Improvement Genetic Model Predicting Genetic Levels Increase Commercial Profitability Lauren Hyde Jackie Atkins Wade Shafer Fall Focus Gettysburg PA Sept 14 th 2015 Punnett Square ID: 622338
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Nuts and Bolts of Genetic ImprovementGenetic ModelPredicting Genetic Levels Increase Commercial Profitability
Lauren HydeJackie AtkinsWade Shafer
Fall Focus, Gettysburg, PA
Sept. 14
th
, 2015Slide2
Punnett SquareSlide3
Qualitative TraitsControlled by one or few pairs of genesMeasured on a categorical (either-or) scale ExamplesBlack or redPolled or hornedGenetic defectsGenotype determined through DNA testingSlide4
Genetic defects?Slide5
Quantitative TraitsControlled by many genesMeasured on a continuous scaleExamplesWeaning weight (lb)Ribeye area (sq in)Transmittable part of genotype determined through statistical techniques (and DNA testing)EPD = ½ * EBVSlide6
Genetic ModelPhenotype = Genotype + EnvironmentPhenotype is the observed level of performanceGenotype is the genetic makeup of the animalEnvironment is the effect that non-genetic factors have on performanceSlide7
Genetic Predictions (EPDs)Separate genetics from environmentNature vs nurtureEstimated using highly advanced statistical methodsBLUPSystem of linear equationsSolve for x and y if 2x + 3y = 6 and 4x + 9y = 15Slide8
Mixed Model EquationsSlide9
HeritabilityHeritability - the proportion of phenotypic variation for a specific trait in a specific population that is due to transmissible genetic meritRanges from 0 to 1h2CE = 0.19h2BW = 0.38h2REA = 0.46Slide10
HeritabilityThe higher the heritability of a trait, the more accurately an individual’s own performance predicts genetic merit Even with high heritability we are limited in what we can learn about an animal’s true breeding value from its phenotypeSlide11
DataLarge amounts of performance data are the solutionAnimal’s own performanceProgeny performancePerformance of ancestors and other relativesProgeny performance records are the most influentialSlide12
Data CollectionAccurate pedigree recordsPerformance records for as many traits as possible on complete contemporary groupsPerformance Advocate Slide13
Contemporary GroupSame sexClose in age (within 90 days)Raised in same management group from birthSame pastureSame feedSlide14
Contemporary GroupShould include as many cattle as can be compared accuratelyBut only takes twoSlide15
Contemporary Group ExampleAnimal IDWeaning Weight (lb)21428012134783
213575621477292139671Slide16
Contemporary Group ExampleAnimal IDWeaning Weight (lb)21428012134783
213575621477292139671
Average WW = 748
lb2142’s WW ratio = 107.1Slide17
Contemporary Group ExampleAnimal IDWeaning Weight (lb)21428012134783
213575621477292139671Slide18
Contemporary Group ExampleAnimal IDWeaning Weight (lb)21428012134783
213575621477292139671
Average WW = 780
lb2142’s WW ratio = 102.7Slide19
Contemporary Group ExampleAnimal IDWeaning Weight (lb)21428012134783
213575621477292139671Slide20
Contemporary Group ExampleAnimal IDWeaning Weight (lb)21428012134783
213575621477292139671
Average WW = 736
lb2142’s WW r
atio = 111.8Slide21
Contemporary Group ExampleWhat happens when 2142 starts getting used in other herds?Slide22
Contemporary Group ExampleProgeny data will get his EPDs going in the right directionFaulty data will get washed awayBLUP is very robustSlide23Slide24
Sire SummarySlide25
Interpretation35RBW EPD = -3.0 (.64)3C Full Figures C288 BLKBW EPD = -0.7 (.96)Difference-3.0 – (-0.7) = -2.3We would expect 35R’s progeny to weigh -2.3 pounds less at birth on average than 3C Full Figures C288 BLK’sSlide26
AccuracyMeasure of the strength of the relationship between the true breeding value and its predictionRange from 0 to 1Affected by the number of progeny recordsHigher values associated with less risk and lower values with moreSlide27