Lean Growth Curves for Swine

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Lean Growth Curves for Swine

• Dr. Bob Thaler
• South Dakota State University

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Lean Growth Rate (LGR)

• Most economically important traits
• Growth rate - feed conversion
• Lean percentage - meat quality
• LGR is a function of both growth rate lean
  percentage
• LGR is correlated with other important traits

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Genetic Correlation Between LRG Performance
Traits
NPPC, 1995
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Importance of Lean Growth
Lean Growth
Body Protein Deposition
Amino Acid Requirement
Energy Requirement
gt85 of Ingredient Cost of Swine Diets
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Lean Growth Curve

• Used to establish nutrient requirement
• Allow animal to achieve full genetic potential
• Decrease over-feeding costly ingredients
• Decrease nutrient excretion manure costs
• Improve efficiency of animals

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Cost of Over- Underfeeding Lysine

• Overfeeding lysine by .1 will increase feed cost
  by 1.20/pig!!!
• Under-feeding lysine that lowers lean percentage
  by .5
• Reduces income by .60/pig
• Increases feed cost by gt.60/pig due to poorer
  feed efficiency

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Genotypical Feeding

• Based on the animals genetic potential
• Is a combination amount of lean and time required
  to put that lean on
• final lbs of lean - initial lbs of lean
  days on test

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Using Packer Data to Calculate LGC

• Assume similar amount of lean at 20 kg
• Get packer data for final amount of lean
• 36.8 kg final lean 7 kg lean
• 100 days
• .30 kg lean/day

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Sources of Error

• Match your values against a standard curve and
  determine proper nutrient levels from a nutrition
  guide
• Curves are not uniform
• Packer Differences
• Cutting methods (head on or off)
• Equations used / definitions of lean
• 0, 5, or 10 fat basis
• ESTIMATE

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Establishing Nutrient Requirements

• Develop protein and fat deposition curves
• Calculate LysineCalorie ratios for specific
  animals
• Use energy density of the diet lyscal ratio to
  determine dietary lysine needed
• Using a ratio to lysine system, determine
  levels of all other amino acids

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Using the Fat-Free Lean Index

• Uses body weight FFLI
• US packers have a standardized formula for
  calculating FFLI
• Can calculate it using ultrasound carcass data

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FFLI Ultra-Sound Calculations

• Barrows
• 1.4357 (.7632 1)
• (14.7839 inches fat)
• (4.9574 loin area in2)
• (.3312 lbs BW) lbs lean
• lbs lean FFLI
• (BW .75)

• Gilts
• 1.4357 (.7632 2)
• (14.7839 inches fat)
• (4.9574 loin area in2)
• (.3312 lbs BW) lbs lean

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Using the Fat-Free Lean Index

• Assumes standard of curves for growth and protein
  deposition
• Assumes the rate of lipid deposition is dependent
  on the FFLI at market weight

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Using the Fat-Free Lean Index

• Assume that the amount of lysine needed per
  calorie of energy remains relatively constant
• Require 4.7 g/day of digestible lysine per 100
  g/day of fat-free lean gain

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Using the Fat-Free Lean Index

• As energy level increases feed intake then
  decreases, need to increase level of other
  nutrients to ensure adequate nutrient intake
• Therefore, can use this method for any dietary
  energy level

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Using the Fat-Free Lean Index to Calculate
LysineCalorie Ratios

• Barrow Equation
• (.0116Wt) - (.3799FFLI) (.000026Wt2)
  (.006052FFLI2) - (.000628WtFFLI) 8.68
• Gilt Equation
• (.019Wt) - (.3369FFLI) (.000021Wt2)
  (.00578FFLI2) - (.000739WtFFLI) 7.046

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Converting LysCal to Lysine

• Multiply the lysinecalorie ratio by the energy
  level in the diet
• (Lyscal Mcal/lb2.205)/10 lysine
• (2.43 1.515 2.205)/10 .81 lysine

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Concerns

• While you use your own herds carcass
  information, you are still balancing it against a
  Standard Curve
• There is variation in shape of curve between
  herds
• Need to develop curve for each herd

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Actual Lean Growth Curve

• Increases from 20-50 kg
• 50-80 kg relatively constant
• gt80 kg decreases to 0 at mature body weight

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Establishing a Lean Growth Curve (LGC)

• Ideally, dissect carcasses of pigs from 20 to 125
  kg into lean and fat sections
• Very expensive, slow, genetic variation within
  herd

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Indirectly Establishing a Lean Growth Curve

• Measuring protein lipid accretion by
• serial ultrasound measurements
• mass ultrasound measurements
• Strength is that you can get data points
  throughout the entire weight range, not just
  beginning end

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Measuring Protein Accretion with Ultrasounding

• Five Steps are involved
• 1. Get weight, age, and carcass measurements
  put in Excel spreadsheet
• (10th rib fat depth loin area)
• 2. Keep track of type and amount of diets fed

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• 3. Kansas State or Purdue University analyzes the
  data and creates protein and lipid accretion
  curves
• 4. Lysinecalorie ratios calculated
• 5. Lysinecalorie ratios are used to calculate
  lysine requirements of the farm

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Ultrasounding

• Protein and lipid accretion curves can be
  determined
• First, an energy requirement is calculated based
  on tissue accretion
• Lysine requirement then calculated from protein
  accretion, lysine content of protein, efficiency
  of lysine utilization, maintenance requirement,
  and digestibility

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Ultrasounding

• The lysinecalorie ratio then calculated from
  that data
• Percent lysine then calculated by multiplying the
  lysinecalorie x the energy content of the diet
• Can plug lean deposition value into new NRC

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• There are 3 essential points in getting an
  accurate prediction of the lysine requirement
• 1. Accurate age assessment
• 2. Scan early in the growth period
• 3. Scan past maximum market weight

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Mass Scanning

• Scan a large number of pigs at 1 time
• Decrease time money involved
• 64 pigs 4/pig 50 travel 306
• Uses pigs of different age groups on 1 day

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Procedure

• Weigh scan 32 pigs/gender
• Pigs selected on weeks in finishing facility
• (weeks 0, 3, 6, 9, 12, 15, and 18)
• Do not collect data from groups that have already
  had pigs marketed at the heavy end

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Mass Scanning

• Can obtain accurate prediction equations for
  protein and lipid mass
• Live weight curves are not accurate
• Can calculate lysine requirement on a
  lysinecalorie basis

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Serial Scanning

• Start as soon as pigs enter the finishing barn
• At random throughout the barn, select 40 pigs/sex
  (can get by with 36)
• Weigh, double tag, and scan within 1 week if
  entering the barn
• Scan same animals every 3 weeks
• Use same technician at every scanning

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Serial Scanning

• Is more accurate
• Can determine lysine requirements as g/d, of
  diet, or gMcal ME
• Assess environmental impact on growth
• More expensive
• 80 pigs x 7 scans x 4/pig 50 travel
  2290 vs 306

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Requirements for Other Amino Acids

• Based on ratio to lysine
• ex Met _at_ 27.5 of lysine
• if lysine .90, then Met .25
• Ideal Protein concept - controversial
• Set-up in a spreadsheet

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Conclusions

• Establishing a Lean Growth Curve for your herd
  will increase profitability by matching your
  nutritional program to your genetics
• It will give you the ability to easily change
  your feeding programs
• Doing a Serial scan and working with Purdue
  University will give the best LGC