Module 2: Nutritional
Strategies to Minimize
Nutrient Loss to Manure
By Dave Hansen
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Goal
The goal of this module is to help
producers maximize nutrient utilization
on their animal operations while avoiding
waste and overfeeding.
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Objectives
The main objectives of this module are to
provide information to CAFO Owner/Operators
regarding:




Basic concepts in animal nutrition.
How to improve nutrient yield.
Techniques for reducing ammonia loss.
Economic considerations when reducing
nitrogen (N) and phosphorus (P) excretion.
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Contents
1. Basic nutrient cycling in animal systems
2. National Research Council (NRC) guidelines
3. Dietary strategies to improve nutrient efficiency

Dairy

Beef

Swine

Poultry
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Basic Nutrient Cycling
 The idea is the same regardless of animal (or
bird) type: to provide adequate nutrients
while minimizing waste.
 Providing nutrients in excess of animal
requirements results in increased costs of
production and contributes to potential
environmental problems.
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Basic Nutrient Cycling
(continued)
Feed provided
Inefficiencies can be
caused by a variety
of factors including
housing conditions,
management,
genetics, and feed
quality.
Waste
Feed waste
Feed consumed
Inefficiencies
Intestinal secretions
(enzymes, cells)
Undigested
feed
and secretions
Nutrients absorbed
Maintenance
Nutrients available for
growth
Mismatch
Nutrients used for
growth
Inefficiencies
Growth
Nutrient paths in animal feeding operations.
Source: van Heugten and van Kempen 2000
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Nutrient Flow in an Animal
Operation
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Basic Nutrient Cycling
Nitrogen and P present different challenges.
Improving the efficiency of N use often includes
changes in the source of N, such as improving
forage quality or supplementing with amino acids.
Improving the efficiency of P use often includes
reducing unnecessary additions of supplemental
P (as with ruminants) or increasing the availability
of dietary P through such techniques as adding
phytase (as with swine and poultry).
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NRC Guidelines
In 1916 the National Academy of Sciences
organized the NRC to “…associate the broad
community of science and technology with the
Academy’s purposes of furthering knowledge
and advising the federal government.”
The various subcommittees address animal
nutrition issues and develop guidelines for each
animal type.
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NRC Guidelines (continued)
These guidelines are updated periodically to
incorporate new information.
The following tables are for dairy, beef cattle,
swine, and poultry.
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NRC Guidelines: Dairy
Holstein, 1,5000 lb.,
average body
condition 65 mo.age
Milk yield, lb/d
90 Days in Milk
Early Lactation
Dry, Pregnant 270
Days in Gestation
BW 1,656 lb
55
77
99
120
55
77
Dry matter intake lb/d
44.7
51.9
59.2
66
29.7
34.3
30.1
Net energy, Mcal/lb
0.62
0.67
0.7
0.73
0.94
1.01
.48
Diet % RDP
9.5
9.7
9.8
9.8
10.5
10.5
8.7
Diet % RUP
4.6
5.5
6.2
6.9
7
9
2.1
Crude Proteina %
14.1
15.2
16.0
16.7
17.5
19.5
10.8
Calcium, %
0.62
0.61
0.67
0.60
0.74
0.79
0.45
Phosphorus,%
0.32
0.35
0.36
0.38
0.38
0.42
0.23
Potassiumb, %
1.00
1.04
1.06
1.07
1.19
1.24
0.52
Sodium, %
0.22
0.23
0.22
0.22
0.34
0.34
0.10
Copperc, ppm
11
11
11
11
16
16
13
Zinc, ppm
43
48
52
55
65
73
22
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NRC Guidelines: Beef, Finishing
Body Weight, lb.
Dry Matter Intake,
lb/d
Daily Gain, lb.
525
650
14
17
19.5
Crude Protein,
1.36 lb/d
1.49
1.0
1.8
2.5
3.3
4.0
1.22
1.55
1.87
2.18
2.49
1.0
1.8
2.5
3.3
4.0
0.04
0.06
0.08
0.10
0.11
0.04
0.06
0.08
0.09
0.11
1.0
1.8
2.5
3.3
4.0
0.02
0.03
0.04
0.04
0.05
0.02
0.03
0.04
0.04
0.05
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775
1.69
2.01
2.32
2.62
1.82
2.13
2.43
2.73
Calcium,
lb/d
0.05
0.06
0.08
0.09
0.10
Phosphorus, lb/d
0.03
0.03
0.04
0.04
0.05
900
1025
1150
21.5
23.5
25.5
1.57
1.86
2.14
2.40
2.66
1.65
1.91
2.15
2.38
2.60
1.72
1.95
2.16
2.36
2.54
0.05
0.06
0.07
0.09
0.10
0.00
0.06
0.07
0.08
0.09
0.05
0.06
0.07
0.08
0.09
0.03
0.03
0.04
0.05
0.05
0.03
0.04
0.04
0.05
0.05
0.03
0.04
0.04
0.05
0.05
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NRC
Guidelines:
Beef,
Cows
Protein, Ca, and P requirements for beef cows
Months
Since
Calving
Body
Weight
lb.
0 (Calving)
1,340
1
1,200
2 (Peak Milk) 1,200
3
1,205
4
1,205
5
1,205
6
1,210
7 (Weaning) 1,215
8
1,225
9
1,240
10
1,260
11
1,290
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DM
Intake
lb.
24.6
26.8
27.8
28.4
27.4
26.5
25.7
24.2
24.1
24.0
23.9
24.1
CP
Ca
P
------------------ lb/d -----------------2.20
0.06
0.04
2.71
0.08
0.05
2.97
0.09
0.06
2.82
0.08
0.06
2.54
0.07
0.05
2.26
0.06
0.04
2.04
0.06
0.04
1.45
0.04
0.03
1.49
0.04
0.03
1.57
0.04
0.03
1.69
0.06
0.04
1.89
0.06
0.04
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NRC Guidelines: Swine
Nutrient
Pig Weight Pig Weight Pig Weight Pig Weight Pig Weight Pig Weight
3-5 kg
5-10 kg
10-20 kg
20-50 kg
50-80 kg
80-120 kg
(7-11 lb)
(11-22 lb) (22-44 lb (44-110 lb) (110-176 lb) (176-265 lb)
Crude Protein,
%
Lysine,
% total
Lysine, % appt.
ileal dig
Calcium, %
P, %
total
P, %
avail.
Potassium,
%
Sodium, %
Copper, mg
Zinc, mg
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26.0
23.7
20.9
18.0
15.5
13.2
1.5
1.35
1.15
0.95
0.75
0.60
1.26
0.90
1.11
0.80
0.94
0.70
0.77
0.60
0.61
0.50
0.47
0.45
0.70
0.65
0.60
0.50
0.45
0.40
0.55
0.30
0.25
6
100
0.40
0.28
0.20
6
100
0.32
0.26
0.15
5
80
0.23
0.23
0.10
4
60
0.19
0.19
0.10
3.5
50
0.15
0.17
0.10
3
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NRC Guidelines: PoultryChickens
Nutrient
Layer80a,b
Layer100a,b
Layer120a,b
Broiler
0-3 wk
Broiler
3-6 wk
Broiler
6-8 wk
Protein, %
18.8
15.0
12.5
23.0
20.0
18.0
Ca, %
4.06
3.25
2.71
1.00
0.90
0.80
Pc , %
0.31
0.25
0.21
0.45
0.35
0.30
Potassium, %
0.19
0.15
0.13
0.30
0.30
0.30
Copper, mg
?
?
?
8
8
8
Zinc, mg
44
35
29
40
40
40
0.19
0.15
0.13
0.20
0.15
0.12
Sodium, %
a Grams feed intake/hen daily
b Based on dietary metabolizable energy concentration of approximately 2,900 kcal/kg (1,318 kcal/lb) and an assumed 90% egg production rate (90 eggs daily
per 100 hens).
c Phosphorus is nPP.
1Adapted from Tables 2-3, 2-6, 3-1, 5-1. Nutrient Requirements of Poultry, 9th Revised Edition, 1994. National Research Council.
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NRC Guidelines: Poultry-Turkeys
Nutrient
Turkey
0-3 wk
3-6 wk
6-9 wk
9-12 wk
12-15 wk
15-18 wk
Protein, %
28.0
26.0
22.0
19.0
16.5
14.0
Ca, %
1.2
1.0
0.85
0.75
0.65
0.55
P, %c
0.6
0.5
0.42
0.38
0.32
0.28
Potassium, %
0.7
0.6
0.5
0.5
0.4
0.4
Copper, mg
8
8
6
6
6
6
Zinc, mg
70
65
50
40
40
40
0.17
0.15
0.12
0.12
0.12
0.12
Sodium., %
a Grams feed intake/hen daily
b Based on dietary metabolizable energy concentration of approximately 2,900 kcal/kg (1,318 kcal/lb) and an assumed
90% egg production rate (90 eggs daily per 100 hens).
c Phosphorus is nPP.
1Adapted from Tables 2-3, 2-6, 3-1, 5-1. Nutrient Requirements of Poultry, 9th Revised Edition, 1994. National
Research Council.
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NRC Guidelines: Poultry-Other
Nutrient
Duck
0-2 wk
Duck
2-7 wk
Duck
Breeding
Turkey
Tom
Turkey
Hen
Protein, %
22.0
16.0
15
12.0
14.0
Ca,%
0.65
0.60
2.75
0.50
2.25
P,%C
0.40
0.30
?
0.25
0.35
Potassium,
%
?
?
?
0.4
0.6
Copper, mg
?
?
?
6
8
Zinc, mg
60
?
?
40
65
0.15
0.15
0.15
0.12
0.12
Sodium, %
a Grams feed intake/hen daily
b Based on dietary metabolizable energy concentration of approximately 2,900 kcal/kg (1,318 kcal/lb) and
an assumed 90% egg production rate (90 eggs/100 hens daily).
c Phosphorus is nPP.
1Adapted from Tables 2-3, 2-6, 3-1, 5-1. Nutrient Requirements of Poultry, 9th Revised Edition, 1994.
National Research Council.
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Feed Waste



Poor feeder design, poor feeder
management, and spoilage during storage
can lead to losses as great as 20%.
Example: Swine “rooting” through feed can
cause 3.4% waste.
Example: Feed costs account for as much as
70% of the cost of raising poultry–a little waste
means big $$.
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Dietary Strategies to Improve
Nutrient Efficiency
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Strategies for Dairy Producers

Properly formulate
rations to

Optimize milk yield.

Minimize N, P, and
potassium excretion
in urine/manure.
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Strategies for Dairy Producers
(continued)

Precisely meet requirements for
 Milk
production.
 Maintenance.
 Gestation.
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Key Concepts of Nutrient
Balance on a Dairy Farm

Understand nutrient INPUTS,
OUTPUTS, and % of nutrients that
remain on the farm or that are lost to
the environment.

Assess your nutrient balance. This
allows you to determine management
options that increase the recycling of
nutrients from cropland to cattle and
back to crops again.
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Key Concepts of Nutrient
Balance on a Dairy Farm
(continued)

The percentage of dietary N and P that remain
on the dairy farm can be as high as 76% and
81% (respectively).

Point: Profitable milk production includes both
milk productivity and efficiency of nutrient
utilization.
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Nitrogen Strategies for Dairy

Increase dry matter uptake.

Improve forage quality.

Consider forage protein fraction.

Consider feeding method.

Consider supplemental protein source.

Monitor blood urea nitrogen (BUN) and milk urea
nitrogen (MUN).
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Nitrogen Balance
Input
Purchased fertilizer
Purchased feed
N fixation by legumes
Purchased cattle
Total inputs
Output
Milk
Cattle sold
Crops sold
Total Outputs
Remainder
% Remaining on farm
Size of Dairy, Number of Cows*
45
320
500
-----(tons of N per year)----1.0
13.5
26.1
3.8
43.8
78.5
1.3
14.6
13.9
0
0.1
0
6.1
72.0
118.5
2.0
0.1
.01
2.2
3.9
64%
18.6
1.9
0
20.5
51.5
71%
26.4
1.9
0
28.3
90.2
76%
Table Mass N balance for New York dairy farms.
Source: Klausner 1993
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A Few Terms and Definitions

Crude protein (CP) = N x 6.25

Rumen degradable protein (RDP) = CP that is
degraded in the rumen; required by bacteria to
grow

Rumen undegradable protein (RUP) = “escape
or bypass” CP that is NOT degraded in rumen
but passes to lower tract
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Increase Dry Matter Uptake




The percentage of CP required to supply adequate
protein for milk production varies
with intake level.
Increasing dry matter intake by 5% reduces the CP
needed by about 1%.
Higher intake levels also increase microbial protein
synthesis in the rumen.
Increasing intake level, then, can decrease the need
for higher dietary protein.
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Improve Forage Quality

“High-quality” forage contains more protein, less
fiber, and more energy, resulting in more protein
and digestible dry matter for the animals, which
can help reduce the amount of N inputs from offfarm sources.
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Forage Protein Fractions

Supplementing a highly degradable (e.g.,
legume silage) forage with a less degradable
forage (e.g., corn silage) can improve milk
production at lower CP levels.

Common supplemental RUP sources include
blood meal, distillers grains, and soybeans.
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Feeding Method

Feeding sequence, frequency, and grouping
strategy can impact N utilization.

Lactating cows require a proper balance of
RUP and RDP to meet requirements for
metabolizable protein (MP).

MP is the protein that the cow actually absorbs
and uses for production.
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Feeding Method (continued)

Requirement for RUP = 35% to 38% of CP

Requirement for RDP = 62% to 65% of CP

A study by Van Horn (1992) showed the impact
of considering RUP and RDP.

The lactating cows fed the proper amount of
RUP to supplement RDP generated 223 pounds
of N per year in manure.
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Feeding Method (continued)

The cows fed simply to satisfy Total CP (i.e., a
higher percentage of RUP) generated 260
pounds of N per year in manure.
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Monitor BUN and MUN


The MUN test
 > 18 mg/dl indicates that too much protein is
being fed or there is not enough dietary starch.
High MUN is related to
 Lower reproductive performance.
 Higher feed costs.
 Health problems.
 Poorer milk production.
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Monitor BUN and MUN
(continued)

MUN analyses can be used to signal potential
problems with feeding programs.
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Phosphorus Strategies for Dairy





Phosphorus is an expensive supplement.
Most commercial mixes include P.
Current guidelines specify 0.32% to 0.42% P for
lactating cows.
It is common for producers to feed as much as
0.60% P.
Numerous studies show no production benefit
from these high levels of P!
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Phosphorus Balance
Input
Purchased fertilizer
Purchased feed
Total inputs
Output
Milk
Cattle sold
Crops sold
Total Outputs
Remainder
% Remaining on farm
Size of Dairy, Number of Cows*
45
320
500
-----(tons of P per year)----1.2
2.0
5.5
1.0
8.4
14.2
0
0.03
0
2.2
10.4
24.2
0.36
0.05
0.01
0.43
1.8
81%
3.8
0.5
0
4.3
6.2
59%
5.5
0.5
0
6.0
18.2
75%
Mass P balance for New York dairy farms
Source: Klausner 1993
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Effect of P Intake on P Excretion
P excretion (lb)

Increasing P content
from 0.40% to 0.60%
of diet dry matter
increases P output
from 40 to 69
lbs/cow/year!
70
60
50
40
30
20
10
0
0.4
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2-37
Sources of P


High availability
 Monocalcium phosphate
 Dicalcium phosphate
 Monosodium or ammonium phosphate
Medium availability
 Steamed bone meal
 Sodium tripolyphosphate
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Sources of P (continued)

Low availability

Low-fluorine rock phosphate

Soft rock phosphate
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Phytate P

Phytate-P is not readily available to nonruminants such as swine.

However, rumen microbes produce phytase.

Releases P from phytate

So, phytate-P is available to ruminants.

And, it is not necessary to over-supplement P
above requirements.
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Feeding Excess P Costs $$$

P is the most expensive mineral commonly
supplemented in dairy cows.

Example: A diet containing 0.45% P vs. a diet
containing 0.55% P would save about $0.05
per cow daily.

For 100 cows a year, that is $1,825.
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Feeding P: The Bottom Line
 The milking herd should be grouped by
production level so that multiple rations
can be formulated over the complete
lactation.
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The Bottom Line for Dairies
 Are high milk yield and minimal nutrient excretion
mutually exclusive?
 No, you can do both!
 Focus on
 Testing all forages/feeds.
 Properly formulating rations.
 Maximizing feed intake.
 Cow comfort and proper grouping.
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Strategies for Beef Cattle
 Develop a general understanding of N (protein)
and P metabolism in feedlot cattle.
 Understand current methods for decreasing N
and P excretion by manipulating beef feedlot
diets

P requirements

Protein requirements
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Nitrogen Management

Discuss protein requirements

Impact of lowering dietary N
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Dietary Protein
Theory for lowering protein
 All excess protein above requirements have
no value.
 Excess protein is absorbed in the small
intestine.


Protein is de-animated in the liver.
Urea is subsequently excreted in urine at
the kidney.
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Dietary Protein (continued)
 Urea is rapidly converted to ammonia following
deposition. Therefore,

Feeding less protein leads to less urea
excretion.

Lower urea excretion should decrease
ammonia.
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Dietary Protein (continued)
CP system
 Assumes all proteins are equal.




Important point: protein is N
% N * 6.25, protein is ~16% N
Does not account for bacterial needs.
Is simple but incorrect!
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Protein Requirements
MP system
 DIP * TDN * microbe efficiency = BCP
(degradable N and energy)




Efficiency dependent on rumen pH, ~8-8.5
BCP*.64 to determine protein at S.I.
UIP * .80 to estimate protein at S.I.
BCP + UIP = MP
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Protein Requirements
(continued)
Rumen
Feed protein
urea, corn
protein
DIP
NH3 + carbon =
microbial protein
(BCP)
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BCP
MP system
UIP
DIP
BCP
Certified Nutrient Management Planning
MP Small
Intestine
2-50
N Balance Summary
 Overfeeding protein increases N losses.
 Nutrition may:

Decrease N inputs by 10% to 20%.

Reduce N excretion by 12% to 21%.

Reduce N volatilization by 15% to
33%.
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N Balance Summary (continued)
 Volatilization depends on the time of year.

Summer–60 to 70% of N excreted

Winter/spring–40% of N excreted
 Based on annual occupancy, lose 50% of N
excreted.
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P Management
x
x
x
x
x
x
x
x
x x x
x
x
x
x
x
x
x
NRC predicts requirements from 0.22% to 0.32% of diet DM.
P intake
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% diet P (DM-basis)
Dietary P in Feedlot Diets
0.7
0.6
0.5
0.4
Supplement
Byproduct
Corn
Roughage
0.59
0.52
0.35
0.27
0.3
0.2
0.1
0
85% Corn 85% Corn + Byproduct Byproduct +
Supplement
Supplement
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P Requirements: Yearlings
Bone Ash
P intake
Phalanx
% DM
0.14
0.19
0.24
g/d
16.4
19.9
27.6
g
28.3
27.5
28.9
% HCW
3.64
3.64
3.72
0.29
0.34
32.0
36.2
27.5
28.5
3.55
3.84
SE
.7
Erickson et al., 1999. J. Anim. Sci.
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1.0
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.20
2-55
P Requirements: Yearlings
(continued)
Metacarpal Phalanx
Erickson et al., 1999. J. Anim. Sci.
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2-56
P Requirements: Calves
Feed
% of Diet DM
%P
High-moisture corn
33.5
0.32
Brewers grits
30.0
0.08
Corn bran
20.0
0.08
Cottonseed hulls
7.5
0.11
Animal fat
3.0
----
Supplement
6.0
0.09
Note: NaH2PO4 provided as top-dress supplement at increments
of 0.06% P.
Base diet = 0.16% P, and 0.22, 0.28, 0.34, 0.40
Erickson et al., 1999. J. Anim. Sci.
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2-57
P Mass Balance: Summer
Yearlings
Feedlot Pen
0.35% P diet
0.24% P diet
10.9 lb
excreted
5.3 lb
excreted
1.9 lb
anima
l
12.8 lb
intake
1.9 lb
anima
l
REDUCE
D
44%
7.2 lb
intake
Erickson et al., ISAAFPW, 2000
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2-58
P Mass Balance: Winter/Spring
Calves
Feedlot Pen
0.40% P diet
0.26% P diet
12.5 lb
excreted
7.5 lb
excreted
2.5 lb
animal
2.4 lb
anima
l
15.0 lb
intake
REDUCE
D
33%
9.9 lb
intake
Erickson et al., ISAAFPW, 2000
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2-59
P Mass Balance (continued)
0.35%-0.40% P
234,000 lb/yr
0.22%-0.30% P
128,000 lb/yr
15,690 acres
Assume:
50% of surrounding land used
30 lb/ac P applied (agronomic)
10,000 hd feedlot, 90 acres
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Certified Nutrient Management Planning
8,624 acres
Assume: (same)
2-60
P Balance Conclusions
 Overfeeding P leads to elevated manure P.
 Nutrition may:
Decrease P inputs by 33% to 45%.
Reduce P excretion by 40% to 50%.
 Direct reduction in acres needed
 Expect manure removal = nutrient excretion for
P
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2-61
Beef Strategies Overview

Test feed.

Use supplemental protein.

Discontinue supplemental P.

Consider phase feeding.

Utilize differences between DIP and UIP.

Use available tools to evaluate your rations.
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2-62
Summary

Nutrition can have a major impact on N and P
excretion for feedlot cattle.
 Phosphorus supplementation is unnecessary.
 It is difficult to further decrease P below what
corn provides.
 Utilizing an MP system may lower N excretion.
 Decreased urinary N excretion decreases N
volatilization losses.
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2-63
Summary (continued)




Volatization is a large concern.
More management options and/or nutritional
techniques need to be explored.
Fine-tuning requirements on the MP system is
needed.
Eventually, metabolizable amino acids (AAs) will
be useful similar to the ideal protein concept in
monogastrics.
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2-64
Strategies for Swine
 Feed waste issues
 Improving N management
AAs
 Improving P management
Phytate-P
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2-65
Nutrition: The Easy Way to
Reduce Waste?
 Under field conditions, animals use nutrients with
mediocre efficiency:
P: 30%
N: 30% to 35%
 Under lab conditions:
N: 70%
P: close to 100%
 There is a lot of potential for reducing waste.
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2-66
The Key: Understanding
Inefficiencies in Nutrient
Utilization
 Many steps are involved
Feed provided
Waste
Feed waste
Feed consumed
Inefficiencies
Undigested
feed
and secretions
Intestinal secretions
(enzymes, cells)
Nutrients absorbed
Maintenance
Nutrients available for
growth
Mismatch
Nutrients used for
growth
Inefficiencies
Growth
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in the utilization of
nutrients.

Each step has
inefficiencies
associated with it.
 The key to reducing
waste is to understand
where utilization can be
influenced.
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2-67
Feed Waste: An Expensive Loss
of Nutrients
Feed waste

Feed provided
Waste

Feed waste

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Adherence: pigs take
1.5 g feed away from
feeder 60 times/day
(~ 4% of “intake”)
 Portion may be
returned.
Spillage: pigs push
3.4% of feed out of
feeder (in practice,
range 1.5% to 20%).
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2-68
Feed Waste: An Expensive Loss
of Nutrients (continued)

Presuming 5% waste on average:

Responsible for 7.5% of N in waste.

Similar contribution for copper, zinc, and P

35% of carbohydrates

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Major source of odor
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2-69
Management: Key to Solving
Feed Waste . . .

Traditional guidelines:

Proper feeder care and adjustment can
reduce feed waste drastically.
 Bottom
of feeders should be 50% covered
with fresh feed.
• Pig needs to exert effort to eat.
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2-70
Management: Key to Solving
Feed Waste . . . (continued)
 Feeders
should be inspected at least
weekly.
• Clean and adjust where necessary.
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2-71
Feeder Design may add to the
Problem.

Feeders should be sized properly.

Only one pig per feeder space
 Challenge

given that pigs change in size
Pigs should not have to step in feeders to
gain access to feed.
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Certified Nutrient Management Planning
2-72
Feeder Design may add to the
Problem. (continued)

Feeders should be deep enough to prevent
pigs from pushing out feed.

Catch 22 but 8 inches deep seems to work
reasonably well.
• Problem exaggerated in wean-finish
buildings.

Feeders should not have “dead” corners
where feed gets trapped and spoils.
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2-73
Feeder Design: The “Ideal”

Pigs like to chew and swallow with their heads
straight.
 Traditional feeder design does not allow this over
the feeder.
 Pig needs to back up.
• Waste falls in the pit.
 Thus, feeders should be “spacious.”
 Filling level not an issue?
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2-74
Present Feed in most Palatable
Form.
 Feed should be pelleted.

Reduces feed waste ~5%
 Dry feed is not very palatable.

Pigs move back and forth from feeder to
waterer while eating, dropping feed.
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2-75
Present Feed in most Palatable
Form. (continued)

Wet-dry or liquid feeders

Back and forth motion is prevented.
 Reduces
feed waste
 Increases
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feed intake and weight gain
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2-76
Select Highly Digestible
Ingredients.
Protein
Digestibility,
Content,
%
%
85
8.5
87
49.0
84
45.6
89
13.3
75
15.7
85
10.6
83
9.2
84
49.1
77
57.7
88
62.9
Phosphorus
Feed Ingredient
Digestibility,
Content,
%
%
Corn
14
0.28
Soybean meal 48
23
0.69
Soybean meal 44
31
0.65
Wheat
50
0.37
Wheat bran
29
1.20
Barley
30
0.36
Sorghum
20
0.29
Meat & bone meal
95
4.98
Poultry byproducts
95
2.41
Fish meal
95
2.20
Dicalcium phosph
100
18.50
Adapted from NRC 1998, and the Rhone-Poulenc Nutrition Guide 1993.
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2-77
New Crops offer new Solutions.
P%
Total
Phytate
Bio-available
Normal Corn
0.25
0.20
0.05
Low-Phytate
Corn
0.28
0.10
0.21
 Low-phytate corn and soybeans have much
higher P digestibility.
 Low-stacchyose soybean meal has higher
protein and energy digestibility.
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2-78
Processing can Improve Nutrient
Digestibility.
 Grinding:

Grind feed to uniform particle size of ~ 600
microns.
 Pelleting:

Improves protein digestibility 3.7%.
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2-79
Processing can Improve Nutrient
Digestibility. (continued)
 Expanding/extruding:

Improves pellet quality.

Effects on digestibility are very dietdependent.
 Effects
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can be negative!
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2-80
Opportunities with Enzymes
 Fiber-degrading enzymes

Wheat/barley/rye as major ingredients:
 Xylanase/beta-glucanase
improve
digestibility 2% to 9%.

Corn-soy diets:
 Alpha-galactosidase,
proteases, etc.
may prove effective.
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2-81
Phytase Effect on P Availability
 Plants contain a large portion of P in the form of
phytate.

Pigs cannot digest phytate.
 Most
plant P is thus unavailable.
 Phytase can break down phytate, releasing the
P.

In a typical diet, P availability increases from
30% to 50%.
 30%
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reduction in P excretion
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2-82
Feed Quality Affects the
Recycling of Enzyme Protein.
 High-fiber diets reduce the absorption of protein,
including enzymes.

Fiber is the single most predictive factor for
apparent protein digestion.
 Has
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a strong negative influence
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2-83
The More Ingredients that are
used, the Better the Match!
 Feed nutrients often
are wasted because
the diet is not ideal.
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No synthetics
Lysine added
Lys, M et, Thr, Try added
1.8
1.6
1.4
1.2
Percent
A 1% point reduction in
dietary protein results in
a 10% decrease in N
excretion and ammonia
emission.
Requirem ent
1.0
0.8
0.6
0.4
0.2
0.0
Protein/10
arginine
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lysine
SAA
threonine
2-84
The More Ingredients that are
used, the Better the Match!
(continued)
 Contributors to this issue:

Small number of ingredients.
 Limits
flexibility in matching animal-specific
profile.
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2-85
Formulate on Available Nutrients.
Availability of nutrients
is not uniform.
 Presuming that all
nutrients are equally
available leads to
larger mismatch,
may hurt performance, and thus
increases waste.
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Digestible lysine
110
100
Gain (relative)
 In typical feed, N > P
and Lys > Cys.
Total lysine
90
80
70
60
50
Soybean
meal
Sunflower
meal
Rapeseed
meal
Diets formulated on total
or digestible amino acids
Certified Nutrient Management Planning
2-86
Diets Should be Optimally
Matched to the Animal’s
Requirement.
 Nutritional requirements change with:

Maintenance requirement (affected by sex,
age, and weight).

Gain and composition of gain.

Health status, environmental conditions, and
activity.
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2-87
Diets Should be Optimally
Matched to the Animal’s
Requirement. (continued)
Examples of nutritional strategies:
 Split-sex feeding

Barrows require more energy for
maintenance than gilts.

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Increase energy-to-protein ratio of the
feed for barrows.
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2-88
Diets Should be Optimally
Matched to the Animal’s
Requirement. (continued)
 Temperature outside of thermo-neutral zone

Energy is used for thermo-regulation.

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Increase energy-to-protein ratio.
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2-89
Phase Feeding Reduces Waste
 Nutritional requirements
change continuously.
Protein-to-energy
ratio of feed decreases with age.

Diet should be
adjusted to
match this
decrease.
Continuous
3 phase
2 phase
1 phase
0.90
Lysine requirement (%)

0.80
0.70
0.60
0.50
0.40
50
100
150
bodyweight (lbs)
200
250
• Phase feeding
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2-90
Phase Feeding Reduces Waste.
(continued)
Inefficiencies occur when the diet provides
more nutrients than the animal needs:
More phases = less waste
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2-91
Phase-Feeding Diets are less
Expensive.
 More phases = less waste and cheaper diets.

But also = more hassle

Compromise between number of phases and
benefits achievable
 In-line mixers/liquid feeding systems allow for
continuously changing the diet composition
without increasing hassle.
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2-92
Phase-Feeding Diets are less
Expensive. (continued)
$43
Diet cost per pig
Diet cost obtained
using least-cost feed
formulation for a
varying number of
phases in the feeding
program.
$42
$41
$40
$39
1 2 3 4 5 6 7 8 9 10 11 12 13
Number of phases
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2-93
Precision Nutrition is Hindered
by Feed Manufacturing Issues.
 Feed manufacturing issues

Variation in ingredient quality
 Somewhat compensated for by over
formulating (= more waste)

Weighing errors

Mixing problems
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2-94
Precision Nutrition is Hindered
by Feed Manufacturing Issues.
(continued)
 All augment waste and possibly reduce
performance.
1000
100
10
1
0
-100
-80
-60
-40
-20
0
20
40
60
80
100
120
140
160
180
200
Weighing errors were
observed in 14 feed
mills specializing in
swine feeds.
Frequency
10000
Weighing error (%±1)
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2-95
Is Mineral Nutrition Overdone?
 Diets are typically over-formulated as a measure
of security.

Increases waste.
Mineral
Calcium, %
Phosphorus, %
Copper, ppm
Zinc, ppm
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Req.
0.75
0.60
5
50
Sow Diets
Range
0.62-2.01
0.45-1.17
12-222
79-497
Median1
1.21
0.84
22
167
Req.
0.50
0.40
3
50
Certified Nutrient Management Planning
Finisher Diets
Range
Median1
0.57-1.38
0.96
0.45-0.78
0.62
9–281
20
103-205
149
2-96
Is Mineral Nutrition Overdone?
(continued)
 The P requirement is higher for maximizing bone
strength than for maximizing gain.

Difference of 0.1% point
 For
non-reproducing animals, formulating
diets to maximize gain may be warranted.
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2-97
Strategies for Poultry
 Nitrogen management
Amino acid
Phase feeding
Enzymes and
additives
 Phosphorus
management
Available P
Phytate-P
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2-98
Tracking N in Broilers
Feed N = 100%
18.3%
30.6%
51.1%
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Certified Nutrient Management Planning
Litter
Carcass
NH3-N
2-99
Dietary Strategies for N





Formulate on amino acids (AAs), not CP.
Optimize the dietary AA profile.
Phase feeding
Utilize the “true AA digestibility” of feeds.
Select feed ingredients with low nutrient
availability.
 Utilize enzymes and feed additives.
 Avoid anti-nutritional factors.
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2-100
Formulate on Amino Acids
 Formulating based on AA rather than CP can
lower N content by lowering dietary N input.
 Utilizing AAs, such as methionine and lysine,
reduces dietary protein from 18% to 16% and
reduces the cost of the diet by more than $4/ton.
 Although it is possible to reduce dietary CP
levels by 3% to 4% (13%-22% N), there are
biological limits to the amount of dietary protein
that can be replaced with synthetic AAs.
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2-101
NRC Requirement vs. 23% CP
Corn/Soy Diet
2.5
2
1.5
%
NRC
requirement
1
23% CP
corn/soy
0.5
0
Arg Gly His
+
Ser
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Ile
Leu Lys Met Phe Thr Val Trp
+
+
Cys Tyr
Certified Nutrient Management Planning
2-102
Optimize the Dietary AA Profile
 Matching the birds' dietary AA with their
biological needs minimizes N excretion.
 However, simply supplementing AAs, such as
methionine and lysine, can result in excesses of
other AAs that are then excreted.
 A possible solution is an “ideal protein”
supplement that provides all the essential AAs in
their proper proportion.
 These “proper proportions” are not always
known!
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2-103
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2-104
Phase Feeding
 The nutritional requirements of birds change
over time.

Example: Broilers require approximately 22%
CP at hatching and 16% CP at four weeks.
 Commercial programs can include as many as
six different phases to step down dietary protein.
 Further refinements are possible based on feed
sources and timing of grow-out period.
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Utilize “True AA Digestibility.”
 Amino acid digestibility varies with feed type.
 Diets should be based on the digestible fraction
rather than simply the amount of AAs present in
the feed.
 Calculated digestible AA requirements can be
8%-10% lower than total AA requirements.
 Formulation based on digestible AAs improves
daily gain and feed conversion.
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2-106
Select “Low-Nutrient” Feeds.
 Variability in the nutrient values of common
feeds leads nutritionists to add a margin of
safety, ensuring that nutritional needs are met.

Example: The AA content of meat meal can
vary by as much as 45%.
 Rapid ingredient analysis techniques, such as
NIR, provide real-time information on the feed's
nutritional value.
 This information reduces the need for overformulation as a safety margin.
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2-107
Meat Meal Variation
AA
Met
Cys
Lys
Thr
Arg
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A
0.61
0.70
2.77
1.73
3.62
B
0.41
0.30
1.93
1.12
3.00
C
0.49
0.39
1.94
1.25
2.90
Mean
0.50
0.46
2.21
1.37
3.17
Certified Nutrient Management Planning
CV %
20.13
45.62
21.82
23.45
12.3
2-108
Utilize Enzymes and Additives.
 Water-soluble, nonstarch polysaccharides
(NSPs) impede digestion and absorption of fats,
proteins, and carbohydrates.
 Many important diet constituents, such as
soybean and peas, contain complex NSPs.
 Phytase improves the digestibility of AAs and
protein as well as phytate-P.
 Dietary enzymes can improve the digestibility of
fiber and carbohydrates.
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2-109
Avoid Anti-Nutritional Factors.
 Many legumes and cereal grains contain
compounds that have a negative effect on
digestion and the availability of AAs and other
nutrients.

Soybean contain, among other things, a
trypsin inhibitor that impedes protein
digestion.
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2-110
Avoid Anti-Nutritional Factors.
(continued)

Some beans, particularly field beans, have
high concentrations of lectins that can reduce
growth and decrease nutrient absorption.
 Minimizing the use of these inputs will increase
nutrient utilization by the birds.
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2-111
Tracking P in Broilers
Feed P = 100%
35.0%
57.4%
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Certified Nutrient Management Planning
Litter
Carcass
2-112
Dietary Strategies for P




Meet bird P requirements.
Select ingredients with available P.
Use vitamin D.
Use feed additives/enzymes.
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2-113
Meet Bird P Requirements.
 The NRC (1994) recommends 250 mg of
available P (non-phytate) per hen per day
 Leghorn breeders guide recommends 450 mg460 mg/day early in lay and 288 mg-390 mg late
in the cycle.
 Research (Scott et al. 1999, Boling et al. 2000,
and Angel 2000) suggests that the NRC
guidelines are adequate.
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2-114
Meet Bird P Requirements.
(continued)
 In a four-week period, 1.2 million hens in a large
complex consume 7.4 million lbs of feed (3,696
tons).
 If dietary available P were reduced from 450 mg
to 250 mg/hen/day, it represents a $4.82/ton cost
savings in dietary dicalcium phosphate, totaling
$17,814 in feed costs.
 With such a formulation, fecal P2O5 is reduced
approximately 35,000 lbs in one month!
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Certified Nutrient Management Planning
2-115
Select Ingredients with Available
P.
 Birds do not absorb phytic acid, or phytate-P,
well.
 Many cereal grains, such as corn and soybeans,
have a high percentage of their total P in the
phytate form, which results in an availability of
less than 20%.
 Animal meals and fish meal have nearly 100%
available P.
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2-116
Select Ingredients with Available
P. (continued)
 Inorganic supplements also have a relatively
high P availability.
 New products, such as low-phytate corn, are not
yet commercially available but have two to three
times as much available P as “standard” corn
varieties.
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2-117
Phosphate Supplement
Comparison
Compound
Biological Value
Beta-trical phosphate Std
100
Reagent: Monocal PO4
120-135
Reagent: Dical PO4
Feed: Phosphoric acid
95-100
115-125
Feed: Dical/Monocal P
105-115
Feed: Bone meal
90-100
Feed: Rock phosphate
55-75
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2-118
Use Vitamin D.
 Vitamin D deficiencies inhibit P metabolism.
 Adding 1,25-dihydroxy vitamin D3 reduced
phytate-P excretion by broilers by 35% and
increased retention by 20% (Edwards 1993).
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2-119
Use Feed Additives/Enzymes.
 Birds absorb phytate-P poorly because they lack
the enzyme phytase.
 In addition to improving AA efficiency, adding
phytase to poultry diets improves the digestibility
of phytate-P.
 Reductions in fecal P excretions from using
phytase can be as much as 40%.
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2-121
Use Feed Additives/Enzymes.
(continued)
 Enzymatic “cocktails” containing a mixture of
enzymes, including phytase, have been found to
be more effective that phytase alone.
 Such cocktails can improve calcium retention,
weight gain, feed conversion, and toe tibia ash.
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2-122
Overall Summary
 Numerous dietary and management strategies
exist to reduce

N excretions.

P excretions.
 Significant reductions can be achieved without
significant expense by using the information and
guidelines available from the NRC and from
various research and Extension publications.
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