Genetic Evaluation of Genetic Evaluation of Carcass Data Using Carcass Data Using Age, Weight, Fat, or Age, Weight, Fat, or Marbling EndpointsMarbling Endpoints
2003 BIF Selection Decisions 2003 BIF Selection Decisions CommitteeCommittee
May 29, 2003May 29, 2003
Janice M. RumphJanice M. Rumph
Montana State University – BozemanMontana State University – Bozeman
Carcass EPDsCarcass EPDs Many breed Many breed
associations are associations are printing some form of printing some form of carcass EPDscarcass EPDs Based on an age constantBased on an age constant
Few producers kill Few producers kill cattle based on an age cattle based on an age constantconstant Back FatBack Fat Carcass WeightCarcass Weight MarblingMarbling
Are we doing things Are we doing things wrong?wrong?
There is nothing There is nothing wrong with wrong with adjusting data to an adjusting data to an age-constant basis…age-constant basis…
If you are killing on If you are killing on an age-constant basisan age-constant basis
If ranking of animals If ranking of animals does not change with does not change with different endpointsdifferent endpoints
??
Initial ResearchInitial Research
Endpoints can alter expression of Endpoints can alter expression of genetic differences (Koch et al., genetic differences (Koch et al., 1995)1995)
Ranking of Simmental sires has been Ranking of Simmental sires has been shown to be differ by slaughter shown to be differ by slaughter endpoint (Shanks et al., 2001)endpoint (Shanks et al., 2001)
DataData
16,081 animals with carcass data16,081 animals with carcass data16,080 16,080 – Carcass Weight– Carcass Weight
15,770 15,770 – Percent Retail Cuts– Percent Retail Cuts12,05612,056 – Marbling– Marbling8586 8586 – Ribeye Area – Ribeye Area 8382 8382 – Fat Thickness– Fat Thickness
18,133 animals in pedigree18,133 animals in pedigree
AdjustmentsAdjustments
Age – 475 dAge – 475 d Had to be at least 365 d at slaughterHad to be at least 365 d at slaughter
Carcass Weight – 750 lbCarcass Weight – 750 lb Had to be less than 1150 lbHad to be less than 1150 lb
Marbling – 500 (Small; Low Choice)Marbling – 500 (Small; Low Choice) Had to be between 100 (Devoid) and Had to be between 100 (Devoid) and
1000 (Abundant)1000 (Abundant) Fat Thickness – 0.35 inFat Thickness – 0.35 in
Had to be less than 1.5 inHad to be less than 1.5 in
Other TraitsOther Traits
Ribeye AreaRibeye Area Had to be greater than 6 inHad to be greater than 6 in22
Percent Retail CutsPercent Retail Cuts Had to be between 40 – 60%Had to be between 40 – 60%
ResultsResults
Estimates of HeritabilityEstimates of Heritability
FatFat MarbMarb CWTCWT REAREA PRCPRC
AgeAge 0.140.14 0.280.28 0.290.29 0.270.27 0.250.25
FatFat -- 0.250.25 0.330.33 0.290.29 0.280.28
MarbMarb 0.110.11 -- 0.280.28 0.240.24 0.260.26
CWTCWT 0.160.16 0.280.28 -- 0.270.27 0.260.26
TraitTrait
Ad
just
men
tA
dju
stm
en
t
Correlations – Fat Correlations – Fat ThicknessThickness
AgeAge CWTCWT MarbMarb
AgeAge -- 0.960.96 0.850.85
CWTCWT -- 0.820.82
MarbMarb --
Fat ThicknessFat Thickness
Age Adjusted Rank
Carc
ass
Weig
ht
Ad
just
ed
Ran
k
r = 0.96r = 0.96
415 Age Adjusted915 Carcass Weight Adjusted
651 Age Adjusted186 Carcass Weight Adjusted
Fat ThicknessFat Thickness
Age Adjusted Rank
Marb
lin
g A
dju
sted
Ran
k
r = 0.85r = 0.85
9 Age Adjusted1000 Marbling Adjusted
988 Age Adjusted92 Marbling Adjusted
Correlations – Carcass Correlations – Carcass WeightWeight
AgeAge FatFat MarMarbb
AgeAge -- 0.820.82 0.870.87
FatFat -- 0.810.81
MarMarbb
--
Carcass WeightCarcass Weight
Age Adjusted Rank
Fat
Th
ickn
ess
Ad
just
ed
Ran
k
r = 0.82r = 0.82
8 Age Adjusted912 Fat Adjusted
1113 Age Adjusted229 Fat Adjusted
Carcass WeightCarcass Weight
Age Adjusted Rank
Marb
lin
g A
dju
sted
Ran
k
r = 0.87r = 0.87
22 Age Adjusted791 Marbling Adjusted
1119 Age Adjusted464 Marbling Adjusted
Correlations – MarblingCorrelations – Marbling
AgeAge CWTCWT FatFat
AgeAge -- 0.990.99 0.850.85
CWTCWT -- 0.850.85
FatFat --
MarblingMarbling
Age Adjusted Rank
Carc
ass
Weig
ht
Ad
just
ed
Ran
k
r = 0.99r = 0.99
395 Age Adjusted658 Carcass Weight Adjusted
638 Age Adjusted319 Carcass Weight Adjusted
MarblingMarbling
Age Adjusted Rank
Fat
Th
ickn
ess
Ad
just
ed
Ran
k
r = 0.85r = 0.85
91 Age Adjusted1159 Fat Adjusted
1178 Age Adjusted384 Fat Adjusted
Correlations – Ribeye Correlations – Ribeye AreaArea
AgeAge CWTCWT MarMarbb
FatFat
AgeAge -- 0.900.90 0.880.88 0.970.97
CWTCWT -- 0.770.77 0.880.88
MarMarbb
-- 0.870.87
FatFat --
Ribeye AreaRibeye Area
Age Adjusted Rank
Carc
ass
Weig
ht
Ad
just
ed
Ran
k
r = 0.90r = 0.90
91 Age Adjusted813 Carcass Weight Adjusted
1157 Age Adjusted382 Carcass Weight Adjusted
Ribeye AreaRibeye Area
Age Adjusted Rank
Marb
lin
g A
dju
sted
Ran
k
r = 0.88r = 0.88
77 Age Adjusted992 Marbling Adjusted
1161 Age Adjusted211 Marbling Adjusted
Ribeye AreaRibeye Area
Age Adjusted Rank
Fat
Th
ickn
ess
Ad
just
ed
Ran
k
r = 0.97r = 0.97
65 Age Adjusted621 Fat Adjusted
1025 Age Adjusted511 Fat Adjusted
Correlations – Percent Correlations – Percent Retail CutsRetail Cuts
AgeAge CWCWTT
MarMarbb
FatFat
AgeAge -- 0.960.96 0.880.88 0.600.60
CWCWTT
-- 0.860.86 0.520.52
MarMarbb
-- 0.540.54
FatFat --
Percent Retail CutsPercent Retail Cuts
Age Adjusted Rank
Carc
ass
Weig
ht
Ad
just
ed
Ran
k
276 Age Adjusted768 Carcass Weight Adjusted
360 Age Adjusted71 Carcass Weight Adjusted
r = 0.96r = 0.96
Percent Retail CutsPercent Retail Cuts
Age Adjusted Rank
Marb
lin
g A
dju
sted
Ran
k
110 Age Adjusted973 Marbling Adjusted
r = 0.88r = 0.88
1247 Age Adjusted265 Marbling Adjusted
Percent Retail CutsPercent Retail Cuts
Age Adjusted Rank
Fat
Th
ickn
ess
Ad
just
ed
Ran
k
r = 0.60r = 0.60
1266 Sires1266 SiresAge AdjustedAge Adjusted
1266 Sires1266 SiresFat AdjustedFat Adjusted
12561256Bottom 1%Bottom 1%
8282Top 7%Top 7%
2121Top 2%Top 2%
10051005Bottom 21%Bottom 21%
104104
269269
5959
517517
288288
169169
22222, 6, 82, 6, 8
Reranking of Sires - PRCReranking of Sires - PRC
Age AdjustedAge Adjusted1122334455667788991010
0.960.96CWT AdjustedCWT Adjusted
112214146644337755101099
0.880.88Marb AdjustedMarb Adjusted
22022044
6396395533662211
53531111
0.600.60Fat AdjustedFat Adjusted
222222
51751710410466
595988
288288269269169169
SummarySummary
Carcass endpoint does alter rankingCarcass endpoint does alter ranking Sometimes significantlySometimes significantly
What is the solution?What is the solution? Different EPDs for different endpoints?Different EPDs for different endpoints? Change all EPDs to a different Change all EPDs to a different
endpoint?endpoint? Do nothing?Do nothing?
Genetic Evaluation of Genetic Evaluation of Carcass Data Using Carcass Data Using Age, Weight, Fat, or Age, Weight, Fat, or Marbling EndpointsMarbling Endpoints
2003 BIF Selection Decisions 2003 BIF Selection Decisions CommitteeCommittee
May 29, 2003May 29, 2003
Janice M. RumphJanice M. Rumph
Montana State University – BozemanMontana State University – Bozeman
