Metabolic Rate

• The sum of all oxidative processes in the body.
• Equivalent to the rate of heat production.
• Can be measured directly as heat or indirectly from oxygen consumption and carbon dioxide production.

Microbial protein

• Protein from microbial cells, including bacteria, protozoa, fungi, and yeasts.
• The principal source of amino acids for ruminants.

Micronutrients

• Nutrients required in small dietary amounts.
• Include vitamins and minerals.

Molasses

• A thick, treacly liquid, a byproduct of sugar production from sugarcane and sugarbeet.

Nutrient Requirement

• The amount of a nutrient needed for a specific purpose, such as maximum weight gain or milk yield.

Mycotoxins

• Toxic metabolites produced by fungi.
• Of concern are mycotoxins produced by fungi that grow on grain crops in the field or during storage.

Palatability

• The degree to which an animal finds the taste of a food pleasant.

Pelleting Feed

• A blend of raw materials that have been ground, conditioned, and pressed into uniform pellets.
• The pellets vary in diameter and length depending on intended use.

Peristalsis

• Propulsive movements of the gut that propel food along.
• Involves a ring of constriction that moves along the gut wall, reducing the lumen diameter and pushing food forward.

Probiotics

• Feed supplements added to animal diets to improve intestinal microbial balance.

Rancidity

• Undesirable flavors (often described as bitter or metallic) in lipid-containing foods.

Prebiotic

• A non-digestible food ingredient that selectively stimulates the growth of beneficial bacteria in the digestive tract.
• Examples include oligosaccharides, resistant starch, and certain non-starch polysaccharides.

Roughage

• Coarse, fibrous plant material that is relatively indigestible.
• Most valuable to ruminants due to their ability to digest cellulose.
• Includes cereal crop residues.

Taint

• Abnormal, often unpleasant, odor or taste in food.

Tricarboxylic Acid (TCA) Cycle

• Also known as the Krebs cycle or citric acid cycle.
• A series of reactions where the carbon in citric acid is converted to CO2.

This quiz covers essential concepts in animal nutrition, including compensatory growth, the importance of complete feed, and the roles of chitin and collagen in animal physiology. Test your knowledge on how nutrition impacts growth and the biological significance of these compounds.