Unit 5: Animal Nutrition

Unit 5: Animal Nutrition
Chapters 15-17

Unit 5 Objectives: Basic understand of nutrients, digestibility, evaluation, and composition of feeds Knowledge of digestibility in both the monogastric and ruminant animal Appreciation for nutrient function and requirements for growth, maintenance, reproduction, and lactation Understanding of ration formulation

Nutrients Any feed that functions to support life Concentrates and roughages What are they? What are the differences nutritionally? Six basic classes Water Carbohydrates Fats Proteins Minerals Vitamins

Water Difference between water & moisture Dry matter Most important nutrient! Functions Metabolic reactions Transport nutrients Temperature maintenance Physical shape of the body (cell contents)

Carbohydrates Found in plant & animal tissue Simple carbohydrates Starch Easily digested High in energy Complex carbohydrates Cellulose, lignin Energy source Present in cell walls

Fats Includes oils A.K.A. lipids Fats are solid, oils are liquid at room temp. 2.25x more energy/lb. than carbs. >100 fatty acids identified Linoleic, and α-Linolenic are essential in livestock diets Precursor of prostaglandins & cell structure

Proteins Simple Amino acids Building blocks of the animal’s body Ex. Complex Glycoproteins Lipoproteins Hemeproteins Only nutrient class that contains nitrogen Ave. ~16% 6.25 multiplier %N X 6.25 = %protein

Essential Amino Acids Must be supplemented in the diet Feed Microbial protein Nonessential Amino Acids are synthesized by the body Various absorption rates Egg Animal Plant

Minerals Chemical elements other than carbon, hydrogen, oxygen, nitrogen Macrominerals Required in larger amounts Ex.? Important for several major bodily functions Micromineral Trace minerals, required in small amounts Important for vitamins, hormone synthesis Usually work together w/ other nutrients Can be harmful in high levels

Vitamins Organic nutrients required for very specific bodily functions 16 vitamins Fat soluble A, D, E, K Water soluble C, B12, B1, Niacin In ruminants, these are synthesized by the microorganisms

Feed Analysis Proximate Feed Analysis Separates feed components into group according to feed value Accuracy of the analysis is dependent upon accuracy of the sample Components measured Water Crude protein Crude Fat Crude Fiber Nitrogen-free extract Ash (minerals)

Determining moisture and/or DM content Feed Digestibility Amount of a feed that is absorbed from the digestive tract Great variance Measuring digestibility Energy Evaluation of Feeds Energy is available in any nutrient with carbon Carbs., protein, fats Driving force in bodily function

Measuring energy TDN Not as accurate ME Very accurate NE DE Calorie (cal) Energy required to raise the temp of 1g of water 1 degree C

Kilocalorie (kcal) Energy needed to raise the temp of 1kg water 1 degree C Megacalorie (Mcal) =1,000 kcal or 1,000,000 cal Some energy is lost, and therefore not digested Feces Urine Gases Heat

Animal uses energy in two ways Maintenance Production GE Amount of heat (cal) released from complete burning of a feed (Bomb Calorimeter) ME is what the animal actually has the opportunity to use NE is what is available after energy used for consumption, digestion, metabolism (heat increment)

In diet formulation: NEm NEg NEl Feeds and Feed Consumption Classification of Feeds Dry roughages & forages Hay Straw Other Range, pasture, green forage

Silages Energy Feeds >18% CF, <20%CP Protein supplements >20% CP Mineral supplements Vitamin supplements Nonnutritive additives Antibiotics Coloring Flavors Medicants Etc.

Nutrient Composition of Feeds Goal of nutrient analysis is to predict the production capability of a feed Tables are an average, true analysis is much more accurate Composition can vary: 15% in CP 10% in energy 30% in minerals

Digestion & Feed Absorption Digestion Mechanical Chemical Role is to produce feed particles the can be absorbed and used by the body Carnivorous, Omnivorous, and Herbivorous animals Which is which?

Carnivores & Omnivores are monogastric animals One, simple stomach Also some herbivores (horse, rabbit) Herbivores Ruminants Stomach compartments

The Monogastric Digestive Tract Mouth Mechanical chewing and swallowing of food Salivary Glands Esophagus Delivery tube from mouth to stomach Valve controls opening Stomach Primary area of reduction in feed particle size

Small intestine Duodenum Jejunum Ileum Split molecules & absorb nutrients Large intestine Cecum Colon Absorb water Forms indigestible waste (Feces)

Ruminants Rumen Fermentation vat Papillae Bacteria & protozoa Reticulum Aka honeycomb Initiate mixing in rumen

Omasum Many folds (manyplies) Grinding action? Not a lot of digestive responsibility Abomasum True stomach Ruminants can rechew feed already consumed for more thorough breakdown of feed particles (Cud) known as rumination Elimination of gases by eructation

Digestion in Monogastrics Begins in the mouth Enzymatic reactions Organic catalyst that speeds a chemical reaction without being altered by the reaction Stomach secretions HCl Mucus Pepsin Gastrin

Mixture and some digestion occurs, resulting in Chyme Amino acids, fatty acids, and monosaccharides are available for absorption Two methods of absorption Passive Molecules diffuse from high concentration area to low concentration Active Engulf molecules in villi, and transport them to bloodstream or lymph

Liver function Metabolizes feed particles in bloodstream Detoxifies harmful substances Digestion in Ruminants Fermentation in rumen & reticulum Microorganisms number in the billions Excess are removed with feed movement and killed by acid in the abomasum Mutually beneficial relationship

Digestion is the same after feed reaches the abomasum Microorganisms use starch and sugar for their growth and development Robs the animal of valuable energy sources Produce Volatile Fatty Acids (VFA) which the animal absorbs and converts to energy Acetic Propionic Butyric Methane gas is released through eructation What if this action fails?

Esophageal groove Pathway directing milk to abomasum Complete function of digestive tract is not complete until: Sheep ~2 mos. Cattle ~3-4 mos. Influenced by feed type Energy Pathways End products of glucose and fatty acids supply body tissues with energy, and become milk fat and lactose in the lactating ruminant

Primary organs and tissues in energy metabolism Rumen Abomasum Small intestine Liver Blood vessels Mammary gland Body tissue Undigested energy products Complex carbos. (lignin) and other (ex. Ketone bodies) Excreted through large intestine or kidneys

Protein Pathways End products of protein and NPN: Amino acids Ammonia Excess formed into urea in liver and excreted in the urine Some is returned to the rumen Synthesized amino acids

Nutrient Requirements for Body Maintenance No gain/loss of weight or production High priority for nutrients Body tissue repair Temp control Energy for vital organ function Water balance maintenance Takes ~½ of all ingested feed

Examples Feedlot steers ~30-40% for maintenance Breeding animals ~90% 100# dairy cow eat 4-5x their daily maintenance requirement Body size & Maintenance Increased body size means increased nutrient requirement But, not at a linear rate

Nutrient Requirements for Growth Occurs when: Protein synthesis is > protein breakdown Cells increase in number & size Both Building of muscle, bone, connective tissue Nutrients needed for growth Energy, protein, minerals, vitamins Muscle growth is due to protein

Ca, P, & NaCl Ca usually plentiful in legume forage P plentiful in grain I & Se Deficiency in I results in goiter Se deficiency-white muscle disease

Vitamin D Needed for proper use of Ca & P Can get from sunshine (conversion of cholesterol in the skin), unless raised inside Vitamin A Can be lost during drying in the sun, or extended dry storage

Nutrient Requirements for Fattening Storing surplus feed in and around body tissue Desirable for quality meat production and energy storage 2.25x more energy to produce 1# fat as opposed to 1# protein Due to excess: carbos, fats, protein

Nutrient Requirements for Reproduction 2 categories Gamete production Nothing above normal maintenance Body condition affects fertility Fetal growth Greatest in last trimester of pregnancy Requirements of the fetus are the same as those after it is born Healthy females can withdraw nutrients from their body for the fetus

Nutrient Requirements for Lactation Requires protein, minerals, vitamins, energy Protein is greatest >3% protein in milk Body protein can be mobilized in deficient times Ca & P are critical Hypocalcemia

Energy Based on amount of milk produced Production can be limited by intake High producing dairy cow may need 3-4x the energy of non-lactating cow of same size Why do some cows continue to lose weight? What is the ideal forage to concentrate ratio in dairy cows?

Energy Requirements for Work Primary requirement is energy Regular exercise schedule is necessary for good health Perspiration removes nitrogenous wastes Ration Formulation Objective is to economically match the animal’s nutrient requirements with available feeds

Things to consider: Palatability Physical form Other Diet Modification to Minimize N & P Pollution Impacts air & water quality

By-product of protein digestion What does it affect? P Mineral nutrient Will be excreted if fed in excess Two concerns Volatility of N in the form of ammonia Distribution of manure nutrients P contaminates surface water N contaminates groundwater

Unit 5 Assignment Chapter 17 review questions Pg. 312 Review next time Exam 2 next Tuesday?

Unit 5: Animal Nutrition

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