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 Materials and methods
 Results and discussion
 Summary and conclusions
 Literature cited
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Title: Breed and heterosis effects in crosses among the Angus, Brahman, and Charolais cattle breeds
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 Material Information
Title: Breed and heterosis effects in crosses among the Angus, Brahman, and Charolais cattle breeds
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
Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville
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Subject: Beef cattle -- Breeding   ( lcsh )
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bibliography   ( marcgt )
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Statement of Responsibility: F.M Peacock ... et al..
Bibliography: Includes bibliographical references (p. 18).
General Note: "March 1982."
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Volume ID: VID00002
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Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Title Page
    Table of Contents
        Table of Contents
    Introduction
        Page 1
    Materials and methods
        Page 2
    Results and discussion
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
    Summary and conclusions
        Page 16
        Page 17
    Literature cited
        Page 18
    Back Cover
        Page 19
        Page 20
Full Text


Bulletin 828 (technical)


Breed and Heterosis Effects in
Crosses among the Angus, Brahman, and
Charolais Cattle Breeds

F. M. Peacock, M. Koger, E. M. Hodges, and T. A. Olson


HUME LIBRARY

JUL 2 9'2

I.F.A.S.- Univ. of Florida


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


i-larcn IYnL












BREED AND HETEROSIS EFFECTS IN CROSSES
AMONG THE ANGUS, BRAHMAN, AND CHAROLAIS
CATTLE BREEDS



F. M. Peacock, M. Koger, E. M. Hodges, and T. A. Olson























Authors
Mr. Peacock is a Professor of Animal Science and Dr. Hodges a Professor
of Agronomy at the Agricultural Research Center, Ona. Dr. Koger is a
Professor and Dr. Olson an Assistant Professor of Animal Genetics in the
Animal Science Department, Gainesville.





















CONTENTS
Page
INTRODUCTION ....................... ...................... 1

MATERIALS AND METHODS ................................ 2
Data Analyses .................... ........................ 2

RESULTS AND DISCUSSION ............ ..................... 3
Reproduction ...................... ....................... 4
Calving Rate ..................... ..................... 4
Survival Rate .................... ..................... 6
W meaning Rate ............................ .............. 8
Weaning Traits ...................... ...................... 8
Age of Calf at W meaning ..................... .............. 8
Condition Score ........................................ 9
Estimated 205-Day Weight and Weaning Weight ............ 13
Efficiency of Production ................................ 15

SUMMARY AND CONCLUSIONS ............................... 16
LITERATURE CITED ............................................. 18







INTRODUCTION
Crossbreeding has long been practiced in commercial beef cattle
herds of Florida and has increased rapidly throughout the United
States during recent years. Designing effective crossbreeding
schemes is dependent upon information with respect to additive
breed and heterosis effects exhibited in crosses among the breeds now
available for crossbreeding. These breeds can be combined conven-
iently into three groups with respect to type, size, and origin: (1) the
British breeds, (2) the large European breeds, and (3) Zebu and
Zebu-derivative breeds. The purpose of this paper is to present
average breed (additive genetic) and heterosis effects obtained from
crosses among the Angus, Charolais, and American Brahman breeds
as representative of the three groups.
The data presented were collected during the second phase of the
project, during which Angus, Brahman, and Charolais sires were
each mated to Angus, Brahman, Charolais, and reciprocal Angus-
Brahman, Angus-Charolais, and Brahman-Charolais Fi females
(Table 1). The data from the first phase were reported previously by
Peacock et al. (6, 7, 8). This phase included all possible straightbred
and F1 crossbred matings among purebreds or high grades of each ol
these breeds, a diallel design. The data presented in this papel
include values for reproduction (Peacock and Koger, 9), production
traits, and production efficiency, which is estimated as the ratio ol
calf weight weaned to weight of dam at weaning (Peacock et al., 10).


TABLE 1. Design and number of matings.

Breed of dama
Breed Brah- Charo- AB+ AC+ BC+
of sire Angus man lais BA CA CB Total

Angus 81 76 83 74 65 67 446
Brahman 71 84 73 66 59 62 415
Charolais 75 80 95 78 61 55 444
Total 227 240 251 218 185 184 1305

aThe data from reciprocal F, dams were combined on the basis of preliminary'
analyses.





MATERIALS AND METHODS
The research was conducted at the University of Florida
agricultural Research Center at Ona, Florida. The center is located
!7 25' north latitude, 81 55' west longitude at an elevation of 85 feet
26 m) on sandy soils of low fertility. Average annual rainfall is 54
nches (1,397 mm), with 75% of the precipitation occurring between
vday and October. The climate is considered semitropical; repeated
rosts with temperatures at 280F (-2.2C) to 34F (1.10C) occur briefly
luring the winter. Lower temperatures occur at less frequent
ntervals.
The cattle were maintained on moderately fertilized improved
,rass pastures consisting mostly of Pangola digitgrass (Digitaria
lecumbens L.) and were supplemented with either 5 lb. (2.27 kg) of
nolasses or citrus pulp-cottonseed meal (4:1 ratio) per head per day
or approximately 90 days during the late winter and early spring.
The Angus (A) and Brahman (B) cows used in the trial were
)urebreds, while the Charolais (C) were high grades (seven-eighths
Tharolais to purebred Charolais). The original F1 cows were produced
luring phase 1 of the project, during which time A, B, and C males and
emales were mated in a diallel design. Heifers were first bred at 2
rears of age. All matings were by natural service. A total of 21 sires
seven per breed) were used in the study. Sires were selected on the
)asis of a favorable fertility test, above average growth rate and
;tructural soundness. Two sires of each breed were mated annually to
k, B, C, and reciprocal AB, AC, and BC dams.
Approximately 16% of the cows were culled annually for
insoundness or reproductive failure. The breeding season was
-estricted to 90 days beginning March 1. Individual records were
maintained for birth, survival, sex, age of calf at weaning, weaning
eight, estimated 205-day weight, and condition score of calves.
Scores of 6, 7, and 8 were used to designate low, medium, and high
standard; 9 to 11, Good grades; and 12 to 14, Choice grades as defined
n the former USDA grade standard for slaughter calves.

DATA ANALYSES

The data analyzed were the individual records for calving, survival
and weaning rates, calf age at weaning, condition score, weaning
weight, estimated 205-day weight, and cow weight at weaning time,
utilizing least squares procedures as outlined by Harvey (2) for both
reproduction and production traits. Preliminary analyses showed
differences between reciprocal groups of F, cows to be small and
generally not significant. The reciprocal groups therefore, were
-ombined to improve proportionality of subclass numbers (Table 1).





The analyses of the data were performed on reproduction (Peacock
and Koger, 9) and weaning traits (Peacock et al., 10). The first
analysis obtained the 18 breed-of-sire x breed-of-dam subclass means
nested within purebred, F,, backcross, and three-breed cross classes.
The second analysis was a multiple regression analysis to obtain
simultaneous estimates of average breed and heterosis effects for
both calf and maternal components as described by Koger et al. (4).
The procedure is based on the assumption that calf and maternal
components combine additively, and that hybrid vigor is linear with
respect to breed heterozygosity.


RESULTS AND DISCUSSION
The analyses of variance for reproductive and production traits are
included in Tables 2 and 3, respectively. Age of dam had significant
effects (P<.01) on all traits. Year effects were significant (P<.01) for
all traits except survival rate of calves. Effects of these types
are commonly observed and thus will not be discussed further.
Significant levels between means were determined by the standard
t-test.
The means and genetic effects for both reproductive and weaning
performance are shown in Tables 4, 5, 6, 7, 8, and 9. In the evaluation
of age of calf at weaning, condition score, estimated 205-day weight,
and weaning weight, the average effects for four mating systems as


TABLE 2. Mean squares from analyses of variance for reproductive traits.


Pregnancy Survival Weaning
Source df rate rate rate

Year 6 1.74** .007 1.62**
Age of dam 2 1.24** .098 1.09**
Breed of sire (S) 1 1.44** .021 1.73**
PB vs F1 dams (C)a 2 .64** .451** 1.36**
PB:C, 2 .27 .648** .47*
F,:C, 2 .56** .034 .67*
SxC 4 .07 .060 .09
Sx PB:C, 4 .24 .037 .22
Sx F,:C2 2 .10 .147 .16
Remainder -b .12 .057 .15
(df in remainder) (1279) (1070) (1279)

*P<.05
**P<.01
aDam classes, purebred and F,; PB=C; F, =C2
bShown below mean square for error





TABLE 3. Mean squares from variance analyses for weaning traits.

Age at Weaning 205-day
Source df weaning Condition weighta weight

Year 6 8930** 11.9** 100.6** 172.4**
Sex 1 1528 39.2** 411.5** 442.4**
Age of dam 2 8988t* 21.8** 157.0** 43.2**
Mating system (S) 3 3604** 48.5** 447.9** 261.9**
Breed: S, 2 5600** 2.9 390.5** 384.1**
F,:S2 5 2775** 7.6** 92.3** 88.7**
Backcross:S, 5 1409 12.1** 94.0** 54.7**
3-breed:S4 2 713 1.6 37.2** 45.1**
Remainder 1002 834 1.7 9.1 4.7

*P<.05
**P<.01
'(Mean squares) x 10-2

well as specific breed and breed cross combinations were considered.
rhe mating systems included purebreed calves on purebred cows (S,),
F1 calves on purebred dams (S2), backcross calves on F, dams (S3), and
three-breed cross calves on F1 cows (84).


Reproduction

Calving Rate
The overall least squares mean for calving rate was 84% (Table 4)
Individual subclass means varied from 70% for Angus x Charolais
matings to 95% for Charolais sires backcrossed to Brahman-
Charolais dams. The trait was influenced significantly by breed oj
sire, class of dam (purebred versus F, crosses), and by breed
combination within F, dams (Table 2).
Mean calving rates by the different breed of sires were 90%, 83%,
and 80% for Brahman, Charolais, and Angus sires, respectively. The
lower calving rates for the Bos taurus sires are in general agreement
with a previous study at this location by Peacock et al. (5) in which
pregnancy rates of 76% and 72%, respectively, were noted for
Brahman and Shorthorn sires; and with the report by Turner et al.
(13) from Louisiana. Data from south Florida by Crockett et al. (1),
however, showed that Angus and Hereford sired larger calf crops
than Brahman sires.
The most significant feature of the calving rate data was the
striking superiority of crosses including Brahman over the cross that





TABLE 4. Least squares means and standard errors for reproduction
traits.

Pregnancy Survival Weaning
Group or effect rate rate rate


Mu 84.4 1.1 92.8 1.1 78.3 1.3

Purebred dams, straightbred matings
Angus (A) 75.3 3.9 89.2 3.1 67.3 4.4
Brahman (B) 89.9 3.8 90.8 2.9 81.9 4.0
Charolais (C) 79.7 3.5 95.0 2.8 75.0 4.0
Purebred dams, crossbred matings
Ax B 78.6 4.0 96.0 3.2 74.1 + 4.5
B x A 92.4 + 4.1 84.1 3.1 77.9 4.7
A x C 69.6 3.8 96.8 3.2 67.4 4.4
C x A 78.6 4.0 83.4 3.1 65.6 4.5
B x C 82.5 4.1 96.8 3.1 80.1 4.6
C x B 82.5 + 3.9 98.8 3.0 81.7 + 4.4
F, dams, backcrossed matings
A x (AB,BA) 92.8 4.0 94.5 2.9 87.9 4.6
A x (AC,CA) 76.9 4.3 91.6 3.4 70.6 4.8
B x (AB,BA) 93.0 4.2 97.9 3.1 91.0 4.8
B x (BC,CB) 91.3 4.4 93.0 3.2 84.8 5.0
C x (AC,CA) 75.1 4.4 88.6 3.6 66.6 5.0
C x (BC,CB) 94.8 4.6 87.9 3.4 83.5 5.3
F, dams, three-breed matings
A x (BC) 84.7 4.2 97.2 3.2 82.6 4.8
B x (AC) 93.0 4.5 96.3 3.3 89.5 5.1
C x (AB) 89.3 + 3.9 91.9 + 2.9 82.1 4.5


Breed of sire
Angus 79.7 + 1.7 94.2 1.4 75.0 2.0
Brahman 90.4 1.8 93.1 1.3 84.2 2.0
Charolais 83.3 1.7 90.0 1.4 75.8 2.0

Breed of dam
Purebred
Angus 82.1 2.4 85.6 1.8 70.3 2.7
Brahman 83.7 2.3 95.2 1.8 79.2 2.6
Charolais 77.3 2.3 96.2 1.8 74.2 2.6
F, dams
(AB, BA) 91.7 2.4 94.8 1.8 87.0 2.7
(AC,CA) 81.7 2.6 92.2 2.0 75.6 2.9
(BC,CB) 90.3 2.6 92.7 1.9 83.6 2.9

'Sire breed is shown first in combinations.





did not. Calving rates for the Angus-Brahman and Brahman-
Charolais crosses were 92% and 90%, respectively, while the rate for
the Angus-Charolais crossbred dams was only 82% (P<.01). The
estimates for maternal heterosis effects for calving rate for the
Angus-Brahman, Brahman-Charolais, and Angus-Charolais
crossbred dams were 8.7% (P<.01), 9.2% (P<.01), and 2.2%,
respectively (Table 6). The mean rates for purebred dams were not
significantly different from each other, being 82%, 84%, and 77%,
respectively for Angus, Brahman, and Charolais dams, but were
lower (P<.01) than the rates for the Angus-Brahman and Brahman-
Charolais crossbred groups. There were no significant breed-of-sire x
breed-of-dam interaction effects influencing calving rate.

Survival Rate
The mean survival rate of calves from birth to weaning was 93%
(Table 4). Values for the breed group subclass means varied from a
high of 99% for calves sired by Charolais mated to Brahman dams, to
a low of 83% for calves sired by Charolais sires and out of Angus dams
(P<.01). The latter was not surprising in view of the small size of
Angus dams and large size of Charolais-sired calves (Sagebiel et al.,
11; Smith et al., 12).
The average survival rates by breed of sire were not significantly
different but were inversely related to mature size of the breeds,

TABLE 5. Summary of results by various mating classes.

Calving Calf Weaning
Class of dams rate, % survival, % rate, %
Purebred dams,
straightbred
matings 81.6 2.2 91.7 -- 1.7 74.7 2.4
Purebred dams,
crossbred
matings 80.7 + 1.6 92.6 1.3 74.5 1.8
Purebred dam means 81.0 1.8 92.3 1.1 74.6 1.7
F1 dams,
backcross
matings 87.3 1.8 92.2 1.3 80.7 + 1.6
F, dams, three-
breed cross
matings 89.0 2.4 95.1 + 1.8 84.7 2.8
F, dam means 87.9 1.5 93.2 + 1.1 82.1 1.7





TABLE 6. Estimated additive breed (A) and heterosis (H) effects for calf
(0) and maternal (M) components for reproductive traits.


Pregnancy Calf Weaning
Effect rate survival rate

Estimated effects- S*E*
% % %
Calf component
Ao (A) -2.4 2.3 1.6 1.7 -1.0 2.7
Ao(B) 3.5 2.3 -1.3 1.7 3.2 2.7
Ao(C) -1.1 2.3 -0.3 2.3 -2.2 2.7
Ho(AB) 4.4 3.5 2.1 2.7 4.6 4.0
Ho(AC) -6.5 3.5 -2.5 2.8 -6.6 3.8
Ho(BC) 0.9 3.4 4.5 2.6 4.9 3.9
Maternal component
Am(A) 1.5 1.7 -2.6 1.3 -0.6 1.8
Am(B) -0.1 1.7 0.6 1.3 -0.3 1.8
Am(C) -1.4 1.7 1.9 1.3 0.9 1.8
Hm(AB) 8.7 2.8** 4.2 2.1* 12.2 3.2**
Hm(AC) 2.2 3.1 1.8 2.4 3.3 3.4
Hm(BC) 9.2 3.0** -2.4 2.2 6.9 3.4*
Heterosis as percent of purebred average
Ho(AB) 5.3 4.3 2.3 3.0 6.2 5.4
Ho(AC) -8.4 4.5 -2.7 3.1 -9.3 5.3
Ho(BC) 1.1 3.9 4.8 2.8 6.2 4.9
Hm(AB) 10.5 3.4 4.7- 2.3 16.4 4.3
Hm(C) 2.8 4.1 1.9 2.6 4.6 4.3
Hm(BC) 10.8 3.5 -2.6-_ 2.3 8.8-t 4.2
aFrom analysis of individual 1.0 records.
* P<.05
** P<.01


being highest for Angus-sired calves (94%) and lowest for Charolais-
sired calves (91%). Conversely, among dam breed groups Angus dams
had the lowest calf survival (86%, P<.01). Differences among other
dam groups were not significant. The highest calf survival rate (96%)
was for calves from Charolais dams.
The estimates for average breed (additive genetic) and heterosis
effects influencing the calf component of survival (Table 6) were small
and not significant. The only estimate which approached significance
was that of 4.5% heterosis for Brahman-Charolais cross calves. The
estimate for maternal heterosis in Angus-Brahman dams was 4.2%
(P<.05). Estimates for other maternal components were small and
not significant.





Veaning Rate
Weaning rate is the product of calving rate and calf survival and is
he trait of greatest economic importance in beef cattle production. Ii
indicates the percentage of the cows of a particular type that were
exposed to breeding that actually weaned live calves. In this study ii
vas influenced by sire breed (P<.01), class of dam (purebred versuE
rossbred) (P<.01), and by breed groups within both classes of damE
P<.05) (Table 2).
Weaning rates for breed group subclasses varied from a high of 910/c
or Brahman sires mated to Angus-Brahman dams, to a low of 66% foi
)harolais sires mated to Angus dams (Table 4). The latter resulted
rom a combination of low values for both calving rate and call
survival. Angus dams mated to Angus sires likewise had a low
leaning rate of 67%. The overall means by sire breed were 84% foi
rahman sires, 76% for Charolais, and 75% for Angus sires. The
purebred dams ranked in the same order with rates of 79%, 74%, anc
10%, respectively. Rates for the FI dams were 87%, 84%, and 76%
respectively, for AB, CB, and AC dams. The respective group mean:
or F, and purebred dams were 82% and 75% with maternal heterosii
Mounting to 9.3% (Table 5).
These data are in agreement with other reports from th(
southeastern United States (Koger et al., 3) which generally shov
uigh levels of maternal heterosis for Zebu-European breed crosses
Drosses among European breeds may result in variable heterosi
-esponses depending on trait and compatibility with respect to size o
theirr characteristics.
The reciprocal Angus-Charolais crosses were not a favorable bree(
combinationn with respect to reproduction in this study. Weaning ratb
or the reciprocal F1 calves was 66% versus an average of 79% for Al
ind BC calves. The weaning rate for calves from the Angus-Charolaii
lams was 76% versus 85% (P<.01), for the AB and BC dami
combined Differences in weaning rate of this magnitude are o
)aramount economic importance in commercial beef cattle
production .

Weaning Traits

Ige of Calf at Weaning
When matings occur in a restricted season and calves are weane(
t one time, age of calf at weaning becomes an important production
rait influencing weight of calf at weaning; consequently, age a
meaning was analyzed as a production trait in this study. The overall
east squares mean for age at weaning was 224 days (Table 7).





Significant (P<.01) differences occurred between mating systems,
and between straightbred matings with only small variations among
F1 calves, backcross, or three-breed cross calves (Table 3). Age at
weaning among mating groups was 220 days for F1 calves compared
to 223 for straightbred and 227 for backcross and three-breed cross
calves (Table 8).Straightbred Brahman calves were youngest at
weaning at 215 days of age; Charolais were 220 days of age at
weaning; and Angus were oldest at 234 days (Table 7). These results
could be due to variations in gestation length among breeds, or could
possibly have been influenced by time of conception. Maternal
heterosis levels for F, cows (Table 9) were positive for age of calves at
weaning: 1.3% for AB, 3.2% (P<.05)'for AC, and 4.5% (P<.01) for
BC cows, indicating conception earlier than the average for their
parental breeds.

Condition Score
Calf condition score reflects thrift and adaptability of the
individual calf and maternal (milking) ability of the cow. The overall
least squares mean for condition score was 9.8 (Table 7). Significant
(P<.01) variations occurred among mating groups; 9.1 for purebreds,
9.7 for F1 crosses, 10.0 for backcrosses, and 10.3 for three-breed cross
calves. No differences were observed among purebreds or three-breed
cross calves (Table 3).
Condition score differences among F, and backcross calves were
significant (P<.01). Combined reciprocal F1 calf averages showed
both the AB and AC calves with higher (P<.01) condition scores than
BC reciprocals. Between reciprocals, A x B calves scored higher
(P<.01) than B x A, and C x B calves higher (P<.01) than B x C
calves. These results show a positive influence of the Brahman
female for calf condition score compared with Angus and Charolais
cows. However, additive maternal effects on calf condition score were
not shown to be significant (Table 9).
Backcross calves from Fi AB cows had a higher (P<.01) condition
score than calves from either AC or BC cows. There were no
differences between backcross calves mothered by the same cow
breed, whereas three-breed calves from both F, AC and BC cows
scored higher than backcross calves from the same dam breeds (Table
7). The coefficients for average breed effects for calf condition scores
were negative (P<.05) for the Brahman breed, and slightly positive
for Angus and Charolais (Table 9).
The heterosis levels for condition score in reciprocal F1 calves were
11.1% for AB, 3.6% for AC, and 4.8% for BC calves (Table 9). Maternal
heterosis for calf condition scores exhibited by F, cows (P<.01) was








TABLE 7. Least squares mating group means and standard errors for weaning traits.


Obser- Age at Weaning 205-day
Group or effect vations, weaning, Condition weight, weight,
n days score Ib t Ib t
Mu 1029 224.3 1.12 9.8 .05 473.4 2.6 441.0 1.9


Purebreds
Angus (A)
Brahman (B)
Charolais (C)
S F, calves, purebred dams
0 Ax B
Bx A
Ax C
C xA
Bx C
Cx B
Backcross calves on F, dams
A x (AB,BA)
A x (AC,CA)
B x (AB,BA)
B x (BC,CB)
C x (AC,CA)
C x (BC,CB)


234.1 + 4.0
215.6 3.6
220.2 3.5

220.7 3.9
217.0 4.0
216.3 3.9
233.0 4.1
211.8 3.8
219.7 3.6

230.9 3.6
226.7 4.3
224.5- 3.8
218.5 4.0
232.6 4.6
231.0 4.3


9.2 .18
8.8 .16
9.2 .1t

10.3 .17
9.6 .18
9.9 .17
9.4 .18
9.6 .17
9.6 .16

10.7 .16
9.6 .19
10.4 .17
9.8 .18
9.7+ .20
9.6 .19


403.8 + 9.1
398.5 8.3
491.7 8.0

452.9_ 8.9
428.0- 9.2
477.6 9.0
449.5- 9.4
464.0- 8.7
503.4 8.3

495.5 8.3
449.4 10.0
488.1 8.7
467.5_ 9.3
507.1 10.5
540.1 9.9


366.6 6.6
384.7 6.0
465.5 5.8

427.5 6.5
412.9 6.7
457.1 + 6.5
406.3 6.8
454.7+ 6.3
474.8 6.1

450.6+ 6.0
415.8 7.2
454.1 6.3
445.9- 6.8
457.0+ 7.6
491.1 + 7.2







TABLE 7. Continued.


Obser- Age at Weaning 205-day
Group or effect vations, weaning, Condition weight, weight,
n days score lbt Ibt

Three-breed calves on F, dams
A x (BC,CB) 56 230.3 3.9 10.5- .17 501.4- 8.9 456.4- 6.5
B x (AC,CA) 52 227.1 4.1 10.2 .18 495.3 9.3 455.8 6.8
C x (AB,BA) 66 223.4 3.6 10.2 .16 528.0 8.3 488.9 6.1


Breed of sire
Angus 339 228.2 1.6 10.0 .07 463.5 3.7 428.9 2.6
Brahman 347 219.1 1.6 9.7 .07 456.9 3.7 434.8 2.6
Charolais 343 226.6 1.6 9.6 .07 503.4 3.7 463.9 2.6
Breed of dam
Purebred
Angus 161 228.0 2.3 9.4 .10 427.1 5.3 395.4 4.2
Brahman 192 218.7 2.1 9.6 .09 451.6- 5.0 429.1-t 3.5
Charolais 191 216.1 + 2.2 9.5 .10 477.8 5.0 459.1 3.5
F, dams
(AB,BA) 193 226.3 2.1 10.4 .09 503.8 5.0 464.6 3.5
(AC,CA) 138 228.8 2.5 9.8 .11 484.0 5.7 442.8 4.2
(BC,CB) 154 226.6- 2.3 10.0 .10 503.0 5.5 464.4 4.0
tKg = xx 0.454















TABLE 8. Least squares mating group means and standard errors for weaning traits.

Obser- Age at Weaning 205-day
Mating Systems vations weaning, Condition weight, weight,
days score Ib t Ib t

Purebred calves 198 223.3 + 2.2 9.1 .10 431.3 5.1 405.6 3.7
F, calves, PB dams 346 219.7 1.7 9.7 .08 462.6 3.9 438.9 2.8
Backcross calves,. 311 227.4 1.8 10.0 .08 491.3 4.0 452.4 2.9
F, dams
Three-breed calves, 174 226.9 + 2.6 10.3 .10 508.2 5.2 467.0 + 3.8
F, dams
tKa =7 x 0.454





TABLE 9. Estimated additive breed and heterosis effects for weaning
traits.

Age at
weaning, Condition Weaning 205-day
Effect days score weight, lb t weight, lb t
Calf component
Ao (A) 1.6+ 3.0 .13+ .09 -6.6- 7.1 -7.9- 5.3
Ao (B) -8.4- 2.9** -.22- Q.09* -58.7- 6.8** -39.7 5.1**
Ao (C) 6.8- 3.1* .09 .09 65.3t 7.3** 47.6 5.3**
Ho (AB) -2.7 3.4 1.00 .09** 46.7- 7.9** 45.6 5.7**
Ho (AC) -4.8 3.5 .33 .10** 3.1 8.2 8.4+ 6.0
Ho (BC) -3.2 3.2 .43 .09** 36.4 7.5** 38.6 5.5**
Maternal component
Am (A) 1.7_ 2.3 .11+ .09 -3.7 5.3 -6.0 4.0*
Am (B) 4.0-- 2.2 .09 .09 17.2 5.1** 7.3- 3.5*
Am (C) -5.7 2.5* .01 .09 -13.5 5.7* -1.3 4.2
Hm (AB) 2.9 2.6 .94- .07** 63.7 6.0** 53.6 4.4**
Hm (AC) 7.1 + 3.1 .41 .09** 34.4 7.1** 19.0 5.1**
Hm (BC) 9.7 2.8** .47+ .08** 41.2 6.4** 21.8 4.6**
Heterosis as percent of purebred average
HoAB -1.2- 1.5 11.1- 1.0 11.6 2.0 12.1 1.5
HoAC -2.1 1.5 3.6 1.1 .7 1.8 2.0 1.5
HoBC -1.5+ 1.5 4.8 1.0 8.2 1.7 9.1- 1.3
HmAB 1.3- 1.2 9.9 .7 14.5- 1.4 13.0- 1.1
HmAC 3.2- 1.4 4.3 .9 7.6+ 1.6 4.5 1.2
HmBC 4.5 1.3 4.9 .8 8.9 1.4 4.9 1.0
tKg 3x 0.454



9.9% for AB, 4.3% for AC, and 4.9% for BC crosses. These values
indicate that all F1 cows provided a more favorable environment for
their calves than the average of their parental breeds, with F, AB
cows especially excelling in these traits.

Estimated 205-day Weight and Weaning Weight
Estimated 205-day weight is a measure of growth rate, while
weaning weight reflects differences in both growth rate and age.
Since these two traits are highly correlated, only weaning weight will
be discussed.
Differences among mating groups for weaning weight were
significant (P<.01): 431 lb (196 kg) for purebreds, 463 lb (210 kg) for
F1, 491 lb (223 kg) for backcross, and 508 lb (231 kgJ for three-breed
cross calves (Table 8). Among the straightbreds, the Charolais calves





were heaviest (P<.01) at 492 lb (223 kg), with Angus and Brahman
calves at 404 lb (183 kg) and 399 lb (181 kg), respectively. Significant
differences (P<.01) were also observed between F, calves (Table 3).
The combined reciprocal F, BC calves weighed 43 lb (20 kg) (P<.01)
more than the AB and 20 lb (9 kg) more than reciprocal AC calves.
These results express the large breed effects for growth of the
Charolais in breed crosses (Table 7).
Significant differences (P<.01) were observed between backcross
calves for weaning weight (Table 3). Although no differences were
observed between A x AB and B x AB calves, C x AC calves were
heavier (P<.01) at 507 lb (203 kg) than the A x AC calves at 449 lb
(204 kg). The C x BC calves were also heavier (P<.01) at 540 lb (245
kg) than B x BC calves at 468 lb (212 kg). These data also express the
large additive genetic potential for growth in the Charolais when
compared to the Angus and Brahman breeds. The only difference
between cow breed type nursing backcross calves was that F, BC cows
weaned heavier calves than F, AC cows (P<.05) (Table 7).
Variations among weaning weights of three-breed cross calves
were significant (P<.05) at 501 lb (227 kg), 495 lb (225 kg), and 528 lb
(240 kg) for A x BC, B x AC, and C x AB calves, respectively. These
results again demonstrate the genetic potential for growth in the
Charolais.
The coefficients for additive breed effects (Table 9) for weaning
weight of calves were large and negative (P<.01) for Brahman, large
and positive (P<.01) for Charolais, and negative but not significant
for Angus. These results for Angus and Charolais calves would be
anticipated considering the general characteristics of the two breeds.
The large negative value for Brahman calves is explained by the slow
growth rate in purebred Brahman calves, coupled with large
heterosis values for Brahman crosses.
Heterosis levels for F, calf weights were all positive: 11.6% (P<.01)
for AB and BA crosses, 8.2% for BC and CB crosses (P<.01), and 0.7%
(not significant) for AC and CA crosses (Table 9). These values show
the importance of including the Brahman breed in crossbreeding
systems in Florida.
Average maternal effects were positive (P<.01) for Brahman and
negative (P<.05) for Charolais, with Angus slightly negative but not
significant. Estimated heterosis for maternal performance for
weaning weight of calves in F, cows was 14.5% (P<.01) for AB, 8.9%
(P<.01) for BC, and 7.6% (P<.01) for AC. Those F, cows with Brahman
as one of the breeds were superior to the all-European crosses, with
the highest heterosis being observed in the F, AB cow.





Efficiency of Production
Significant differences (P<.01) were found among weights of
purebred cows; as would be expected, Angus were lowest and
Charolais highest (Table 10). Among crossbreds the F, BC cows were
heavier (P<.01) than AB and AC cows. The F, cow weight average
was larger (P<.01) than the purebred cow average. Heterosis levels
for weights of F, cows were 8.7% for AB, 2.3% for AC, and 4.1% for BC
cows. These results are interesting since they parallel the relative
ranking calf weights of the three F, crosses.
A measure of production efficiency can be expressed as a ratio of
calf weaning weight to cow weight. These ratios for each mating
system and each specific cross within each system are shown in Table
11. An additional important component of overall production
efficiency is weaning rate. Therefore, the calf weight to cow weight
ratio was multiplied by weaning rate to provide a measure of
production per unit of cow weight exposed to breeding (Table 11).
Average production efficiency ratios were 0.34, 0.36, 0.40, and 0.43
for purebred, F1, backcross, and three-breed cross production,
respectively. Using the average value for purebreds (0.34) as the
basis for comparison, the advantages for the F, calves on purebred
dams, backcross calves on F, dams, and three-breed calves on F, dams
were 5.9, 17.6, and 26.5%, respectively. The mean ratios for
Brahman-Angus and Brahman-Charolais F, females were 0.45 and
0.40, respectively. Both surpass that of the Charolais-Angus crosses
(0.33). These values reemphasize both the importance of crossbreed-
ing and the effect of the Brahman breed for improvement of
production efficiency in beef cattle.


TABLE 10. Least squares means for cow weights and condition score
recorded when their calves were weaned.

Weight, Ibt Condition
Breed Group ----- --------------
Mean + SE Mean SE

Purebreds
Angus 856_- 7.7 5.3 .09
Brahman 946 + 8.2 5.7 .08
Charolais 1076 8.4 5.4- .09
Fi crosses
AB,BA 979 7.9 5.8 + .08
AC,CA 988 8.6 5.8 .09
BC,CB 1052 8.4 5.6+ .09
tKg =x 0.454





TABLE 11. Relative production efficiency.


Calf
weaning weight Weaning Productive
Group +cow weight rate, % efficiency ratio

Purebreds
Angus (A) .47 67.3 .32
Brahman (B) .42 81.9 .34
Charolais (C) .46 75.0 .35
System mean .45 74.7 .34
Purebred dams with F, calves
Ax B .48 74.1 .36
B x A .50 77.9 .39
A x C .44 67.4 .30
C x A .53 65.6 .35
B x C .43 80.1 .34
C x B .53 81.7 .43
System mean .49 74.5 .36
F, dams with backcross calves
A x (AB,BA) .51 87.9 .45
A x (AC,CA) .45 70.6 .32
B x (AB,BA) .50 91.0 .46
B x (BC,CB) .44 84.8 .37
C x (AC,CA) .51 66.6 .34
C x (BC,CB) .51 83.5 .43
System mean .49 80.7 .40
F1 dams with three-breed cross calves
A x (BC,CB) .48 82.6 .40
B x (AC,CA) .50 89.5 .45
C x (AB,BA) .54 82.1 .44
System mean .51 84.7 .43

aEfficiency = (Calf weaning weight/cow weight) x weaning rate.



SUMMARY AND CONCLUSIONS
Additive breed and heterosis effects for maternal and calf
components for reproductive and weaning traits were examined by
the mating of Angus (A), Brahman (B), and Charolais (C) sires to A,
B, C, and reciprocal AB, AC, and BC dams. Each sire breed was mated
to all breed groups of cows.
The most important influences on calving rate were breed of sire
(90%, 83%, and 80% for B, C, and A sires, respectively) and class of
dam (88% versus 81% for F1 versus purebreds). The highest calving





rate among dam groups was 92% for reciprocal F1 AB crossbreds; the
lowest was 82% for A and F, AC dams. Survival rate of calves from
Angus dams was 86% compared to 95% and 96% for Brahman and
Charolais dams, respectively. Calf survival rates were 94% for A
sires, 93% for B, and 91% for C sires. The most important influence on
weaning rate was breed group of dams. Means varied from 70% for
Angus to 87% for AB dams. The mean weaning rate of F1 dams was
82% versus 75% for purebreds. Among crossbred cows, the two groups
of Brahman crosses, AB and CB (86%), had higher weaning rates
than the AC crosses (76%).
There were no significant additive breed or maternal effects for
reproductive traits. Estimates for maternal heterosis for calving rate
ofF, dams were 8.7% (P<.01), 9.2% (P<.01), and 2.2% for AB, BC, and
AC dams, respectively. The only significant (P<.05) estimate of
heterosis for calf survival rate was 4.2% for the F, AB dams. Heterosis
estimates for weaning rate were'12.2% (P<.01), 6.9% (P<.05), and
3.3% for F1 AB, BC, and AC dams, respectively.
Heterosis for early calving was negative for straightbred cross
matings, but positive for F, dams at 9.7 (P<.01) for BC dams, 7.1
(P<.05) for AC, and 2.9 for F, AB dams. Calf condition scores were
negatively (P<.01) influenced by Brahman breeding; whereas
heterosis for condition score was positive (P<.01) for all F, calves and
calves on F, dams, with the F, AB calf and dam highest.
Estimates for additive breed effects on weaning weights were
negative for Brahman (P<.01) and positive for Charolais (P<.01);
whereas maternal effects were positive for Brahman dams (P<.01)
and negative for Charolais (P<.01). Heterosis estimates for weaning
weight were 12% (P<.01), 1%, and 8% (P<.01), for Fi AB, AC, and BC
halves, respectively. Maternal heterosis estimates were 15% (P<.01),
S% (P<.01), and 9% (P<.01) for F, AB, AC, and BC dams.
Approximate relative production efficiency ratios were computed
for different mating groups as (calf weight + cow weight) x weaning
rate. Using the average value of purebred (0.34) as a basis of
comparison, the advantages for F, calves on purebred dams,
backcross calves on F, dams, and three-breed calves on F, dams were
5.9, 17.6, and 26.5%, respectively. The mean efficiency ratios for the
Brahman-Angus and Charolais-Brahman F, females were 0.45 and
0.40, respectively, both values surpassing that of the Angus-
Charolais. The value of incorporating Zebu (Brahman) germ plasm
into crossbreeding systems in this region is made very clear in this
study; it is also becoming apparent that Zebu germ plasm can have
application in more temperate areas (14).














LITERATURE CITED
L. Crockett, J. R., R. W. Kidder, M. Koger, and D. W. Beardsley. 1973. Beef
production in a crisscross breeding system involving the Angus,
Brahman and Hereford. Florida Agri. Exp. Sta. Tech. Bull. 759.
2. Harvey, W. R. 1975. Least squares analyses of data with unequal
subclass numbers. USDA ARS. 11-4.
3. Koger, M., T. J. Cunha, and A. C. Warnick (eds.). 1973. Crossbreeding
beef cattle. Series 2. Univ. of Florida Press, Gainesville.
4. Koger, M., F. M. Peacock, and J. R. Crockett. 1975. Heterosis effects on
weaning performance of Brahman-Shorthorn calves. J. Anim. Sci.
40:826.
5. Peacock, F. M., M. Koger, W. G. Kirk, E. M. Hodges, and A. C. Warnick.
1971. Reproduction in Brahman, Shorthorn and crossbred cows on
different pasture programs. J. Anim. Sci. 33:458.
6. Peacock, F. M., M. Koger, J. R. Crockett, and A. C. Warnick. 1977.
Reproductive performance and crossbreeding Angus, Brahman and
Charolais cattle. J. Anim. Sci. 44:729.
7. Peacock, F. M., M. Koger, and E. M. Hodges. 1978. Weaning traits of
Angus, Brahman, Charolais and F, crosses of these breeds. J. Anim.
Sci. 47:366.
8. Peacock, F. M., M. Koger, E. M. Hodges, J. R. Crockett, and A. C.
Warnick. 1979. Beef production from reciprocal crosses of Angus,
Brahman and Charolais cattle. Fla. Agr. Exp. Sta. Tech. Bul. 810.
9. Peacock, F. M., and M. Koger. 1980. Reproductive performance of
Angus, Brahman, Charolais and Crossbred dams. J. Anim. Sci. 50:689.
). 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.
L. Sagebiel, J. G., G. F. Krause, B. Sebbit, L. Langford, J. E. Comfort, A. J.
Dyer, and J. F. Lasley. 1969. Dystocia in reciprocally crossed Angus,
Hereford and Charolais cattle. J. Anim. Sci. 29:245.
2. Smith, Gerald M., D. B. Laster, and Keith E. Gregory. 1976.
Characterization of biological types of cattle. 1. Dystocia and
preweaning growth. J. Anim. Sci. 43:27.
3. Turner, J. E., B. R. Farthing, and G. L. Robertson. 1968. Heterosis in
reproductive performance of beef cows. J. Anim. Sci. 27:336.
4. USDA. 1979. Germ plasm evaluation program. Prog. Rep. No. 7.
ARM-NC-6.

































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