The Concept of Lean Growth Modeling

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The Concept of Lean Growth Modeling

• AnS 320
• Fall 2006

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Priority of Nutrient Usage
IV. Fat
III. Muscle
II. Bone
Nutrient Supply
I. Maintenance
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What Is a Lean Growth Model?

• Mathematical model designed to attempt to
  accurately quantify the daily nutrient
  requirements of pigs during the grow-finish
  stages of production based on inputs that effect
  performance
• Mathematical model to identify means to improve
  efficiency of lean pork production
• Integration of current knowledge of genetic
  potential, nutrient intake and environmental
  conditions on pig growth

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Why the Interest in Lean Growth Modeling by the
Pork Industry?

• Feed industry perspective
• Old nutritional approaches did not adequately
  meet the needs of todays pigs
• Base nutrient level recommendations are not
  appropriate in all situations
• Need for a structured method to design feeding
  programs for specific situations

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Why the Interest in Lean Growth Modeling by the
Pork Industry?

• Producer perspective
• Efficiency of production is a key to
  competitiveness
• Decisions on the implementation of cost-effective
  management changes to optimize expression of
  genetic potential for lean tissue growth
• The number of diets fed and the composition of
  the diet
• Diet changes for different seasons
• Target slaughter weight or weights
• Choice of genotypes
• Split-Gender feeding and management

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What measurement encompasses all of these
variables?
Disease
Weight
Protein deposition rate
Genetics
Building type

health
Temperature
Sex
humidity
Space allowance
Number of pigs/pen
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Variables Required for Accurate Lean Growth
Modeling

• Daily protein (lean tissue) accretion rate
• Partitioning of energy intake over maintenance
  between protein and lipid accretion (lean to fat
  ratio)
• Daily feed intake
• Major hindrance to implementation is accurate,
  economical means to estimate these

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Factors Affecting Rate of Protein Accretion

• Genetic Type
• Major differences are
• overall mean protein accretion rate
• rate of decline after 200 lb
• Related to maturity patterns
• Genetic capacity sets the maximum rate, but many
  other factors contribute to the realized rate of
  protein accretion
• Under Ideal Commercial Conditions 80 of Max
  can be achieved

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Measuring On-Farm Protein Deposition

• Using ultrasound equipment, we can measure
  protein and fat deposition as a pig grows.
• Select a sub-sample of pigs and scan every three
  weeks from 50 lb to market.
• Based on the protein and fat accretion, we can
  then back-calculate a lysine requirement and feed
  intake.

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Real-time Ultrasound
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Measuring On-Farm Protein Deposition

• By calculating the changes in
• Weight
• Loin muscle area
• Backfat thickness
• We can develop mathematical equations to
  calculate daily protein and lipid accretion

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Estimated Protein Deposition Using Serial
Ultrasound Measurements
Farm 1
Farm 2
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Lysine Requirement
Farm 1
Farm 2
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Factors Affecting Rate of Protein Accretion

• Genetic Type
• Gender
• Health Status and Environment
• herd health status and management level
• interaction of health status x genetic type

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Protein Accretion Rate Genetic Type Effects
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Factors Affecting ProteinAccretion Rate

• Gender Effects
• Gilts exceed barrows in protein accretion even at
  lighter weights and the differences increase with
  weight.
• Basis for split-gender feeding and phase feeding
  as the differences in overall rate of lean growth
  and the rate of lean growth decline are different
  for barrows and gilts.

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Gender Effect on Growth Rate Commercial
Conditions
Schinckel and Delange
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Gender Effect on Protein Accretion Rate
Commercial Conditions
Schinckel and Delange
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Modeled Impact of Gender and Farm on ADG
Tokach, et. al, 1997
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Modeled Protein AccretionBarrows and Gilts
Tokach, et. al, 1997
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Modeled Percent Lysine Needed Based on Protein
and Lipid Accretion
Tokach, et. al, 1997
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Health and Management Effects on Protein
Accretion Rate
Schinckel, 1996
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Commercial vs Optimal Environmental Conditions
Schinckel, 1997
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Commercial vs Optimal Environmental Conditions
Schinckel, 1997
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Commercial vs Optimal Environmental Conditions
Schinckel, 1997
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Commercial vs Optimal Environmental Conditions
Schinckel, 1997
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Partitioning of energy intake over maintenance
between protein and lipid accretion

• Genetic Type
• High lean growth lines require less energy to
  achieve the same lean growth rate as moderate
  genetic types.
• However, high lean growth lines are more affected
  by situations where energy intake is limited and
  respond with larger absolute and percentage drops
  in lean growth rate when compared to other
  genotypes

Schinckel and Delange
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Importance of Feed Intake

• Voluntary feed intake is a driven by the pigs
  requirements for nutrients
• Feed intake is reduced as a function of
  constraints imposed on the animal
• Diet characteristics
• bulk density, fiber content, nutrient content,
  etc.)
• Environment
• thermal, social, physical, disease
• Pigs physical capacity to ingest feed

Schinckel and Delange
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Feeding Paylean

• Paylean Technical Manual
• Swine feed premix containing ractopamine which
  directs nutrients to increase the amount of
  quality meat in high value cuts and improves
  production efficiency
• Beta-Andrenergic Agonist Mode of action is the
  stimulation of beta-receptors (Beta-1 type) in
  the cell

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Paylean Effects on the Pig

• Production Effects (Asset Utilization)
• Increased Average Daily Gain
• Potential to increase throughput if pigs
  available to fill barns
• Potential to market at heavier weights (gt
  pounds/space/year)
• Improved Feed Efficiency
• Reduced feed cost/lb of gain (lean)
• Decreased Carcass Fat
• Reduces fat deposition
• Increased Carcass Muscle (loin, ham, etc)
• Increases muscle development

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Paylean Effects on the Pig

• Higher Percent Lean (less fat, more muscle)
• Opportunity to obtain higher lean premium
• Depends on packer merit system
• Higher Dressing Percentage
• Heavier carcass at a standard weight
• Potential to increase frequency of Slow and
  Downer Pigs
• Heavier muscled pigs more susceptible to stress
• Physiologically more muscle may put stress on
  tendons, ligaments, etc.

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Paylean Effects - ADG
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Paylean Effects - Feed Efficiency
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Influence of Paylean? Level on Margin /pig
greater than controls
Main et al., 2001
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Nutrients of Primary Concern in Waste Management

• Nitrogen
• Amino Acids that comprise the Proteins required
  for life
• Phosphorus
• Mineral required for bone development, body
  function, health, etc.

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Environmental Concerns for Nitrogen

• Volatilization of Nitrogen to Ammonia (NH3)
• Returns to land or water via rainfall, dry
  precipitation, or direct absorption
• Potential for significant odor generation
• Community/neighbor relations can be strained
• Nutrient distribution
• Meeting agronomic needs without the adverse
  effects of over-application

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Environmental Issues for Phosphorus

• Direct and indirect contamination of water
  resources
• Surface and sub-surface waters
• Nutrient distribution
• Meeting agronomic needs without the adverse
  effects of over-application

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Nitrogen and Phosphorus Intake, Excretion and
Retention in Swine
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Nutritional Approaches

• High quality protein
• Balance of amino acids in protein sources defines
  quality
• Soybean meal and fish meal High Quality
• Peanut meal and cottonseed meal Low Quality
• Excess nitrogen excretion occurs when using too
  much low quality protein in feed
• Most limiting AA can define the amount of protein
  included in a diet thus feeding protein to meet
  the most limiting AA can increase Nitrogen
  excretion

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Nutritional Approaches

• Dietary formulation
• Formulate and balance diets to meet the Amino
  Acid requirement, rather than the Crude Protein
  requirement, for the optimal lean growth rate of
  the genetic type of pigs you raise
• Crystalline lysine and methionine are generally
  cost effective
• Synthetic threonine, valine, isoleucine,and
  tryptophan are available, but may not be cost
  effective
• Lysine substituted for soybean meal reduces CP by
  2 in the diet and can result in a 20 to 25
  reduction in N excretion (Pierce et al, 1994)

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On-Farm Strategies to Improve P Utilization and
Reduce P Excretion

• Phosphorus excretion is Influenced by
• Amount of phosphorus consumed
• Excess fortification of P in diets was common in
  the past, but not wise and unjustified today
• Form or bioavailability of the phosphorus in the
  diet
• Phosphorus in the Phytate or phytic acid form is
  largely unavailable to swine because swine lack
  the intestinal enzyme phytase to break down the
  phytate
• Large differences in bioavailability of
  phosphorus in common feedstuffs

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Nutritional Approaches to Reducing Phosphorus
Excretion

• Poultry and swine lack a critical enzyme
  (phytase) which releases phosphorus from phytic
  acid and makes it available for utilization
• Approximately 2/3 of plant phosphorus is bound to
  phytic acid and is unavailable for utilization by
  both swine and poultry
• Thus, inorganic P sources (Di-calcium phosphate,
  de-fluorinated phosphate) are added to diets

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New Approaches to Phosphorus Utilization and
Management

• Synthetic phytase enzyme added to the feed
• Phytase releases 20 to 40 of the bound P in
  typical dietary ingredients
• The addition of phytase combined with a reduction
  from 0.6 P to 0.5 P (inorganic) in the pig diet
  results in a 20 to 50 reduction in Phosphorus
  excretion
• In addition, Ca is more readily absorbed
  resulting in reduced Ca excretion

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Low Phytate Corn and/or Low Phytate Soybean Meal

• Use of Low Phytate Corn (HAP corn)
• Genetically enhanced corn varieties are now
  available
• Lpa1 mutant gene in corn inhibits phytate
  synthesis
• Reduction by 50 the amount of P in the phytate
  form
• Phosphorus is 3 to 4 time more bioavailable
  compared with normal corn (Cromwell 1998, Douglas
  et al. 2000)
• Up to 40 reduction in phosphorus excretion when
  fed to swine (Pierce Cromwell 1999, Spencer et
  al., 2000)
• Further reduction in Phosphorus excretion when
  phytase is used in conjunction with low-phytate
  corn

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Low Phytate Corn and/or Low Phytate Soybean Meal

• Normal Corn Low-Phytate
• Total P 0.25 0.26
• Phytate-P 0.21 0.08
• Non-Phy P 0.05 0.18
• (Li et al., 2000)

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Low Phytate Corn and/or Low Phytate Soybean Meal

• Use of low phytate soybeans
• Genetically enhanced soybeans recently developed
• Response similar to those observed when feeding
  low-phytate corn
• More available form of phosphorus
• Reduction in phosphorus excretion

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Feeding Management Considerations

• Feeding for Optimal vs Maximum Performance

• Incremental change in performance is reduced as
  nutrient levels increase
• Law of Diminishing Returns
• Added cost of diet and nutrient level excretion
  potential dictates formulation for optimal
  nutrient levels

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Feeding Management
Multiple Phase Nutrition Program designed to
meet genetic capacity, health and facilities of
the pig
Minimize overfeeding of essential nutrients
CP and Nutrient Levels changed frequently to
closely match pig needs
50
250
Live Weight
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Effect of Phase Feeding

• Inefficiencies occur when the diet provides more
  nutrients than the animal needs
• 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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Impact of Phase- Feeding on Nitrogen Excretion
Dietary Crude Protein Dietary Crude Protein Dietary Crude Protein
Single Feed 17 Two-Feeds 17 15 Three Feeds 17 15- 13
Nitrogen output/day lb 0.070 0.064 0.059
of two - feeds 110 100 92
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Nutritional Approaches

• Split-sex feeding (gilts vs barrows)
• Sex differences may dictate feed formulation
• Gilts are generally higher in lean, have lower
  feed intake, and better feed efficiency
• Require higher levels of CP and more energy dense
  diets than barrows at a given weight
• Complements the goals of phase feeding
• NOTE Gender differences today are less in leaner
  genetic types, thus some producers have abandoned
  this concept

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On-Farm Strategies to Improve N Utilization and
Reduce N Excretion

• Focus on Feed Efficiency
• Monitor Diet Quality and Form
• Proper grind (700 microns) enhances nutrient
  availability and nitrogen utilization
• Ohio Study from the late 90s showed a wide range
  in particle size from both on-farm and feed mill
  processed grains, with most samples too coarse
• Pelleted diets improve feed efficiency compared
  with meal diets (pelleting costs may be an issue)
• High-quality feedstuffs improve conversion
  efficiency

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Recommended Feeder Adjustments after Weaning
Initial feeder adjustment
2 to 3 weeks into turn
Final feeder adjustment
Courtesy Steve Dritz, KSU
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Nutritional Approaches

• Feed Additives
• Use of a Beta-Agonist (Paylean) to improve
  feedlean conversion efficiency
• Reduction in nitrogen excretion
• Increased efficiency of nitrogen utilization
  through an improvement in lean tissue growth,
  reduction in fat deposition and or increase in
  fat degradation
• Reduced total volume of manure
• Feed intake is reduced and feed efficiency
  improved
• Improved P retention

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Production Management

• Facilities and Herd Health
• Proper ventilation rates and temperature control
  enhance productivity and efficiency
• All-in, All-out production flow improves pig
  health and production efficiency

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Summary

• Enhance nutrient (N and P) availability,
  utilization efficiency, and reduce excretion
• Phase-feeding Easy, low cost
• Crystalline Amino Acids Cost effectiveness?
• Micron size Fast, easy
• Feeder management Easy
• Feed additives Cost effectiveness?
• HAP-corn/soy Agronomic production cost, yield,
  etc. must be considered
• Today a question of AVAILABILITY
• Microbial phytase Appears quite effective
• Used extensively