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1. To identify structures and functions of the digestive
system of ruminant and non-ruminant animals.
2. To identify and describe vitamins, minerals and additives
in livestock feed.
3. To analyze feeding rations, principles and practices
based on nutritional requirements of livestock animals.
4. To explore livestock feed quality issues and determine
the effect on animal health.
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1. Digestive Systems of Ruminant and
Non-Ruminant Animals
2. Nutrients, Vitamins, Minerals and
Additives in Livestock Feed
3. Livestock Feed and Feedstuff
4. Rations, Quality and Feeding
Practices of Livestock Animals
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Breaks down feed into smaller molecules of nutrients
Absorbs the nutrients used by the body for energy
Is achieved by both chemical and physical means
Is made up of the Gastrointestinal Tract (GIT), which
extends from the mouth to the anus
Fun Fact: Parts of food which cannot be broken down,
digested or absorbed are excreted as bowel movements.5
• Functions :
 to break down feed particles (proteins, fats and
starches) into smaller molecules (amino acids, fatty
acids and glucose)
 to absorb the molecules produced by digestion into
the circulatory system for distribution around the
body
 to eliminate the undigested and unabsorbed feed
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• Is separated into the following three steps:
 mechanical forces
 chemical action
 hydrolysis of ingesta
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• Is the way animals gather the food into their mouths
 horses use their lips
 cows use their tongues
 sheep and goats use both tongue and lips
 chickens use their beak and gravity to throw food to
the back of their throats and swallow
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•
•
•
Is where food enters the digestive tract
Reduces size of food particles by grinding or chewing
Is the place of mechanical breakdown (mastication)
Is the start of enzymatic breakdown (saliva is added and
contains enzymes which break down feed)
• Mixes food with saliva to create a bolus
Bolus - a mass of food and saliva formed in the mouth after
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thorough chewing
• Is also known as chewing
• Breaks down the particle size to increase surface area,
allows enzymes and chemicals to more readily
break down nutrients
• Is a repetitive sequence of the
jaw opening and closing, known as
the chewing cycle
Fun Fact: Ruminant animals chew food more than once to
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extract more nutrients.
• Is the muscular tube which takes food from the mouth to
the stomach
• Consists of peristalsis muscle contracting to push the
food toward the stomach
• Also contains cardiac valve, which prevents food from
passing from the stomach back into the esophagus
Esophagus
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• Are animals with a multi compartment stomach
• Spend about eight hours a day grazing, eight hours a day
ruminating and eight hours a day resting
• Are often called “cud chewers”
• Have the unique ability to break down very
fibrous feedstuffs (cellulose)
• Have no upper incisors
 have a harden gum called a
“dental pad”
Examples: cattle, sheep, goats, buffalo and deer
Fun Fact: Ruminants eat fibrous feed and later regurgitate
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the material, called the cud, and chew it again.
• Include the following:
 rumen
 reticulum
 omasum
 abomasum
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• Allows the ruminants to digest celluse
• Is the first of three stomachs which make up the
forestomach
• The food is mixed with fluid to form
a soft mass – the cud – or bolus
• Is the largest of the four compartments
• Acts as a storage or holding vat for feed
Rumen
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• Contains anaerobic bacteria to initiate breakdown of
cellulose
• Functions include:
 location where the plant material is broken down
 fermentation of protein and carbohydrates
Rumen
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• Are microorganisms which continually eat away at the
rumen contents to help decrease particle size, which will
increase absorption
 ruminants depend on rumen microbes to convert feed
components into useable sources of energy and
protein
 the number and proliferation of microbes depends on
the rumen pH and the supply of energy and protein
 bacteria and protozoa are the most important
microbes and they digest approximately 70 to 80
percent of digestible dry matter
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• Is separated from the rumen by a ridge of tissue
• Is made up of a tough lining to catch foreign material
which might have been present in the feed
• Also known as the honeycomb because the lining
resembles a honeycomb
• Works with the rumen to provide
an additional area for fermentation
Reticulum
Enzymes - proteins which increase the rate of chemical
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reactions
• Is the third division of the forestomach
• Is located between the reticulum and the abomasum
• Acts as a type of pump which moves the food from the
reticulorumen to the true stomach
• Can also be known as the manyplies
• Contents are about 90 to 95 percent water
Omasum
Fun Fact: The omasum is sometimes referred to as “the
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butcher’s bible” because of its similarity to pages of a book.
• Functions include:
 removal of water
 further grind and break down of feed
 contain plate-like folds known as laminae which
extend from the wall of the omasum, like pages
in a book extend from the binding
 the laminae are covered with papillae which
control the directional flow of particles to the
abomasum
Omasum
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• Connects omasum to small intestines
• Is the ruminant's true stomach and is very similar to the
stomach of monogastrics
• Almost always contains a continuous flow of food
because of the large amount of food eaten
• Utilizes acid digestion instead of microbial fermentation
like rumen
 lining contains folds which produce gastric juices
containing enzymes (pepsins) and hydrochloric acid
Abomasum
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• Have one stomach (mono: one, gastric: stomach)
• Are usually carnivores or omnivores
• Usually eat small quantities of forage or fiber
• Have a simple stomach similar to humans
Examples: horses, poultry and swine
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• Is a sack-like organ lined with a glandular, absorptive
mucosa
• Is involved in the second phase of digestion
• Secretes pepsin and hydrochloric acid to break down food
particles
Stomach
Fun Fact: A horse’s stomach contains less than ten percent
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of the GI tract.
• Is divided into the following four sections:
cardia (entrance)
fundus (left portion of the stomach)
body (main portion of the stomach)
pylorus (termination)
Stomach
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• Is the portion of the digestive tract between the stomach
and anus
• Is the longest section of the digestive system
• Is the location where most chemical digestion takes place
• Is the location where most of the nutrients in food are
digested
• Is where most food products are absorbed
Small
Intestine
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• Is divided into three sections:
duodenum
jejunum
Duodenum
Jejunum
ileum
Ileum
Small Intestine
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• Is the first section of the small intestine
• Mixes chyme with digestive fluids from the
gallbladder (bile) and pancreas (pancreatic juices)
• Is the location where most chemical digestion
takes place
Duodenum
Chyme - the partially digested mass of food from the
stomach
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• Is the long, coiled mid-section of the small intestine
• Is the location where breakdown of the chyme is
completed
• Is lined with villi
Jejunum
Villi - small, finger-like outgrowths which make it easier for
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digested material to be absorbed
• Is the final section of the small intestine
• Is the site of absorption of vitamin B
• Also absorbs bile salts and products not absorbed by
the jejunum
Ileum
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• Includes:
 both exocrine and endocrine functions
 endocrine glands do not have ducts, therefore release
hormones into the interstitial spaces surrounding the
cells
 exocrine glands secrete substances through ducts and
discharge them into the external environment, organs
or outside the body
Pancreas
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• Produces enzymes to aid in the break down of
carbohydrates, fats, proteins and acids in the duodenum
• Produces two hormones to help regulate blood:
 insulin
 glucagon
Pancreas
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• Is the largest gland in the body
• Stores vitamins, iron and glycogen
• Detoxifies chemicals, pollutants and poisons
• Connected to gallbladder (except in horses)
• Is the place bile is stored
Liver
Bile - a thick greenish-yellow digestive fluid, aids in the
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digestion of fats
• Main function is removal of water from food waste
• Compresses waste into a form easier for expulsion
from the body
• Mixes chyme with mucus and bacteria, converts to
feces
• Is shorter than small intestine, but larger in diameter
• Varies from species to species
Large Intestine
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• Consists of:
 cecum
 colon
 rectum
 anus
Cecum Rectum
Colon
Anus
Large Intestine
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• Also known as the blind gut
• Is the main place for fiber digestion in horses
• Utilizes hind-gut fermentation which mainly takes place
in their oversized cecum
• Is similar to the cow’s rumen
• Breaks down feed not digested in the small intestine
• Is the beginning of the large intestine
Cecum
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• Extracts water and salt from waste before it is extracted
from the body
• Does not play a major role in the absorption of nutrients
and foods
Colon
• Includes:
 ascending colon
 transverse colon
 descending colon
 sigmoid colon
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• Is the terminal portion of the large intestine
• Stores solid waste (feces)
• Is the area used in some animals for entry during artificial
insemination
Rectum
Fun Fact: Large animals, specifically cattle, when being
artificially inseminated will have one hand placed into the
rectum to locate the cervix to feed the A.I. rod through the
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cervix to the uterus.
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• Is the last part of the digestive tract
• Is the opening for undigested food to pass from the body
• Controls the extraction of feces
Anus
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Small Intestine
Rectum
Duodenum
Esophagus
Pancreas
Rumen
Colon
Anus
Recticulum
Omasum
Abomasum Liver
Villi
Large Intestine
Gall
Bladder
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Esophagus
Jejunum
Duodenum
Ileum
Pancreas
Colon
Anus
Rectum
Stomach
Liver
Villi
Cecum
Large Intestine
Gall
Bladder
Small Intestine
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Esophagus
Large Intestine
Rumen
Small
Intestine Cecum
Anus
Reticulum
Omasum
Abomasum
Duodenum
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Esophagus
Rumen
Cecum
Large Intestine
Anus
Reticulum
Omasum
Small Intestine
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Proventriculus
Liver
Small Intestine Cloaca
Pancreas
Esophagus
Anus
Crop
Ceca
Spleen
Gizzard
Duodenum
Large Intestine
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Esophagus
Stomach
Cecum
Anus
Duodenum
Small Intestine
Large Intestine
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• Can also be termed nourishment or aliment
• Is the step involved in absorption of feed by the body,
utilized for maintenance (normal function), reproduction
and growth
• Aids in preventing disease and promoting health
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• Are substances or chemical compounds required by the
animal for productive purposes
• Are essential for life and required for diet
• Build and repair tissues, give heat and energy, and
regulate body processes
Diet - a mixture of the feedstuffs available for the animal to
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provide the nutrients
• Include:
 proteins
 carbohydrates
 lipids (fat)
 vitamins
 minerals
 water
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• Are composed of 20 amino acids
 ten can be synthesized by tissue in the body –
non-essential amino acids
 ten must be provided in the diet – essential amino
acids
• Can be calculated by multiplying
percentage of nitrogen by 6.25
Amino Acids - organic compounds containing an amino
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group and a carboxylic acid group
• Are composed only of carbon, hydrogen and oxygen
• Are the main source of energy
• Comprise 65 to 75 percent of dry weight in grains,
forages and roughages
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• Are made up of:
 simple carbohydrates (sugars)
 quickly digested
 quick source of energy
 contain refined sugars and few essential
vitamins and minerals
 complex carbohydrates (starches)
 require longer to digest
 usually packed with fiber, vitamins and minerals
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• Are used as energy
• Are broken down into two types
 fats – typically of animal origin (saturated fatty acids
and are solid at room temperature)
 oils – typically of plant or marine origin (unsaturated
fatty acids and are liquid at room temperature)
• Are composed of glycerol esterified to three fatty acid
molecules
• Fatty acids can vary in length and saturation
 saturation – is the presence of double bonds
 saturated fatty acids – have no double bonds
 unsaturated fatty acids – have one or more double
bonds
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• Are present in food and required by the body in small
amounts
• Regulate metabolism and maintenance for normal growth
and functioning
• Are most common in the forms of :
 A, D, E, K vitamins (fat soluble)
 B, C vitamins (water soluble)
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• Are stored in body fat
• Are also stored in the liver when not in use
• Taken in excess can be harmful, as they do not
readily leave the body
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• Can be dissolved in water
• Are not stored in the body and must be replenished daily
• Contain little health concern if excessive amounts are
consumed
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• Aids in releasing energy from carbohydrates
• Helps with nerve function
• Plays a key role in glucose metabolism
• Requirements are influenced by animal size, genetic
factors and physiological status
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• Is required for normal cell activity to occur
• Is required for maturation of red blood cells
• Is more important in a ruminant than in a non-ruminant
• Involved in carbohydrate and fat metabolism, helps with
protein synthesis
• Is mainly stored in the liver
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• Is found only in animals
• Aids in an animal’s vision and night vision
• Is essential for proper kidney function
• Is also used for development of bones, teeth and nerve
tissue
• Helps maintain a healthy immune system
• Is mostly (90 percent) stored in the liver
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• Is formed by the presence of sunlight upon certain sterols
• Promotes growth and maintenance of bones and teeth
• Aids in regulation of blood calcium levels
• Increases the absorption from the digestive tract and
metabolic use of phosphorus and calcium
• Is stored mainly in the blood
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• Is made by bacteria in the rumen
• Is essential in the liver for the production of prothrombin
• Is required for the synthesis of plasma clotting factors
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• Are needed for digestion to form skeletal structures and
in metabolic processes within the body
• Aid in formation of muscles, tissues and bones
• Are broken down into two types:
 macrominerals - calcium, phosphorus and salts
(required in large amounts)
 microminerals - zinc and selenium (required in small
amounts)
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• Macrominerals (major minerals) are required in large
quantities
• Microminerals (trace minerals) are required in smaller
quantities
• Can be added to the feed directly or in the form of mineral
blocks
 trace mineral block (red)
 salt block (white)
 salt plus sulfur (yellow)
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• Are generally acquired with consumption of forages,
especially legumes
• Play an important role in muscle function
• Are responsible for development and maintenance of
the skeletal system
• 98 to 99 percent (calcium) is stored in bones
• Plays a role is synoptic nerve transmission
 Ca:P ration in bones are 2:1
 Ca:P ration in muscles is 1:2
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• Is present in enzymes, protein, certain vitamins and other
compounds
• Is found in high levels in soybean products, alfalfa hay and
corn byproducts
• Can also be found in water
• Is needed for hemoglobin function
• Is a crucial mineral for wool and feather growth
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• Work together to maintain cellular volume, pH and water
balance of body fluids
• Are commonly expressed as a salt requirement
• Are involved in muscle and nerve function
• Regulate cation and anion equilibrium
• Assist in transport of amino acids, minerals and vitamins
into cells (Sodium)
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• Is needed to maintain normal body and organ function
• Helps to transport nutrients in and out of cells
• Helps with water balance, active transport of nutrients into
the cell and nerve transmission
• Assists in regulating heartbeat
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• Is required for synthesis of vitamin B-12
• Can also act as a substitute for zinc in the large intestine
• Must be consumed in the animal’s diet
• Must be supplemented to monogastric animals
• Can be supplied by rumen organisms
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• Is required in very low levels
• Is essential for production of thyroxin
• Is extremely important in diet of pregnant animals to
ensure normal development of fetus
• Supplement is commonly iodized salt
• Deficiency and toxicity can cause Goiter
Thyroxin - a hormone which regulates metabolic rate
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• Plays an important role in growth and reproduction
• Functions as a part of the numerous enzyme systems
• Vary depending on the stage of production
• Supplementation is needed in poultry and cattle
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• Plays an important role in DNA, RNA and protein
production
• Plays a role in immune response, hoof health and
enzyme systems
• Is contained in forages, grains and proteins
• Is stored in liver and bones
• Is important for skin and wound healing
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• Is the most important nutrient
• Helps to regulate body temperature
• Aids in transporting nutrients throughout the body
• Rids the body of waste materials
• Makes up more than 50 percent of the blood system
Fun Fact: Two to five pounds of water will be consumed for
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every pound of feed consumed by the animal.
• Can be accessed by an animal from:
 tank or pond
 bowl waterer
 automatic waterer
 nipple waterer (swine)
Fun Fact: Nipple waterers used for swine are healthier with
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a lower risk of bacteria unlike with pools and tanks.
• Purposes:
 preserve flavor
 improve taste and appearance
 supply medication
• Provide no nutrition, although some are added for extra
vitamins and minerals
• Are important in young animals’ diets (flavoring
compounds) as they learn to
eat dry feed rather than
milk from mother
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• Ruminants
microbial additive
 development of rumen microflora
 increase feed intake
acid additive
 feed preservative
 silage additive
 prevention of ketosis
 milk replacer
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• Non-Ruminants
probiotics
 prevention of intestinal disease
enzyme additive
 improves digestibility of poor-quality feed
amino acids
 fermentation
 chemical synthesis
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• Include:
 dry: hay, grains, oilseed, straw, corn husks, soybeans
and hulls
 cereal grains, cotton seed meal/hulls
 green: pasture and green chop
 high moisture: haylage, wet byproduct feeds, roots,
tubers and silages
Feed - grains and byproducts eaten by the animal
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• Four primary purposes in livestock feeding:
to improve palatability
to alter the particle size
to improve digestibility
to facilitate preservation, storage or transportation
of the grain
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• Grinding
• Dry rolling, cracking, crimping
• Pelleting
• Steam rolling
• Steam flaking
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• Is usually done with a hammer mill
• Grinds the grain to a very small particle size which
drastically increase surface area and rate of digestion
• Is a common process for swine and poultry feeds
• Is not common in beef cattle because it decreases
palatability and increases the potential for ruminal
acidosis (bloat)
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• Is done by passing grain through a set of grooved
(corrugated) rolls
• Particle size can vary from fine to coarse
• Is not frequently used for swine or poultry
• Is common for beef and dairy cattle
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• Is ground or cracked grain before being steamed and
forced through a pellet mill
• Increases product density and decreases fine particles
which typically decreases wastage
• Makes grains easier to store and transport
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• Is commonly used in poultry and swine and has been
shown to increase their weight gain and feed efficiency
• Is not cost effective to use in a beef feedlot or on dairy
cattle
• Is a common way to supplement protein and/or energy
to range cows and horses (i.e. range cubes)
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• Grain is exposed to steam one to eight minutes before
rolling
• Process can also be known as crimping or steam crimping
• Particle size and physical form of crimped grain may
improve palatability and animal acceptance in some
instances
• Offers little to no advantage in feed efficiency over
grinding or rolling
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• Grain is steamed for 15 to 30 minutes and then rolled to
produce a thin flake
• Starch digestibility is increased because of extensive
gelatinization and rupture of the starch granules
• For corn, feed efficiency is improved seven to ten percent
versus dry rolling or cracking methods
• Steam flaking is the most common processing method
utilized in the feedlot industry
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• Is defined as feed for livestock
• Refers to food given to the animals, rather than food they
forage for themselves
• Includes:
 hay
 straw
 feeds
 sprouted grains
 legumes
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• Most common and abundant cereal grain
• High in energy but has a low protein level
 eight to ten percent
• Often used because of cost efficiency
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• Is the most important protein supplement for livestock
feeding in the United States
• Contains 44 to 50 percent protein
• Has a good balance of amino acids suitable
for feeding swine and poultry
• Is the product remaining after extracting
most of the oil from whole soybeans
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• Is the second most important livestock protein supplement
in the United States
• Has a lower palatability than soybean meal, especially for
non-ruminants
• Contains approximately 44 percent crude protein content
and 12 percent crude fiber
Fun Fact: Cottonseed hulls are commonly fed to cattle on
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an as-is basis.
• Is produced in areas where water is not available for corn
to survive
• Has hard seed coat which must be processed to improve
the nutrients available to the animals
• Has a relatively low quality protein
• Contains 8 to 12 percent
crude protein
Crude protein - an estimate of the total protein of a feed
includes nitrogen containing substances such as ammonia,
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amino acids and nitrates
• Is a popular cereal grain but is
generally too expensive
• Protein is superior to corn and grain
sorghum
• Grows in many areas, used for
grazing and grain
 soft wheat from the western
United States: 10 to 11 percent
protein
 hard red winter wheat of the
United States Great Plains: 12 to
14 percent protein
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• Possess the highest quality protein of all the cereal grains
 13 to 14 percent
• Contain a large hull which is less digestible, but usually
removed when processed
• Are an ideal grain for starting cattle on feed because of its
high fiber and hull content
• Causes less colic compared to other grains in horses
Hull - the outer covering of a seed or fruit
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• Is commonly used in diets of feedlot cattle
• Is also a strong component of horse feed
• Contains water-soluble carbohydrates which are poorly
digested and lower its energy content
• Outside hull makes it less digestible than corn, wheat or
milo
• Contains 12 to 13 percent
crude protein content
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• Is primarily grown for grain, but
occasionally for hay or pasture
• Has a fairly bitter taste
• Is normally mixed with other grains
• Contains 12 to 13 percent crude
protein content
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• Is a crop species resulting from a plant breeder's mix
between wheat and rye
• Is used mainly as a hay source
• Is more palatable than rye
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• Is cut, dried and baled grass
• Is high in fibrous materials and contains a lot of
carbohydrates
• Is used with inadequate availability of rangeland or pasture
due to weather
• Is also used if animal is unable to access pastures, such
as animals kept in a stable or barn
• Nutritional value will vary greatly between
hay type, time of harvest and storage
Fun Fact: Protein content can be determined by the stage
of growth of the plants at time of harvest. The more
immature the plants are when harvested, the higher the
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protein content.
• Common grasses include:
 fescue
 Bermuda grass
 brome grass
 matua
 coastal
 sorghum
 alfalfa
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• Are used for their high protein content, roughly 18 percent
protein
• Are used in pastures to be grazed or cut for hay
• Include:
 alfalfa
 clovers
 vetches
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• Are blended from various raw materials and additives
• Are formulated according to the specific requirements of
the target animal
• Contain a complete diet in each pellet
• Differ in size depending
on animal size
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• Are a matter of combining feeds
• Are effective when consumed at a level to supply an
efficient amount of energy in relation to body weight
• Are the amount needed to supply the daily nutrient
requirements of the animal
• Should normally be economical,
palatable and free of toxic substances
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• Can be provided to animals in a number of different ways
• Include:
 feeders
 range cubes
 lick tanks for liquid feeds
 tub feeders
 protein blocks
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• Affects its value for animal nutrition
• Includes palatability and nutrient content
• Is higher if produced on well fertilized soils
• Can decline with improper harvesting or handling
• Can also decline with extreme in weather
 hot, cold, wet or dry
102
• Is affected by harvesting and handling methods
• Must reduce moisture contents so it can be stored
without spoiling or undergoing serious loss of nutrients
• Should be baled as soon as possible after it reaches a
safe moisture level for storage
103
• Refers to how well the animal will accept feed
• Can cause difficulties if animal does not find a feed
acceptable
• Problems include:
 animals not eating enough
 reduced growth and gains
 low production of meat, milk or eggs
 increased sickness
104
• Is a subjective measurement of the amount of fat on an
animal’s body
• Scores cows from 1 (thin) through 9 (fat)
 1 (emaciated)
 2 (very thin)
 3 (thin)
 4 (borderline)
 5 (moderate)
 6 (good)
 7 (fleshy)
 8 (fat)
 9 (extremely fat)
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• Include:
 maintenance: 70 to 80 percent
 gestation: 18 to 20 percent
 lactation (milk): 6 to 8 percent
Fun Fact: Younger animals will also have
growth as a percentage of their feed uses.
Gestation - the carrying of an embryo or fetus inside a
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female animal
• Include:
 breed
 sex
 body size
 ruminal capacity
 body condition
 grazing time
 weather
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1. The muscular tube which takes food from the mouth to the
stomach is known as which of the following?
A. Ruminant
B. Microbes
C. Jejunum
D. Esophagus
2. Carbohydrates make up what percentage of the dry weight in
grass, forages and roughages?
A. 65 to 75
B. 35 to 45
C. 5 to 15
D. 75 to 85
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3. Which vitamin helps with vision and night visions in animals?
A. Vitamin D
B. Vitamin K
C. Vitamin A
D. Vitamin B-12
4. Which of the following is the largest and first compartment of a
ruminant stomach?
A. Aejunum
B. Abomasum
C. Reticulum
D. Rumen
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5. Which of the following rids the body of waste and transports
nutrients through the body?
A. Sulfur
B. Water
C. Vitamins
D. Fat
6. Which of the following does NOT consist of fat soluble
vitamins?
A. Vitamin D
B. Vitamin C
C. Vitamin A
D. Vitamin K
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7. What type of mineral block is usually a white color?
A. Sodium
B. Trace
C. Calcium
D. Salt
8. The desired number wanted in cattle body condition scoring is
which of the following?
A. Four
B. Seven
C. Three
D. Six
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9. The repetitive sequence of opening and closing the jaw takes
place during which process?
A. Mastication
B. Prehension
C. Digestion
D. Reticulum
10. Which of the following minerals plays an important role in
DNA and RNA production?
A. Potassium
B. Iodine
C. Zinc
D. Manganese
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Galyean, M., Hutcheson, D. P., et al. (1996). Nutrient
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