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Transcript of 2005 Paul VanRaden Animal Improvement Programs Laboratory Agricultural Research Service, USDA,...
2005
Paul VanRadenPaul VanRaden
Animal Improvement Programs LaboratoryAgricultural Research Service, USDA, Beltsville, [email protected]
An Example from Dairy Cattle An Example from Dairy Cattle Selection: The Net Merit IndexSelection: The Net Merit Index
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The Old Way of Selecting CattleThe Old Way of Selecting Cattle
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ObjectivesObjectives
Document USA Net Merit index
Compare national selection indexes for dairy cattle
Discuss traits that affect profit and direction of selection
Outline approach for estimating economic values
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Selection TheorySelection Theory
Progress = accuracy intensity genetic SD / generation interval
Multiply above by directional lossAccuracy = Corr (EBV, BV)
Directional loss = Corr (e EBV, a EBV)
Estimated (e) vs. actual (a) economic values
Direction may be the most important factor
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Direction of SelectionDirection of SelectionTrait 1
Trait 2
Accuracy contours
Animalsselected
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Trait Direction Not ClearTrait Direction Not Clear
Concentrated (less) or diluted (more) milk?
Large or small cows? Skinny or fat cows? Dairy or beef or dual purpose?
• Can change direction by replacing a population instead of selecting within
• Specialized populations can be useful
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Coefficients of variation (CV)Coefficients of variation (CV)
TraitHerit-ability
CV (%)Pheno- typic Genetic
Stature .42 3 2
Protein yield .30 13 7Longevity .08 54 16Fertility .04 65 13
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Measures of accuracyMeasures of accuracyAverages for recently proven Holstein bullsAverages for recently proven Holstein bulls
TraitACC rBV,EBV
REL r2
EBV,BV
BIF ACC 1 - 1-r2
Protein yield .92 .85 .61SCS (mastitis) .77 .59 .36Productive life .78 .61 .38Cow fertility .75 .56 .34Calving Ease .85 .72 .47
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Relative EmphasisRelative Emphasis
Easily compare selection goals independent of trait units• Trait economic value times genetic SD• Divide by the sum across all traits• Multiply by 100
Expresses relative emphasis as percent of total selection• Added traits decrease emphasis on others• Convenient way to display indexes
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History of USDA economic indexesHistory of USDA economic indexes(PD$, MFP$, CY$, and NM$)(PD$, MFP$, CY$, and NM$)
and Holstein Association TPIand Holstein Association TPIYear Introduced and Index Name
1971 1976 1977 1980 1984 1987 1989 1992 1994 1997 2000 2000Trait PD$ TPI MFP$ TPI CY$ TPI TPI TPI NM$ TPI TPI NM$
Protein 27 53 40 34 50 43 50 41 36Fat 48 46 45 40 34 17 25 17 16 21
Milk 52 60 27 60 -2 6 5
% Fat 20
Longevity 20 13 14
SCS 6 1 9
Udder 17 17 11 9 7
Feet / legs 5 5 4
Size -4
Final Score 40 20 20 17 17 17 14
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Current National Selection Indexes:Current National Selection Indexes:Yield and Health TraitsYield and Health Traits
Country (Interbull Code)
USA DEU FRA NZL NLD CAN GBR AUS ITA DNK SWE
% of Interbull Population 17.4 15.3 12.3 10.6 9.3 4.7 4.7 4.5 4.3 4.1 1.5
Index Name NM$ TPI RZG ISU BW DPS LPI PLI APR PFT S – I TMI
TraitProtein 33 32 36 35 34 32 31 57 36 42 21 21
Fat 22 18 9 10 13 7 20 11 12 12 10 4
Milk -17 -12 -19 -20 -3 -4
% Protein 4 2 2 3
% Fat 1 2 1 2
Longevity 11 8 25 13 8 8 7 15 12 8 6 6
SCS / mastitis 9 5 5 13 14 3 7 10 15 12
Fertility 7 5 2 13 10 10 5 9 10
Other diseases 2 3
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Current National Selection Indexes:Current National Selection Indexes:Conformation and Management TraitsConformation and Management Traits
Country (Interbull Code)
USA DEU FRA NZL NLD CAN GBR AUS ITA DNK SWE
% of Interbull Population 17.4 15.3 12.3 10.6 9.3 4.7 4.7 4.5 4.3 4.1 1.5
Index Name NM$ TPI RZG ISU BW DPS LPI PLI APR PFT S – I TMI
TraitUdder traits 7 10 6 8 16 13 9 12
Feet / legs 4 5 4 1 5 11 6 5 9
Size -3 2 2 -18 -5 4 -4 2
Dairy character -2 2
Rump 1 1
Final score 13 4 2
Calving ease 4 2 4 7 6 12
Growth / meat 4 6
Milking Speed <1 4 6
Temperament 5 2 3
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Milk Pricing and Feed CostMilk Pricing and Feed Cost($ per pound)($ per pound)
Index Milk Fat Protein
Fluid Merit .051 1.30 1.00
Net Merit .012 1.30 2.30
Cheese Merit -.009 1.30 3.00
Feed Cost -.012 -.35 -.50
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Value of Cow FertilityValue of Cow Fertility
Daughter pregnancy rate (DPR)• Pregnancies achieved per 21-day cycle• 1% higher DPR = 4 fewer days open
Fertility expenses per day open• Heat detection ($20 / lact .005) = $.10• Semen ($15 / unit + $5 labor) *.025 = $.50• Pregnancy exam ($10 / exam)*.012 = $.12• Lactations too long or short = $.75
Relative value of DPR = 7% of total
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Value of Calving EaseValue of Calving Ease
Daughter CE value / difficult birth• Veterinary, labor costs = $50• Calf death (20% prob) = $25• Cow deaths before 1st test (1% prob) = $15
Service sire CE also includes• Yield losses / lactation = $40• Fertility and longevity losses = $30
Relative values of each are 2% of total
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Linear vs Non-linear ProfitLinear vs Non-linear ProfitCalculation of Net Merit $Calculation of Net Merit $
Non-linear profit = (income – expense per lactation) number of lactations + cull value – raising cost
Linear profit obtained by taking partial derivatives at trait means
Corr (linear, non-linear) = .999
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LifetimeLifetime Net Merit Net Merit $$
Incomes and expenses estimated from yield traits, SCS, longevity, fertility, conformation, calving ease
Example: body size• Convert from visual scores to weight• Cull price - growth cost + lactations
(calves – maintenance) = $-1.28 / kg• Less beef = more profit to dairy farmer
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Goals of Index CalculationGoals of Index Calculation
Give breeders the index they want• Breed association or AI committees• Emotional approach (TPI)
Give scientists the index they want• Add incomes, subtract expenses• Mathematical approach (NM$)
Future prices difficult to prove
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Top Net Merit BullsTop Net Merit BullsMay 2005May 2005
Bull Cntry DtrsNM$ REL
Net Merit $
Pro-tein
O Man USA 230 93 729 57
Loe Martin NLD 166 74 657 79
Lombard DEU 93 70 655 73
Mascol DEU 98 68 645 59
Marion USA 56 76 613 74
S D Jordan NLD 120 76 595 61
Alton USA 97 82 585 55
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Trait HarmonizationTrait HarmonizationMark, 2003 EAAP meetingMark, 2003 EAAP meeting
Trait
Coun-tries
Average corr.
Avg. cor w / USA
Protein 27 .87 .89
Stature 21 .89 .90
Fore Udder 21 .75 .79
SCS 20 .85 .86
Longevity 14 .59 .74
D. CalvEase 10 .83 .86
M. CalvEase 10 .58 .64
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Paul’s Beef ExperiencePaul’s Beef Experience
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Interbull Beef ProposalInterbull Beef Proposal
Provide international evaluations within ICAR subcommittee
Combine raw data files instead of national evaluations
Favorable responses received from many countries
Charolais, Limousin most likely
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Conclusions - DairyConclusions - Dairy
Many traits in addition to yield contribute to dairy cattle profit
Longevity, fertility, health, and type traits get half of emphasis
Direction unclear for some traits
Indexes began in 1970’s and have improved rapidly in recent years
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Conclusions - BeefConclusions - Beef
An official, published goal:• Stimulates economic research• Gives breeders direction
An overall index helps breeders:• Promote their own animals • Locate superior breeding stock• Compete to improve the breed