Unit 5: Animal Nutrition
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Transcript Unit 5: Animal Nutrition
Unit 7: Animal Nutrition
CHAPTERS 15-17
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
1.
2.
3.
4.
5.
6.
Water
Carbohydrates
Fats
Proteins
Minerals
Vitamins
Nutrients
Water
Difference between water & moisture
Dry matter
Most important nutrient!
Functions
Metabolic reactions
Transport nutrients
Temperature maintenance
Physical shape of the body (cell contents)
Nutrients
Carbohydrates
Found in plant & animal tissue
Simple carbohydrates
Starch
Easily digested
High in energy
Complex carbohydrates
Cellulose, lignin
Energy source
Present in cell walls
Nutrients
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
Nutrients
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
Nutrients
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
Nutrients
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
Ex.?
Important for vitamins, hormone synthesis
Usually work together w/ other nutrients
Can be harmful in high levels
Nutrients
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)
Feed Analysis
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
Feed Analysis
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
Feed Analysis
Kilocalorie (kcal)
Megacalorie (Mcal)
Energy needed to raise the temp of 1kg water 1 degree C
=1,000 kcal or 1,000,000 cal
Some energy is lost, and therefore not digested
Feces
Urine
Gases
Heat
Feed Analysis
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)
Feed Analysis
In diet formulation:
NEm
NEg
NEl
Figure 15.3
Measures of energy and energy utilization.
Feeds and Feed Consumption
Classification of Feeds
1.
Dry roughages & forages
•
•
•
2.
Hay
Straw
Other
Range, pasture, green forage
Feeds and Feed Consumption
3.
4.
Silages
Energy Feeds
•
5.
Protein supplements
•
6.
7.
8.
>18% CF, <20%CP
>20% CP
Mineral supplements
Vitamin supplements
Nonnutritive additives
•
•
•
•
•
Antibiotics
Coloring
Flavors
Medicants
Etc.
Feeds and Feed Consumption
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, & 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
The Monogastric Digestive Tract
Small intestine
Duodenum
Jejunum
Ileum
Split molecules & absorb nutrients
Large intestine
Cecum
Colon
Absorb water
Forms indigestible waste (Feces)
Figure 16.1
Digestive tract of the pig as an example of the digestive tract of a monogastric animal.
Figure 16.2 Digestive system of the horse. The posterior view shows the colon or large intestine proportionally larger than the rest of
the digestive tract. Note particularly the location of the cecum at the anterior end of the colon.
Ruminants
Rumen
Fermentation vat
Papillae
Bacteria & protozoa
Reticulum
Aka honeycomb
Initiate mixing in rumen
Ruminants
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
Figure 16.4
Beef cattle digestive tract.
Figure 16.5 Lining of the four compartments of the ruminant stomach (goat). (A) Compartments intact.
(B) Compartments separated. Courtesy of George F. W. Haenlein. University of Delaware.
Figure 16.7 The esophageal groove, with its location relative to the esophagus, reticulum, and rumen. Courtesy of N. J. Benevenga et
al., 1969. Preparation of the ruminant stomach for classroom demonstration. J. Dairy Sci. 52:1294.
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
Digestion in Monogastrics
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
Digestion in Monogastrics
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?
Digestion in Ruminants
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
Digestion in Ruminants
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
Figure 16.8
Energy pathways in the ruminant. Source: J. Bryant and B. R. Moss, Montana State University.
Digestion in Ruminants
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
Figure 16.9
Protein pathways in the ruminant. Source: J. Bryant and B. R. Moss, Montana State University.
Nutrient Requirements for Body Maintenance
No gain/loss of weight or production
High priority for nutrients
1.
2.
3.
4.
•
Body tissue repair
Temp control
Energy for vital organ function
Water balance maintenance
Takes ~½ of all ingested feed
Nutrient Requirements for Body Maintenance
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
Nutrient Requirements for Growth
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
Nutrient Requirements for Growth
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
Nutrient Requirements for Lactation
Energy
Based on amount of milk produced
Production can be limited by intake
High producing dairy cow may need 3-4x the energy of nonlactating 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
N
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