2006 George R. Wiggans Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD USDA Genetic Evaluations for Type Traits
ADGA 2006 (2) G.R. Wiggans 2006 Type Traits Describe physical characteristics of animal Final Score (overall assessment) Scored Linear traits (13 traits) Scored 1-50
ADGA 2006 (3) G.R. Wiggans 2006 History of Type Evaluations 1986 – Sire model for final score 1988 – Collection of linear traits 1989 – Sire model for linear traits 1995 – Multi-trait animal model 2000 – Base change 2005 – Base change
ADGA 2006 (4) G.R. Wiggans 2006 Numbers of Appraisals of Does Alpine8881, ,3681,0611,2541,185 Nubian1,0991, ,3451,1611,1731,330 Toggenburg LaMancha Saanen Oberhasli Experimental Sable Total3,6924,4083,6124,9814,3944,593 5,238
ADGA 2006 (5) G.R. Wiggans 2006 Appraisals for Does in 2005 (n=4,593) TraitMeanSDMinMax Final score Stature Strength Dairyness Teat diameter Rear legs Rump angle Rump width Fore udder attachment Rear udder height Rear udder arch Udder depth Suspensory ligament Teat placement
ADGA 2006 (6) G.R. Wiggans 2006 Evaluation model An equation that indicates what factors contribute to an observation Separates the genetic component from other factors Solutions used to predict the genetic potential of progeny
ADGA 2006 (7) G.R. Wiggans 2006 Type Evaluation Model MODEL:y = h + a + p + e y = Adjusted type record h = Herd appraisal date a = Animal genetic effect (breeding value) p = Permanent environment Non-genetic effect common to all a doe's appraisals e = Unexplained residual
ADGA 2006 (8) G.R. Wiggans 2006 Multi-trait Model Scores from one trait affect the evaluation of other traits through the genetic correlations
ADGA 2006 (9) G.R. Wiggans 2006 Genetic Correlations Final ScoreStrengthDairyness Fore Udder Attachment Final Score Strength Dairyness F. Udder Att.1.00
ADGA 2006 (10) G.R. Wiggans 2006 Genetic Parameters Heritability – Portion of variation due to genetics Repeatability – Similarity of repeated records, includes genetic and permanent environmental effects
ADGA 2006 (11) G.R. Wiggans 2006 Heritability and Repeatability
ADGA 2006 (12) G.R. Wiggans 2006 Genetic Change per year from does born 1990 – 2003 TraitTrendR2R2 Rear legs Rear udder height Udder depth Fore udder attachment Rear udder arch Final score Dairyness Rump width Teat diameter Strength Suspensory ligament Teat placement Rump angle Stature
ADGA 2006 (13) G.R. Wiggans 2006 Breeding value trend for type
ADGA 2006 (14) G.R. Wiggans 2006 Herds for Bucks Born 1999 – 2003 (n=2,451)
ADGA 2006 (15) G.R. Wiggans 2006 Daughters for Bucks Born 1999 – 2003 (n=2,451)
ADGA 2006 (16) G.R. Wiggans 2006 Distribution of Reliability for Final Score
ADGA 2006 (17) G.R. Wiggans 2006 Methods of Expressing evaluations Estimated breeding value (EBV) Animal’s own genetic value Predicted transmitting ability (PTA) ½ EBV Expected contribution to progeny
ADGA 2006 (18) G.R. Wiggans 2006 Combining type and production Production-Type index(PTI) Combines yield and type evaluations into a single value There are 2 versions: PTI 2:1, weights 2 production : 1 type PTI 1:2, weights 2 type : 1 production
ADGA 2006 (19) G.R. Wiggans 2006 AIPL web services #GoatsTBL Queries provide display of: Pedigree information Yield records Herd test characteristics Genetic evaluations of does & bucks Yield Type Access information using: ID number Animal name Herd code
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ADGA 2006 (24) G.R. Wiggans 2006 Summary Type data contributes to genetic evaluations of Final Score and 13 linear traits Multi-trait Animal Model combines information from all relatives and traits Few bucks have many daughters in many herds so reliability is low Production-type index combines evaluations Substantial genetic progress is occurring in several traits