• TABLE OF CONTENTS
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 Copyright
 Front Cover
 Table of Contents
 Introduction
 Review of literature
 Materials and methods
 Experimental results
 Discussion of experimnetal...
 Summary and conclusions
 Literature cited






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 624
Title: Genetic and environmental influences on weaning weight and slaughter grade of Brahman, Shorthorn and Brahman-Shorthorn crossbred calves
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027490/00001
 Material Information
Title: Genetic and environmental influences on weaning weight and slaughter grade of Brahman, Shorthorn and Brahman-Shorthorn crossbred calves
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 15 p. : ; 23 cm.
Language: English
Creator: Peacock, F. M ( Fentress McCoughan ), 1922-
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1960
 Subjects
Subject: Zebus -- Growth -- Florida   ( lcsh )
Zebus -- Genetics -- Florida   ( lcsh )
Zebus -- Grading -- Florida   ( lcsh )
Shorthorn cattle -- Growth   ( lcsh )
Shorthorn cattle -- Genetics   ( lcsh )
Shorthorn cattle -- Grading   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 14-15.
Statement of Responsibility: F.M. Peacock ... et al..
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027490
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000927065
oclc - 18302786
notis - AEN7768

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Review of literature
        Page 4
    Materials and methods
        Page 5
        Page 6
    Experimental results
        Page 7
        Years
            Page 7
        Pasture
            Page 7
            Page 8
            Page 9
        Sex
            Page 10
        Age of dam
            Page 10
        Breeding of calves
            Page 10
        Interactions
            Page 10
    Discussion of experimnetal results
        Page 11
        Page 12
    Summary and conclusions
        Page 13
    Literature cited
        Page 14
        Page 15
        Page 16
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida






August 1960


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
J. R. BECKENBACH, Director
GAINESVILLE, FLORIDA




Genetic and Environmental Influences on
Weaning Weight and Slaughter Grade of

Brahman, Shorthorn and Brahman-

Shorthorn Crossbred Calves

F. M. PEACOCK, W. G. KIRK, E. M. HODGES, W. L. REYNOLDS
and M. KOGER



TECHNICAL BULLETIN


Fig. 1.-Crossbred cows, 1/ Shorthorn-1/ Brahman,
11 to 13 years of age from the Barn pasture.


Bulletin 624

























CONTENTS


Page


INTRODUCTION ................... ............


REVIEW OF LITERATURE ..................


MATERIALS AND METHODS .................


EXPERIMENTAL RESULTS ..................


Y ears -... ........ ......--


Pasture ..--- --


Sex o ...... .................. ------. ..


Age of Dam .. --.--..--...- ...------ --


Breeding of Calves ........................ ....... ......


Interactions ............ ...... ..... .......-..


DISCUSSION OF EXPERIMENTAL RESULTS ....................


SUMMARY AND CONCLUSIONS ........................- ......


LITERATURE CITED .............................. ....


------ -- ---- ---..----------... 3

-......- .....-- -- ..-- 4


..--.......-- .- ........ .------....---- 5


.-.... .----. -..... ----...-------- 7


----- .--- -- .- -. ------- 7
.7


............ 10


............ 10


..-...-........... 10


--.....-...... ... 10


............. 11


..... ........... 13


................. 14









Genetic and Environmental Influences on
Weaning Weight and Slaughter Grade of
Brahman, Shorthorn and Brahman-

Shorthorn Crossbred Calves
F. M. PEACOCK, W. G. KIRK, E. M. HODGES, W. L. REYNOLDS
and M. KOGER 1

INTRODUCTION
The beef industry in Florida began with the introduction of
Spanish stock early in the 16th century. The only feed avail-
able in the early years was native forage. Cattle were small
and slow maturing, and the return in beef per unit was low.
Despite the long years of production, it was only during the past
quarter century that much progress has been made in the im-
provement of beef cattle in Florida. This has been brought
about by: 1, establishment and maintenance of productive grass
and legume pastures to supplement native forage; 2, improved
management practices; 3, breeding cattle adapted to the condi-
tions under which they are raised.
Brahman cattle were found to be well adapted to the hot,
humid conditions of the coastal regions of Florida. Mating
Brahman bulls to grade and native cows resulted in offspring
superior to the foundation animals. The first cross gave the
largest improvement in beef production, and continued use of
the same breed gave less effect with each succeeding generation.
Mating bulls of English breeding to grade Brahman cows pro-
duced offspring superior to the foundation cows in gaining ability.
This study is concerned with the influence of certain heredi-
tary and environmental factors on weight and slaughter grade
of calves at weaning. Information concerning the effect of these
factors on beef production is essential in planning a program
to obtain the greatest return from a beef cattle enterprise. The
need for information on the performance of Brahman and Euro-
pean cattle and their crosses led to the initiation of a crossbreed-
ing project using Brahman and Shorthorn cattle at the Range
Cattle Station in 1942.

1 Peacock: Assistant Animal Husbandman, Kirk: Vice-Director in Charge,
Hodges: Agronomist, Range Cattle Station, Ona; Reynolds: Research As-
sistant and Koger: Animal Husbandman, Main Station, Gainesville.







Florida Agricultural Experiment Stations


REVIEW OF LITERATURE

The effect of sex on weaning weight and slaughter grade
has been measured by various research workers, using both
purebred and crossbred cattle. Koger and Knox (14),2 study-
ing influence of sex on the weaning weight of calves (1936-1943),
found a 32-pound increase in favor of bull calves when mean
weights were corrected for differences in age. Knapp et al (11),
studying normal growth and efficiency of production of Here-
ford cattle under range conditions in Montana from 1926 to
1940, found that male calves were 22 pounds heavier at weaning
than females. Knapp and Black (12) showed by analysis of
variance of daily gains during the suckling period that weight
differences due to sex were highly significant.
Many workers have reported on effect of age of dam on
weaning weight of European-bred beef cattle, with results being
fairly consistent. Koger and Knox (15) found a close correla-
tion between age and weight of cow and weight of calf at wean-
ing. The lightest calves were from cows 3 years of age, and
the weight of calves gradually increased as age of dam rose to
7 years, which was the peak age for production. Calf weights
decreased gradually as cow age increased from 7 through 10
years.
Knapp et al (10) showed that the average weight of calves
corrected for age at weaning indicated the maximum calf weight
may be expected from 6-year-old cows. There was a gradual
increase in weaning weight of calves as cows increased from
2 to 6 years of age and a more rapid decrease in weight as cows
advanced from 6 to 11 years in age. Sawyer et al (21) con-
cluded that weaning weight of calves increased with age of dam
up to 8 years, followed by a gradual decrease as cows became
older.
The breeding and acclimation of cattle usually determine
their ability to produce under a given set of environmental con-
ditions. Damon et al (5) initiated a study in 1952 to evaluate
the performance of different beef breeds and their crosses with
respect to weaning weight and slaughter grade of calves in the
Gulf Coast region. Results showed that Brangus and Brahman
females bred to Charolaise, Hereford and Shorthorn bulls raised
calves that were not only heavier at weaning but also graded
higher than purebreds.

SItalic figures in parentheses refer to literature cited.






Genetic and Environmental Influences on Calf Breeds 5

McCormick and Southwell (19) concluded that calves from
Brahman x Hereford cows were 18 percent heavier and slightly
higher in slaughter grade at weaning than calves from Angus
x Hereford cows.
A study by Peacock et al (20) showed that calves mothered
by 1/2 Brahman cows were heavier to a highly significant degree
than those from cows with other proportions of Brahman breed-
ing. This effect was observed, irrespective of sires, when Brah-
man, Shorthorn or Shorthorn-Brahman crossbred bulls were
used.
In a crossbreeding study from 1943 to 1951, Kidder and
Chapman (9) found the reciprocal crosses of both Brahman-
Angus and Brahman-Devon matings superior to any of the pure-
bred lines in weight gains from birth to weaning. Data ob-
tained by Baker and Black (2) showed that half-breed Brahman-
Angus cows produced calves that were significantly heavier at
6 months of age than did cows of pure breeding, irrespective
of sires. Their results indicated that the full value of hybrid
vigor obtained from mating Brahman and Angus cattle in a
crossbreeding program cannot be realized until the hybrid cows
have produced calves.

MATERIALS AND METHODS
The data used in this study are from the records of cattle
under Project 390, "Breeding Beef Cattle for Adaptation to
Florida," initiated in 1942 to determine the productivity of Short-
horn and Brahman cattle and their crosses under conditions pre-
vailing at the Range Cattle Experiment Station. This area is
typical of much of the flatwoods range found in central Florida,
with the predominant soil types being Immokalee and Leon fine
sand. Native vegetation consists of palmetto, wiregrass and
various species of broadleaf paspalums, with a scattering of
Southern longleaf pine and an occasional wooded area of oak.
The total average rainfall from June through September for the
years 1942-1957 was 33.13 inches with measurable rain for 63
days during these months. Average daily maximum and mini-
mum temperatures for the same period were 910 and 710 Fahren-
heit, respectively (18).
The breeding program began with the purchase of 5 2-year-
old Brahman heifers and a Shorthorn bull in 1942. Five addi-
tional Brahman heifers were secured in each of the 3 years,
1943, 1944 and 1945. These 20 Brahman females and the Short-







Florida Agricultural Experiment Stations


horn bull were the foundation stock for the crossbreeding project.
The program involved breeding Shorthorn bulls to: 1, Brahman
cows to produce 1/2 Shorthorn-1/2 Brahman calves; 2, one-half
of the first cross females to get 3/4 Shorthorn-14 Brahman calves;
3, 3 Shorthorn-1/4 Brahman cows to obtain 7/8 Shorthorn-I/8
Brahman; 4, purebred Shorthorn cows to produce Shorthorn
calves. Brahman bulls were bred to: 1, one-half of the first
cross cows to get 3/4 Brahman-1/4 Shorthorn calves; 2, 3/ Brah-
man-14 Shorthorn females to produce 7/8 Brahman-1/ Shorthorn
calves; 3, purebred Brahmans to get Brahman calves.
Four pastures were used in the production of the calves.
The pasture designated Barn consisted of improved grasses with
some winter clover and native range. The cows received limited
amounts of supplemental feed during poor grazing periods. The
Irrigation pasture was pangolagrass, part of which was over-
seeded to clover and irrigated. The East pasture was a com-
bination of improved grass and native range used under a rota-
tional and deferred system of management (8), while the West
pasture was wiregrass-palmetto range with no improvement but
with limited supplemental feeding. All pastures were stocked
according to their estimated carrying capacity. Animals had
access to fresh water and a complete mineral mixture at all
times (3).
The breeding season from 1942-1952 was 120 days, begin-
ning in early April. Starting in 1953, bulls were put out around
March 20 for 120 days. Records included breeding, weight
changes and productivity of all animals. Calves were weighed
at birth, and all animals were weighed at 28-day intervals until
1952 when weights were taken every 90 days. Calves were
weighed and weaned at an average age of 200 days and were
rated by a committee with respect to conformation, finish and
slaughter grade. Data were obtained on 804 calves from 167
cows.
Weaning weights of all calves were adjusted to a mean wean-
ing age of 205 days by a method reported by Koger and Knox
(16). The years 1943-1950 were grouped for the analysis because
of small numbers of cattle and the concentration of 1/2 Short-
horn-1/2 Brahman calves due to the slow build-up of cattle num-
bers in the breeding program. The remaining sources of vari-
ability involved effects due to year, pasture, sex, age of dam
and breeding of calf.
The mathematical model assumed for the analysis was:







Genetic and Environmental Influences on Calf Breeds 7

Yijklmn = U + Yi + Pj + Sk + A1 + Bm + Eijklmn; where
Yijklmn was the weight or slaughter grade of the ijklmnth calf;
U was the adjusted mean;
Yi was the ith year effect;
Pj was the effect of the jth pasture;
Sk was the effect of the kth sex;
A1 was the effect of the Ith age of dam;
Bm was the effect of the mth breed of calf;
Eijklmn was the effect of nth individual in the ijklmnth group.
Each observation was assumed to be the sum of influences
of effects of the variables as follows: weaning weight = ad-
justed mean + year effect + pasture effect + sex effect + age
of dam effect + breed effect + error. This linear combination
of effects is similar to that used by Koch (13) and Peacock
et al (20).
The least squares solution for disproportionate frequency
distribution was employed for the data. Based on the mathe-
matical model given above, 30 simultaneous equations were solved
by the method of matrix inversion (1, 6, 7). Adjusted sums of
squares for main effects were determined by the regression co-
efficients for the different variables and selected elements of the
inverse matrix as described by Chew (4).
Sums of squares for interactions were computed by squaring
the mean difference between actual and expected values and
multiplying by number of animals in the category (17). Degrees
of freedom for interactions were obtained by the orthodox
method. However, because of the nature of the data, 1 degree
of freedom was lost for each vacant cell.

EXPERIMENTAL RESULTS
YEARS
A summary of the analysis of variance is given in Table 1.
Differences among years were highly significant for both wean-
ing weight and slaughter grade. The adjusted means for years
for weaning weight and slaughter grade are shown in Table 2.

PASTURE
The effect of pasture on weaning weight and slaughter grade
of calves is given in Table 3. There was a highly significant
difference in calf production among pastures. The breed x pas-
ture interaction was used to test for significance.







Genetic and Environmental Influences on Calf Breeds 7

Yijklmn = U + Yi + Pj + Sk + A1 + Bm + Eijklmn; where
Yijklmn was the weight or slaughter grade of the ijklmnth calf;
U was the adjusted mean;
Yi was the ith year effect;
Pj was the effect of the jth pasture;
Sk was the effect of the kth sex;
A1 was the effect of the Ith age of dam;
Bm was the effect of the mth breed of calf;
Eijklmn was the effect of nth individual in the ijklmnth group.
Each observation was assumed to be the sum of influences
of effects of the variables as follows: weaning weight = ad-
justed mean + year effect + pasture effect + sex effect + age
of dam effect + breed effect + error. This linear combination
of effects is similar to that used by Koch (13) and Peacock
et al (20).
The least squares solution for disproportionate frequency
distribution was employed for the data. Based on the mathe-
matical model given above, 30 simultaneous equations were solved
by the method of matrix inversion (1, 6, 7). Adjusted sums of
squares for main effects were determined by the regression co-
efficients for the different variables and selected elements of the
inverse matrix as described by Chew (4).
Sums of squares for interactions were computed by squaring
the mean difference between actual and expected values and
multiplying by number of animals in the category (17). Degrees
of freedom for interactions were obtained by the orthodox
method. However, because of the nature of the data, 1 degree
of freedom was lost for each vacant cell.

EXPERIMENTAL RESULTS
YEARS
A summary of the analysis of variance is given in Table 1.
Differences among years were highly significant for both wean-
ing weight and slaughter grade. The adjusted means for years
for weaning weight and slaughter grade are shown in Table 2.

PASTURE
The effect of pasture on weaning weight and slaughter grade
of calves is given in Table 3. There was a highly significant
difference in calf production among pastures. The breed x pas-
ture interaction was used to test for significance.







Genetic and Environmental Influences on Calf Breeds 7

Yijklmn = U + Yi + Pj + Sk + A1 + Bm + Eijklmn; where
Yijklmn was the weight or slaughter grade of the ijklmnth calf;
U was the adjusted mean;
Yi was the ith year effect;
Pj was the effect of the jth pasture;
Sk was the effect of the kth sex;
A1 was the effect of the Ith age of dam;
Bm was the effect of the mth breed of calf;
Eijklmn was the effect of nth individual in the ijklmnth group.
Each observation was assumed to be the sum of influences
of effects of the variables as follows: weaning weight = ad-
justed mean + year effect + pasture effect + sex effect + age
of dam effect + breed effect + error. This linear combination
of effects is similar to that used by Koch (13) and Peacock
et al (20).
The least squares solution for disproportionate frequency
distribution was employed for the data. Based on the mathe-
matical model given above, 30 simultaneous equations were solved
by the method of matrix inversion (1, 6, 7). Adjusted sums of
squares for main effects were determined by the regression co-
efficients for the different variables and selected elements of the
inverse matrix as described by Chew (4).
Sums of squares for interactions were computed by squaring
the mean difference between actual and expected values and
multiplying by number of animals in the category (17). Degrees
of freedom for interactions were obtained by the orthodox
method. However, because of the nature of the data, 1 degree
of freedom was lost for each vacant cell.

EXPERIMENTAL RESULTS
YEARS
A summary of the analysis of variance is given in Table 1.
Differences among years were highly significant for both wean-
ing weight and slaughter grade. The adjusted means for years
for weaning weight and slaughter grade are shown in Table 2.

PASTURE
The effect of pasture on weaning weight and slaughter grade
of calves is given in Table 3. There was a highly significant
difference in calf production among pastures. The breed x pas-
ture interaction was used to test for significance.







Florida Agricultural Experiment Stations


TABLE 1.-ANALYSIS FOR THE ADJUSTED EFFECTS OF YEAR, PASTURE, SEX,
AGE OF DAM AND BREEDING FOR WEANING WEIGHT AND SLAUGHTER
GRADE OF CALVES.


Source of
Variation


Total ........................


SSR' .-.......--...........
Years .....................
Pastures .--- -
Sex .............
Age of dam ......---
Breeding ..........--


Residual ....................


B x P 16 201,923 12,620** 147 9.2**
B x S ..................... 6 41,434 6,906** 19 3.2
B x A ...................... 25 85,895 3,436 42 1.7

**Significant at .01 level of probability.

TABLE 2.-EFFECT OF YEARS ON WEANING WEIGHT AND SLAUGHTER GRADE
OF CALVES UNADJUSTED AND ADJUSTED FOR PASTURE, SEX, AGE OF
DAM AND BREEDING OF CALF.

Weaning Weight Slaughter Grade t
No. | Devia- I
Years of Unad- Ad- tion f Unad- Ad- | Devia-
Calves justed justed from justed justed I tion I
Means Means Mean Mean Mean from
(Pounds) (Pounds) (Pounds) I Mean

1943-1950 104 449.9 402.0 + 8.7 9.5 8.9 -0.3

1951 46 450.1 418.5 +25.2 10.0 9.4 +0.2

1952 54 460.2 420.6 +27.3 9.6 8.9 -0.3

1953 59 398.3 365.0 -28.3 9.6 8.8 -0.4

1954 58 421.1 387.4 5.9 9.5 8.8 -0.4

1955 94 416.3 395.5 + 2.2 10.5 10.1 +0.9

1956 116 431.1 412.1 +18.8 10.8 10.3 +1.1

1957 132 389.1 377.1 -16.2 9.1 8.8 -0.4

1958 141 374.9 361.5 -31.9 8.9 8.7 -0.5
t U.S. lauhte graes:5, ighStanard 9.LowGood 10 God; nd 1, Hgh ood


t U. S. slaughter grades: 8, High
$ Deviations from adjusted mean.


Standard; 9. Low Good; 10, Good; and 11, High Good.







Genetic and Environmental Influences on Calf Breeds 9

TABLE 3.-EFFECT OF PASTURE ON WEANING WEIGHT AND SLAUGHTER GRADE
OF CALVES UNADJUSTED AND ADJUSTED FOR YEAR, SEX, AGE OF DAM
AND BREEDING.

I Weaning Weight Slaughter Grade
No. Unad- Ad- Devia- Devia-
Pasture of justed justed tion from Unad- Ad- tion
Calves Means Means Mean justed justed from
(Pounds) (Pounds) (Pounds) Mean Mean Mean

Barn ...... 315 445.0 416.3 +23.0 9.8 9.8 +0.6

Irri-
gation 185 414.8 412.6 +19.3 10.1 9.9 +0.7

East ...... 248 395.9 382.1 -11.2 9.6 9.2

West ...... 56 331.0 362.2 -31.1 7.6 7.9 -1.3



TABLE 4.-EFFECT OF SEX ON WEANING WEIGHT AND SLAUGHTER GRADE
OF CALVES UNADJUSTED AND ADJUSTED FOR YEAR, PASTURE, AGE OF
DAM AND BREEDING.

No Weaning Weight I Slaughter Grade
No. Unad- Ad- Devia- Devia-
Sex of justed Ijusted [tion from Unad- Ad- tion
Calves Means Means Mean justed justed from
(Pounds) (Pounds) (Pounds) Mean Mean Mean

Male ...... 395 431.2 407.3 +14.1 9.5 9.0 -0.2

Female .. 409 399.3 379.2 -14.1 9.9 9.4 +0.2
I _ _ _ _


TABLE 5.-EFFECT OF AGE OF DAM ON WEANING WEIGHT AND SLAUGHTER
GRADE OF CALVES UNADJUSTED AND ADJUSTED FOR YEAR, SEX, PASTURE
AND BREEDING.

I Weaning Weight I Slaughter Grade
Age of No. Unad- Ad- ] Devia- Devia-
Dam of justed justed ] tion from Unad- I Ad- I tion
Calves Means IMeans I Mean justed ] justed from
(Pounds) (Pounds) 1 (Pounds) IMean I Mean Mean


2-yr. ------ |
2-yr. ........
3-yr.

4-5-6 ..--.

7-8-9 ......

10-11-12.

13-18 ....


16 348.4

256 388.4

213 418.1

193 432.0

87 446.1

39 446.0


345.9

380.6

403.3

405.6

416.4

407.9


-47.4

-12.7

+10.0

+12.3

+23.1

+14.6


9.0

9.3

9.6

10.1

10.0

9.8


-0.5

-0.1

+0.1

+0.2

+0.4


I


I







Florida Agricultural Experiment Stations


SEX
The difference in weaning weight and slaughter grade be-
tween sexes was highly significant. Male calves were heavier,
while the females had the higher slaughter grade. The adjusted
means for sex on weaning weight and slaughter grade are tabu-
lated in Table 4.
AGE OF DAM
The estimated effect for age of dam on weaning weight and
slaughter grade is shown in Table 5. When residual mean squares
were used as error, differences in weaning weight were highly
significant and slaughter grade non-significant.

BREEDING OF CALVES
Differences among breed groups were highly significant for
weaning weight and slaughter grade, using breed x pasture inter-
action for error. The adjusted means of breeding of calves are
shown in Table 6.

TABLE 6.-EFFECT OF BREEDING ON WEANING WEIGHT AND SLAUGHTER
GRADE OF CALVES UNADJUSTED AND ADJUSTED FOR YEAR, SEX, PASTURE
AND AGE OF DAM.

Weaning Weight Slaughter Grade
Breed- No. Unad- Ad- Devia- | Devia-
ing of ousted justed tion from Unad- Ad- tion
Calves Means Means Mean justed justed from
(Pounds) (Pounds) (Pounds) Mean Mean Mean

Brahman I 141 374.6 369.8 -23.5 8.9 8.5 -0.7
%Br-
/ Sh... | 107 385.0 400.9 + 7.6 9.1 9.1 -0.1
% Br-
14 Sh.... 165 445.5 442.4 +49.1 10.4 10.1 +0.9
1/2 Sh-
%Br.... 187 458.5 419.0 +25.7 9.7 9.1 -0.1
% Sh-
Br .... 122 443.7 435.5 +42.2 10.8 10.3 +1.1
% Sh-
YBr.... 35 354.9 377.5 -15.8 9.0 9.0 -0.2
Short-
horn.... 47 297.1 307.9 -85.4 8.3 8.2 -1.0

INTERACTIONS
All first order interactions involving breed groups were cal-
culated and are given in analysis of variance, Table 1. Breed x







Florida Agricultural Experiment Stations


SEX
The difference in weaning weight and slaughter grade be-
tween sexes was highly significant. Male calves were heavier,
while the females had the higher slaughter grade. The adjusted
means for sex on weaning weight and slaughter grade are tabu-
lated in Table 4.
AGE OF DAM
The estimated effect for age of dam on weaning weight and
slaughter grade is shown in Table 5. When residual mean squares
were used as error, differences in weaning weight were highly
significant and slaughter grade non-significant.

BREEDING OF CALVES
Differences among breed groups were highly significant for
weaning weight and slaughter grade, using breed x pasture inter-
action for error. The adjusted means of breeding of calves are
shown in Table 6.

TABLE 6.-EFFECT OF BREEDING ON WEANING WEIGHT AND SLAUGHTER
GRADE OF CALVES UNADJUSTED AND ADJUSTED FOR YEAR, SEX, PASTURE
AND AGE OF DAM.

Weaning Weight Slaughter Grade
Breed- No. Unad- Ad- Devia- | Devia-
ing of ousted justed tion from Unad- Ad- tion
Calves Means Means Mean justed justed from
(Pounds) (Pounds) (Pounds) Mean Mean Mean

Brahman I 141 374.6 369.8 -23.5 8.9 8.5 -0.7
%Br-
/ Sh... | 107 385.0 400.9 + 7.6 9.1 9.1 -0.1
% Br-
14 Sh.... 165 445.5 442.4 +49.1 10.4 10.1 +0.9
1/2 Sh-
%Br.... 187 458.5 419.0 +25.7 9.7 9.1 -0.1
% Sh-
Br .... 122 443.7 435.5 +42.2 10.8 10.3 +1.1
% Sh-
YBr.... 35 354.9 377.5 -15.8 9.0 9.0 -0.2
Short-
horn.... 47 297.1 307.9 -85.4 8.3 8.2 -1.0

INTERACTIONS
All first order interactions involving breed groups were cal-
culated and are given in analysis of variance, Table 1. Breed x







Florida Agricultural Experiment Stations


SEX
The difference in weaning weight and slaughter grade be-
tween sexes was highly significant. Male calves were heavier,
while the females had the higher slaughter grade. The adjusted
means for sex on weaning weight and slaughter grade are tabu-
lated in Table 4.
AGE OF DAM
The estimated effect for age of dam on weaning weight and
slaughter grade is shown in Table 5. When residual mean squares
were used as error, differences in weaning weight were highly
significant and slaughter grade non-significant.

BREEDING OF CALVES
Differences among breed groups were highly significant for
weaning weight and slaughter grade, using breed x pasture inter-
action for error. The adjusted means of breeding of calves are
shown in Table 6.

TABLE 6.-EFFECT OF BREEDING ON WEANING WEIGHT AND SLAUGHTER
GRADE OF CALVES UNADJUSTED AND ADJUSTED FOR YEAR, SEX, PASTURE
AND AGE OF DAM.

Weaning Weight Slaughter Grade
Breed- No. Unad- Ad- Devia- | Devia-
ing of ousted justed tion from Unad- Ad- tion
Calves Means Means Mean justed justed from
(Pounds) (Pounds) (Pounds) Mean Mean Mean

Brahman I 141 374.6 369.8 -23.5 8.9 8.5 -0.7
%Br-
/ Sh... | 107 385.0 400.9 + 7.6 9.1 9.1 -0.1
% Br-
14 Sh.... 165 445.5 442.4 +49.1 10.4 10.1 +0.9
1/2 Sh-
%Br.... 187 458.5 419.0 +25.7 9.7 9.1 -0.1
% Sh-
Br .... 122 443.7 435.5 +42.2 10.8 10.3 +1.1
% Sh-
YBr.... 35 354.9 377.5 -15.8 9.0 9.0 -0.2
Short-
horn.... 47 297.1 307.9 -85.4 8.3 8.2 -1.0

INTERACTIONS
All first order interactions involving breed groups were cal-
culated and are given in analysis of variance, Table 1. Breed x







Florida Agricultural Experiment Stations


SEX
The difference in weaning weight and slaughter grade be-
tween sexes was highly significant. Male calves were heavier,
while the females had the higher slaughter grade. The adjusted
means for sex on weaning weight and slaughter grade are tabu-
lated in Table 4.
AGE OF DAM
The estimated effect for age of dam on weaning weight and
slaughter grade is shown in Table 5. When residual mean squares
were used as error, differences in weaning weight were highly
significant and slaughter grade non-significant.

BREEDING OF CALVES
Differences among breed groups were highly significant for
weaning weight and slaughter grade, using breed x pasture inter-
action for error. The adjusted means of breeding of calves are
shown in Table 6.

TABLE 6.-EFFECT OF BREEDING ON WEANING WEIGHT AND SLAUGHTER
GRADE OF CALVES UNADJUSTED AND ADJUSTED FOR YEAR, SEX, PASTURE
AND AGE OF DAM.

Weaning Weight Slaughter Grade
Breed- No. Unad- Ad- Devia- | Devia-
ing of ousted justed tion from Unad- Ad- tion
Calves Means Means Mean justed justed from
(Pounds) (Pounds) (Pounds) Mean Mean Mean

Brahman I 141 374.6 369.8 -23.5 8.9 8.5 -0.7
%Br-
/ Sh... | 107 385.0 400.9 + 7.6 9.1 9.1 -0.1
% Br-
14 Sh.... 165 445.5 442.4 +49.1 10.4 10.1 +0.9
1/2 Sh-
%Br.... 187 458.5 419.0 +25.7 9.7 9.1 -0.1
% Sh-
Br .... 122 443.7 435.5 +42.2 10.8 10.3 +1.1
% Sh-
YBr.... 35 354.9 377.5 -15.8 9.0 9.0 -0.2
Short-
horn.... 47 297.1 307.9 -85.4 8.3 8.2 -1.0

INTERACTIONS
All first order interactions involving breed groups were cal-
culated and are given in analysis of variance, Table 1. Breed x







Genetic and Environmental Influences on Calf Breeds 11

year, breed x pasture and breed x sex were highly significant
for weaning weight, while breed x age of dam was non-significant.
Breed x year and breed x pasture were highly significant for
slaughter grade, while breed x sex and breed x age of dam
were non-significant. Other interactions were not calculated
because the principal interest of this study was effect of breed-
ing. The sums of squares unaccounted for and inspection of
the data indicated that few, if any, of the interactions not tested
were of significant magnitude.

DISCUSSION OF EXPERIMENTAL RESULTS
Variation of animal performance among years is usually due
to environmental conditions beyond the control of the producer.
Amount and distribution of rainfall, coupled with temperature,
affect the growth of forage. Flooding in low areas and extreme
temperatures not only affect feed supply but exert an adverse
influence on the animal itself.
Differences among pastures were highly significant for wean-
ing weight and slaughter grade. Calves produced in the Barn
pasture, where improved grasses, legumes and supplemental feed
were used, proved superior in both weaning weight and slaughter
grade. Those in the West pasture, where the cows grazed only
native grass with limited supplemental feed, were 54 pounds
lighter and rated 2/3 of a slaughter grade lower. Calf production
was directly proportional to the nutritional level of the herd
which in turn was determined by quality and uniformity of dis-
tribution of feed. A highly significant breed x pasture inter-
action shows that Shorthorn and Brahman breeds and their
crosses used in this study do not respond in a similar manner to
the different levels of nutrition. One-half Shorthorn-1/2 Brah-
man calves accounted for over 50 percent of the sums of squares
for interaction of breed x pasture.
Differences between sexes were found to exist at a highly
significant level, steer calves having a heavier weaning weight
and heifer calves a high slaughter grade. These results could
be accounted for by the growth pattern of calves, steers having
a higher growth potential, resulting in larger size, and heifers
putting on more fat because they mature more quickly. A
highly significant breed x sex interaction for weaning weight
shows that sex effects are not the same for all breed groups used
in this study.







Florida Agricultural Experiment Stations


There was a highly significant difference in weaning weight
among calves from cows of the various age groups, while slaugh-
ter grade variations were non-significant. Offspring from 3-year-
old cows average 35 pounds heavier than calves from 2-year-olds
and 23 pounds lighter than those from 4- to 6-year-old cows.
There was little difference in weaning weight among calves
from cows in the 4- to 6-year-old group and cows through 18
years of age, with the exception of cows 10 to 12 years of age
that produced calves 13 pounds heavier than the 4- to 6-year-olds.
The 10- to 12-year-old group was made up predominantly of
Brahman and crossbred Shorthorn-Brahman cows, while the 13-
through 18-year-old group was largely Brahman. These results
show that the period of peak productivity of these 2 cow groups
extends beyond the normal ages as reported by Koger and Knox
(15) for Hereford cows.
Weaning weight and slaughter grade differences among calves
of the various breed groups were highly significant. The heaviest
and highest grading calves were out of crossbred 1 Shorthorn-
1/2 Brahman cows. Three-fourths Brahman-1/4 Shorthorn calves
out of 1/2 Shorthorn-1/ Brahman cows were the heaviest, while
the 3/ Shorthorn-1/4 Brahman calves from cows of the same
breeding were second in weight with the highest slaughter grade.
The growth potential of 3/4 Brahman-1/ Shorthorn calves was
the highest of the two groups of calves and resulted in a heavier
weaning weight, while the 3/ Shorthorn-1/ Brahman calves
weighed slightly less but had a higher slaughter grade. The
fact that both of these breed groups of calves were out of cross-
bred 1/ Shorthorn-1/Brahman cows indicates the superior ability
of these cows to produce under the conditions prevailing in this
study.
Crossbred calves out of Brahman cows and sired by Shorthorn
bulls were rated third in both weaning weight and slaughter
grade. The superiority of these calves over animals of the
parental breeds, Shorthorn and Brahman, is considered to be
the result of heterosis.
Next in descending order were the 7/8 Brahman-i/8 Short-
horn, 7/8 Shorthorn-I/8 Brahman and Brahman calves, with Short-
horns being lowest in average weaning weight and slaughter
grade. Lack of heterosis in calves having 7/8 or more Brahman
or Shorthorn blood and the lack of hardiness of Shorthorns are
considered partly responsible for the lowered production of these
breed groups. These results are similar to those obtained by
Peacock et al (20).







Genetic and Environmental Influences on Calf Breeds 13

SUMMARY AND CONCLUSIONS
A crossbreeding project was initiated in 1942 at the Range
Cattle Experiment Station, Ona, Florida, to determine the per-
formance of Brahman and Shorthorn cattle and their crosses
under the conditions prevailing in central Florida. This study
includes records from 804 calves out of 167 cows, all descending
from either purebred Brahman or Shorthorn for the years 1943
through 1958. Calf data were analyzed to determine weaning
weight and slaughter grade differences as affected by: 1, year
of birth; 2, differences in pastures; 3, sex; 4, age of dam; 5,
breeding of calf.
Year of birth had a highly significant effect on weaning
weight and slaughter grade of calves, resulting from weather
and pasture variations.
Weaning weight and slaughter grade differences among pas-
tures were highly significant, with calves from the Barn pasture
being highest and those from the West pasture lowest.
The effect of sex on weaning weight and slaughter grade was
highly significant, with the steer calves weighing heavier and
heifer calves grading higher.
Weaning weight differences of calves from cows of different
age groups were highly significant, while slaughter grade vari-
ations were non-significant. Calves from 2-year-old cows were
the lightest, weighing 346 pounds, those from 3-year-olds were
35 pounds heavier. Cows from 4 to 6 years of age produced
calves weighing 403 pounds, which was comparable to the 7-
to 9- and 13- to 18-year-olds which weaned calves weighing 406
and 408 pounds, respectively. The heaviest calves, 416 pounds,
were from the 10- to 12-year-old group.
There was a highly significant difference in weaning weight
and slaughter grade among calves of varying proportions of
Shorthorn-Brahman breeding. The heaviest calves were %
Brahman-1/4 Shorthorn, weighing 442 pounds, and the lightest
were Shorthorns, weighing 308 pounds, a difference of 134
pounds. The other breed groups in descending weight order
were: 3/ Shorthorn-1/ Brahman, 436 pounds; 1/2 Shorthorn-1/
Brahman, 419 pounds; 7/8 Brahman-1/ Shorthorn, 401 pounds;
7/8 Shorthorn-1/8 Brahman, 378 pounds; and Brahman, 370
pounds. The 3/ Shorthorn-1/' Brahman calves rated highest in
slaughter grade with a 10.3 score, while the 3/% Brahman-l/
Shorthorn were in second place with a 10.1 grade. The other
breed groups in descending order of slaughter grade were: 1/2







14 Florida Agricultural Experiment Stations

Shorthorn-1/2 Brahman and 7/8 Brahman-1/ Shorthorn, both
grading 9.1; 7/8 Shorthorn-1/ Brahman, 9.0; Brahman, 8.5; and
Shorthorn, 8.2.
Calves with the heaviest weaning weight and highest slaugh-
ter grade were 3/ Brahman-1/4 Shorthorn and % Shorthorn-1/
Brahman, both out of crossbred 1/2 Shorthorn-1/2 Brahman cows.

LITERATURE CITED
1. Anderson, R. L., and T. A. Bancroft. Statistical theory in research.
1st Ed. McGraw-Hill Book Co. 1952.
2. Baker, A. L., and W. H. Black. Crossbred types of beef cattle for the
Gulf Coast Region. USDA Cir. 844. 1950.
3. Becker, R. B., P. T. Dix Arnold, W. G. Kirk, George K. Davis and R. W.
Kidder. Minerals for dairy and beef cattle. Fla. Agr. Exp. Sta.
Bul. 513. 1953.

4. Chew, Victor. Experimental designs in industry. John Wiley & Sons,
Inc. 1958.

5. Damon, R. A., S. E. McCraine, R. M. Crown and C. B. Singleton. Per-
formance of crossbred beef cattle in the Gulf Coast Region. Jour.
An. Sci. 18:1:437. 1959.

6. Dwyer, Paul S. Linear computations. John Wiley & Sons, Inc. 1951.

7. Goulden, Cyril H. Methods of statistical analysis. 2nd Ed. John Wiley
& Sons, Inc. 1956.

8. Jones, D. W., E .M. Hodges and W. G. Kirk. Year-round grazing on a
combination of native and improved pasture. Fla. Agr. Exp. Sta. Bul.
554. 1954.

9. Kidder, Ralph W., and Herbert L. Chapman. A preliminary report of
weight performance of crossbred and purebred cattle at the Ever-
glades Experiment Station from 1943 to 1951. Proc. Assoc. So. Agr.
Wkrs. 49: 56. 1952.

10. Knapp, Bradford, Jr., A. L. Baker, J. R. Quesenberry and R. T. Clark.
Performance testing of beef cattle. Mont. Agr. Exp. Sta. Bul. 417.
1944.

11. Knapp, Bradford, Jr., A. L. Baker, J. R. Quesenberry and R. T. Clark.
Growth and production factors in range cattle. Mont. Agr. Exp.
Sta. Bul. 400. 1942.

12. Knapp, Bradford, Jr., and W. H. Black. Factors influencing rate of
gain of beef calves during the suckling period. Jour. Agr. Res.
63:4: 249-254. 1941.

13. Koch, Robert M. Size of Calves at weaning as a permanent character-
istic of range Hereford cows. Jour. An. Sci. 10: 3: 768-775. 1951.








Genetic and Environmental Influences on Calf Breeds 15

14. Koger, Marvin, and J. H. Knox. The effect of sex on weaning weight
of range calves. Jour. An. Sci. 4: 1: 15-19. 1945.

15. Koger, Marvin, and J. H. Knox. Effect of age on the weight and pro-
duction of range cows. N. Mex. College and N. Mex. Exp. Sta.
Press Bul. 1004. 1945.

16. Koger, Marvin, and J. H. Knox. A method of estimating weaning
weights of range calves at a constant age. Jour. An. Sci. 4: 3: 285-
290. 1945.

17. Landblom, Nellie Thompson. Nellie Landblom's copybook for begin-
ners in research work. Multigraph Service Bureau, Colorado A. &
M. College, Fort Collins, Colorado. 1955.

18. McCaleb, J. E., and E. M. Hodges. Climatological records at the Range
Cattle Experiment Station, from 1942-1958. Fla. Agr. Exp. Sta.
Circ. S-124. 1960.

19. McCormick, W. C., and B. L. Southwell. A comparison of Brahman
crossbred with British crossbred cattle. Jour. An. Sci. 16: 1:207.
1957.

20. Peacock, F. M., W. G. Kirk and Marvin Koger. Factors affecting wean-
ing weight of range calves. Fla. Agr. Exp. Sta. Bul. 578. 1956.

21. Sawyer, W. A., Ralph Bogart and Mohamed M. Olorefa. Weaning
weight of calves as related to age of dam, sex and color. Jour. An.
Sci. 7: 4. 1948.





3* WHO WINS THE

BLUE-RIBBON JOBS

IN ANIMAL HUSBANDRY?



The BES;T POSITIONS goj to the prIeple BEl T
PREPARED. The '.t p reparati ion is oblitained i through
P du_ l o.atiulln J.l trailing. Y, %i ill gain experience.

The Uini\er ,il\ of Florida offers unexeelleidl t-rain-
ig in all please of animal hullanldry- -l-ree.ding. fee.l-
ing. management. plihyiologv. showingg and judging,
selling cattle. hqog-.. hep and other li'e-tojck.

The Uni\eril\ ihas aii excellent Meatl
Lahojratarv. an ouit-landing research division.
anidl re-earch uiits deu.tel to aniidal nutri-
lion, purebl ed beef cattle, range callle, s\'iiln
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win blue riMt.i ns- in dani dal liu-baiii.li y. l rite

DR. ANl\R\1 I A. BOOKER
D[adii. (u.llege of Agriculture
thine'.\ ille. Flori.da





ED C TO y u b s0rprto




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