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Group Title: Bulletin / University of Florida. Agricultural Experiment Station ;
Title: Additive genetic and heterosis effects for calf and maternal influence on post-weaning growth and carcass traits of Angus, Brahman, and Charolais crosses
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 Material Information
Title: Additive genetic and heterosis effects for calf and maternal influence on post-weaning growth and carcass traits of Angus, Brahman, and Charolais crosses
Series Title: Bulletin / University of Florida. Agricultural Experiment Station ;
Physical Description: 17 p. : ; 23 cm.
Language: English
Creator: Peacock, F. M ( Fentress McCoughan ), 1922-
Publisher: Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1982
Copyright Date: 1982
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Subject: Beef cattle -- Breeding   ( lcsh )
Beef cattle -- Carcasses   ( lcsh )
Heterosis   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
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Statement of Responsibility: F.M. Peacock ... et al..
Bibliography: Includes bibliographical references (p. 17).
General Note: "September 1982."
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Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
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Resource Identifier: ltuf - ACF1230
oclc - 10736617
alephbibnum - 000405001

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Full Text

September 1982 Bulletin 832 (technical)





Additive Genetic and Heterosis Effects for
Calf and Maternal Influence on
Post-Weaning Growth and Carcass Traits of
Angus, Brahman, and Charolais Crosses

F. M. Peacock, M. Koger, A. Z. Palmer,
J. W. Carpenter, and T. A. Olson




















Florida Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
F. A. Wood, Dean for Research












Additive Genetic and Heterosis Effects for
Calf and Maternal Influence on
Post-Weaning Growth and Carcass Traits of
Angus, Brahman, and Charolais Crosses

F. M. Peacock, M. Koger, A. Z. Palmer,
J. W. Carpenter, and T. A. Olson





















AUTHORS
F. M. Peacock is a Professor of Animal Husbandry at the Agricultural
Research Center, Ona. Dr. Koger is a Professor of Animal Genetics, Dr.
Palmer and Dr. Carpenter are Professors of Meat Science, and Dr. Olson is an
Assistant Professor of Animal Breeding in the Animal Science Department,
University of Florida, Gainesville.








CONTENTS
Page
INTRODUCTION............... ..................... 1
MATERIALS AND METHODS ............................ 1
Design of Research............... .................. 1
Data Analyses.............. ....................... 4
RESULTS AND DISCUSSION............................. 4
Growth Related Traits .............................. 4
Carcass Composition ............................... 9
Ribeye area ............... ...................... 9
Fat over the eye ............. .................... 9
Kidney, pelvic, and heart fat percent .................... 10
Estimated carcass yield ........................... 10
Qualitative Carcass Traits . .......... .............. 10
Maturity score ............... .................. 10
Conformation score .............................. 10
Marbling score ............... .................. 11
Carcass quality grade ............................ 11
W arner-Bratzler shear . ........... ............... 11
Panel tenderness score .............................. 11
SUMMARY AND CONCLUSIONS ........................ 15
LITERATURE CITED ............................... 17








INTRODUCTION

Crossbreeding has become an important component in commercial
beef production in recent years. Thus, information on the influence of
breed (additive genetic) and heterosis effects both of calf and that of
dam on postweaning growth and carcass characteristics is important
in designing effective beef production systems.
Gregory et al. (3), reported significant effects of individual heter-
osis on carcass weight and other carcass traits of crosses among
Angus, Hereford, and Shorthorn breeds. Gaines et al. (2), working
with the same breeds, presented post-weaning data on crossbred
calves from straightbred and crossbred cows showing significant
effects due to individual heterosis but not due to maternal heterosis.
Information on quantitative and qualitative carcass characteristics
of crosses involving the Angus, Hereford, and Charolais breeds was
reported by Lasley et al. (8), Hedrick et al. (5), and Alenda et al. (1),
likewise showing maternal heterosis to have nonsignificant effects
on post-weaning and carcass traits. Positive breed effects of the
Charolais on size and leaness of carcass have been presented from
research at the Roman L Hrusks U.S. Meat Animal Research Center,
Clay Center, Nebraska (Koch et al., 6, and Koch and Dikeman, 7).
The objective of this study was to obtain information on breed and
heterosis effects on calves and dams for postweaning growth and
carcass traits of the Angus, Brahman, and Charolais, reciprocal F,
crosses, backcrosses, and three-breed cross steers of these breeds.
These breeds represent the three distinctly different types of cattle in
the United States.

MATERIALS AND METHODS

Design of Research

Steers used in this study were produced over a seven-year period at
the Agricultural Research Center, Ona during the second phase of a
crossbreeding project designed to evaluate Angus, Brahman and
Charolais breeds and their crosses. Results of the first phase were
previously reported by Peacock et al. (10), and for reproductive and
preweaning traits of the second phase (Peacock and Koger, 9, and
Peacock et al., 11). During phase 2 of the trial, bulls of each of the
three breeds were mated annually to cows of each breed plus the
three F, cow groups of the three breeds. The number of steers pro-
duced in each of the 18 mating groups is shown in Table 1. There were
a total of 455 steers sired by 21 bulls, seven of each breed.


1


















Table 1. Design and number of observations.

Breed of Dam

Breed of Sire Angus Brahman Charolais AB + BA AC + CA BC + CB Total

Angus (A) 16 23 21 31 14 30 135
Brahman (B) 30 30 26 30 29 22 167
Charolais (C) 13 36 27 27 23 27 153

Total 59 89 74 88 66 79 455







Mating occurred during the 90-day breeding season. Calves were
born from December to March. Calves were weaned from dams the
latter part of September. After an adjustment period following wean-
ing, the calves were fed a concentrate diet ad libitum for an average of
174 days. The diet was composed of 15% cottonseed meal, 50% dried
citrus pulp, 29% cracked corn, 5% alfalfa, and 1% minerals. In addi-
tion the calves were fed an average of 2.5 lb (1.14 kg) per head daily of
Pangola digitgrass (Digitaria decumbens) hay.
The data utilized in evaluating the pre-slaughter performance of
steers included weight when placed on feed and standardized final
weight determined from carcass weight, assuming a chilled dressed
yield of 60%. Daily gain was calculated using standardized final
weight.
The finished steers were slaughtered at the University of Florida
meats laboratory, Gainesville, where slaughter and carcass data
were collected. Cold carcass weights were obtained after chilling for
48 hours at 2C to 30C. Estimated percent yield was used as a measure
of boneless, closely trimmed major cuts from the round, rump, loin,
rib and chuck. This variable was determined from estimated kidney
fat, fat over the longissimus muscle (ribeye), ribeye area, and hot
carcass weight. Beef carcass quality grades were based on USDA
grade standards in effect prior to April 14, 1975. Carcass maturity
values were converted to scale for statistical analysis, with A-
maturity being represented by 1, typical A maturity by 2, and A+
maturity by 3. Carcass conformation and USDA quality grade scores
were derived as follows: average Choice, 17; low Choice, 16; high
Good, 15; etc. Degree of marbling scores were given numerical values
as follows: average small, slight, and traces, 11, 8, and 5, respec-
tively. Measurements of the ribeye area and thickness of fat over the
ribeye were made between the 12th and 13th ribs.
Shortloin samples were removed from carcasses after the 48-hour
chill, wrapped, and frozen at 180C. Steaks were cut approximately
1 in (2.5 cm) thick and defrosted 48 hours between 0C and 2C before
broiling. Steaks were cooked to a medium degree of doneness by
broiling 9 minutes on the first side and 8 minutes on the second side
at a distance of approximately 4 in (10 cm) from the heating element;
this procedure provided steaks cooked to an approximate internal
temperature of 700C, although final internal temperature of indi-
vidual steaks was not monitored. One steak from each carcass was
broiled for taste panel evaluation and another was broiled for War-
ner-Bratzler shear determination.
For the taste panel evaluation, the broiled steaks were cooled at
room temperature for at least 30 minutes. The longissimus muscle of
each steak was then cut into four sections and served to an experi-

3







enced four-member taste panel. Tenderness was evalutated on a scale
varying from 1 (extremely tough) to 9 (extremely tender) with 5
designating average tenderness. Steaks broiled for Warner-Bratzler
shear measurements were cooled similarly, and three 1.27 cm cores
were removed parallel to the direction of the muscle fiber. Each core
was sheared twice, resulting in six shear readings per steak.

Data Analyses
The data were analyzed by least squares procedures outlined by
Harvey (4). Data from calves of reciprocal groups of F, dams were
combined. An initial analysis was performed using the model shown
in Table 2 to provide the 18 breed of sire x breed of dam subclass
means nested within the purebred, F1, backcross, and three-breed
cross classes (Tables 3 and 5). The second analysis utilized multiple
regression procedures to provide simultaneous estimates of additive
breed and heterosis effects for both calf and maternal components
(Tables 4 and 6). The procedure was based on the assumption that calf
and maternal components combine additively and that hybrid vigor
is linear with respect to the percentage of loci where the alleles
originate from different breeds. The procedure was explained in more
detail by Peacock et al. (11) in the analysis of the weaning traits of
these animals. Selected components of this study have previously
been presented by Peacock et al. (12).

RESULTS AND DISCUSSION

Analyses of variance for traits measured are shown in Table 2. The
least squares means for the 18 subclasses (purebred and various
crossbred combinations) for the various traits are presented in Tables
3 and 5, and the additive breed and heterosis effects for calf and dam
are shown in Tables 4 and 6.

Growth Related Traits
Weights taken on cattle directly from the feedlot may reflect sig-
nificant biases due to differences in fill. Carcass weights and stan-
dardized final feedlot weights, assuming a chilled dressing yield of
60%, were used in evaluating the principal growth responses realized
in this study. The growth related traits measured were initial feedlot
weights, daily gain in feedlot, final weight, and chilled carcass weight
(Table 3).
The additive breed effects (Table 4) for all growth related traits
were similar by breed ranking, in ascending order for the Brahman,
Angus, and Charolais breeds. This result showed that the contribu-

4





Table 2. Mean squares from variance analyses for growth traits, carcass composition, and qualitative carcass traits.

Chilled Ribeye/ Estimated
Standardized Carcass 100 lb Carcass
Source DF Daily Gain Weight Ribeye Carcass FOEt KPHt Yield, %

Year 6 .47** 1979** 10.48** .08 .06** 7.68** 5.29**
System (S) 3 .92** 8266** 19.97** .20** .07** 2.49** 5.57*
Purebreeds: S1 2 2.16** 9551** 40.65** .09 .23** 1.52* 23.27**
Fi: S2 5 .15 583 4.53* .12** .19** 2.20** 18.84**
Backcross: S3 5 .14 624* 11.26** .13** .34** 1.90** 27.12**
3-Breed: S4 2 .32 447 9.36** .26** .08** 2.62** 20.84**
Calf age-B Linear 1 .09 27879** 38.30 .66** .20** 2.90* 12.91
Dam age-B Linear 1 .00 1120* .05 .22** .04** .37 13.01*
Dam age-B Quadratic 1 .03 868 .00 .10 .05* .01 8.93
Remainder 428 .11 272 1.31 .04 .01 .35 1.76

Degree Carcass
Carcass Carcass of Quality Panel
Source DF Maturity Conformation Marbling Grade WBStt Tenderness

Year 6 3.85** 26.94** 57.16** 12.12** 320.6** 3.19**
System (S) 3 .63* 1.70 14.28 1.34 1.7 1.05
Purebred: Si 2 .36 27.40** 107.75** 24.25** 60.4** 12.63**
F2: S2 5 .21 4.25** 33.12** 7.71** 20.6** 3.30**
Backcross: S3 5 .13 6.41** 75.85** 17.13** 26.0** 3.64**
3-breed: S4 2 .19 1.54 9.71 4.66* 8.2 .48
Calf age-B Linear 1 .11 11.14** 159.85** 28.71** 21.1 1.27
Dam age-B Linear 1 .75 0.10 .00 .17 7.0 .47
Dam age-B Quadratic 1 .43 6.99 .15 .00 15.0 .46
Remainder 428 .19 1.01 7.05 1.46 7.7 .91

Fat over ribeye
*Kidney, pelvic, and heart fat %
"Warner-Bratzler shear force, lb
*Significantly different, P<0.05
"**Significantly different, P<0.01










Table 3. Least square mating group means for growth and carcass composition.

Standardized Chilled Estimated
Initial Daily Final Carcass REA/100 lb Carcass
Breed Subclasst Weight Gain Weight Weight REA Carcass FOE KPH' Yield

(lb)* (lb)* (lb)* (lb)* (in2) (in2) (in)ttt (%) (%)
Least squares mean 507 2.15 882 529 10.2 1.96 .30 3.0 50.9
Purebreds
AA 396 1.88 723 434 9.1 2.10 .38 2.9 50.3
BB 440 1.81 755 453 8.8 1.96 .25 2.8 50.8
CC 512 2.34 921 553 11.1 2.03 .16 2.5 52.3
S F calves, purebred dams
AB 495 2.14 868 520 10.1 1.93 .36 3.3 50.4
BA 487 2.37 900 540 9.9 1.84 .42 3.4 49.6
AC 517 2.26 913 548 10.8 1.98 .26 3.0 51.3
CA 476 2.23 863 518 10.6 2.06 .27 3.1 51.3
BC 528 2.29 928 557 10.6 1.90 .27 3.3 50.8
CB 538 2.24 928 555 10.9 1.97 .19 2.7 51.9
Backcross calves, Fi dams
AX (AB) 519 2.11 888 532 10.2 1.92 .46 3.3 50.0
BX (AB) 521 2.05 879 527 9.5 1.82 .46 3.4 49.2
AX (AC) 481 2.24 874 524 10.0 1.91 .37 3.2 50.2
CX (AC) 541 2.19 922 553 11.1 2.01 .23 2.7 51.7
BX (BC) 510 2.07 870 522 9.6 1.85 .29 3.0 50.4
CX (BC) 561 2.21 945 560 10.9 1.96 .20 2.8 51.7













Table 3. Continued.

Standardized Chilled Estimated
Initial Daily Final Carcass REA/100 lb Carcass
Breed Subclasst Weight Gain Weight Weight REA Carcass FOE KPH' Yield

Three-breed calves, Fi dams
CX (AB) 570 2.16 948 569 11.5 2.03 .25 2.8 51.8
BX (AC) 536 2.32 940 564 10.3 1.85 .34 3.5 50.0
AX (BC) 539 2.12 909 545 10.8 1.99 .34 3.1 50.8
Mating systems
Purebred 449 2.01 800 480 9.7 2.03 .27 2.7 51.2
F1 507 2.25 900 540 10.5 1.95 .30 3.1 50.9
Backcross 522 2.14 896 537 10.2 1.91 .33 3.1 50.6
3-breed 548 2.20 933 559 10.9 1.96 .31 3.2 50.9

'Breed designation: A, B, and C indicate Angus, Brahman, and Charolais, respectively. Sire breed is shown first in combination.
*kg = x x 0.454
ttcm2 = X x 6.45
*Ucm2/100 kg = Y x 14.22
"tttcm = x x 2.54
'Kidney, pelvic, and heart fat, %











Table 4. Additive breed (A) and Heterosis (H) effects of calf (0) and maternal (M) for growth and carcass composition.

Chilled Estimated
Initial Daily Final Carcass Ribeye REA/100 lb Carcass
Effect Weight Gain Weight Weight Area Carcass FOE KPH8 Yield

(lb)t (lb)t (lb)t (lb)t (in2)* (in2)tt (in)$$ (%) (%)
Calf Component
AO(A) -12.7 -.03 -18.0 -10.7 -.14 .01 .04* -.07 -.19
AO(B) 35.3** .15** 62.7** 35.7** 1.29** -.11** .07** .37** 1.31**
AO(C) 48.0** .18** 80.7** 46.4** 1.43** .10** -.11** -.44** 1.50**
HO(AB) 75.5** .36** 137.2** 82.3** .13 -.10* .06** .39 -.45
HO(AC) 40.8** .08 54.9** 35.2** .82** -.01 -.03 .16 +.27
HO(BC) 55.2** .20** 90.8** 53.9** .84** -.04 .00 .31 -.04
Maternal Component
AM(A) -4.9 .01 -3.0 -1.9 -.04 .00 .00 .01 -.08
AM(B) 4.3 .08* 10.0 -6.9 .20 .06** .05** .23 .62**
AM(C) .6 .07 13.0 8.8 .15 .06** .04** .22 -.55**
HM(AB) 63.1** .01 62.2** 37.5** .14 .05 .08** .17 -.43**
HM(AC) 32.8** -.01 32.1* 19.0* .14* -.05 .01 .12 -.26
HM(BC) 31.9** -.06 21.5 10.7 .10 -.02 .03 .07 -.24
'kg = x 0.454
*cm2 = x 6.45
"ttcm2/100 kg = x x 14.22
"#cm = R x 2.54
*P<0.01
**P<0.05







tion of the Brahman breed to growth potential apart from its con-
tribution through crossbreeding is less than that of the Angus breed
and much less than that of the Charolais. Additive maternal breed
effects for growth traits were similar to those for breed of calf except
for initial weight where the effect of the Brahman cow was highest
and that of the Angus, lowest. Heterosis effects for growth traits in
ascending order for reciprocal F1 crosses were Angus-Charolais,
Brahman-Charolais, and Brahman-Angus. The net effect of these
heterosis influences are reflected in carcass weight. Heterosis in
carcass weights were 35 lb (15.9 kg) for Angus-Charolais, 54 lb
(24.5 kg) for the Brahman-Charolais, and 82 lb (37.2 kg) for Angus-
Brahman cross.
Maternal heterosis effects are those effects on calf productivity due
to the effect of crossbred dams. Maternal heterosis effects were highly
positive at weaning as shown by the effects of crossbred dams on
initial weight (Table 4). This effect is probably a result of increased
milk production by the crossbred cow. This advantage at weaning,
however, is partially negated by slightly negative effects on post-
weaning average daily gain, the most pronounced effect being from
the BC F, dams. Not all of the advantage at weaning is lost during
this period as highly positive maternal heterosis effects remain for
final weight and chilled carcass weight. Maternal heterosis effects for
chilled carcass weight were 11 lb (5.0 kg) for Brahman-Charolais, 19
lb (8.6 kg) for Angus-Charolais, and 37 lb (17.0 kg) for Angus-
Brahman F1 cows. These results emphasize the importance of ensur-
ing that heterozygosity is high in both the calf and the cow.

Carcass Composition

Ribeye area. Ribeye area (REA) is associated with yield or percent-
age of lean in the carcass. Therefore, to indicate relative meatinesss,"
the ribeye area of each breed and breed cross is expressed as square
inches of ribeye by carcass weight (Table 2, 3, 4). Additive breed
effects (Table 4) were similar for both REA and REA per 100 lb
carcass, with Brahman having lowest, Charolais intermediate, and
Angus highest. Heterosis effects in the calf were positive for total
REA due to heavier carcasses but not when expressed as a percentage
of carcass weight. Maternal heterosis effects showed the same trend.
These results are not surprising in that REA is a highly heritable
trait which would not be expected to be improved through cross-
breeding.
Fat over the eye. Fat over ribeye (FOE) is extremely important
because of its relationship with carcass yield grade. In this study,
FOE ranged from 0.16 in (0.41 cm) for Charolais steers to 0.46 in (1.2

9







cm) for backcross Brahman-Angus carcasses (Table 3). Additive
breed effects were significantly negative for the Charolais breed
(Table 4). Calf heterosis effects were positive and significant only for
the AB cross. Additive maternal effects for FOE were essentially zero
for the Angus, significantly positive for the Charolais and signifi-
cantly negative for Brahman dams. Maternal heterosis effects were
small, with only that due to the AB cross being significant. The
positive value for F1 AB cross dams is probably a carry-over effect
from the superior milk production.
Kidney, pelvic, and heart fat percent. The kidney, pelvic, and heart
fat (KPH) % is one of the components used in estimating percent
yield. Carcasses with the lowest % of KPH were those sired by
Charolais bulls (Table 3). Additive breed effects were negative
(P<.01) for the Charolais and positive for the Brahman (Table 4).
There were no significant calf or maternal heterosis effects for
KPH%.
Estimated carcass yield. The estimated carcass yield in this study
ranged from 49.2% for B x AB crosses to 52.3% for straightbred
Charolais (Table 3). The additive breed effects were negative (P<.01)
for the Brahman breed and positive (P<.01) for the Charolais (Table
4). These results were reversed for additive maternal effects, as the
Brahman was positive (P<.01) and Charolais negative (P<.01).
Heterosis effects for calf were nonsignificant. Heterosis for maternal
effects were all negative, with only that for the AB dam significant,
reflecting the higher fat content of steer carcasses from Fi dams and
especially for the AB Fi dams.

Qualitative Carcass Traits

Qualitative traits of carcasses are those grade components that
contribute to eating quality of beef. Genetic effects for these traits are
usually additive without improvement from crossbreeding (heter-
osis).
Maturity score. Carcass maturity score reflects the physiological
age of cattle. It is one of the components that determined final carcass
quality grade prior to 1975. Animals in this study averaged 439 days
of age when slaughtered, and thus the steer carcasses were classified
A- or A maturity (Table 5). The mean carcass maturity score was 1.7,
with variations from 1.4 for straightbred Angus to 1.9 for the AB
crosses. Heterosis was exhibited only in the AB cross, and appeared
in both the calf and the dam (Table 6).
Conformation score. Conformation score was based on thickness of
muscling and overall thickness and fullness of the carcasses in rela-
tion to length. Prior to 1975 this trait was one of the components used

10







in determining final carcass quality grade. The mean conformation
score was 15.8, ranging from 14.5 for purebred Brahman to 16.9 for
purebred Angus (Table 5). Additive breed effects were significantly
positive for the Angus and significantly negative for the Brahman
(Table 6). With the exception of significantly positive calf heterosis
for the BC cross, there were no significant heterosis effects exhibited
for carcass conformation.
Marbling score. Marbling intramuscularr fat) in the longissimus is
the most important trait in determining carcass quality grade. In this
study, the mean marbling score was 9.1, ranging from 6.9 for the
Charolais to 12.1 for the backcross A x AB carcasses (Table 5). The
additive breed effects for marbling scores were significantly positive
for the Angus breed and negative for the Charolais, with Brahman
intermediate (Table 6). Heterosis in calf or dam was not significant
for marbling; the expression of this trait was relative to breed com-
position of carcasses.
Carcass quality grade. Quality grade was based on separate evalu-
ation of marbling, conformation, skeletal maturity, and characteris-
tics of the lean tissue, i.e. firmness, color, and texture. The genetic
values for quality grade paralleled those for marbling, with additive
breed effects being significantly negative for Charolais and positive
for the Angus breed (Table 6). The only heterosis effect was in the BC
calf (P<.05), with all other values nonsignificant.
Warner-Bratzler shear. Warner-Bratzler shear (WBS) force pro-
vides a measure of tenderness. The mean WBS value in this study
was 11.3 lb (5.1 kg), varying from 8.7 lb (4.0 kg) for the Charolais x
Angus to 13.2 lb (6.0 kg) for purebred Brahman (Table 5). The
straightbred Angus scored at 10.2 lb (4.6 kg) and Charolais at 10.7 lb
(4.8 kg). Additive breed effects of WB shear force for tenderness
favored the Charolais breed with the Angus intermediate and the
Brahman breed least tender (Table 6). Heterosis effects were negligi-
ble indicating tenderness was determined by breed composition of
carcasses.
Panel tenderness score. The mean score for tenderness by taste
panel was 5.1 (Table 5). Additive breed effects in calf were positive for
Charolais (P<.05) and negative (P<.01) for the Brahman, with the
Angus breed intermediate and positive (Table 6). Heterosis effects for
both calf and F, dams were negative for panel tenderness. These
results again show that genetic effects for quality traits are usually
additive and that improvements should not be expected through
crossbreeding.





11









Table 5. Least square mating group means for qualitative carcass traits.

Carcass
Carcass Carcass Degree of Quality Panel
Breed Subclasst Maturity Conformation Marbling Grade WBS Tenderness

score score score score (lb)* score
Least square means 1.7 15.8 9.1 14.5 11.3 5.1
Purebreds
AA 1.4 16.9 11.5 15.7 10.2 6.0
BB 1.5 14.5 7.7 13.8 13.2 4.5
CC 1.6 15.5 6.9 13.5 10.7 5.4
- Fi calves, purebred dams
AB 1.9 15.9 9.0 14.5 11.8 4.8
BA 1.6 16.1 10.3 15.2 11.0 5.2
AC 1.7 16.4 8.9 14.3 11.3 5.4
CA 1.6 15.7 8.9 14.5 8.7 5.9
BC 1.7 15.7 8.4 14.3 12.0 4.6
CB 1.7 15.2 7.2 13.7 11.7 4.9
Backcross calves, Fi dams
A(AB,BA) 1.8 16.3 12.1 15.7 10.9 5.1
B(AB,BA) 1.7 15.4 8.6 14.1 12.4 4.6
A(AC,CA) 1.6 16.2 11.3 15.6 10.6 5.7
C(AC,CA) 1.7 16.0 8.6 14.0 10.5 5.6
B(BC,CB) 1.7 15.1 7.9 13.8 13.1 4.6
C(BC,CB) 1.7 15.3 8.5 14.1 10.6 5.0








Table 5. Continued.

Carcass
Carcass Carcass Degree of Quality Panel
Breed Subclasst Maturity Conformation Marbling Grade WBS Tenderness

Three-breed calves, F1 dams
C(AB,BA) 1.8 16.2 8.6 14.1 10.7 5.0
B(AC,CA) 1.7 15.8 9.7 14.9 11.9 4.8
A(BC,CB) 1.7 15.8 9.5 14.8 11.1 5.1
Mating systems
Purebred 1.5 15.6 8.7 14.3 11.4 5.3
F1 1.7 15.9 8.8 14.4 11.1 5.2
Backcross 1.7 15.7 9.5 14.6 11.4 5.1
3-breed 1.7 16.0 9.3 14.6 11.2 5.0

*Breed designation: A, B, and C indicate Angus, Brahman, and Charolais, respectively. Sire breed is shown first in combination.
*Warner-Bratzler shear force, lb











Table 6. Additive breed (A) and Heterosis (H) effects of calf (0) and maternal (M) for qualitative carcass traits.

Degree Carcass
Carcass Carcass of Quality Panel
Effect Maturity Conformation Marbling Grade WBS' Tenderness

score score score score (lb)* score
Calf component
AO(A) -.02 .34* 1.06* .52* -.16 .14
AO(B) -.07 -.48** -.14 -.04 1.85** -.56**
AO(C) .09 .14 .92* .48* 1.69** .42*
HO(AB) .24** .32 -.06 .12 -.34 -.22
HO(AC) .08 .12 -.99 -.43 -.17 -.01
HO(BC) .07 .47** .59 .43* .10 .17
Maternal component
AM(A) -.04 .02 .06 .03 -.30 .10
AM(B) .05 -.21 -.41 -.25 -.24 .04
AM(C) -.01 .19 .35 .22 .54 -.14
HM(AB) .19** .25 .64 .10 .17 .31*
HM(AC) .06 -.04 .69 .23 .32 -.09
HM(BC) -.01 -.13 .67 .23 -.24 -.05

*Warner-Bratzler shear force
*kg = R x 0.454
*P<0.05
**P<0.01







SUMMARY AND CONCLUSIONS

Angus (A), Brahman (B), and Charolais (C) bulls were mated to A,
B, and C straightbred and reciprocal AB, AC, and CB F, crossbred
cows. A total of 455 steers were produced and fed an average of 174
days after weaning until slaughtered at an average of 439 days. The
steers and their carcasses were evaluated for growth traits, carcass
composition, and beef quality traits.
The data were analyzed in a manner which allowed the determina-
tion of additive breed effects on both the calf itself and on the mater-
nal ability of the cow. Additive breed effects essentially measure the
performance of animals, relative to breed composition, independent
of any effect due to crossbreeding. In addition, the effects of heterosis
resulting from a particular cross were measured on both the calf itself
and on the maternal ability of the dam.
The additive breed effects for growth-related traits strongly fa-
vored the Charolais breed, whereas the Brahman breed effects were
strongly negative and those of the Angus intermediate. For carcass
composition, ribeye area (REA), and REA/100 lb of carcass, the Brah-
man breed effects were again decidedly inferior while the Charolais
was superior and Angus intermediate. The breed effects for fat over
ribeye (FOE) were positive and essentially the same for the Angus
and Brahman breeds, whereas that of the Charolais was negative.
Marbling effects favored the Angus breed, with the Charolais being
lowest and Brahman intermediate. Measures of tenderness favored
the Charolais breed, with the Brahman being very negative and the
Angus intermediate. In general, Charolais breed effects were posi-
tive for all traits except marbling, FOE, and quality grade, whereas
Brahman effects were negative in all traits except for marbling and
FOE, surpassing the Charolais in these traits.
The effects of heterosis in the calf were of importance only for
growth-related traits where the AB and BC crosses showed large
positive effects and the AC cross a relatively small positive effect.
Effects of heterosis on other traits were either nil or biologically
unimportant, indicating that effects were due to breed composition.
Additive maternal breed effects were not large enough to be of
importance except for the negative effects of the Brahman dam for
daily gain and FOE, and positive effects for REA/100 lb carcass and
carcass yield. Maternal heterosis effects were large and positive in
initial weight for all crosses, indicating the superior ability of cross-
bred dams up to weaning. Part of this advantage, however, was lost
during the postweaning feeding phase in which the effects of cross-
bred dams on daily gain were slightly negative. Maternal heterosis
values were large only in the Fi AB dams and to a lesser degree in AC

15







dams for final weight and chilled carcass weight. Even though AB
dams excelled in growth related traits, the largest FOE resulted in
the smallest carcass yield. Marbling scores were all positive but
nonsignificant for maternal heterosis.
In general, crossbreeding in the calf will increase feedlot growth
rate, but this is not increased further and may be decreased slightly
through crossbred dams. The Brahman breed, while very important
in producing productive crossbred cows, seems to have the disadvan-
tages of a slower growth rate, smaller REA, and less tender steaks
than the Angus and Charolais breeds. In the evaluation of a breed in
crossbreeding programs, however, all aspects of the production sys-
tem, including reproduction, must be considered.



































16







LITERATURE CITED

1. Alenda, R., T.G. Martin, J.F. Lasley, and M.R. Ellersieck. 1980. Estima-
tion of genetic and maternal effects in crossbred cattle of Angus, Charo-
lais, and Hereford parentage. II. Postweaning growth, ribeye area and
fat cover. J. Anim. Sci. 50:235.
2. Gaines, J.A., C. Hill, R.C. Carter, W.H. McClare, and W.T. Butts. 1978.
Heterosis from crosses among British breeds of beef cattle. Straightbred
versus crossbred cows. II. J. Anim. Sci. 47:1254.
3. Gregory, K.E., L.A. Swiger, L.J. Sumption, R.M. Koch, J.E. Ingalls,
W.W. Rowden, and J.A. Rothlisberger. 1966. Heterosis effects on carcass
traits of beef steers. J. Anim. Sci. 25:311.
4. Harvey, W.R. 1975. Least-squares analyses of data with unequal sub-
class numbers. USDA, ARC H-4.
5. Hedrick, H.B., G.F. Krause, J.F. Lasley, B. Sibbit, L. Langford, and A.J.
Dyer. 1975. Quantitative and qualitative carcass characteristics of
straightbred and reciprocally crossed Angus, Charolais and Hereford
steers. J. Anim. Sci. 41:1581.
6. Koch, R. M., M.E. Kikeman, D.M. Allen, M. May, J.D. Crouse, and D.R.
Campion. 1976. Characterization of biological types of cattle. III. Car-
cass composition, quality and palatibility. J. Anim. Sci. 43:48.
7. Koch, R.M., and M.E. Dikeman. 1977. Characterization of biological
types of cattle. V. Carcass wholesale cut composition. J. Anim. Sci. 45:30.
8. Lasley, J.F., G.F. Krause, J.P. Jain, H.B. Hedrick, B. Sibbit, L. Langford,
J.E. Comfort, and A.J. Dyer. 1971. Carcass quality characteristics and
Hereford breeds. J. Anim. Sci. 32:406.
9. Peacock, F.M., and M. Koger. 1980. Reproductive performance of Angus,
Brahman, Charolais and crossbred dams. J. Anim. Sci. 50:689.
10. Peacock, F.M., A.Z. Palmer, J.W. Carpenter, and M. Koger. 1979. Breed
and heterosis effects on carcass characteristics of Angus, Brahman,
Charolais and crossbred steers. J. Anim. Sci. 49:391.
11. Peacock, F.M., M. Koger, T.A. Olson, and J.R. Crockett. 1981. Additive
genetic and heterosis effects in crosses among cattle breeds of British,
European and Zebu origin. J. Anim. Sci. 52:1007.
12. Peacock, F.M., M. Koger, A.Z. Palmer, J.W. Carpenter, and T.A. Olson.
1982. Additive breed and heterosis effects for individual and maternal
influence on feedlot gain and carcass traits of Angus, Brahman, Charo-
lais and Crossbred Steers. J. Anim. Sci. 55 (in press).









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