Some genes may affect more than one trait. Therefore, the traits can be genetically correlated. Knowledge of genetic correlations among traits is useful for efficient selection of replacement bulls and heifers if the breeder considers more than one trait. In designed selection programs, emphasis to be placed on the various traits can depend, in part, on the genetic correlations among them. In addition, genetic correlations can be used to predict what is expected to happen to traits other than those used in selection as a result of that selection. This effect on traits other than those used in selection is referred to as correlated response.
The objective of this study was to estimate from experimental data the genetic correlations between reproductive and maternal traits of beef females and growth and carcass traits of paternal half-sib steers. A more detailed account of the methodology and results can be found in the Journal of Animal Science, volume 58, pages 1171 to 1180

Cundiff, Larry V.

Dinkel, C. A.

Koch, Robert M.

MacNeil, Michael D.

English

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Roman L. Hruska U.S. Meat Animal Research Center U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska 1985 Genetic Correlations of Reproductive and Maternal Traits with Growth and Carcass Traits in Beef Cattle Michael D. MacNeil U.S. Meat Animal Research Center Larry V. Cundiff U.S. Meat Animal Research Center, Larry.Cundiff@ars.usda.gov C. A. Dinkel South Dakota State University Robert M. Koch U.S. Meat Animal Research Center Follow this and additional works at: https://digitalcommons.unl.edu/hruskareports  Part of the Animal Sciences Commons MacNeil, Michael D.; Cundiff, Larry V.; Dinkel, C. A.; and Koch, Robert M., "Genetic Correlations of Reproductive and Maternal Traits with Growth and Carcass Traits in Beef Cattle" (1985). Roman L. Hruska U.S. Meat Animal Research Center. 49. https://digitalcommons.unl.edu/hruskareports/49 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Roman L. Hruska U.S. Meat Animal Research Center by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. - --GeneticCorrelations of Reproductiveand MaternalTraitswith Growthand CarcassTraits in Beef CattleMichael D. MacNeil,Larry V. Cundiff, C. A. Dinkel,and RobertM. Koch'IntroductionSome genes may affect more than one trait.Therefore, thetraits can be genetically correlated. Knowledge of geneticcor-relations among traits is useful for efficient selection of re-placementbulls and heifers if the breederconsiders more thanone trait.In designedselectionprograms,emphasistobe placedon the various traits can depend, in part, on the genetic cor-relations among them. In addition,genetic correlationscan beused to predictwhat is expected to happen to traitsother thanthose used in selection as a resultof thatselection.This effecton traits other than those used in selection is referred to ascorrelated response.The objectiveof this studywas to estimatefromexperimentaldata the genetic correlations between reproductive and ma-temal traits of beef females and growth and carcass traits ofpaternal half-sib steers. A more detailed account of the meth-odology and results can be found in the Journal of AnimalScience, volume 58, pages 1171to 1180.ProcedureThis study includes data on calves born at MARC during1970, 1971, and 1972. StraightbredHereford and Angus cowswere mated to either Hereford, Angus, Jersey, South Devon,Limousin, Charolais, or Simmental sires to calvefrom late Feb-ruary to early May. Bull calves were castrated at birth,and allcalves had access to creep feed from mid-July until weaningin late October.After weaning, heifers were fed ad libituma diet of approx-imately50 percent corn silage and 50 percent grass haylagewithsupplementalproteinand minerals.Heifers were observedfor estrous activitytwice daily from approximately250 to 510days of age, except in 1971, when estrous detection ceasedat about 480 days of age. A breeding season of approximately65 days started when the average age of all heifers was 430days. During the first two-thirds of the breeding season, allheifers were artificially inseminated with semen from eitherHereford, Angus, Devon, Holstein, or Brahman bulls. In thelatter one-third of the breeding season, natural service Here-ford and Angus sires were used.Postweaning managementof steer calves differedfrom thatof their half-sib heifers.After a 25- to 30-day adaptationperiod,steers were implantedwith 36 mg diethylstilbestrol(DES) andassigned to feedlot pens with fence-line bunks. Steers werealso fed ad libitum, but the dietary energy density increasedperiodically as they matured. Steers were slaughtered in oneof threegroups at aboutone-month intervals.The initialslaugh-ter group was killed after 190 days on feed in 1971, 169 daysin 1972, and 194 days in 1973. The rightside of each carcasswas transported to Kansas State University. Sides were cutinto wholesale cuts and cuts fabricated into boneless (exceptfor rib and short loin), closely trimmed (.3 in) retail product(steaks, roasts, and lean trim), fat trim, and bone.ResultsEstimated heritabilities for the traits studied are presentedin Table 1. Heritability estimates for age and weight at firstobserved estrus, or puberty (61 pet and 70 pet, respectively),'MacNeil is agriculturalstatistician,ProductionSystemsUnit,andCundiffis the researchleader,GeneticsandBreedingUnit,MARC;Dinkelis professorof animalscience,SouthDakotaStateUniversity,Brookings;andKochis professorof animalscience,Universityof Ne-braska-Lincoln,stationedat MARC.are somewhat higher than previously reportedestimates.The3 percent heritabilityfor conceptions/service in this study is inagreement with previous estimates for fertility,whether meas-ured as calving rate, conception/service, or services/concep-tion. Gestationlengthand calf birthweighthave been implicatedin the incidence of dystocia and calf mortality. In this study,gestation length, calf birth weight, calving difficulty,and pre-weaning daily gain were treatedas traitsof the cow. Heritabilityestimates were 30 percent for gestation length,37 percentforcalf birthweight, and 22 percent for calving difficulty.The her-itabilityestimate for preweaning gain of the calf, as a trait ofthe dam, was 9 percent. Previous studies suggest the herit-ability of preweaning gain, as a trait of the dam, lies in therange of 17 to 34 percent.The heritabilityof preweaninggain,as a trait of the calf, was also found to be low (7 pet) in thesedata.The amount of feed eaten by a cow is relatedto her weight.Therefore, cow size may be important in the evaluation ofalternativeselection objectives. Mature weight has been onecommonly used measure of size. The estimatedheritabilityofthe average of four weights taken at 7 years of age was 54percent in this study.Heritabilityestimates for daily gain (36 pet),carcass weight(44 pet), retail productweight (45 pet), and trimmedfat weight(50 pet)found in this studyare comparablewithotherestimatesin the literature. Selection to increase (or decrease) any ofthese traits measured on steers should be effective.Also presented in Table 1 are estimatedgenetic correlationsof traits expressed in males and females. Postweaning dailygain, carcass weight, and retail product weight at a constantage seem to have similargeneticassociations withthe complexof female reproductive and productivitytraits studied.Since retail product weight and carcass weight had essen-tiallyequal heritabilities,predictedcorrelated responses to se-lection for either trait are also similar. Predicted correlatedresponses to selection for either retail product weight or car-cass weight are greater in magnitudethan those for daily gainselection, due primarilyto the higher heritabilitiesof the formertraits. Selection for increased carcass weight or retail productweight of steers at a constant slaughter age should result inheifers that are older and heavier at pubertyand have slightlyimprovedfertility.The gestation lengthof these heifersand calfbirthweight would increase slightly,although,maternally,calv-ing would occur with less difficulty. The inconsistency of alarger calf and less calving difficulty is perhaps explained bythe increased size of the heifer.Selection for decreased fat recently has received consid-erable attention.While this course of action may result in moredesirable carcasses, thegeneticcorrelationsfoundinthis studymay indicate possible problems. Females from sires selectedfor reduced fat trim of steer progeny would be expected toreach puberty later and at a heavier weight, have reducedfertility,and be larger at 7 years of age. These data also sug-gest a longer firstgestation with the resultantcalf born heavierand with greater difficulty.These resultsdocumenttheexistenceof unfavorablegeneticcorrelations between component traits of female productivityand progeny carcass value. Therefore, specialized sire anddam lines appear to merit consideration in beef production.Alternatively, selection indexes that incorporate both carcassvalue traits and maternal productivitytraits provide logical se-lection objectives in general purpose populations. Geneticprogress in a general purpose populationwould be slower thanprogress thatcould be made from crossing sire and dam linesselected for specialized roles.8-+ _.-----Table1.-Estlmatedgeneticcorrelationsof reproductiveand materialtraits with growthand carcass traitsIn parenthesesare the respectiveheritabilityestimates(h2)and the numberof heifersor steers (n)8Growthandcarcasstraitsof steersCercasswt Fettrimwt(h"=.44;n=1,071) (h2=.50;n=1,071).17 -.29.07 -.31.61 .21.03 -.07-.31 -.36.37 -.07_b _bReproductive andmaternal traits of femalesDailygain(h"=.36;n=1,095).16.07+b-.10-.60.34Age at puberty(h2=.61;n=813).............Weightat puberty(h2=.70;n=841)..........Conceptions/service (h2= .03; n = 771). . . . . . . .Gestation length (h2= .30; n = 580) . . . . . . . . . . .Calving difficulty (h2 = .22; n = 590) . . . . . . . . . . .Birthweight(h2=.37;n=581)...............Preweaning daily gain (h2= .09; n =624)Matureweight(h2=.54;n=639)............. .07 .21 -.09Retailproductwt(h"=.45;n=1,(64).30.08.28.13-.02.30-.26.25"Geneticcorrelationshavean expectedrangefrom - 1.0to +1.0.Estimatesin theranges.7 to .10and -.7 to -1.0 indicatestrongpositiveand negativegeneticrelationshipsbetweentraits.respectively.Estimatesfrom -.2 to .2 indicateweakgeneticrelationshipsbetweentraits.bTheestimatedgeneticcorrelationwaseithergreaterthan+1.0or lessthan - 1.0.Onlythesignof theestimatehasbeenreported.9

Genetic Correlations of Reproductive and Maternal Traits with Growth and Carcass
Traits in Beef Cattle

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Roman L. Hruska U.S. Meat Animal Research 
Center 
U.S. Department of Agriculture: Agricultural 
Research Service, Lincoln, Nebraska 
1985 
Genetic Correlations of Reproductive and Maternal Traits with 
Growth and Carcass Traits in Beef Cattle 
Michael D. MacNeil 
U.S. Meat Animal Research Center 
Larry V. Cundiff 
U.S. Meat Animal Research Center, Larry.Cundiff@ars.usda.gov 
C. A. Dinkel 
South Dakota State University 
Robert M. Koch 
U.S. Meat Animal Research Center 
Follow this and additional works at: https://digitalcommons.unl.edu/hruskareports 
 Part of the Animal Sciences Commons 
MacNeil, Michael D.; Cundiff, Larry V.; Dinkel, C. A.; and Koch, Robert M., "Genetic Correlations of 
Reproductive and Maternal Traits with Growth and Carcass Traits in Beef Cattle" (1985). Roman L. Hruska 
U.S. Meat Animal Research Center. 49. 
https://digitalcommons.unl.edu/hruskareports/49 
This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research 
Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in 
Roman L. Hruska U.S. Meat Animal Research Center by an authorized administrator of DigitalCommons@University 
of Nebraska - Lincoln. 
- --
GeneticCorrelations of Reproductiveand MaternalTraitswith Growthand Carcass
Traits in Beef Cattle
Michael D. MacNeil,Larry V. Cundiff, C. A. Dinkel,and RobertM. Koch'
Introduction
Some genes may affect more than one trait.Therefore, the
traits can be genetically correlated. Knowledge of geneticcor-
relations among traits is useful for efficient selection of re-
placementbulls and heifers if the breederconsiders more than
one trait.In designedselectionprograms,emphasistobe placed
on the various traits can depend, in part, on the genetic cor-
relations among them. In addition,genetic correlationscan be
used to predictwhat is expected to happen to traitsother than
those used in selection as a resultof thatselection.This effect
on traits other than those used in selection is referred to as
correlated response.
The objectiveof this studywas to estimatefromexperimental
data the genetic correlations between reproductive and ma-
temal traits of beef females and growth and carcass traits of
paternal half-sib steers. A more detailed account of the meth-
odology and results can be found in the Journal of Animal
Science, volume 58, pages 1171to 1180.
Procedure
This study includes data on calves born at MARC during
1970, 1971, and 1972. StraightbredHereford and Angus cows
were mated to either Hereford, Angus, Jersey, South Devon,
Limousin, Charolais, or Simmental sires to calvefrom late Feb-
ruary to early May. Bull calves were castrated at birth,and all
calves had access to creep feed from mid-July until weaning
in late October.
After weaning, heifers were fed ad libituma diet of approx-
imately50 percent corn silage and 50 percent grass haylage
withsupplementalproteinand minerals.Heifers were observed
for estrous activitytwice daily from approximately250 to 510
days of age, except in 1971, when estrous detection ceased
at about 480 days of age. A breeding season of approximately
65 days started when the average age of all heifers was 430
days. During the first two-thirds of the breeding season, all
heifers were artificially inseminated with semen from either
Hereford, Angus, Devon, Holstein, or Brahman bulls. In the
latter one-third of the breeding season, natural service Here-
ford and Angus sires were used.
Postweaning managementof steer calves differedfrom that
of their half-sib heifers.After a 25- to 30-day adaptationperiod,
steers were implantedwith 36 mg diethylstilbestrol(DES) and
assigned to feedlot pens with fence-line bunks. Steers were
also fed ad libitum, but the dietary energy density increased
periodically as they matured. Steers were slaughtered in one
of threegroups at aboutone-month intervals.The initialslaugh-
ter group was killed after 190 days on feed in 1971, 169 days
in 1972, and 194 days in 1973. The rightside of each carcass
was transported to Kansas State University. Sides were cut
into wholesale cuts and cuts fabricated into boneless (except
for rib and short loin), closely trimmed (.3 in) retail product
(steaks, roasts, and lean trim), fat trim, and bone.
Results
Estimated heritabilities for the traits studied are presented
in Table 1. Heritability estimates for age and weight at first
observed estrus, or puberty (61 pet and 70 pet, respectively),
'MacNeil is agriculturalstatistician,ProductionSystemsUnit,and
Cundiffis the researchleader,GeneticsandBreedingUnit,MARC;
Dinkelis professorof animalscience,SouthDakotaStateUniversity,
Brookings;andKochis professorof animalscience,Universityof Ne-
braska-Lincoln,stationedat MARC.
are somewhat higher than previously reportedestimates.The
3 percent heritabilityfor conceptions/service in this study is in
agreement with previous estimates for fertility,whether meas-
ured as calving rate, conception/service, or services/concep-
tion. Gestationlengthand calf birthweighthave been implicated
in the incidence of dystocia and calf mortality. In this study,
gestation length, calf birth weight, calving difficulty,and pre-
weaning daily gain were treatedas traitsof the cow. Heritability
estimates were 30 percent for gestation length,37 percentfor
calf birthweight, and 22 percent for calving difficulty.The her-
itabilityestimate for preweaning gain of the calf, as a trait of
the dam, was 9 percent. Previous studies suggest the herit-
ability of preweaning gain, as a trait of the dam, lies in the
range of 17 to 34 percent.The heritabilityof preweaninggain,
as a trait of the calf, was also found to be low (7 pet) in these
data.
The amount of feed eaten by a cow is relatedto her weight.
Therefore, cow size may be important in the evaluation of
alternativeselection objectives. Mature weight has been one
commonly used measure of size. The estimatedheritabilityof
the average of four weights taken at 7 years of age was 54
percent in this study.
Heritabilityestimates for daily gain (36 pet),carcass weight
(44 pet), retail productweight (45 pet), and trimmedfat weight
(50 pet)found in this studyare comparablewithotherestimates
in the literature. Selection to increase (or decrease) any of
these traits measured on steers should be effective.
Also presented in Table 1 are estimatedgenetic correlations
of traits expressed in males and females. Postweaning daily
gain, carcass weight, and retail product weight at a constant
age seem to have similargeneticassociations withthe complex
of female reproductive and productivitytraits studied.
Since retail product weight and carcass weight had essen-
tiallyequal heritabilities,predictedcorrelated responses to se-
lection for either trait are also similar. Predicted correlated
responses to selection for either retail product weight or car-
cass weight are greater in magnitudethan those for daily gain
selection, due primarilyto the higher heritabilitiesof the former
traits. Selection for increased carcass weight or retail product
weight of steers at a constant slaughter age should result in
heifers that are older and heavier at pubertyand have slightly
improvedfertility.The gestation lengthof these heifersand calf
birthweight would increase slightly,although,maternally,calv-
ing would occur with less difficulty. The inconsistency of a
larger calf and less calving difficulty is perhaps explained by
the increased size of the heifer.
Selection for decreased fat recently has received consid-
erable attention.While this course of action may result in more
desirable carcasses, thegeneticcorrelationsfoundinthis study
may indicate possible problems. Females from sires selected
for reduced fat trim of steer progeny would be expected to
reach puberty later and at a heavier weight, have reduced
fertility,and be larger at 7 years of age. These data also sug-
gest a longer firstgestation with the resultantcalf born heavier
and with greater difficulty.
These resultsdocumenttheexistenceof unfavorablegenetic
correlations between component traits of female productivity
and progeny carcass value. Therefore, specialized sire and
dam lines appear to merit consideration in beef production.
Alternatively, selection indexes that incorporate both carcass
value traits and maternal productivitytraits provide logical se-
lection objectives in general purpose populations. Genetic
progress in a general purpose populationwould be slower than
progress thatcould be made from crossing sire and dam lines
selected for specialized roles.
8
-+ _.-----
Table1.-Estlmatedgeneticcorrelationsof reproductiveand materialtraits with growthand carcass traits
In parenthesesare the respectiveheritabilityestimates(h2)and the numberof heifersor steers (n)8
Growthandcarcasstraitsof steers
Cercasswt Fettrimwt
(h"=.44;n=1,071) (h2=.50;n=1,071)
.17 -.29
.07 -.31
.61 .21
.03 -.07
-.31 -.36
.37 -.07
_b _b
Reproductive and
maternal traits of females
Dailygain
(h"=.36;n=1,095)
.16
.07
+b
-.10
-.60
.34
Age at puberty(h2=.61;n=813).............
Weightat puberty(h2=.70;n=841)..........
Conceptions/service (h2= .03; n = 771). . . . . . . .
Gestation length (h2= .30; n = 580) . . . . . . . . . . .
Calving difficulty (h2 = .22; n = 590) . . . . . . . . . . .
Birthweight(h2=.37;n=581)...............
Preweaning daily gain (h2= .09; n =624)
Matureweight(h2=.54;n=639)............. .07 .21 -.09
Retailproductwt
(h"=.45;n=1,(64)
.30
.08
.28
.13
-.02
.30
-.26
.25
"Geneticcorrelationshavean expectedrangefrom - 1.0to +1.0.Estimatesin theranges.7 to .10and -.7 to -1.0 indicatestrongpositiveand negativegeneticrelationshipsbetween
traits.respectively.Estimatesfrom -.2 to .2 indicateweakgeneticrelationshipsbetweentraits.
bTheestimatedgeneticcorrelationwaseithergreaterthan+1.0or lessthan - 1.0.Onlythesignof theestimatehasbeenreported.
9


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Genetic Correlations of Reproductive and Maternal Traits with Growth and Carcass Traits in Beef Cattle

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