Module 2: Nutritional Strategies to Minimize Nutrient Loss to Manure

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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 utilizationon 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

• Basic nutrient cycling in animal systems
• National Research Council (NRC) guidelines
• 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)
Inefficiencies can be caused by a variety of
factors including housing conditions, management,
genetics, and feed quality.
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
Academys 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
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NRC Guidelines Beef, Finishing
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NRC Guidelines Beef, Cows
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NRC Guidelines Swine
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NRC Guidelines Poultry-Chickens
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
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
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 poultrya 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
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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
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
  off-farm 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
• gt 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
Mass P balance for New York dairy farms Source
Klausner 1993
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Effect of P Intake on P Excretion

• Increasing P content from 0.40 to 0.60 of diet
  dry matter increases P output from 40 to 69
  lbs/cow/year!

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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
  non-ruminants 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)
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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.
• Summer60 to 70 of N excreted
• Winter/spring40 of N excreted
• Based on annual occupancy, lose 50 of N excreted.

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P Management
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Dietary P in Feedlot Diets
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P Requirements Yearlings
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P Requirements Yearlings (continued)
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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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P Mass Balance Summer Yearlings
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P Mass Balance Winter/Spring Calves
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P Mass Balance (continued)
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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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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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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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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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Strategies for Swine

• Feed waste issues
• Improving N management
• AAs
• Improving P management
• Phytate-P

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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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The Key Understanding Inefficiencies in
Nutrient Utilization

• Many steps are involved 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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Feed Waste An Expensive Loss of Nutrients

• Feed waste
• 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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Feed Waste An Expensive Lossof 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
• Major source of odor

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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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Management Key to Solving Feed Waste . . .
(continued)

• Feeders should be inspected at least weekly.
• Clean and adjust where necessary.

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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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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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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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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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Present Feed in most Palatable Form. (continued)

• Wet-dry or liquid feeders
• Back and forth motion is prevented.
• Reduces feed waste
• Increases feed intake and weight gain

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Select Highly Digestible Ingredients.
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New Crops offer new Solutions.

• Low-phytate corn and soybeans have much higher P
  digestibility.
• Low-stacchyose soybean meal has higher protein
  and energy digestibility.

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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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Processing can Improve Nutrient Digestibility.
(continued)

• Expanding/extruding
• Improves pellet quality.
• Effects on digestibility are very diet-dependent.
• Effects can be negative!

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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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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 reduction in P excretion

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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 a strong negative influence

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The More Ingredients that are used, the Better
the Match!

• Feed nutrients often are wasted because the diet
  is not ideal.

A 1 point reduction in dietary protein results
in a 10 decrease in N excretion and ammonia
emission.
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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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Formulate on Available Nutrients.

• Availability of nutrients is not uniform.
• In typical feed, N gt P and Lys gt Cys.
• Presuming that all nutrients are equally
  available leads to larger mismatch, may hurt
  perfor-mance, and thus increases waste.

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Diets Should be Optimally Matched to the Animals
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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Diets Should be Optimally Matched to the Animals
Requirement. (continued)

• Examples of nutritional strategies
• Split-sex feeding
• Barrows require more energy for maintenance than
  gilts.
• Increase energy-to-protein ratio of the feed for
  barrows.

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Diets Should be Optimally Matched to the Animals
Requirement. (continued)

• Temperature outside of thermo-neutral zone
• Energy is used for thermo-regulation.
• Increase energy-to-protein ratio.

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Phase Feeding Reduces Waste

• Nutritional requirements change continuously.
• Protein-to-energy ratio of feed de-creases with
  age.
• Diet should be adjusted to match this decrease.
• Phase feeding

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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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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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Phase-Feeding Diets are less Expensive.
(continued)
Diet cost obtained using least-cost feed
formulation for a varying number of phases in the
feeding program.
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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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Precision Nutrition is Hindered by Feed
Manufacturing Issues. (continued)

• All augment waste and possibly reduce performance.

Weighing errors were observed in 14 feed mills
specializing in swine feeds.
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Is Mineral Nutrition Overdone?

• Diets are typically over-formulated as a measure
  of security.
• Increases waste.

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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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Strategies for Poultry

• Nitrogen management
• Amino acid
• Phase feeding
• Enzymes and additives
• Phosphorus management
• Available P
• Phytate-P

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Tracking N in Broilers
18.3
30.6
51.1
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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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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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NRC Requirement vs. 23 CP Corn/Soy Diet
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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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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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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
  over-formulation as a safety margin.

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Meat Meal Variation
109
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.

110
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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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.

112
Tracking P in Broilers
35.0
57.4
113
Dietary Strategies for P

• Meet bird P requirements.
• Select ingredients with available P.
• Use vitamin D.
• Use feed additives/enzymes.

114
Meet Bird P Requirements.

• The NRC (1994) recommends 250 mg of available P
  (non-phytate) per hen per day
• Leghorn breeders guide recommends 450 mg-460
  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.

115
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!

116
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.

117
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.

118
Phosphate Supplement Comparison
119
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).

120
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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122
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.

123
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.