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Mongastric Production Swine Section

Learn about the key factors affecting swine performance, breeding stock selection methods, and how to predict genetic progress for optimal results in pork production.

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Mongastric Production Swine Section

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  1. Mongastric ProductionSwine Section Breeding and Selection of Swine

  2. 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)

  3. Composite swine breeds developed by breeding Co. • PIC (Pig Improvement Co.) • Monsanto Choice Genetics • Genetipork • Babcock (www.babcockswine.com) • Danbred

  4. What general factors determine swine performance? • Genetics • Environment • Genetics x Environment (generally referred to as the interaction of genetics and environment)

  5. What methods are used by swine producers to select breeding stock? • 1) Visual appraisal • 2) Performance data • 3) Pedigree

  6. Why visual appraisal? • Type (conformation) • Soundness: feet and legs; underline & reproduction. • Health • Behavior

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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”

  12. 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”

  13. 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

  14. 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

  15. Comparison of terms • GP = S.D. x Heritability • EBV = Reach x Heritability • EPD = ½ EBV • GP = EPD (male) + EPD (female)

  16. Heritability of economically important traits • High >40% • Med 20-40% • Low <20%

  17. 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%)

  18. 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.

  19. 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.

  20. 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.

  21. 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.

  22. 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%

  23. 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.

  24. 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.

  25. 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.

  26. What breeds are used? • Actually most of today’s 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.

  27. Website for breeds of swine • http://www.ansi.okstate.edu/breeds/swine

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