Transcript Balancing Rations

Balancing Rations
Animal Science II
Unit 8
Objectives




Classify feeds as roughages and concentrates
Describe the six functions of a good ration
Explain the characteristics of a good ration
Balance livestock rations using commonly
accepted practices
Classification of Feeds
Roughages



Contain more than 18% crude fiber when dry
Includes: hay, silage, pasture, fodder
2 general class: legume roughage and nonlegume roughage
Legume Roughages



Can take nitrogen from the air
Able to due so because they have nodules on their
roots that contain bacteria
These bacteria fix the nitrogen from the air in soil
and make it available for the plant to use



Do so by combining the free nitrogen with other elements
to form nitrogen compounds
All the clovers, alfalfa, soybeans, trefoil, lespedeza,
peas and beans
Usually higher in protein than nonlegume roughages
Nonlegume Roughages



Cannot use nitrogen from the air
Lower in protein
Many common livestock feeds are nonlegume

Corn silage, sorghum silage, fodders, bluegrass,
timothy, redtop, bromegrass, orchardgrass,
fescue, costal Bermuda grass, common Bermuda
grass, prairie grass (Western wheatgrass,
Kentucky bluegrass, etc)
Concentrates


Less than 18% crude fiber when dry
Two classes


Protein supplements
Energy feeds
Protein Supplements


20% or more protein
Divided into 2 groups based on their source
Protein Supplements

Animal proteins

Come from animals or
animal by-products

Common: tankage, meat
scraps, meat and bonemeal,
fish meal, dried milk (whole
& skimmed), blood meal,
feather meal

Most contain more than 47%
crude protein

More balanced essential
amino acids

Variable quality compared
to vegetable proteins

Vegetable Proteins

Come from plants

Common: soybean oil meal,
cottonseed meal, linseed oil
meal, peanut oil meal, corn
gluten feed, brewers dried
grains, distillers dried grains

Most contain less than 47%
crude protein

Soybean oil meal is used
most

Can supply necessary
amino acids for swine
and poultry

Only protein source that can
be used for ruminants
Commercial Protein Supplements





Made by commercial feed
companies
Mixes of animal and plant
protein feeds
Usually made for 1 class of
animal
Often mix of minerals,
vitamins, antibiotics
Feed tag needs to be read
and feeding directions
followed
Energy Feeds


Feeds with less than 20% crude protein
Most grains



Oats, corn, sorghum, barley, rye, wheat, ground
ear corn, wheat bran, wheat middling's, dried
citrus pulp, dried beet pulp, dried whey
Corn is the most widely used
Followed by sorghum grain, oats, barley
Ration Characteristics
Ration Characteristics




Animals need proper nutrition to efficiently produce
meat, milk, eggs, wool, work, etc
A ration is the amount of feed given to an animal to
meet its needs during a twenty-four hour period
A balanced ration is one that has all the nutrients the
animal needs in the right proportions and amounts
Diet refers to the ration without reference to a
specific time period
Palatability


Ration must taste good
Mold, insect and weather damage all lower
palatability
Feed & Economics


Feed accounts for approximately 75% of the
total cost of raising livestock
Therefore it is necessary to develop rations
that are as economical as possible
Poisonous Plants



Should not be included in the diet
Sometimes grow in hay fields or pastures
See Table 8-1 p.165
Balancing for Species and Age



Ruminants use more roughage than
nonruminants
Younger animals cannot use as much
roughage either
Also need to consider the purpose for which
the animal is being fed

For example fattening animals generally should
be fed less roughage than breeding animals
Micronutrients and Feed Additives



Used in small quantities
Care needs to be taken to thoroughly mix
these for uniform distribution
Excessive amounts of micronutrients can be
harmful
Functions of the Ration
Functions of Rations


Must be considered when determining
nutrient requirements
Functions include





Maintenance
Growth
Fattening
Production
Work
Maintenance






Primary use of nutrients is to maintain life
Animals must have energy for the functioning of the
heart, breathing and other vital body processes or the
basal metabolism
Energy is also needed to maintain body temperature
The ration must also provide protein, vitamins and
minerals, fatty acids to replace those that are
naturally lost
About ½ of the ration fed is needed for maintenance
An animal on full feed will use about 1/3 of the
ration for maintenance
Growth


Nutrients can only be used for growth after
maintenance requirements are met
Animals mature by growing


Larger species mature slower
Growth rate of large animals is faster than that
of smaller animals
Fattening



Nutrients that are not used for maintenance or
growth may be used for fattening
Fat is stored into the tissues of the body
Fat within the muscle is called marbling



Marbling makes meat juicy and good tasting
The object of fattening is to obtain the right amount
of fat in the muscle without getting too much fat
Feeds that are high in carbohydrates and fats are
used for fattening
Production





Cows, swine, horse, sheep, goats all produce
milk to feed their young
Dairy goats and cows produce milk for human
use as well
Chickens produce eggs
Sheep and goats produce mohair
All this production requires nutrients. The
nutrients depend on the kind of production
Reproduction



Requires proper nutrition
Animals may become sterile
Extremely important for pregnant animals


Most of the fetus’s growth takes place during the
last third of the pregnancy
Additional amounts of nutrients are needed
during pregnancy
Work





Horses-riding, driving
Energy needed for work comes from carbohydrates,
fats, extra protein
Other needs of the body are met before nutrients are
available for work
Animal will use fat stored in the body for work if the
ration does not supply enough
Extra salt is also needed due to animals sweating
Balancing Rations
General Principals


Must meet the nutritional needs
Nutrient allowance should be met as close as
possible

Not more than 3% below the requirement
Dry Matter





Must have a certain amount in the ration
If not the animal will be hungry
The digestive system will not function properly
Also an upper limit that varies with the animal being
fed and its size
Total dry matter in the ration of a full fed animal
should not be more than 3% above its need
Protein




Measured by the total protein (TP) need of the
animal
Digestible protein may also be used to
balance the ration
Essential amino acids must be included when
balancing a ration for nonruminants
Acceptable to allow 5-10% more protein in
the ration than the animal needs
Energy

Four methods of measurement





Digestible Energy (DE)
Total Digestible Energy (TDE)
Metabolizable Energy (ME)
Net Energy (NE)
Gross energy of feed is measured in a lab using a
bomb calorimeter

The feed is burned completely and the total amount of
heat released from the burning is the gross energy
Digestible Energy

The gross energy of the feed minus the energy
remaining in the feces of the animal after the
feed is digested
Metabolizable Energy

For Ruminants


The gross energy in the feed minus the energy
found in the feces, gaseous products of digestion
and urine
For Non Ruminants

The gross energy in the feed minus the energy
found in the feces and urine
Net Energy


Metabolizable energy minus the heat increment
Energy used for

Maintenance only NEm



Amount of energy used to keep the animal’s energy in
equilibrium-there is no net gain or loss of energy in the animal’s
body tissues
Maintenance plus production NEm+p
Production only NEp

Amount of energy need above the amount used for maintenance
that is used for work, tissue growth, fat production, fetus growth,
or milk, egg, or wool production and so on
Total Digestible Nutrients (TDN)




Total of the digestible protein, digestible nitrogenfree extract, digestible crude fiber and 2.25 X’s the
digestible fat
Gives a measure of the total energy value of the feed
when it is fed
Varies with the class of animal to which it is fed
Should not be more than about 5% more than what
the animal needs
Balancing Calcium and Phosphorus



Important in balancing rations
Should be between a 1:1 and 2:1 ratio
The ratio is more important than the total amount
being fed


Total Ca and P are often more than needed when other
requirements are met
Other mineral needs are usually not considered and
can be met with trace-mineralized salt
Vitamins




Vitamin A is taken into account when balancing the
ration
Other vitamin needs are added with out calculating
the vitamin content of the feed
Vitamin A will often be more than needed but is not
harmful
Vitamin deficiencies can occur in cattle and sheep
during pregnancy if low quality legume hay is fed

Vitamin supplements should always be added to
pregnancy rations
Getting the Most Bang for Your Buck




Some feeds are cheaper sources of nutrients than
others
Energy feeds should be compared based on the price
per pound of energy (TDN, DE, ME or NE)
Protein feeds should be compared in terms of price
per pound of total protein or digestible protein
The least expensive source of nutrients should be
used as much as possible
Relationship Between 100% Dry
Matter Basis and As-Fed Basis


All feed contains some moisture and the
amount varies with the feed, form of feed,
stage of growth at harvest, length of time in
storage, storage conditions
The appendix in the back of the book shows
the average percent dry matter in the feeds
listed
100% Dry Matter Basis

Data presented is calculated on the basis that
all moisture has been removed
As-Fed Basis

Data is calculated on the basis of the average
amount of moisture found in the feed as it is
used on the farm
Steps in Balancing a
Ration
Step 1


Identify the kind, age, weight and function of
the animal(s) for which the ration is being
formulated.
In our text suggested rations and feeding
programs are found in the units on the specific
species; these may be used for formulating
rations.
Step 2


Consult the table of nutrients to determine the
nutrient need(s) of the animal(s)
These requirements are called FEEDING
STANDARDS



Based on average requirements
May not meet the needs under specific conditions
Adjustments may be needed if unusual conditions
exsists
Step 3



Choose the feeds to be used
Consult the feed composition table to
determine the nutrient content of the selected
feed
Nutrient contents differ with species
Step 4


Calculate the amount of each feed to be used
in the ration
Sevral methods are available to do this but we
will use the Pearson Square Method
Step 5


Check the ration formulated against the needs
of the animal(s)
If there is/are excessive amount(s) of a
nutrient(s) present it may be necessary to
reformulate the ration
Determining Ration Costs



Check the ration cost to see if it is the most
economical
Calculate cost per pound or per ton
Daily cost of feeding may also be calculated if
a daily consumption rate is know
Pearson Square
45
The Pearson Square



Cannot balance rations by trial and error
Pearson Square simplifies balancing rations
Can only use two feeds at a time
Using the Pearson Square

EXAMPLE

2,000 pounds of feed is needed to feed a 100pound growing hog. A feeding standards table
shows that a 14% crude protein ration is needed.
Corn and Soybean oil meal (SBOM) are selected
as feeds. A feed composition table shows that
corn has 8.9% and SBOM has 45.8% crude
protein on an as-fed basis. How much corn and
soybean oil meal need to be mixed together for
2,000 pounds of feed?
STEP 1

Draw a square with lines connecting the
opposite corners.

Write the percent of crude protein (14) in the
center of the square.
14
STEP 2

Write the feeds to be used and their crude
protein percents at the left hand corners of the
square.
Corn 8.9
14
Soybean
oil meal 45.8
STEP 3

Subtract the smaller number from the larger,
along the diagonal lines. Write the differences
at the opposite end of the diagonals.
31.8= 45.8-14
Corn 8.9
14
Soybean
oil meal 45.8
5.1=14-8.9
STEP 3



The difference between the percent protein in the
soybean oil meal and the percent protein in the ration
are the parts of corn needed.
The difference between the percent protein in the
corn and the percent protein in the ration are the
parts of soybean oil meal neeeded.
The sum of the numbers on the right equals the
difference in the numbers on the left. This fact is
used as a check to see if the square is set up
correctly.
STEP 3
31.8 Parts Corn
Corn 8.9
14
Soybean
oil meal 45.8
36.9
5.1 Parts SBOM
36.9
STEP 4

Divide the parts of each feed by the total parts
to find the percent of each feed in the ration
 Corn 31.8/36.9x100=86.2%
 Soybean oil meal 5.1/36.9x100=13.8%
STEP 5

It is known that 2,000 pounds of the mixture
is needed. To find the pounds of each feed in
the mix, the percent of each feed is multiplied
by the total pounds of the mix


Corn 2,000 x 0.862= 1,724 pounds
SBOM 2,000 x 0.138= 276 pounds
*Numbers have been rounded to full pounds.
STEP 6

Check the mix to ensure that the protein need is met.
Multiply the pounds of the feed in the it’s precent
protein .



Add the pounds of protein together


153 + 126 = 279
Divide by the total weight of the mix


Corn 1,724 x 0.089= 153 lbs of Corn
SBOM 276 x 0.458= 126 lbs of SBOM
279/2,000 x 100= 14%
The mix is balanced for crude protein content!
Using the Pearson Square to Mix Two
Grains with a Supplement (START)


Can be used to find out how much of two
grains should be mixed with a supplement
Proportions of grain must be known first
EXAMPLE

2,000 pound mix of corn, oats and soybean oil
meal is needed. The mix is to contain 16%
Digestible Protein. A decision is made to use
¾ corn and ¼ oats in the mix. Thus, the
proportion of corn to oats is 3:1. How many
pounds of corn, oats and soybean oil meal are
needed?
STEP 1


Need to find the weighted average percent of
protein in the corn and oats first.
To do this

Multiply the proportion of corn (3) by the percent
digestible protein in corn (7.1). Do the same for
oats. Then add the two answers together and
divide by the total parts (4). This answer is the
weighted average percentage of digestible
protein in the corn oats mix.
STEP 1 cont…



3 x 7.1=21.3 (Corn)
1 x 9.9= 9.9 (Oats)
31.2
31.2/4= 7.8% Digestible Protein in the cornoats mix
Using the Pearson Square X


Used in the same method as before to mix two
feeds.
On a sheet of paper, work out this problem
3 parts Corn, 1 part oats 7.8
16
Soybean oil meal 41.7
Using the Pearson Square


Same method can be used for mixing two protein
supplements and 1 grain
Can also be used to mix 2 grains and 2 protein
supplements


Just remember that the proportions of like feed must be
decided upon before hand and the weighted average
percent of protein found
Any measure of nutrients in the feed may be used


Energy- TDN, NE, ME, DE
Protein- CP, DP
Balancing A Swine Ration

See p. 178-179 in Text
Balancing a Ration for Beef

See p. 179-181 in Text
Using Algebraic Equation to Balance
Ration


May be used instead of Pearson Square
Basic equations are



Equation #1


X= pounds of grain needed
Y= pounds of supplement
X+Y= Total Pounds of Mix Needed
Equation # 2

(% Nutrient in grain) x (X) + (% Nutrient in Supplement)
x (Y)= pounds of nutrient desired in mix
EXAMPLE


Same problem as the 1st Pearson Square
Example
Mix of 2,000 lbs is to be balanced for protein
using two feeds.
EXAMPLE cont…

Place the desired values in equation 2


REMEMBER TO EXPRESS % AS DECIMALS
0.089X+0.458Y=280

280 is found by multiplying the quantity of feed
(2,000 lbs) by the percent (14) [or the amount] of
nutrient desired: 2,000x0.14)
EXAMPLE cont…

Either X or Y must be canceled by the
multiplication of equation 1 by the percentage
of nutrients for either X or Y, and the
resulting equation 3 is subtracted from
equation 2. This example uses the percentage
crude protein for corn (0.089), giving
equation 3

0.089X+0.089Y=178 (178 is found by
multiplying 0.089 times 2,000 lbs)
EXAMPLE cont…

SUBTRACT equation 3 from equation 2


0.089X+0.458Y=280
-0.089X-0.089Y= -178
0.369Y=102
Y= 276 lbs soybean meal
X may then be found by substituting the value of Y
in equation 1 and solving



X+276=2,000
X=2,000-276
X= 1,724 lbs of corn
Algebraic Equations



Get the same result as Pearson square
May be used to balance rations using 3 or
more feeds
Same initial step must be taken as when using
the Pearson Square—group similar feeds into
two groups and determine the proportions of
each to be used in each group

After this is done the same procedure as above is
followed.