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Bob Weaber, Ph.D. Assistant Professor and Cow/calf Extension Specialist
Department of Animal Science and Industry Kansas State University
785-532-1460
www.nbcec.org Beef Sire Selection Manual Brown Bagger Webinar Series (Archive)
eXtension-Beef Cattle Clearinghouse CoP Webinars (archive) http://www.extension.org/beef_cattle
ASI K-State Across Breed EPD converter Adj BW, WW, YW calculator http://ksubeef.org
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 2
If you don’t measure it, you can’t manage it! The best way to know how much something
weighs…is to weigh it! Not all traits should be measured… Populations respond to selection. Selection without an objective that includes
profit is a hobby. Sire selection should address additive and
non-additive merit.
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 3
DNA Markers EPD Ratios Adjusted weights Raw Weights Visual Appraisal
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 5
Ability to generate response to selection Cost
Includes all sources of variation Management (i.e. feed)
Differences in age
Sex
Age of dam
Climate
Genetics
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 6
What is the data ‘adjusted’ for? Sex
Age of calf
Age of dam
Why? Compare ‘apples to apples’
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 7
A way of comparing animals within a contemporary group Contemporary group average = 500
Animal = 550
Ratio = 110
▪ (550/500)*100
Why not outside of that group? Different environmental influences
Group averages may not be equal 11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 8
Separates the ‘wheat from the chaff’ What information is included?
Pedigree information
▪ (Parents, grand-parents, half –sibs, etc.)
Individuals’ own record (very important)
Progeny information
Correlated traits (BW, WW, YW)
REMOVES ENVIRONMENTAL EFFECTS
Can be used across herds but only within a breed
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 9
Expected Future, average, mean
Progeny Offspring
Difference Implies comparison between animals NOT phenotypic performance
Measure of relative merit among individuals Estimate of average effect of animal as parent Estimate of average gamete genetic merit
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 10
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 11
Average value of gametes EPD = 40
20 30 40 50 600
0.01
0.02
0.03
0.04
0.05
0.06
Perc
ent o
f cal
ves
obse
rved
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 12
20 30 40 50 60 70 0
0.01
0.02
0.03
0.04
0.05
0.06
10 lb. Difference in EPD of Two Bulls
Perc
ent o
f cal
ves
obse
rved
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 13
Cumulative (net) effect of all genes and their interactions on a trait.
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 14
KCF Bennett 3008 M326
TRAIT CED BW WW YW MILKEPD 5.5 0.8 51 91 24
TRAIT CED BW WW YW MILKEPD 9 1.3 42 83 32
Bon View New Design 878
S A F Strategy 9015
TRAIT CED BW WW YW MILKEPD 6 2 58 106 30
Consists of animals that are: Given equal opportunity to perform
Of similar age and sex Identify fair competition Formed from management information The basis of all genetic comparisons
Phenotype = CG + Genetics + e
Genetics = Phenotype - CG 11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 15
7-9 times more effective generating response to selection than phenotypic selection Can be used to: Increase performance
Decrease performance
Optimize performance Do not select for maximum genetic expression
w/o regard to other factors Nutritional conditions
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 17
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 18
-20
0
20
40
60
80
100
800
850
900
950
1000
1050
1100
1150
1200
1970 1975 1980 1985 1990 1995 2000 2005 2010
YW
EP
D
Bul
ls A
djus
ted
YW
(lb)
Year of Birth
YW-Bulls YW EPD Data Source: 2009 Am. Angus Sire Evaluation Report; Phenotypic and Genetic Trends
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 19
800 850 900 950
1000 1050 1100 1150 1200 1250
-20 0 20 40 60 80 100
YW
-Bul
ls
YW EPD
YW Line Fit Plot
YW-Bulls Predicted YW-Bulls Data Source: 2009 Am. Angus Sire Evaluation Report; Phenotypic and Genetic Trends
YWPheno = 910 + 3.38*YWEPD R2 = 0.96
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 20
-3
-2
-1
0
1
2
3
65 67 69 71 73 75 77 79 81 83 85
1970 1975 1980 1985 1990 1995 2000 2005 2010
BW
EP
D
Adj
uste
d B
W -
Bul
ls
Year of Birth
BW-Bulls BW EPD Data Source: 2009 Am. Angus Sire Evaluation Report; Phenotypic and Genetic Trends
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 21
65
70
75
80
85
-3 -2 -1 0 1 2 3
BW
-Bul
ls
BW EPD
BW Line Fit Plot
BW-Bulls Predicted BW-Bulls Data Source: 2009 Am. Angus Sire Evaluation Report; Phenotypic and Genetic Trends
BWPheno = 75 + 2.68*BWEPD R2 = 0.95
Weaber and Fennewald, 2009
0
10
20
30
40
50
60
70
80
90
1985
19
86
1987
19
88
1989
19
90
1991
19
92
1993
19
94
1995
19
96
1997
19
98
1999
20
00
2001
20
02
2003
20
04
2005
20
06
2007
Mea
n YW
EPD
Across Breed EPD Genetic Trends- YEARLING WEIGHT All Breeds Presented on ANGUS EPD Base
AN AR HH CH GV LM MA SM
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 22
Weaber and Fennewald, 2009
-10
-5
0
5
10
15
20
25
1985
19
86
1987
19
88
1989
19
90
1991
19
92
1993
19
94
1995
19
96
1997
19
98
1999
20
00
2001
20
02
2003
20
04
2005
20
06
2007
Mea
n M
ilk E
PD
Across Breed EPD Genetic Trends-MILK All Breeds Presented on ANGUS EPD Base
AN AR HH CH GV LM MA SM
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 23
Sire WW EPD A 40 B 49 C 52
Avg. 47
Average Adjusted 205 d
Weaning Weight
560 lb.
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 24
Selection is challenging Not all economically
important traits have EPD Fertility
Disease resistance
Fescue fitness
Conformation traits
Mature weight
Use the right tool for job! Multiple trait selection
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 25
10/15/2007
Our objective is to breed cattle that breed as yearlings, calve unassisted and rear a good
calf for sale at weaning every year. We aim to breed functional cattle that flesh easily and can forage on the hills over winter but must have the temperament and soundness to be
farmed intensively during calving and the breeding season.
27 Vienna, MO
A trait that has a direct cost or return associated with it is an Economically Relevant Trait (ERT). Traits that are correlated to ERTs are
indicator traits. Example: Is Birth Weight or Calving East the
ERT? Why?? Weaning Weight or Yearling Weight?
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 28
Reproduction:Growth:End Product
2:1:1
(Melton, 1995)
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 29
$W - One number to use in selection that summarizes five
Appropriately weights each trait for its influence of profit
Selection on ‘aggregate merit’ (Hazel, 1943) Value of each trait - increase in satisfaction with one
unit change in a trait, all others held constant Selection index is formal statement of trade-offs
among traits used to evaluate selection candidates (MacNeil et al., 1997)
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 30
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 32
Marker 1
But What About These Genes?
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 33
Cumulative effect of all genes and their interactions on a trait.
EPD Sum of the additive
effect of all genes that influence a given trait divided by two
Genes are unknown Time delay in collecting
phenotypes
MBV (MVP, ETC.) Sum of the additive
effect of SNP alleles (multiplied by copy number) that influence a trait
These are not genes, but associated with genetic variance
Can be collected at birth
Eastern Animal Science Agent Update - Topeka, KS 34
Spangler, 2011
11/15/2011
EPD (index or interim)
MBV (correlated indicator trait)
MA-EPD
Eastern Animal Science Agent Update - Topeka, KS 35
Spangler, 2011
11/15/2011
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 36
0.0
0.2
0.4
0.6
0.8
1.0
0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00
Accuracy (rTI)
Relationship between Accuracy (rTI), R2 (% Genetic Variance Explained) and BIF Accuracy
r(TI) R^2 (%GV) BIF accuracy
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 37
Spangler, 2011
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 38
Spangler, 2011
Thank You!
Questions?
Selection tools for beef cattle improvement
Measures used for selection
The basics of EPDs
Where EPDs fit in selection
EPDs work! (and not just to increase a trait)
What they can and can’t do
EPDs – making the tools work together
Multiple trait selection
EPDs – Future
New sources of genetic information
Old and new living together – convergence 11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 40
Cattle have 30 pairs of chromosomes
29 autosomes, 1 sex determining
Diploid (2 copies of each chromosome)
Meiotic cell division forms gametes
Eggs and sperm are haploid
1 chromosome from each pair; random
Recombination or cross-over events
Fertilization restores diploid chromosome count
Two copies of each gene
Alternate forms are called alleles
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 41
Genet. Mol. Biol. 1999, vol.22, n.3, pp. 369-373
Difficult? Lots of EPDs
Some for Economically Relevant Trait (ERT) some for Indicator Traits
Important? More than one trait is important for enterprise,
operation or industry profitability
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 42
0
2
4
6
8
10
12
1985
19
86
1987
19
88
1989
19
90
1991
19
92
1993
19
94
1995
19
96
1997
19
98
1999
20
00
2001
20
02
2003
20
04
2005
20
06
2007
Mea
n BW
EPD
Across Breed EPD Genetic Trends-BIRTH WEIGHT All Breeds Presented on ANGUS EPD Base AN
AR HH CH GV LM MA SM
Weaber and Fennewald, 2009
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 43
Weaber and Fennewald, 2009
0
10
20
30
40
50
60
70
1985
19
86
1987
19
88
1989
19
90
1991
19
92
1993
19
94
1995
19
96
1997
19
98
1999
20
00
2001
20
02
2003
20
04
2005
20
06
2007
Mea
n W
W E
PD
Across Breed EPD Genetic Trends-WEANING WEIGHT All Breeds Presented on ANGUS EPD Base
AN AR HH CH GV LM MA SM
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 44
BW – Mature Wt. 0.61 WW – Mature Wt. 0.65 YW – Mature Wt. 0.65 Feed Intake – Mature Wt. 0.75
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 45
Did EPDs make big cows??
NO, people made big cows!
Selection works! So does correlated response
We can use EPDs to: Increase performance Decrease performance Maintain performance
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 46
Two Step approach by Henderson (1950s) Calculate predictions of merit (EPD) for each trait
in selection objective
Weight each prediction by it’s Relative Economic Value (REV)
Equivalent to Hazel (1943) approach
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 47
Large marker panels or whole genome selection system Incorporate marker data into EPD calculation Am. Simmental used WBSF markers in computation
of EPD
Am. Angus Association debut of Genome Assisted EPDs
Improves accuracy for young animals/selection candidates Reduces need to collect expensive phenotypes
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 48
Genetic Correlation % GV BIF Accuracy
0.1 1 0.005
0.2 4 0.020
0.3 9 0.046
0.4 16 0.083
0.5 25 0.132
0.6 36 0.2
0.7 49 0.286
Spangler, 2011
11/15/2011 Eastern Animal Science Agent Update - Topeka, KS 49