Influence of heredity and environment on weaning and post-weaning weights in beef cattle

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Title:
Influence of heredity and environment on weaning and post-weaning weights in beef cattle
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iv, 59 leaves : ill. ; 28 cm.
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English
Creator:
Meade, J. H ( James Horace ), 1932-
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Subjects / Keywords:
Beef cattle   ( lcsh )
Heredity   ( lcsh )
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bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )

Notes

Thesis:
Thesis (Ph. D.)--University of Florida, 1961.
Bibliography:
Includes bibliographical references (leaves 55-59).
Statement of Responsibility:
by James Horace Meade.
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Typescript.
General Note:
Vita.

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University of Florida
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All applicable rights reserved by the source institution and holding location.
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aleph - 000405251
notis - ACF1483
oclc - 24682985
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Full Text











Influence of Heredity and Environment on

Weaning and Post-Weaning Weights

in Beef Cattle










By
JAMES HORACE MEADE, JR.


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY









UNIVERSITY OF FLORIDA
June, 1961




















AC 'i ,I DGMEITS


The author wishes to express his sincere appreciation to

Dr. ,Marvin Koger, chairman of his supervisory committee, for his

guidance and assistance throughout this study and in the preparation

of this dissertation.

Appreciation is also expressed to Dr. A. C. Warnick, Dr. T. J.

Cunha, Dr. J. R. Edwardson and Dr. A. E. Brandt for their supervision

and advice.

Special thanks are expressed to Ir. R. W. Kidder and the other

personnel at the Everglades Experiment Station who collected the data

used in this study and made it available for analysis.

Appreciation is expressed to D. D. Ilargrove and R. E. Deese

for reading the rough manuscript.

The author wishes to give special thanks to his wife PIarion iell

for her encouragement and help throughout his graduate career.















ii


*//y-.f


















TABLE OF CONTENTS


Page

ACi'iOWLZ; DGMI- ilTS . . ii

LIST OF TABLES ............... iv

INTRODUCTION . .... .. 1

REVIEW OF LITERATUIE . .... .. 3

Weaning Performance . . 3
Post-Weaning Performance . .. 11

MATERIALS AND METHODS ................... 13

FLJ7LLT . ... . .20

205-Day Weight . . ... .. 20
12- and 18-Month Weight . ... 29

DI.-CU.. lcri . . . 35

SU MARY . . ... .. 42

APPENDIX. .......................... 44

LITERATURE CITED .. . .... 55
















LIST OF TABLES


Table Page

1. Variance Analysis for Main Effects Influencing
205-Day WJeights . . 21

2. Approximate "en '.uares for First-Order Interactions 22

3. Least Squares Effects by Year . .... 23

4. Least Squares Effects by Breed . ... 25

5. Least Squares Effects by Sex and Age of Dam .. 27

6. Least -quares Effects by Lactation St tus -nd Month of
Birth . . ... .. .. 28

7. Variance An--lysis for '-MIonth Weight ... 30

8. Variance Analysis for 18-M!onth Weight ... 30

9. Interaction of Year with Breed . .... 31

10. Least Scuares Effects of Year of Birth on 12- '%nd 18-
Month Weights . . .... 31

11. Least Scwures Effects of Breed on 1 and l -Month
Weights . . ... .. .. 32

12. Partial regression Coefficients for Regression of
Weight on Age at Weaning . 34

13. Multiple Correlation Coefficients with Certain Classi-
fications Omitted from Nodel . .... 36

14. Original Least Squares Equ'ations . .. 45

15. Inverse of Reduced Coefficient Matrix ... 49

16. Cows Bred and Calves Weaned by Year and Breed Group 53


















IiT. '-'L i' ACTION


Inherent biological factors create much variability in measure-

ments taken to evaluate beef cattle performance. Some of this

variability can be attributed to genetic differences between animals,

some to environmental influences and some to genetic-environmental

interactions. In order to accurately evaluate beef cattle performance,

estimates of the various factors which influence performance are

necessary. A thorough knowledge of these factors should enable the

livestock breeder to develop more accurate breeding and selection

programs.

During recent years there have been many papers published con-

cerning the performance of different populations of beef cattle.

However, due to environmental differences and genetic-environmental

interactions, the livestock producer must have valid estimates of the

factors influencing performance in the specific population which con-

cerns him. This is particularly true in Florida because the environ-

mental conditions are quite different from those prevailing throughout

most of the United States. Therefore, the ability of an animal to

adapt to his environment takes on added significance. Consequently,

accurate estimates of the factors which influence beef cattle perform-

ance under Florida conditions should be of value to Florida cattlemen.









2


This study was undertaken with the purpose of obtaining estimates

of genetic and environmental influences on weaning and post-weaning

gains of beef cattle under south Florida conditions. The specific

population involved was that of the Everglades Experiment Station beef

cattle herd. This population contained Angus, Brahman, Devon, Brahman-

Angus and Brahman-Devon cattle. Weaning weights were available for all

calves. Also, since very little culling was practiced, 12- and 18-month

weights were available for practically all heifers.
















REVL-W OF LITERATURE


Weaning Performance


Effect of Year

Numerous investigations have shown that the effects of year

cause the weaning weights of calves to fluctuate widely. Burgess,

Landblom and Stonaker (1954) reported the effects of year on the

weaning weight of Hereford calves. They obtained a range in year

effects of 44 pounds for a six-year period. Similar year effects

were found by Godbey et ,al. (1959), Brown (1960) and Godley et al.

(1960). In a study of the Everglades Experiment Station beef cattle

herd from 1931 to 1955, Clum (1956) obtained a range in year effects

of over 100 pounds. Brown (1958) also obtained a range in year effects

of over 100 pounds. Reynolds (1960) analyzed the records of the Range

Cattle Experiment Station, Ona, Florida, for a 15-year period. He

found that the range in year effects was 85 pounds.


Effect of Sex

The fact that sex has an effect on the weaning weights of calves

has been known for some time. Koger and Knox (194)), using data col-

lected over an eight-year period on 863 Hereford calves, determined the

mean weaning weights of male and female calves corrected for differences











in weaning age. The average weaning weight was 443 pounds for 419 steers

and 411 pounds for 444 heifers. The steers were heavier than the

heifers each year. However, Gregory, Blunn and Baker (1950) found

little difference in weaning weight between male and female calves.

Botkin and Whatley (1953) analyzed the weaning weights of 701 calves

produced by range Hereford cows and reported that the males averaged

25 pounds heavier than the females. In a review of the influence of sex

of calf on weaning weight, fmith and Warwick (1953) determined that male

calves averaged 23 to 49 pounds heavier than females. Bull calves were

22 pounds heavier and steer calves 2 pounds heavier than heifers at

weaning in a study by Burgess, Landblom and L'tonaker (1954). Rollins

and Guilbert (1954) observed that bull calves were 68 pounds heavier

than heifer calves at 240 days of age.

A study conducted by Koch and Clark (1955) showed that male

calves averaged 26 pounds heavier at weaning than female calves. Clum

(1956) noted that male calves averaged 25 pounds heavier at 180 days

of age than females. Marlowe and Gaines (1958) averaged the records

of 4166 calves in the Virginia performance testing program. The data

were pooled over all years and over 44 Angus, 19 Hereford and 3 Short-

horn herds located in the state. At 210 days of age steers were 30

pounds heavier than heifers. Similar estimates were obtained by Koch

(1951), Brown (1960), Reynolds (1960) and Meade, lHrmmond and Koger

(1961). A difference of 41 pounds in favor of steer calves was reported

by Godbey et al. (1959) and Godley et al. (1960).









5
Effect of Age of D:un

The age of the dam at calving has been shown to influence the

weaning weights of calves to a certain extent. Knapp, Baker, Quesen-

berry and Clark (1942) observed that maximum weaning weights of calves

may be expected from six-year-old cows with a gradual increase from two

to six years and a more rapid decrease from six to 11 ye-r,. Knox and

Koger (1945) showed that the age of maximum production of range cows

was from six to eight years with the peak at seven years. Sawyer,

Bogart and Oloufa (1949) noted that two-year-old cows weaned calves

75 pounds lighter than mature cows. The weaning weight of calves in-

creased with increasing age of darmi through eight years but then

declined. Botkin and Whatley (1953) considered all cows five years

old and older as mature. We ning weights were adjusted to a mature

cow equivalent by adding 35 and 15 pounds to the weights of cloves

from three- and four-year-old cows, respectively.

In a review of the influence of age of dam on calf weights,

Smith and Warwick (1953) found that maximum weaning weights were

usually obtained from dams six to nine years of age. Lurgess, Landblom

and Stonaker (1954) developed a series of constants to increase effec-

tiveness of selection for weaning weights. They adjusted for age of

dam by adding 15 pounds to calves from two-year-old cows, 10 pounds to

calves from cows nine years and over, and subtracting 5 pounds from calves

weaned by cows three to five years of age and 21 pounds from calves

weaned by cows six to eight years of age. Koch and Clark (1955) used

a number of correction factors to correct for the effect of age of dam












on weaning weight. They corrected by adding to the weaning weights of

calves produced by: 3-year-old dams, 46 pounds; 4-year-old, 21 pounds;

5-year-old, 8 pounds; 6-year-old, 0 pounds; 7-year-old, 2 pounds;

8-year-old, 4 pounds; 9 year-old, 7 pounds; and 10-year-old, 14 pounds.

McCormick and others (1956) determined that age of dam exerted a

significant influence on 210-day weights of calves. Calves produced

by two-year-old cows were 107 pounds lighter than those produced by

eight-year-old cows. Calves from three-year-old dams were 63 to 73

pounds lighter than those from mature dams. Weaning weights of the

calves produced gradually increased with age of dam until the cows

reached maturity at seven or eight years of age.

Clum (1956) adjusted calf weights to a mature dam equivalent by

adding 35, 12, 5, 3, 8, 18, 34, 53 and 53 pounds to calves from cows

aged 2, 3, 4, 11, 12, 13, 14, 15 and 16 years, respectively. Marlowe

and Gaines (1958) reported that maximum production was obtained from

six- to eight-year-old cows. They made adjustments for age of dam on

calves from cows that were 2, 3, 4, 5 and over 10 years of age at

date of calving. Results similar to these were obtained by Brown

(1958), Clark et al. (195&), Reynolds (1960) and Meade, Hammond and

Koger (1961).


Effect of Month of Birth

Clum (1956) reported that within year variability due to month

of birth influenced the 180-day weights of calves. He found that

calves born in the months of December thLbou,_h May were heavier than









7
calves born from July through November. Peacock, Kirk and Koger (1956)

stated that calves born during December, January and February were

14 pounds heavier at 180 days of age than calves born during Larch,

April and May. Koger (1958) indicated that December and January

calves were heavier than February, IMarch or April calves. Results of

a study by Marlowe, Kincaid and Litton (1958) gove evidence that sea-

son of birth contributed to the variability in preweaning gain. Brown

(1958) reported that calves born during February, Larch -nd April were

heavier than calves born from September through January. Reynolds

(1960) found that the weaning weights of c-lves born from January

through April were heavier by 7 pounds than calves born in December

or May, and were 15 pounds heavier than those born from June through

November. Marlowe and Gaines (1958) and Brown (1960) have also shown

that season of birth influences the weaning weights of calves.


Effect of Lactation Status

Reynolds (1960) found that lactation status of the dam during

the breeding season exerted a significant influence on weaning weight.

He obtained an interaction of lactation status with pasture, year and

breed. However, Mieade, Hanmmond and Koger (1961) reported that lacta-

tion status of the dam did not influence weaning weight in a purebred

Brahman herd.


Effect of Breed

Numerous investigations have shown that under specific environ-

mental conditions breed of calf exerts a significant influence on









8


weaning weight. Bray (1933) reported that half-Brahman calves were

heavier at weaning than either Hereford or Angus calves. In 1934,

Black, Semple and Lush reported the results of mating Brahman bulls

to Shorthorn and Hereford cows. At weaning, the steers containing

Brahman blood were heavier than the non-Brahman steers. Phillips and

others (1942) found that Shorthorn-Hereford steers out of Hereford

cows were slightly heavier at weaning than purebred Hereford steers.

For the Gulf Coast area, Rhoad and Black (1943) recommended Brahman

hybrid beef-type bulls for use on range cows with one-half to three-

fourths the blood of a pure beef breed. They stated that one parent

of the hybrid bulls should be of the same pure beef breed that sired

the range cows and the other parent predominately of Brahman breeding

and of acceptable beef-type conformation.

In a study by Rhoad, Phillips and Dawson (1945), calves from

Angus dams when mated to Angus bulls were lighter at six months of

age than when mated to Africander or Zebu bulls. Baker and Black

(1950) found that average weight at six months of age was significantly

greater for calves out of Brahman-Angus cows than for calves out of

purebred Angus cows, irrespective of sire. In a review, Warwick (1950)

reported that Brahman crossbred calves were 35 pounds heavier at wean-

ing than British type calves. Calves from Brahman crossbred dams

were 81 pounds heavier at weaning than calves from British type cows.

Gerlaugh, Kunkle and Rife (1951) made reciprocal crosses with Angus

and Hereford cattle. The crossbred calves had only a slight advantage

in weight at weaning over the purebreds.












Kidder and Chapman (1952) gave a preliminary report of weight

performance of crossbred and purebred cattle at the Everglades Experi-

ment Station. Their results indicated that progeny of reciprocal

crosses of Brahman X Angus and Brahman X Devon were superior in weight

gains to either of the purebred lines of the respective cross.

The results from 22 published experiments in crossbreeding

beef cattle were appraised by Holt (1955). These included British

breeds, other European breeds, Zebus and unimproved cattle. Crossbred

calves averaged 3.5 per cent above the parental average in weaning

weight. McCormick and Southwell (1955) summarized the weaning per-

formance of British and British-Brahman F1 calves. The British calves

were 30 pounds lighter at weaning.

Kidder, Liddon, Clum and I:o,rer (1956) analyzed the growth re-

sponse of Angus, Brahman and Devon cattle and various crosses of these

breeds. A marked heterosis effect on growth to 180 days resulted from

the various Brahman-Devon crosses. Calves from crossbred dams by

crossbred sires were lighter than F1 calves or calves from crossbred

dams by purebred sires. They stated that in the Angus-Brahman groups,

heterosis effects were marked in both growth rate of calves and mother-

ing ability of dams.

McComas, Cook and Dawson (1956) found that F1 Red Dane X Red

Poll heifers made more rapid gains from birth to weaning than did Hed

Poll heifers. Peacock, Kirk and Koger (1956) obtained a significant

difference between weaning weights of calves mothered by dams of dif-

ferent breeding. Cows with one-half Brahman breeding weaned the

heaviest calves and cows containing no Brahman breeding weaned the












lightest calves. Weaning weights of calves from cows with 1/32 to

15/32 and 17/32 to 31/32 Brahman breeding were intermediate.

McCormick and Southwell (1957) stated that c:ives from Brahm an bulls

mated to Hereford cows were 27 pounds heavier at weaning than calves

from Angus bulls mated to Hereford cows. Using a rotational cross-

breeding system with iAngu, Hereford and Shorthorn cattle, Quesen-

berry (1958) found that the crossbred steers weighed more at any age

than did the Hereford steers with which they were compared.

Burns, Koger, Warnick and Kincaid (1959) reported that the

weuning weights of Angus, Brahman and Hereford calves were lighter

than Santa Gertrudis or Brahman-Angus calves. Damon et al. (1)59)

studied the performance of crossbred beef cattle in the Gulf Coast

region. Crosses among Brahman and other breeds of cattle gave a

considerable advantage over the purebred cattle with respect to wean-

ing weights. However, the advantage w-s not so marked when slaughter

calf grades were considered. These crosses were generally superior

when the Brahman breeding was in the females. They obtained little

advantage by crossing the English beef breeds. Godbey et al. (1959)

reported that Angus cows produced lighter calves at weaning when mated

to Angus bulls than when mated to Brahman or Hereford bulls. Likewise,

Hereford cows produced lighter calves when mated to Hereford bulls than

when mated to Angus or Brahman bulls. Godley et al. (1960) found that

Brahmnan-Angus and Brahman-Hereford damis produced heavier calves than

Hereford-Angus or purebred Angus dams when mated to the same Shorthorn

bull.











Reynolds (1960) stated that breed group comparisons indicated

that hybrid vigor was an important factor influencing growth of calves

at the Range Cattle Station. Generally the breed groups with less

than 75 per cent of any one breed weaned the heaviest calves. Hargrove

(1960) individually fed Shorthorn, brahman and Shorthorn X Brahman

calves which were weaned at an average age of 86 days. The Shorthorn

calves gained 169 pounds, the Birahmin calves 224 pounds and the cross-

bred calves 238 pounds for a 147-day feeding period.


Post-Weaning Performance

Bray (1933) stated that half-Brahman yearling heifers averaged

733 pounds while beef type non-Brahman heifers averaged 649 pounds.

Baker and Black (1950) found that yearling heifers out of Brahiman-Angus

cows were heavier than heifers out of purebred Angus cows. Warwick

(1950) reported that Brahman crossbred cattle were 46 pounds heavier

than British type cattle at 12 months of age. The crossbred cattle

were 80 pounds heavier at 24 months of age.

Liddon (1957) studied post-weaning growth of Angus, Brahman,

Devon and crossbred cattle at the Everglades Experiment Station. First-

cross females were superior in weight to the two parental breeds from

six months to five ve.rs of age. The FI females had a 7.7 to li.7

per cent advantage over the heavier of the parental breeds. The 3/4

Devon backcross group was equal in weight to the Brahman-Devon Fl

groups. When all of the purebreds were compared with all of the cross-

breds the crossbreds showed greater weight for age at all ages. Burns

et al. (1959) reported that yearling Santa Gertrudis and Brahman-Angus









12

heifers were heavier than Angus, Brahman and Hereford heifers. McDowell

et al. (1959) compared Jersey and Red Sindi-Jersey crossbred calves at

the Beltsville and Jeanerette stations. They found that the FI calves

were heavier than the purebred Jersey, 1/4 Jersey and 3/4 Jersey calves

at 6, 12 and 18 months of age.
















I.TATERALS AI)D Li -T7i-lJF;


I'ature of D'ta

The data used in this study were obtained from the beef cattle

records of the EverClades Experiment Ctation, Belle Glade, Florida.

Records were available on Anr4us, Brahman, Devon and various crosses of

these breeds of cattle. The Devon herd was established at the station

in 1)31 and maintained until 1960. Herds of purebred Angus and

Brahmnn cattle were added and a crossbreeding program was started in

1946.

Very little culling took place in this population. Since

practic-ally all of the heifers were kept in the herd, little selection

was practiced except for the choice of sires used. Therefore, the

records used in this study were from a relatively unselected popula-

tion compared to most beef cattle herds today.

The data ansly. ed were the 205-uay weights of 933 calves and

the 12- and 1 -nonth weights of 41; heifer.. All of the heifers

having 12- :-nd l-month weights were included in the 205-day weight

analysis. The records covered the ten-year period from 195D through

1959. For 205-day weight, the data were classified by year of birth,

breed group, age of dam, se::, month of birth -nd lactation status of

the damr. For L-- and 1 '-mionth weights, the data were classified by

year and breed group.













Although reproduction was not considered in this study, the

nuRmber of cows bred and calves weaned by year iad breed group is

shown in table 16.


Factors Included in Analysis

The record of each individual was classified by year of birth

and the following factors.

Age of Dam. Age of dam was classified six ways.

1. Two years. Heifers which calved at two years of age.

2. Three years. Cows which calved at three years of age.

3. Four years. Cows which calved at four years of age.

4. Five years. Cows which calved at five years of age.

5. Six to eleven years. Cows which calved from six to

11 years of age were grouped together since prior

knowledge indicated that their influence on weaning

weight was similar.

6. Twelve to seventeen. Since nmjbers were small in the

higher age classifications, cows which calved from 12

to 17 years of age were grouped together.

Sex.

1. Bull calves.

2. Steer calves.

3. Hieifer c .lves.

Month of Birth. Previous research and a preliminary inspection

of the data indicated that month of birth could be grouped into

three classifications.












1. Calves born during the months of December through June.

2. Calves born during the months of July through October.

3. Calves born in November.

Lactation tatuss of Dar:. The term lactation status refers to

the lactation record of the dam the previous year. It is based

on whether or not a damr weaned a calf the previous year. In

this study lactation status was classified two ways.

1. Lactating dams. Dams which weaned a calf the previous

year.

2. Non-lactating dams. Dams which did not wean a calf

the previous year.

Breed Group. Breed groups were classified on the basis of the

breeding of the calf. There were three purebred groups and

five crossbred groups as follows:

1. Angus. Purebred Angus calves.

2. Brahm an. Purebred Brahman calves.

3. Devon. Purebred or high grade Devon calves.

4. Brahman-Angus Fl's. One-half Brahman one-half Angus

calves.

5. Brahman-Angus Backcrosses. Calves obtained by mating

Brahman or Angus bulls to BrlmL':n-Anus- Fl dams.

6. Brahman-Devon F 's. One-half Brhman one-half Devon

calves.

7. Brahman-Devon Backcrosses. Calves obtained by mating

Brahman or Devon bulls to Brahman-Devon F1 dams.












8. Brtahman-Devon Rotation Crosses. Calves resulting

from a Brahman-Devon rotational mating system.

9. Inter-se. Calves resulting from the inter-se mating

o' Brahman-Devon crossbreds.


Method of Analysis

Like most animal breeding data the records in this study were

not balanced with respect to their frequencies in the different sub-

claEses. Therefore, a specialized statistical analysis was necessary

in order to obtain the best estimates of the different parameters which

were of interest. Various authors have discussed the problem of

analyzing data involved in multiple classifications with disproportion-

ate subclass frequencies. For data where the frequency of observations

in some of the subclasses is zero, use of the method of fitting constants

by least squares seems to be the best solution. This method of analysis

was used in the present study.

Yates (1934) was the first to publish the method of least squares

for the analysis of multiple classifications with unequal numbers in

the different subclasses. Since then, others such as Hazel (1946),

Anderson and Bancroft (1952), Kempthorne (1952), Henderson (1953) and

Harvey (1960) have outlined this method and given the computational

details involved in its use.

Due to the complexity of the data and the computational facilities

available, it was impossible to analyze a model which included inter-

action effects by least squares. Consequently, it was necessary to use












some other method to obtain estimates of interaction. Estimates of

all first-order interactions were obtained using an approximate method

described by Hazel (1946) and Landblom (1955). Sum of squares for

interaction were obtained by summing the squared differences between

actual and expected subclass values divided by their subclass frequency.

Expected values were those obtained from the least squares analysis

assuming no interaction. One degree of freedom was subtracted for

each missing subclass in the two-way interaction tables.


Model for Weaning Data

The method of fitting constants by least squares was used to

analy-e the 205-day weights of 933 calves. The following mathematical

model was assumed to fit the biology involved.

Yijkpqrt = u + yi + bj ak + + my + 1r + eijkpqrt

i = 1, 2, .. 10

j = 1, 2,... 9

k = 1, 2, 6

p = 1, 2, 3

q = 1, 2, 3

r= 1, 2

where:

Yijkprt = the 205-day weight of the tth calf in the ijkpqrth

subclass,

u = the general mean,
th
yi = effect of i year,

bj = effect of jth breed group,












ak = effect of k age of dam,

Sp = effect of pth sex,

= th
m = effect of th month of birth,

1r = effect of rth lactation status of darn,

eijkpqrt = random errors assumed to be LID (3, 6e2).

Using this model, 34 least squares e uations were derived rnd

are shown in table 14. Since these equations were not independent,

the following restrictions were imposed in order to obtain a solution.
A A A
i = -bj = = = tp = __ q = --r =
i J k p q r

The reduced equations were solved simultaneously by using matrix

inversion procedures. The matrix inverse is given in table 15. Sums

of squares for main effects were computed by subtracting the reduction

sum of squares, with a particular classification deleted, from the

reduction sum of squares obtained with all elements in the model.


Model for Post-Weaning Data

The following mathematical model was used to analyze the 12- ind

16-month weights of 415 heifers.

Yijk = o + yi + b + dDijk + eijk

i = 2, 10

j = 9

where:

Yijk = the 1'- or 16-month weight of the kth heifer in the
.th
ijth subclass,

oC = the theoretical population mean with equal subclass

frequencies when weaning age is zero,














yi = effect of ith year,

bj = effect of jt breed group,

d = partial regression of 12- or 18-month weight on age at

weaning,

Dijk = age at weaning for the kth heifer in the ijth subclass,

eijk = random errors assumed to be NID (0, 6 2).
e
A A
The restrictions were that y = b = 0. Estimates of the
1 j
A A -
general mean were obtained from the relationship u = o + d D, where D

is the mean age at weaning.

















RESULTS


205-Day Weight


The 205-day weights of 933 calves were used in this analysis.

The unadjusted mean weight was 365 pounds while the adjusted mean or

general mean obtained from the least squares analysis was 372 pounds.


Effect of Year

Differences in 205-day weights due to year effects were found

to be highly significLnt (P<0.01), as shown in table 1. In these

data, years were an important source of variability as indicated by

the mean square for year being more than twice as large as any other

mean square. Although numerous reports state that year is an important

source of variability, it seems that under the conditions of this

study years were more variable than would be expected from a review

of the literature.

Also, it is interesting to note that year was involved in all

of the significant interactions (table 2). There were significant

interactions of year with breed, sex, month of birth and lactation

status. Age of dam was the only classification not involved in an

interaction with year.

The least squares effects by year are given in table 3. The

range in year effects was from 44 pounds in 1956 to -101 pounds in 1958.
















Table 1.--VARIANCE AlALY;IS FOR MAIN EFFECTS IilFLU]EICITG 205-DAY ULIGHTj



Source df SS MS


R(u,y,b,a,c,nm,l) 27 2,950,32'
R(u,b,a, s,m,l) lc 1,165,90
R(u,y, s,m, ) 19 2,169,0o4
R(u,y,b,s,m,l) 22 2, 47,y
R(u,y,b,, ,m,l) 25 2,770,747
E(u,y,b,,0,l1) 25 2,905,954
R(u,y,b,',c, m) 26 2,946,7!7

Year 9 1,7c4,737 19&,304**
Breed 8 7cl, 2C`0 97,660**
Age of D'-m 5 102,70 20,556**
Sex 2 179, cO 89,790**
Month of Eirnth 2 44,373 22,187**
Lactation :t.tus 1 3,5 1 3,561

Residu-l 905 3,344,204 3,695


Total 932 6,94,31


**Significant at J.01 level of probability.















Table 2.--APPROXIMATE MEAN L..jJikUi FOR FIRST-OPDER IITE]RACTIONS



Source df SS MS


Year x Breed 58 373,507 6,440**
Year x Age of Dam 39 152,378 3,907
Year x Sex 16 138,161 ,635*
Year x Month of Birth 18 161,064 8,949-
Year x Lactation Ltatus 9 7;,251 ,361*
Breed x Age of Dam 33 147,680 4,475
Breed x Sex 16 93,015 5,813
Breed x Month of Birth 16 63,061 3,941
Breed x Lactation Status 8 28,822 3,603
Age of Dam x Sex 10 43,858 4,386
Age of D;aL x ionth of Birth 10 36,462 3,646
Age of Dam x Lactation Status 4 12,666 3,166
Sex x Month of Birth 4 11,216 2,804
Sex x Lactation Status 2 3,112 1,556
Month of Birth x Lactation Status 2 1,612 9,306


**Significant at 0.01 level of probability.
*Significant at 0.05 level of probability.


















Table 3.--LEAST SHARES EFFECT BY YEARa


Classificntion Humber of 205-Day
C-lves Weight

YEAR ($i)

1950 49 38.31
1951 67 -21.19
1952 79 -1.58
1953 115 -15.63
1954 0 27.39
1955 107 39.11
1956 99 44.17
1957 141 20.34
1958 14 -1oo.56
1959 56 -30.05

OVER-ALL (-) 933 372.23

'In this study, all effects "re deviations from the jver-?ll
meLn (ui).













Effect of Breed Groun

There were highly significant differences in 205-day weights due

to the effects of breed group. Also, there was a highly significant

interaction of breed group with year. The Brahnman-Angus backcross

calves were the heaviest in this study with an effect of 50 pounds

while the purebred Angus calves were the lightest with an effect of

-49 pounds (table 4).

The purebred Devon calves were heavier than the purebred Brahman

and Angus calves by 20 and 27 pounds, respectively. All of the purebred

groups were lighter than any of the crossbred groups.

In the Brahman-Angus crosses, the backcross calves were 63

pounds heavier than the Fl calves.

In the Brahman-Devon crosses, the backcross calves were 2 pounds

heavier than the Fl calves. The backcross calves were heavier than the

rotation-cross and inter-se calves by 6 and 24 pounds, respectively.

The Brahman-Angus F calves were 38 pounds lighter than the

Brahman-Devon Fl calves. In contrast to this, the Brahman-Angus back-

cross calves were 22 pounds heavier than the Brahman-Devon backcross

calves.


Effect of Sex

Sex of calf was found to be a highly significant source of

variability and was involved in a highly significant interaction with

year.

Least squares estimates of the effects of sex revealed that

bull calves were 11 pounds heavier than steer calves and 3-pounds
(3 -,
















Table 4.--LEAST SQUARES EFFECTS BY BREED


Classification Lumber of 205-Day
C lives Weight


BREED G (OUP (tj)

Purebreds
Angus 143 -49.35
Brahman 67 -42.07
Devon 171 -22.52
Brahman-Angus Crosses
FI's 34 -12.74
Backcrosses 51 49.89
Brahman-Devon Crosses
F1's 82 25.28
Backcrosses 106 27.39
Rotation Crosses 102 20.98
Inter-se 177 3.12

OVER-ALL (Q) 933 372.28














heavier than heifer calves (table 5). These effects are similar to

those reported by most research workers.


Effect of Age of D-am

There were highly significant differences due to age of dam.

The heaviest calves were produced by cows which were six to 11 years

old while the lightest calves were produced by cows which were two

years old (t-ble 5). Calves from cows2, 3, 4, 5 and 12 through 17

years old were lighter than calves from cows six through 11 years old

by 46, 26, 6, 12 and 5 pounds, respectively.


Effect of Lactation Status

The effects of lactation status were not significantly different.

However, there was a significant (P < 0.05) interaction between lacta-

tion status and year.

The calves from cows which were non-lactating the previous year

were 5 pounds heavier than calves from cows which were lactating the

previous year (table 6).


Effect of Month of Birth

Month of birth exerted a highly significant influence on 205-day

weights and was involved in a highly significant interaction with year.

Calves born during the months of December through June were heavier

than :;o'.'crmer calves by 7 pounds and July through October calves by

18 pounds (table 6).

















Table 5.--LEAST SCU.nJS EFFECTS BY SEX AND AGE OF DAMI


Classification Number of 205-Day
Calves Weight


SEX (Qp)

Bulls 281 14.28
Steers 173 3.02
Heifers 479 -17.30

AGE OF DAM (ak)

2 years 61 -30.14
3 years 200 -10.40
4 years 155 9.42
5 years 151 4.30
6-11 years 333 10.82
12-17 years 33 11.00

OVER-ALL (Q) 933 372.28

















Table 6.--LEAST SCUA.1- EFFECTS BY LACTATION STATUS AID IOI;TH OF BIRTH



Classification Number of 205-Day
Calves Weight


LACTATION STATUS (1r)

Lactating 497 -2.44
Non-lactating 436 2.44

MOTHII OF BIRTH ( q)

December-June 368 8.32
July-October 249 -10.09
November 316 1.77

OVER-ALL (u) 933 372.28











12- and 18-Month Weight


The 12- and 13-month weights of 415 heifers were used in this

analysis. The unadjusted mean weight was 488 pounds for the heifers

at 12 months of age and 630 pounds for the heifers 'it 1i, months of age.

The adjusted means for the 12- and 18-month-old heifers were 485 and

632 pounds, respectively.


Effect of Year of Eirth

Year of birth exerted a highly significant influence on the 12-

and 18-month weights of the heifers in this study (tables 7 and 8). The

magnitudes of the mean squares for ye.r in respect to breed were similar

to that found in the 205-day weight analysis where the year mean square

was more than twice as large as the breed mean square.

The year x breed interaction mean squares are given in table 9

and are not signific ,nt. There was tremendous variability in the year

effects (table 10). The range in year effects for 12-month weight was

166 pounds while for 18-month weight it was 215 pounds.


Effect of1 Breed Group on 12-Month Weight

There were highly significant differences in the 12-month

weights due to breed group. The purebred Angus heifers were the

lightest breed group while the Brahrman-Devon 1l' heifers were the

heaviest (table 11).

The purebred Devon heifers were 18 pounds heavier than the

Brahman -heifers and 76 pounds heavier than the Angus heifers.












T-ble 7.--VARIAICE ANALYSIS FOR 12-IO~TH- '.,:77r


Source df SS MS


R( w,y,b,dD) 18 2,027,398
R( o,b,dD) 9 617,455
R( -,y,dD) 10 1,407,129
R( ,y,b) 17 1,886,742

Year 9 1,409,944 156,660*
Breed 8 620,269 77,534**
Regression of Weight
on Age at Weaning 1 140,656 140,656**

Residual 396 1,396,746 3,527


Total 414 3,424,145


**Significant at 0.01 level of probability.


Table 8.--VARIAIICE AliALYSIS FOR 1t-MOI1TH WEIGHT



Source df SS MS


R( o,y,b,dD) 1l 2,530,362
R(o ,b,dD) 9 523,763
R(x ,y,dD) 10 1,87, 56o
R( ,y,b) 17 2,51L,703

Year 9 2,006,599 222,955**
Breed 8 642,802 80,350**
Regression of Weight
on Age at Weaning 1 17,659 17,659
Recidual 396 1,830,853 4,623


Total 414 4,361,215


**Significant at 0.01 level of probability.














Table 9.--IITERACTIOII OF YEAR WITH BREED


Source df S MS


Year x Breed (12-.onth Weight) 54 225,262 4,171.5
Year x Breed (1E-1onth Weight) 54 33(,91 6,223.9


Table 10.--LEAST SQUARES EFFECTS OF YEAR OF BIRTH Oil 12- AND 18-MOflTI
WEIGIfTS



Classification Lumber of 12-M'onth 18-Month
Heifers Weight Weight


TYA2 (y^)

1950 28 -6.22 -15.54
1951 35 -)4.46 -49.15
1952 29 -50.90 -37.30
1953 45 -47.76 -52.50
1954 31 -23.83 4.70
1955 47 111.85 106.36
1956 50 87.32 129.76
1957 63 54.51 -84.94
1958 60 -50.18 30.52
1959 27 -20.33 -31.91

OVER-ALL (u) 415 485.46 631.90
















Table 11.--LEAST SCSUIj S EFFECTS OF BREED ON 12- AFD l8-rC!.Thi WEIGHTS



Classification Number of 12-Month 18-Month
Heifers Weight Weight


BREED GOUP (bj)

Purebreds
Angus 52 -89.00 -85.59
Brahman 33 -30.89 -47.94
Devon 67 -12.99 -3.61
Brahman-Angus Crosses
Fl's 17 29.98 5&.94
Bz-ckc losses 22 5.25 -5.13
Brahman-Devon Crosses
FI's 45 58.72 64.12
Backcrocses 48 29.65 1&.96
Rotation Crosses 48 26.83 21.71
Inter-ue 83 -17.75 -21.46

OVER-ALL (u) 415 485.46 631.90












In the Brahman-Angus crosses, the FI heifers were 25 pounds

heavier than the backcross heifers. Both the FI and backcross groups

were heavier than the purebred Angus and Brahman heifers.

In the Brahnu. n-Devon crosses, the F1 heifers were 29 pounds

heavier than the backcross heifers. 1'Te Fl heifers were 32 pounds

heavier than the rotation-cross heifers and 76 pounds heavier than the

inter-se heifers. All of the Braiiman-Devon crosses were heavier than

the purebred Brahiman and Devon heifers with the exception of the inter-se

heifers. The inter-se heifers were 13 pounds heavier than the Br-hman

heifers but were 5 pounds lighter than the Devon heifers.

The Brahman-Devon Fl and backcross heifers were 29 and 25 pounds

heavier than the Br-'lmian-Angus FI and backcross heifers.


Effect of Breed Group on l8-Month Weight

Breed Croup exerted a highly significant influence on l1-month

weights. The purebred Angus heifers were the lightest breed group

while the Brahman-Devon FI heifers were the heaviest (table 11).

The purebred Devon heifers were 44 pounds heavier than the

Brahman heifers and 82 pounds heavier than the Angus heifers.

In the Brahman-Anv. u. crosses, the F1 heifers were 64 pounds

heavier than the backcross heifers.

In the Brahman-Devon crosses, the Fl heifers were 45 pounds

heavier than the backcross heifers. The Fl heifers were 42 pounds

heavier than the rotation-cross heifers and 86 pounds heavier than the

inter-se heifers.












The Brahman-Devon FI and backcross heifers were 5 and 24 pounds

heavier than the Brahman-Angus F1 and backcross heifers.

The purebred Angus and Brahman heifers were lighter than any of

the crossbred groups. The purebred Devon heifers were heavier than the

inter-se and Brahman-Angus backcrosses but lighter than the other cross-

bred groups.


Regression of Weight on Age at Weaning

Table 12 gives the partial regression coefficients for the re-

gression of 12- and 13-month weights on age of calf at weaning. The

partial regression coefficients are 0.77 pounds for 12-month weight and

0.27 pounds for 13-month weight.


Table 12.--PARTIAL RGC. L IOli COEFFICIEnITS FOR REGRESSION OF WEIGHT OI
AGE AT WEANING



12-Month Weight 1-L-Mionth Weight


Regression of 12- *nd lk -Month
Weight on Age at Weaning 0.7744585 0.2744128



Influence of Age of Dam

In order to determine if calves from two- and three-year-old

cows were as heavy at 12- and lb-months of age as calves from older

cows, age of dam was placed in the post-weaning model. This gave a

valid comparison of the heifers from the two- and three-year-old cows

and the older cows. Using this comparison, there were no significant

differences in the 12- or 18-month weights due to the influence of age

of dam.
















DISCUSSION


In general, the results of this study are in agreement with the

published reports of other similar investigations. However, the envi-

ronmental conditions during the period of this study caused the dependent

variables to fluctuate widely. This is shown by the tremendous year to

year variability in the 205-day, 12- and 18-month weights. An indication

of the magnitude of the year effects is shown in table 13. The square

of the multiple correlation coefficient gives the amount of variability

in the dependent variable that can be explained by a knowledge of the

independent variables. It is interesting to note that if year is omitted

from the model only about 18 per cent of the variability can be explained

by a knowledge of the other independent variables. However, when year

is included in the model R2 is increased to approximately 47 per cent.

Breed group was the only other classification which changed R2 greatly

when omitted from the model.

Even though most research workers agree that year effects are an

important source of variability, the variation in year effects found in

this study is greater than would be expected from a review of the litera-

ture. It is interesting to note that year was involved in significant

interactions with breed group, sex, month of birth and lactation status.

None of the other first-order interactions was significant. Also, it

should be pointed out that even though there was a highly significant



















Table 13.--IMULTIPLE CORRELATION CCOFT iCTI:Ti WITH C. iTTI:i CLASSIFICATIONS
01 ITT'ID FROI I1ODLL



Classificatlon Oaitted Ri2


All Elements in Model 0.6646 0.4687

Year 0.4303 0.1852

Breed Group 0.5-70 0.3446

Age of Dam 0.6726 0.4524

Sex 0.6635 0.4402

Month of Birth 0.6795 0.4617

Lactation Status 0.6642 0.4681











year x breed group interaction for 205-day weight there were no significant

interactions for 12- and 1-month weights. From these results the fol-

lowing statements about the Everglades Experiment Station beef cattle

population appear to be justified:

1. Environmental influences create much variability in beef

cattle weights.

2. IExperiments involving beef cattle should be designed so that

the desired comparisons can be made on a within year basis.

3. Since year was involved in all significant interactions,

experiments should be repeated for several years before

any definite conclusions are drawn.

The effects of sex were in close agreement with most estimates

obtained under different conditions. Almost all investigations have

revealed that bulls are heavier than steers and that steers are heavier

than heifers. The same situation was true in this study. However,

contrary to most reports, sex was involved in an interaction with year.

This may be due to the fact that the year to year variation was ex-

tremely great.

The variability due to age of dam in this study was less than

that usually reported. The differences between the two- and three-year-

old cows and the mature cows were not as great as those obtained in

most studies. The fact that age of dam did not influence 12- and 18-month

weights gives validity to the practice of adjusting weaning weights for

the effects of age of dam before replacements are selected.

The significant influence of month of birth indicates that this

factor should be considered in beef cattle research at the Everglades

Experiment Station.











Lactation status of the dam the previous year did not exert a

significant influence on weaning weights. Even though the effect of

lactation status was not significant, the calves from cows which were

non-lactating the previous year were 5 pounds heavier than calves from

cows which were lactating. Also, there was a significant interaction

(P < 0.05) between lactation status and year. However, the multiple

correlation coefficients obtained with lactation status in and out of

the model were practically the same. Therefore, very little precision

was gained by including lactation status in the model.

There were significant differences (P < 0.01) in the 205-day,

12- and 18-month weights due to the influence of the different breed

groups. With the exception of year, breed group was the largest source

of variability in the 205-day weights. Since one of the primary objec-

tives of crossbreeding is to increase weaning weights, this variability

created by breed groups would be expected if the breeding programs under

consideration were successful. The results of this study clearly point

out that increased weaning weights can be obtained through the use of

crossbreeding progroansinvolving Angus, Brahman and Devon cattle at the

Everglades Experiment Station. Even though this is true, careful con-

sideration should be given to other important factors before a cross-

breeding program is used in an economic enterprise. Certainly the

reproductive rate should be considered since it probably influences

economic return more than any one single factor.

All of the crossbred groups in this study involved the Brahman

breed of cattle. This means that rate of reproduction should be evaluated

even more critically because most evidence indicates that the rate of











reproduction in Brahman cattle may be lower than in some of the other

breeds. Also, there is the possibility of partial genetic incompatibility

between the Brahman and European breeds of cattle as far as reproduction

is concerned (Koger, 1960). Other very important factors to be con-

sidered are the practical limitations of crossbreeding programs.

The relative influence of breed group on 205-day, 12- and 10-

month weights is shown in figure 1. At 205 days of age, all of the pure-

bred groups were lighter than any crossbred group. For the Brahman and

Angus groups, this held true at 12 and 18 months of age. However, the

Devon heifers were heavier than the inter-se heifers at 12 and 18 months

of age and heavier than the Brahman-Angus backcross heifers at 18 months.

It is interesting to compare the Fl's and backcrosses at different

ages. At 205 days of age, the Brahman-Angus and Brahman-Devon backcross

calves were the two heaviest breed groups. However, at 12 and 18 months

of age they were considerably lighter than their respective FI breed

groups. Since these calves from F1 dams were heavier at weaning but

were lighter at later ages, it seems plausible to state that the F1

cattle expressed hybrid vigor in the form of growth potential and milking

or mothering ability.

In general, the Brahman-Devon inter-se cattle did not perform

as well as the Fl, backcross and rotation-cross breed groups. A pos-

sible explanation for this is the loss of hybrid vigor in the inter-se

mat ings.

With the exception of the Brahrman-Devon FI and backcross groups,

the Brahman-Devon rotation-cross cattle were the only breed group whose

weights were above the mean of the population at all ages. Considering


















B-D F1


.......... .-D tat


1 \ B1-A ck





1--D Interse


.- '

*-*-
-r


Angus
0*oinm -mu -ia roll o m,em m l l


r- I
(iD


00
I -r-I


Figure 1. Relative influence of breed group on 205-day,
12-month and 13-month weights.


-25







-50







-75


A 2I











only the weights of the different breed groups and the practical aspects

of the different breeding program involved, the Brahman-Devon rotation-

cross cattle may possibly be one of the best breed groups in this popula-

tion from an economic viewpoint.

The regression coefficients obtained from the post-weaning analysis

point out one interesting fact. Age differences within a breeding season

do not influence the 13-month weights of heifers very much. This is

indicated by a partial regression coefficient of 0.27 pounds for the

regression of 18-month weights on age at weaning. If the same situation

prevails in beef cattle under other conditions, care should be taken in

the interpretation of the commonly used measurement "weight per day of

age."















SUISARY


Estimates of the factors which influenced the 205-day, 12- and

18-month weights of the Everglades Experiment Station beef cattle popula-

tion were obtained using the method of fitting constants by least squares.

This population contained Angus, Brahman, Devon, Brahman-Angus and

Brahman-Devon cattle. The 205-day weights of 933 calves and the 12-

and l1-month weights of 415 heifers were included in the analyses. The

records covered the ten-year period from 1950 through 1959.

There was tremendous variability in the year effects. The ranges

in year effects were 145 pounds for 205-day weight, 166 pounds for 12-

month weight and 215 pounds for 18-month weight. All of the significant

first-order interactions were involved with year.

Bull calves were 11 pounds heavier than steer calves and 32 pounds

heavier than heifer calves at 205 days of age.

The heaviest calves were produced by cows which were six to 11

years old while the lightest calves were produced by cows which were

two years old. Calves from cows 2, 3, 4, 5 and 12 through 17 years old

were lighter than calves from cows six through 11 years old by 46, 26,

6, 12 and 5 pounds, respectively.

There w-is a significant influence of month of birth on 205-day

weights. Calves born during the months of December through June were

heavier than November calves by 7 pounds and July through October calves

by 18 pounds.











The effects of lactation status were not significantly different.

However, there was a significant (P< 0.05) interaction between lactation

status and year.

All of the purebred breed groups were lighter than any of the

crossbred groups at 205 days of age. For the Brahman and Angus groups,

this held true at 12 and 18 months of age. However, the Devon heifers

were heavier than the inter-se heifers at 12 and 13 months of age and

heavier than the Brahmarn-Angus backcross heifers at 18 months.

The Brahman-Angus and Brahman-Devon backcross calves were the two

heaviest breed groups at 205 days of age. At 18 months of age, the

Erahman-Angus and Brahmian-Devon F heifers were the heaviest breed groups.

With the exception of the Brahman-Devon FI and backcross groups, the

Brahman-Devon rotation-cross cattle were the only breed group whose

weights were above the mean of the population at all ages. The Brahman-

Devon inter-se cattle did not perform as well as the Fl, backcross and

rotation-cross breed groups.

Partial regression coefficients of 0.77 and 0.27 pounds were

obtained for the regression of 12- and 18-month weights on age at weaning,

respectively.




































APPZIIDX














Table 14.-- IGCLAL LEAST SCUARED'S UATIOTNS


u 0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9


u : 933
YO: 49
Yi: 67
Y2 : 79
y3: 115
y4: 60
Y5: 107
Y6: 99
Y7: 141
y : 140
Y9: 56
bl: 143
b2: 67
b3: 171
b4: 34
b5: 51
b6: 82
byo: 106
bc : 102
bg: 177
a1: 61
a,: 200
a3: 155
a4: 151
a5: 333
a6: 33
SI: 281
s3: 173
s : 479
mi: 366
m2: 249
m3: 316
lI: 497
12: 436


49 67 79 115 80 107 99 141 140 56
49


115


141


16 25 30
2 7 11
21 25 12
1
7 11 12
7 6 5
5 14
17 21 20
27 41 35
3 15
24 24 36
12 34 24
23 15 23
33 48 54
4 5 3
41 5 78
2 65
56 71 62
43 35 39
34 61 26
22 45 75
54 70 99
45 71 41












Table 14 (continued)


b b b3 b4 b b b b 9


34 51 82
5 20
7 19
2 6
8 9 15
7 1 4
6 4
7 7
11 6
1 12 5
5



34
51
82


106
7
14
23
22
11
5

5
14
5


102



6
12
19
17
21
20
7


106
102
177
6 9 11 16 4 15
36 16 36 2 13 1 31 18 47
22 6 20 4 10 6 15 29 43
19 12 21 6 9 18 17 16 33
45 33 74 18 8 57 25 34 39
15 11 4 2 1
60 24 53 7 17 19 27 32 42
18 6 32 9 10 14 25 20 39
65 37 86 18 24 49 54 50 96
51 28 70 12 23 24 44 45 71
57 10 43 12 14 30 26 12 45
35 29 58 10 14 28 36 45 61
89 33 78 16 24 54 63 55 85
54 34 93 18 27 28 43 47 92


143
4
1
11
7
17
14
18
25
30
16
143











Table 14 (continued)


al P2 a3 a4 a a El s s5
a1 a2 35 26


61 200
3 9
5 10
13 11
17 24
24
5 13
3 24
15 24
36
25
6 36
16
9 36
2
11 13
1
16 31
4 18
15 47
61
200




11 71
26 26
24 103
44 74
10 49
7 77
35
61 165


155
6
9
7
14
7
31
12
34
24
11
22
6
20
4
10
6
15
29
43


155



38
46
71
57
45
53
91
64


151
16
10
12
11
13
15
23
15
23
13
19
12
21
6
9
b1
17
16
33



151


45
16
90
64
39
48
103
48


333
15
33
33
42
31
37
33
48
54
7
45
33
74
18
8
57
25
34
39




333

106
54
173
115
96
122
242
91


33 281
13
22
3 35
7 17
5 16
6 28
4 41
5 5
3 78
24
15 60
24
11 53
4 7
17
19
2 27
1 32
42
11
71
38
45
106
33 10
10 2-1


102
68
111
15E
123


173
2
8
6
43
25
22
2
65


18
6
32
9
10
14
25
20
39
26
26
46
16
54
5

173

81
55
37
85
8W-


479
34
37
38
55
37
57
56
71
62
32
65
37
86
18
24
49
54
50
96
24
103
71
90
173
18


479
185
126
168
254
225











Table 14 (continued)


1 1 m n3 1 12 I


368
14
25
56
54
42
41
43
35
39
19

28
70
12
23
24
44
45
71
44
74
57
64
115
14
102
lo2
L1
185
366


199
169


249
26
15
10
30
15
25
34
61
26
7
57
10
43
12
14
30
26
12
45
10
49
45
39
96
10
68
55
126

249

126
123


316
9
27
13
31
23
41
22
45
75
30
35
29
58
10
14
28
36
45
61
7
77
53
48
122
9
111
37
166


316
172
144


497
16
37
42
62
51
36
54
70
99
30
89
33
78
16
24
54
63
55
85

35
91
103
242
26
158
85
254
199
126
172
497


436
33
30
37
53
29
71
45
71
41
26
54
34
93
18
27
28
43
47
92
61
165
64
48
91
7
123
88
225
169
123
144

436


340,789
19,878
23,726
29,012
41,166
31,721
43,636
40,843
53,969
3),364
16,454
45,223
21,934
60,624
12,657
20,479
33,130
40,463
40,596
65,483
22,089
69,104
5E, 318
55,671
123,857
11,750
102,418
67,758
170,613
137,610
90,247
112,732
1-0,171
160,61


---- --













Table 1,. --fVERSE OF REDUCED COi: :CL! T :AT:.I:D7


Y0 Y1 Y2 Y3 Y4 Y5


yo: .207126 -.00737 -.01352 -.017593 -.029396 -.024643
yi: .147307 -.309012 -.009006 -.019945 -.o01341
Y2: .130372 -.008557 -.0163.1 -.013958
Y3: .090040 -.006315 -.007476
Y4: .120971 -.)091l01
Y5: .097266
Y6:
y7:

bly
bo:
b3:
b 5:
b(:

bc:
b9:
al:
a2:
a4:

cl:
s5:

mn:




a
Symmetric .atrix.
Inverse of corrected sum of squares and crossproducts.
Values in table are actual values divided by 10.













Table 15 (continued)


Y6 7 Y8 bl b2 b3 b5

-.022348 -.025341 -.026596 .012222 .000565 .001234 .020518
-.019904 -.019765 -.o1 943 .01o176 -.0001D7 -.005710 .017283
-.013687 -.018210 -.01150 .00186 .0130C -.006457 .008594
-.001146 .001705 -. 009907 .3,221 .003319 -.000879 -.003140
-.001106 -.003501 -.007231 -. )'162 .005135 .005972 .003462
-.005804 .002277 -.003'972 -. 30 07 -. 004111 .002160 .002985
.101362 -.004854 -.000177 -.003515 .007774 -.002479 -.008940
.088716 -.o00487L -.00662 -.000482 -.000520 -.011577
.0.-2104 -.006114 .001444 .006125 -.012592
.077159 -.012082 -.000994 -.011084
.136038 -.007661 -.028184
.062045 -.017001
.161293












Table 15 (continued)


b6 27 b b a a 2a3

-.045771 -.002347 .016208 .019182 -.005705 .002531 -.002950
-.027235 -.008983 .017805 .016532 -.010982 .300559 -.003092
-.000476 -.020689 .012764 .008395 -.013933 .007878 .002677
-.003821 -.oo3884 .005485 .00o193 -.010563 .300843 .006697
.010941 .000353 -.006770 -.003146 .012694 -. 307781 .006907
.018611 .005336 -.009916 -.009729 .013375 .012567 -.007581
.006894 .010824 -.013114 -.011252 .005837 -.001090 .003209
.013753 .011478 -.012005 -.012104 -.002086 .003718 .000286
.013o38 .002497 -.006733 -.009322 .005321 -.004757 -.001366
-.016111 -.005943 -.002171 .002989 -.001184 -.300659 .003850
-.014052 -.013173 -.013895 -.010659 .011735 -.004641 .000777
-.003895 -.003530 -.005019 -.000913 .008520 .000996 .002703
-.035263 -.017285 -.012973 -.005395 -.030934 -.002120 -.000389
.135222 -.009499 -.020978 -.017818 .015146 .006573 .001836
.098140 -.012974 -.005089 -.016733 -.008631 .002953
.100624 .004666 -.000932 .000509 -.009891
.066826 -.008922 -.005057 -.005893
.167941 -.006960 -.022807
.064634 -.002839
.067073














T-ble 15 (continued)


A A A A A
a4 a5 s1 s5 3 1

-.010636 .005841 -.003384 -.005694 .002349 .007414 .005833
.001732 -.000542 -.003473 -.001349 -.000836 -.001332 -.000565
.003302 -.001169 -.00L599 -.000500 -.001069 .005455 .000500
.00803 .002621 .009527 .003153 -.000695 .000946 -.001994
.o00286 -.003006 .00733 8i .003873 -.00374C .000302 -.002870
.000369 -.004699 .003071 .000470 .000937 -.002030 .007577
-.003711 -.000731 -.006041 -. 002191 -.000491 .304433 -.000561
.004802 -.001145 .017772 .003630 .00~291 -.001057 .000053
.000569 -.002527 -.010756 .001053 .003351 -.006662 -.004782
.007580 .007495 -.005046 .00733 .0o0044 .305272 -.002799
-.005150 -.008426 -.001768 -.001302 -.001659 -.oo2627 .002066
.002186 -.003076 -.000399 .000791 -.000494 -.000642 .002603
.002711 .012559 -.3 03158 -.000502 -.001: 5 .002866 -.002251
-.006620 -.017392 .003875 -.000142 .003117 -.001749 .000492
.003358 .009540 .003797 .000130 .00'328 -.001476 -.005727
-.000519 .000934 -.001925 .000062 -.003947 -.002922 .000525
-.001731 .006554 .000697 -.001449 -.001377 .000420 -.000576
-.003022 -.029371 .004351 .00' 10 -.009395 .003367 .017911
-.003471 -.001230 -.002436 -.000513 .000906 -.001313 .011865
-.ooo00 6 .004428 .003152 .D02359 .002415 -.000285 -.003842
.069369 .007765 -.000575 -.302437 .000921 .000133 -.006581
.048407 -.001668 -. 00987 .003754 -.001176 -.0 0700
.032351 -. 04597 .002224 -.0302210 -.000134
.020650 .000411 -. 001O' .000246
.022868 -.009693 -.001600
.024046 .000276
.016677

















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LITERATURE CITED


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59



Warwick, E. J. 1950. Summary of some performance items of Brahman
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BIOGRAPHICAL ?'il.TCil


James H. Meade, Jr. was born November 1, 1932, at Vicksburg,

Mississippi. He graduated from Jett Vocational High School in

1950. In May, 1954, he received the degree Bachelor of Science

in Agriculture from i ississippi State University. After serving

two years in the United States Army, the author returned to

Mississippi State University where he received the degree Master

of Science in Agriculture in January, 1959.

The author is now a candidate for the degree Doctor of

Philosophy at the University of Florida.


















This dissertation was prepared under the direction of the chairman

of the candidate's supervisory committee and has been approved by all

members of that committee. It wis submitted to the Dean of the College

of Agriculture and to the Graduate Council, and was approved as partial

fulfillment of the requirements for the degree of Doctor of Philosophy.



June 5, 1961




Dean, College of Agriculture



Dean, Graduate School


Supervisory Committee:


Chaila mr

A- tax



/y~y^^JT"






AGR-
CULTURAL
LIBRARY














































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