Mongastric Production Swine Section

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Mongastric ProductionSwine Section

• Breeding and Selection of Swine

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Eight major breeds of swine in the U.S. today
include

• Berkshire (England)
• Chester White (U.S.)
• Duroc (U.S.)
• Hampshire (England)
• Landrace (Denmark)
• Poland (U.S.)
• Spotted Breed or Spots (U.S.)
• Yorkshire (England)

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Composite swine breeds developed by breeding Co.

• PIC (Pig Improvement Co.)
• Monsanto Choice Genetics
• Genetipork
• Babcock (www.babcockswine.com)
• Danbred

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What general factors determine swine performance?

• Genetics
• Environment
• Genetics x Environment (generally referred to as
  the interaction of genetics and environment)

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What methods are used by swine producers to
select breeding stock?

• 1) Visual appraisal
• 2) Performance data
• 3) Pedigree

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Why visual appraisal?

• Type (conformation)
• Soundness feet and legs underline
  reproduction.
• Health
• Behavior

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What kind of performance data is used for
selection?

• Sow productivity index (SPI) which may include
  number of pigs born and litter weight at weaning.
• Growth rate (ADG or perhaps days to a given
  weight)
• Feed efficiency (F/G or G/F)
• Backfat (BF)at a given weight
• Loin eye area (LEA) at a given weight

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Where are pigs performance tested?

• From the late 50s until about the mid 80s boars
  were often tested in Central Test Stations.
• Seedstock producers have also tested their own
  boars (and some gilts) on their own farm. This
  is known as on-the-farm testing.
• Today breeding companies collect their own
  performance data on boars and gilts sold for
  breeding.
• Some Individual seedstock producers collect
  progeny data from prospective sires via
  commercial swine producers

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Performance vs Progeny Testing

• Performance testing is collecting performance
  data on the individual you use in the breeding
  herd as the boar or the sow.
• Progeny testing is collecting performance data on
  the offspring of the boar (sometimes gilts) you
  plan to use in your breeding herd.

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Predicting Genetic Progress

• GP S.D. x Heritability
• S.D. refers to selection differential.
• Selection Differential refers to the average
  reach or superiority of selected boars and gilts.
• Reach is the superiority of individuals (boars
  and gilts) compared to the herd average.
• Heritability is the percent of the total
  variation of a trait that is due to heredity.

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Example of calculating GP

• Herd average BF at 250 lbs 1.25
• Select a boar .70
• Select a group of gilts that average 1.0
• Reach of the boar -.55
• Reach of the gilts -.25
• Average reach (S.D.) -.40

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GP calculation continued

• Assume heritability for BF 50
• GP -.40 x .50 -.20
• (S.D.) x (Heritability)
• Expected BF of the progeny
• 1.25 minus .20 1.05

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SD vs EBV vs EPD

• EBV Estimated Breeding Value
• EBV Reach x Heritability
• EBV of boar -.55 x .50 -.275
• EBV of gilt -.25 x .50 -.125
• EBV of boar gilt -.40
• EPD Expected Progeny Difference

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SD vs EBV vs EPD continued

• EPD ½ EBV (Reach x Heritability)
• EPD of boar -.275/2 -.1375
• EPD of gilt -.125/2 -.0625
• EPD of boar EPD of gilt -.20
• So, G.P. EPD of boar EPD of gilt

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Comparison of terms

• GP S.D. x Heritability
• EBV Reach x Heritability
• EPD ½ EBV
• GP EPD (male) EPD (female)

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Heritability of economically important traits

• High gt40
• Med 20-40
• Low lt20

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Heritabilities of various swine traits

• Reproductive traits low
• NBA (10)
• Production traits medium
• ADG (30) F/G (35)
• Carcass traits high
• BF (50) LEA (50)

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How are pedigrees used for breeding stock
selection?

• To avoid inbreeding
• To identify productive families
• To avoid genetic defects, such as PSS, scrotal
  hernias, etc.

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Crossbreeding Programs for Commercial Swine
Producers

• Nearly all commercial hogs are crossbred.
• Which commercial hogs are not crossbred?
• Answer purebred animals that do not meet the
  selection criteria to be marketed as breeding
  animals.

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Why raise crossbred hogs?

• To capitalize on hybrid vigor (heterosis).
• Lowly heritable traits benefit the most from
  heterosis.
• To combine the desirable characteristics of
  different breeds.
• From a practical standpoint crossbred sows farrow
  more pigs, wean more pigs and wean heavier
  litters.

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What is heterosis?

• H.V. the average superiority of the crossbred
  offspring compared to the parent average for a
  particular trait.
• H.V. ((F1-P1)/P1) x 100) where F stands for
  filial or offspring and P refers to the
  parents.

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Calculating heterosis

• Duroc boar from a litter of 10 pigs
• Landrace sow from a litter of 12 pigs
• NBA of crossbred offspring 13
• Avg litter size of parents 11
• Heterosis (13 11)/11 x 100))
• (F1 P1)/P1 18.2

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Systems of crossbreeding

• Rotational cross generally uses home raised
  replacements
• Illustrate a three breed rotational cross through
  several matings.
• Terminal cross all progeny are marketed.
• Illustrate how a terminal crossbreeding system
  works.

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What breeds should be used to produce commercial
hogs?

• Research and practical experience have shown that
  all breeds were not created equal.
• White breeds such as Landrace, Yorkshire and
  Chester White excel in sow productivity traits.
• Durocs are recognized for their superiority in
  ADG and F/G.
• Hampshires are well known for superior carcass
  traits.
• Colored breeds seem to be more hardy and are
  especially durable in outside systems.

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Coat Color Inheritance in Pigs

• Self Black (unbelted Hampshire) and Black Spotted
  (Poland and Berkshire) are both dominant to Red
  (Duroc).
• Self White (Chester White, Landrace and
  Yorkshire) is dominant over most black and red
  breeds.
• Self Black x Self White commonly produces a
  blue roan (white hair with patches of dark
  pigmented skin). Referred to as Blue Butts.

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What breeds are used?

• Actually most of todays seedstock are composite
  breeds that have been developed by the various
  breeding companies based upon a combination of
  white and colored breeds.
• Landrace and Yorkshires are commonly used as
  maternal lines.
• Durocs and Hampshires are used as paternal lines.

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Website for breeds of swine

• http//www.ansi.okstate.edu/breeds/swine