Beef Cattle Nutrition
Beef Cattle Nutrition
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diagram of ruminant-handout
– Esophageal groove – immature ruminants
– Rumen, omasum, abomasum and
reticulum
– Small Intestine-duodenum, illeum,
jejunem
– Large Intestine-colon, cecum, rectum
Digestive System
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stomach in ruminants comprises 25 %
of body
rumen comprises 75 % of stomach
fermentation: digest cellulose, plant
tissue, urea, NPN, B & K vitamins
consist of bacteria and protozoa (200
billion/teaspoon)
Characteristics of
Ruminants
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Mouth
– no upper incisor or wolf teeth
– use lips and tongue to grab food
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four compartments to the ruminant
– Consist of microorganisms
– Produce Volatile Fatty Acids/ acetic,
propionic, butyric
Volatile fatty acids (VFA)
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Produced in large amounts through
ruminal fermentation and are of
paramount importance in that they
provide greater than 70% of the
ruminant's energy supply. Virtually all
of the acetic, proprionic and butyric
acids formed in the rumen are
absorbed across the ruminal
VFA’s cont.
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epithelium, from which they are
carried by ruminal veins to the portal
vein and hence through the liver.
Continuous removal of VFA from the
rumen is important not only for
distribution, but to prevent excessive
and damaging drops in pH of rumen
fluid.
Ruminants
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Prehension- the process of gathering
food to the mouth
Mastication - the process of chewing
Eructation (belching of gas)
– Carbon DiOxide and Methane
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Enzymes- organic catalyst which speed
up a biochemical reaction without
being used up
Rumination
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Rumination-fermentation
– rechewing usually > 8 hours/day
dependent on diet (increase fiber,
increase rumination time)
– CO2 and Methane are the primary gases
given off during rumen fermentation
Digestion and Utilization
of Prot, CHO and Fats
FUNCTION OF FEEDS
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Maintenance- a ration which is adequate to prevent
any loss or gain of tissue in the body when there is
no production
– the difference in energy needs are related to the
amount of activity
Growth- increase in size of muscles, bones, internal
and external parts of the body (the foundation of
animal production)
Finishing- the laying on or deposition of fat
Production – lactation, conception, etc.
FEEDS
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Definition- any ingredients or material
fed to animals for purposes of
sustaining them
Classes of Feeds
– roughages
– concentrates
– by-products
– protein supplements
– minerals, vitamins, and additives
Classes of FeedsRoughages
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Definition:
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Generally; TDN=40-60%
>18% fiber and lower in energy &
low digestibility compared to concentrates
and is high in Ca & K
– Forage/Pasture, hay, crop-residue (corn, milo),
silage (fermented, high-moisture forage),
haylage (low-moisture type silage), green chop
Classes of Feeds cont.
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Concentrates- high in energy, low in
fiber and < 20% protein – Corn, milo, oats, etc.
By-product feeds (from plant and
animal processing) carrots, turnip tops, fodder beets
Protein supplements- high in nitrogen
– Oilseed Plant by-products (SBM, CSM)
Classes of Feeds cont.
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NPN= non-protein nitrogen
– urea, ammoniated molasses or chloride,
biruet, etc
– Urea=45% Nitrogen X 6.25 = 281%
protein equivalent
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Minerals - NaCl, limestone, dical, etc.
– major -Ca, P, Mg, S
– trace - Cu, Fe, I, Mn, Zn, Se, etc.
Classes of Feeds
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Vitamins
– Natural versus synthetics
– water vs fat soluble classification
– A,D,& E are most common in ruminants
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Special Feeds
– Fats and oils (increase calories without
bulk)
– molasses (increase energy and
palatability)
Classes of Feeds
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Feed additives and implants
– increase efficiency of gain, prevent
diseases, preserve the feed
 antibiotics,
hormones, growth promotants,
repartitioning agents, etc.
Evaluation
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of Feedstuffs
Measuring Energy
– TDN= sum total of the digestible protein,
fiber, and nitrogen free extract, and fat X
2.25
– 40% is low for forages while 60% is high
– Most concentrates are 80-90%
Calorie or California Net Energy System
Net Energy= gross energy-fecal energy-gaseous
energy-urinary energy-heat increment
 gross energy = combustion heat
 digestible energy = portion of gross energy that is
not excreted in feces
 Metabolic energy = portion of gross energy that is
not lost in feces, urine and gas
 heat increment = difference between ME & NE
– heat unavoidably produced by an animal in
digestion and metabolism
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Evaluation of Feedstuffs
– Analyzing Feedstuffs
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Proximate analysis
– 1) H2O (DM vs As Fed),
– 2)CP
3) Ash
4) Fat
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Fiber (ADF, NDF)
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Energy (Net or TDN) – bomb calorimeter
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Minerals & Vitamins
Ration Formulation
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Consideration points
– availability and cost of feedstuffs
– moisture content
– composition of feedstuffs
– soil analysis
– nutrient allowances and requirements
– composition of ration and ingredients
Beef Cow Nutrition
Objective
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feed little as possible as long as we don’t
damage reproduction, milk, or longevity
overfeeding causes decreased longevity,
dystocia, reprod. rate, and milk prod.
underfeeding causes delayed estrus,
puberty, lowers conception rate and milk
prod.
Phase Feeding for the
Beef Female
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feeding accounts for approx. 2/3 of total
costs after real estate acquisition
feeding has the greatest influence on
growth and performance
Yet, reproduction is the most important
economic important trait
feeding influences growth, reproduction
(most critical), lactation, etc.
Phases of Feeding
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Birth to weaning
Weaning to first breeding
First breeding to first calving
First two productive years (1st two
calves)
Third and subsequent years of
production
Phase Feeding
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Plane of nutrition is dependent upon
energy and protein requirements along
with forage quality and availability
Can be somewhat breed dependent
European cattle are later maturing and
will utilize more forage
Phase Feeding
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First phase- Birth to Weaning
objective is to develop replacement
females to weaning with maximum
subsequent productivity at minimum
costs
Phase Feeding
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Growthier females at weaning will
usually reach puberty earlier, calve on
time and return to rebreeding earlier
than slower growing heifers
Weaning is usually around 205 days or
7 months of age
Phase Feeding
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Second phase - Weaning to First
Breeding
objective is to promote adequate
growth to insure sexual maturity
first breeding should be done at 60-65
% of the estimated mature weight
ADG of 1-1.5 lbs. per day is
recommended
Phase Feeding
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Third phase - First Breeding to First
Calving
objective is to promote sufficient
growth and body development to
allow heifers to deliver a calf, and to
prepare the heifers physiologically to
be able to withstand the rigors of first
lactation and rebreeding.
Phase Feeding
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Females should gain 70-75% of their
weaning weight or be 70-75% of their
mature weight at their first calving
time.
Phase Feeding
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Fourth phase -
First two productive years
Objective is to provide a sufficient plane of
nutrition to allow the young cows to lactate,
rebreed and continue to grow
cows should not lose more than 15% of
their weight during the winter
Phase Feeding
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Fifth phase - Third and subsequent
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productive years
Objective is to maintain efficient productivity
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nutrient requirements actually decrease
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Should not lose more than 20% during the
winter
Feeding in General
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Obesity can be a major problem
Body Condition Scores should be
utilized
Scores of 1-9, where 1 is very thin and
9 is obese : Handout
This can be breed, feed or frame size
dependent
Feeding in General
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Heifers - breed more than needed
breed 30 days before the mature cows
palpate 60 days after breeding season
Cows > 10 years of age; the physical
condition will diminish
Bulls - during intense breeding season;
requirements may increase by 2-3 X
If forage is limiting, feed bulls separate
Feeding Systems
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Creep feeding– the supplemental feeding of young nursing
animals in an enclosure which is accessible to
them but not to their parent
 gains for young animals are cheap gains due
to less fat content in young animals and less
consumption/body wt.
 adv.- increases weaning wt., facilitates fall
calving, uniformity, achieve genetic potential,
assists first calf heifers, etc.
Creep feeding- is it
feasible?
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whenever it is most likely profitable
usually when forage or milk is limited
conditions we see in drought that results in
overgrazing by mother, thus forage is limited
young cows or very old cows
To be feasible, value difference of the calf should
be over the cost of the creep feed
Over creep feeding can cause reduced subsequent
milk production because of excessive fat in udders
Feeding and Management
of Brood Cows
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critical time of nutrition
– 30 days before calving
– 70 days after calving
 growth
of calf
 reproduction efficiency of cow
 Lactation
 Rebreeding
Feeding and Management
of Brood Cows
– feed the herd according to cow
reproductive pattern
 dependant
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upon:
dry pregnancy
lactating
replacement heifers
Feeding and Management
of Brood Cows
– heifers – the last 3-4 months before
parturition is important
– weight makes a difference
– provide for maintenance and growth
BCS
Feeding and Management
of Brood Cows
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Reproduction and Nutrition
– energy is more important than protein
– P supplementation increases % calf crop
– increase Vit A
– level of feed before and after calving
– pregnant cows should not gain over 100
lbs during gestation
Feeding and Management
of Brood Cows
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Winter Feeding
– grass decreases in protein
– must either drylot or supplement
– energy is important and should be increased by
10% for every 10 degrees below 20 degrees F
Range Feeding Deficiencies
– energy- lack of feed
– protein - mature grasses
– minerals - lowered salt and P/ vit. - A & ? D, E
Feeds for
supplementation
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Oilseed meals
Grain
Breeder/range cubes
Protein blocks
Liquid feeds (protein or protein/energy)
Syrup blocks or tubs
Hays
Supplementation
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when supplementing; need to know 4
things:
– nutrient composition
– availability
– Intake
– requirements
Supplementation
questions
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how much to feed and still make max
use
what kind
what form
how often
additives
Alternatives
Factors affecting
supplementation
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Forage quality
Forage quantity and availability
Body condition score
Body size
Milking level
Age
Feeding of Bulls
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age and condition / exercise
increase bulk, decrease grain ( do not
want them too fat)
feed young bulls more for growth and
development- overfeeding results reduced
sperm counts, unsoundness, etc.
mature bulls- increase lbs of grain plus
roughage as needed to fit BCS
Bulls cont.
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Young bulls
– Feed a 12-14% CP ration at 1.5-2% of
CWT
– Make sure they have plenty of free choice
forage
– Thumb rule is to feed a 14% CP ration
until 14 months of age
Pastures
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two kinds- native and improved
range covers > 40% of the world land area
grasses, browse (woody stem perennial),
forbs (hollow stem annual)-weeds
cattle prefer grasses, deer prefer browse
thumb rule- graze 1/2 in summer and save
1/2 for the winter
Forages
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Forage intake vs digestibility
Factors that influence intake
body size
forage availability- biggest problem we
face
forage palatability
gut fill
rate of passage
Forage intake
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higher the Quality forage, higher intake
early maturity
lower proportion of cell walls
higher protein
increased rate of passage
digestibility increases
lowers gut fill
Forages
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Rate of passage or digestion depends
on:
plant species
plant maturity- more mature, less
digestible
cell walls=cellulose vs
cell contents=sugars
Forages
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maturity increases, cell content
decreases
protein content> 6% for optimum
digestion
preparation method - pelleting,
grinding, etc
Characteristics of grasses
on native range
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slower growth rate- reduces quality
longer period to reach maturity
slower re-growth
Proper utilization of
range
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maintain grazing distribution through:
fencing
water
shade
burning
mowing or spraying
fertilizer
supplemental feeding
Improved pastures
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Don’t graze in early fall or late summer
bermuda grass- adaptable
hybrids- *coastal, Tifton 85, common
good response to N and water
problems- requires cross fencing & N
Proper Management
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graze when 6-8”, fertilize NPK early spring
and N in summer and late summer
can overseed with fescue, wheat, rye in the
fall for winter pasture
an increase in N does not necessarily
increase performance
yet, it increases quantity, thus stocking rate
Thumb Rules
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when a cow consumes enough energy,
she usually consumes enough protein
Winter- cow should consume 1.5% of
body wt with poor forage
2.0% with good quality hay
2.5% with excellent forage such as
alfalfa or wheat
NPN- non-protein
nitrogen
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Urea is most popular; other
ammonium chloride, biuret, etc.
most effective with high CHO source
diet and low protein requirement,
twice daily feeding, bacteria in the
rumen require energy
not as well utilized at > 12 % protein
or in young growing calves or creep