A Summary of

Reported Estimates of Heritabilities

and of

Genetic and Phenotypic Correlations

For Traits of Chickens

OCT 3 0 1969

CURRENT SERIAL BECÛRDS

Agriculture Handbook No. 363

Agricultural Research Service

U3N^ITEI> ST^^ES DEPARIME^T OF AGRICULTURE
A Summary of

Reported Estimates of Heritabilities

and of

Genetic and Phenotypic Correlations

For Traits of Chickens/,

Agriculture Handbook No. 363

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE

O Wa8hmgton,,D.C. Issued October 1969,

For sale by the Superintendent of Document«, U.S. QoYMimuait Printing;pffi««,

Washington, D.C. 20402 - Pri<J 5& cents V^^ ^ //
Contents

Page

Introduction1

Methods of summarization2

Discussion of summaries3

Heritability estimates3

Genetic and phenotypic correlations estimates 32

General conclusions 39

References 39

Unpublished materials 49
A««J^OOv>

A Summary of Reported Estimates

of Heritabilities and of

Genetic and Phenotypic Correlations

For Traits of Chickens

.Or, «By TEHET B. KINNEY, Jit., aooiatamt-direeéeVr-Ammftl-liusbnndry ResBäfcH ÜivííTón,'

Agricultural Research Service

INTRODUCTION

Definitions, methods of estimation, and biases

associated with heritabüity estimates have been

presented in considerable detail by Lush {112),

Lemer {105), Dickerson {32), Falconer (57)/ and

others. The methods that have been most commonly used to estimate the heritabilities of

various traits observed in chickens are:

(1) Ca^üThalf-sib correlation [^o^^V

(2) Maternal half-sib correlation [4(Td/o"p],

(3) Full-sib correlation [2 (^+a'|)/ö-|],

(4) Parent-offspring regression [(TOP/^¿]í and

(5) Realized heritabüity [R/S]. ^

Where:

ig and o-^f are the estimated sire and dam

components of variance, respectively,

cr^ is the phenotypic variance,

iop is the parent-offspring covariance,

R is the estimate response to selection, and

S is the selection differential.

The estimation methods that have been used

by most researchers have been determined by

the mating system of the chickens, the trait of

interest, or m some cases, unfortunately, the

availabihty of computer programs.

The hierarchal mating system has been the

most commonly used method of propagation in

poultry breeding studies. Thus, a major part of

the heritability estimates reported in the literature have been obtained by methods (1), (2),

and (3). Estimates based on any of these three

methods will be biased upward if epistatic variance is important. In any case (1) is expected to

be less biased than (2) because of the confounding

of maternal effects or dominance variance with

the dam component of variance in the hierarchal

mating structure. Obviously, (3) is expected to

be intermediate between (1) and (2) in value and

amount of bias.

1 Italic numbers refer to References, page 39.

The least biased heritability estimates and the

best estimates of effective heritability are probably obtained from (4) and (5) although (5) has

been little used for the estimation of heritability

of traits of chickens.

Heritability estimates are of value because they

are an estimate of the proportion of phenotypic

variance that is additiveiy genetic and thus serves

as an indication of the rate of improvement that

might be realized by selection. Perhaps more

importantly, the estimates are of value in making

decisions regarding the type of mating system that

will allow the greatest or most rapid improvement,

or both. For example, if a trait is highly heritable,

the most economical and rapid improvement will

likely be made through mass selection. If a trait

is lowly heritaole, some form of family selectioa or

progeny testing, or both, will likely be more

effective than mass selection.

Although heritability estimates permit one to

predict the amount of gain expected from a given

amount of selection, the accuracy of prediction is a

direct function of the accuracy of the heritability

estimate. For this reason an estimate of the heritability of a trait in one population of chickens may

or may not be a reliable parameter estimate to use

for prediction of gain due to selection in a genetically different population. For any trait an average

of heritability estimates from many populations is

useful only to categorize expected gain in another

population as large, medium, or small. Thus, if one

is interested in predicting genetic gain in a specific

population as accurately as possible, then he must

estimate the heritability from the population for

which prediction is to be made. It seems apparent

that heritabihty estimates as such are of little

value except as they contribute to an average that

is itself useful only to categorize heritabüity as

high, low, or medium for various genetic types of

populations; for example, light breeds or heavy

breeds.
AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

Early attempts to determine the genetic relationships among traits were restricted by lack of

appropriate statistical methods for separating the

genetic and environmental portions of phenotypic

correlations. In 1943 Hazel {67) developed a

method of calculating the genetic correlation

among traits. Since that time, many estimates

of the genetic correlations among various traits

of poultry have been published. Smce the genetic

correlation is a function of the covariance and

respective variances of two traits, it is subject

to the same sources of bias mentioned earlier

with regard to variance component estimation.

Genetic correlation estimates quantitate the

extent to which two traits are controlled by the

same genes. The estimates permit one to predict

the correlated response of one trait to selection

for a different trait. However, as clearly indicated

by the work of Bohren, Hill, and Robertson (ÍS),

prediction of correlated responses to selection

beyond a single generation is likely to be highly

inaccurate without some prior knowledge of the

magnitude and composition of the genetic covariance. This finding implies that highly accurate

estimates of the genetic correlation within a population are necessary to accurately predict correlated responses even for a single generation.

Thus it seems logical to conclude that genetic

correlation estimates as such are of little value

except as they may be used in the population

in which they are estimated.

An average of genetic correlation estimates

from different popiüations is probably of value

only as an indicator of the expected genetic correlation between two traits. It should be kept in

mind that, depending on the trait, the individual

estimates can vary from large negative to large

positive in different populations or even within

the same population during different generations

of selection.

The summaries contained herein will serve as a

reasonably complete review of the literature to

the present time. It is virtually impossible to

summarize aU estimates of heritabilities or genetic correlations because many have been published only in theses, progress reports, or other

publications that are not readily accessible. A

request for references was addressed to at least

one researcher at all experiment stations throughout the United States and a number of references

were obtained from them. Many of the publications reviewed did not report specific estimates

but rather indicated the approximate magnitude of

the estimate. These reports were not used.

METHODS OF SUMMARIZATION

The heritability estimates as reported in the

literature have been listed by traits in tabular

form indicating the method of estimation, the

number of sires and dams, the breed or cross, and

sex when pertinent. When two or more estimates

were obtamed by the same method, in the same

population, the estimates were averaged unless

standard errors were reported. If standard errors

were reported, aU estimates and the standard

errors were tabulated. Reported estimates of

genetic and phenotypic correlations were averaged

and the average value is presented in tabular

form. When pertinent, an average of tabulated

values of heritabilities was calculated and included in the tables; for example, average of

reported estimates of the heritability of 8-week

weight of males.

Heritability estimates are summarized in tables

1, 2, 3, and 4. Genetic and phenotypic correlations

are summarized in table 5. Definitions and abbreviations of terms used in the discussion of the

summaries and in the tables are as follows:

Trait—Continned

Feed consumption.

Feed efficiency

Trait

... Pounds of feed consumed.

. - - Pounds of feed per

pound of gain.

Survivor production. _

First n months or

days.

S.M

To December 31 or

some other time.

Annual production.

Hen housed production.

Egg mass

Early egg weight

Matiure egg weight.«

Hen day production.

LH_.

FSH.

Number of eggs laid by

surviving heiis.

Number of eggs laid in the

first n months or days

after sexual maturity

(usually early fall).

Sexual maturity.

Number of eggs laid or

rate of production

from sexual maturity

to that time.

Number of eggs laid in

1 year.

Number of eggs laid by

all birds housed.

Total weight of eggs.

Egg weight taken during the first 2 to 3

months of lay.

Egg weight taken after

3 months of lay.

Production estimate

based on number of

hen days.

Leuteotropic hormone.

Follicle stimulating

hormone.
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS

Breed

A Australorp.

AC Athens Canadian randombred.

ARB Athens randombred.

BL Brown Leghorn.

BIC Black Castelana.

BR Barred Rock.

C Combined sexes.

Cross Undesignated cross.

D Durham.

F Fayoumi.

G Gatinaise.

Heavy Undesignated heavy

breed.

Inbred A strain specified as

inbred.

J Jungle fowl.

Light Undesignated light

weight breed.

Mix Several strains or breeds.

Nag Nagoya.

NH New Hampshire.

Ot Ottawa control.

RIR Rhode Island Red.

S Sussex.

SO SUver Oklabar.

Syn Synthetic line.

WC White Cornish.

WG White Gold.

WL White Leghorn.

WR \\liite Rock.

WW White Wyandotte.

X's Refers to crosses; for

example, WLX'smeans

several White Leghorn

crosses.

Breed—Continued

's Denotes plural; for example, WL's means

White Leghorn lines.

* Indicates an unselected

line.

(in stub column Indicates breed or cross

of table). not reported.

— (in field oí Indicates no data

table). available.

Heritability

S Refers to estimation by

paternal half-sib

correlation.

D Refers to estimation by

maternal half-sib

correlation.

S+D Refers to estimation by

fuU-sib correlation.

bop Refers to estimation by

parent-offspring

regression.

Real Refers to realized

heritability.

Degree of Freedom

S Refers to approximate

degrees of freedom,

for sires.

D Refers to approximate

degrees of freedom

for dams.

Ref Refers to the number

of the reference in

the list of references.

DISCUSSION OF SUMMARIES

Heritability Estimates

Table 1 is a sununary of reported heritabihty

estimates of body weight, weight gain, feed consumption, feed eflSciency, conformation, market

quality traits, and pigmentation.

There are few reported estimates of the heritabihty of body weight before 4 weeks of age. Although there is wide variation in some of the

individual reports, the averages of estimates

indicate that if there are any differences in the

heritability of body weight at 4 weeks of age or

later, they are small. There is no strong evidence

for a difference in sexes or in light and heavy

breeds as far as the magnitude of the heritability

is concerned. There is, however, a strong indication

of either maternal or dominance effects, or both,

up to maturity. The presence of either or both of

these effects is evidenced by the rather consistently

higher average estimates from the maternal halfsib correlations as opposed to paternal half-sib

correlations for body weights before pullet age.

Although some individual estimates indicate the

possible existence of either important maternal or

dominance effects, or both, for pullet and mature

body weights, the averages of estimates indicate

no importance of these effects.

Weight gain heritabihty appears to be similar in

magnitude to body weight heritability (0.35 to

0.53) based on averages of three reports. Estimates by a single investigator indicate that feed

consumption is highly heritable (greater than

0.50). The heritability of feed efficiency is much

lower (0.39 or less). The heritability of feathering

traits, breast angle, body depth, keel length,

dressing percent, and shank pigmentation apparently fall within the approximate range of 0.25
4 AGRICULTURE HANDBOOK 3'6'3, U.S. DEPT. OF AGRICULTURE

to 0.40. Heritability estimates of shank diameter provide a reasonable expectation for this paramand weight/shank length, based on a single report, eter. For all other traits reported in table 1

are about 0.60 and 0.50, respectively. there are too few reports to serve as reliable estiTable 1 summaries indicate that there have mates of the heritabilities, but these traits all

been sufficient reports of the heritability of body appear to be quite highly heritable (in the approxiweights from 4 weeks of age through maturity to mate range of 0.25 to 0.60).

TABLE 1.—Reported heritability estimates of body weight, weight gain, feed consumption, feed efficiency,

conformation, market quality traits, and pigmentation, by age, breed, and sex of chickens

Heritability estimate Degree of

Trait, age, and breed of Sex freedom Ref.

chicken - _______^___^____

S D S+D bop ReaL S D

BODY WEIGHT

2-week embryo: Meat cross — 0.18 — — — — 40 320 20Í

2 weeks:

NH cf

NH 9

3 weeks: RIR C

4 weeks:

WL cf

WL cf

WR cf

WR cf

NH d^

NH cf'

NH <f

DXNH d"

DXNH cf

Mix cf

Average —

WR 9

WR 9

NH_._ 9

NH 9

NH 9

DXNH 9

DXNH 9

Mix 9

Average —

6 weeks:

NH d^

NH cf

Ot* cT

Ot* d^

DXNH d^

DXNH d^

Average —

NH 9

NH 9

Ot* 9

Ot* 9

DXNH 9

DXNH 9

Average —

.05 — 0.40 — — 8 66 35

.01 — .44 — — 8 66 36

— — .31 — — 24 71 Í26

.29±. 63 _ _ _ _ 40 fiOO 10

.21±. 44 — — — — 40 600 10

— — .47 — — 64 380 167

— — .43 — — 32 192 168

.75 0.74 — — — 56 218 183

.58 .45 — — — 25 125 43

.54 .32 — — — 25 125 AS

. 19 .72 — — — 45 400 138

.20 .81 — — — 45 400 138

. 66 — — — — — — U

.43 .61 .45 — — —

— — .47 — 64 380 167

— — .53 — — 32 192 168

.53 .96 — — — 56 218 183

.19 .98 — — — 25 125 43

.35 1.01 — — — 25 125 43

.31 .81 — — — 45 400 138

.20 .99 — — — 45 400 138

.25 — — — — — — 74

.31 .95 .50 — — — — —

.09 32 8 66 33

.50 .83 — — — 56 218 183

.39±. 07 .92±.07 — 0. 51±.03 — 395 1,128 129

— — .74 — — 240 675 130

.24 .72 — — — 45 400 138

.28 .78 — — — 45 400 138

.30 .81 .53 ,51 — — ' — —

.65 1.02 — — — 56 218 183

. 18 — .32 — — 8 ,66 35

.46±. 07 .61±.08 — .45di.03 — 395 1,128 129

— — .64 — — 240 675 130

.36 .65 — — — 45 400 138

. 27 .84 — — — 45 400 138

.38 .78 .48 .45 — — ' — —-
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 5

TABLE 1.—Reported heritability estimates of body weighty weight gaiuj jeed consumption^ feed eßxiiency,

conformation, market quality traits, and pigmentation, by age, breed, and sex of chickens—Coiúumeá

Trait, age, and breed of

chicken.

Sex

Heritability estimate

D S+D ReaL

Degree of

freedom Ref.

D

BODY WEIGHT-^Con.

6 weeks—Continued

NH C

RIR C

ot* c

Average —

8 weeks : WR cf

WR d^

WR cf

WR d^

WR d^

WR d^

WR d"

NH d"

NH d"

NH d»

NH d»

NH d"

NH d"

Syn d"

Syn d^

Syn d*

Syn d"

Syn d"

Syn d«

DXNH d«

DXNH d'

Mix d^

dd"

d"

Average

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL* 9

WR 9

WR 9

WR's 9

WR 9

WR 9

WR 9

WR 9

WW 9

NH 9

NH 9

NH 9

NH 9

NH 9

NH 9

NH 9

RIR 9

RIR* 9

BR 9

Syn 9

Syn 9

,51 .98 —

29

40±.05 .72±.05 ' — .46±.02 —

.46 .85 29 46

64

29

.25

.01

.07

.26

.28

.55

. lli.Ol

.48

.36

. 24±.07

. 36±.08

.39

. 20

.65

.69

.47

.32

34

60

. 13

.54

.34

. 15

.86

1. 07±.25

.52

.25

.52

. 65

.57

,85

. 16

.75

.63

.49

.44

.26

.32

22

.35±.09

.05±.22

0.31

.30

.31

. 63±. 10

.45

.37±.04

.33±.03

— .38 .50 ,50 .26 31

. 52±.05

. 26±.31

. 48±.09

. 43±. 10

. 66±.93

. 41±.68

,29

,22

12

. 25±.09

.21

.06

. 16

. 35

. 15

.88

. 34±. 55

. 50±. 09

, 69±.39

69

35

58

.77±. 10

.36

. 95

.03

.63

.63

.69

. 28±. 66

, 10

,82

,42

,35

63

14

36

. 51±.12 —

,27

,27

, 15±.04 .69di.l3

.33

33

!39±.05

.49

. 65±. 14

. 23±.12

56 218 183

24 71 126

395 1, 128 129

32

36

64

64

32

25

25

8

106

106

56

109

115

120

44

45

45

160

160

20

192

161

380

380

192

125

125

66

218

756

450

405

428

400

400

160

160

164

188 728

100 500

684 2, 364

684 2, 364

40 600

40 600

300 1,500

60 260

71

64

64

32

46

8

25

25

9

128

128

56

100

273 1,825

18 85

318

380

380

192

232

66

125

125

48

218

500

9

9

164

171

165

167

168

45

45

35

53

53

183

41

97

97

202

138

138

7k

83

83

15

109

75

769

500

96

96

9

9

H

186

153

10

ms

165

10

167

168

62

35

43

4S

79

53

53

183

207

95

79

41

85
6 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 1.—Reported keritability estimcUes of body weight, weight gain, jeed consumption, jeed e^ciency,

conformation, market quality traits, and pigmentation, by age, breed, and sex of chickens—Continued

Trait, age, and breed of

chicken

Sex

Heritability estimate

D S+D Real.

Degree of

freedom

S D

Ref.

BODY WEIGHT—Con.

8 weeks—Continued

Syn 9

Syn 9

Syn 9

Mix 9

Mix 9

Mix 9

DXNH 9

DXNH 9

RIRXWL 9

WLXRIR 9

9

Average —

F C

WR C

WR C

NH C

NH C

NH C

NH C

Mix C

Cross C

Average —

9 weeks:

WR cf

NH cf

NH cf

Ot* d^

Ot* cf

SO d^

SO cT

Average —

NH 9

NH 9

Ot* 9

Ot* 9

SO 9

SO 9

Average —

NH C

NH C

NH C

RIR-. C

Ot* c

NH C

NH C

NH C

Average —

10 weeks:

WW 9

NH 9

NH 9

Mix 9

Average —

.37 .53 .42 — — 44 428 202

,24±.06 — — .33d=.04 — 110 440 97

.31±.09 — — .22±.04 — 110 360 97

.51 — — — — — -— 74

— — — .31 — 193 980 117

— — .46 .40 — 159 609 197

.65 .57 — .— — 45 4Ö0 138

.68 .94 — — — 45 400 138

.95i. 34 . 64±. 35 — — — 100 500 207

.20±.34 .89±.40 — — — 100 500 207

.55 — — — — 20 164 15

.39 .61 .42 .36 .27 — — —

.67 .84 .76 — — 70 488 6

. 21 .58 .39 .29 .29 64 380 166

— — .20

.34

— — 64 380 167

.49±.13 122 __ i

.36±.22 — — — — .— 122

. 64 . 85 — — — 56 218 183

.35 — — — — 59 457 Â5

— — L25 — — 220 220 176

.45 .76 .59 .29 .29 — — —

.63 50 1Ö9 172

. 17 .45 . 31 .35±. 17 — 12 120 48

. 16 .55 .35 . 28d=. 04 — 15 156 61

— — .73 — — 240 675 130

.40±.06 .81±.08 — .56±.03 — 395 1, 128 129

.54 .72 .63 .49±. 17 — 14 110 48

.63 .49 .56 .20±.08 — 10 98 61

.38 .60 .54 . 38 — — '— —

.13 .96 .54 .55±.13 — 12 no 48

.23 .65 .44 .36dz.04 — 15 1:58 51

— — .58 — — 240 675 130

.44±.06 .49±.07 — .49±.03 — 395 1, 1:28 129

.38 .45 .41 .47±.16 — 14 110 48

.56 .42 .49 . 20±. 07 — 10 ^6 61

.35 .59 .49 .41 — — — —

. 28 .65 . 48 . 22±.04 10 129 61

.28 .52 .40 .49±.03 — 12 131 61

.08 .74 .41 .34±.03 — 12 140 61

— — .27 — — 24 71 126

.40db.05 .62±.05 — .52±.02 — 395 1,128 129

.30 .51 .41 .34±.03 — 8 -87 61

.41 .80 . 60 .50±.06 — 8 67 61

.45 .51 .48 .37±.05 — 9 86 61

.31 .62 .4.4. .40 — — — —

.36 .91 .63 8 545 206

.24 — .47 — — 8 66 36

.94 .60 — — — 56 218 183

— — .46 .33 — — ;— 101

.51 .76 .52 .33 — — :— —
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS

TABLE 1.—Reported heritabUity estimates of body weight, weight gain, jeed consumption, jeed efficiency,

conformation, market quality traits, and pigmentation, by age, breed, and sex oj chickens—Continued

Heritability estimate Degree of

Trait, age, and breed of Sex freedom Ref.

chicken

S D S+D boD Real • S D

BODY WEIGHT—Con.

10 weeks—Continued

NH .- & .09 — . 33 — — 8 66 S6

NH

_ C

.45 .78 — — — 56 218 183

Average .27 .78 .33 — — — — —

NH .62 .29 .45 10 100 n

NH _ C .56 .81 — — — 56 218 183

RIR _ c .29 — .38 . 15±.08 — 18 140 U9

SO . c .50 . 17 .34 — —. 10 100 21

NHXSO - c .45 — — — — 82 440 19

NHXSO _ c .65 .31 .48 — — 10 100 21

SOXNH - c .69 .35 .52 — —, 10 100 21

Average .54 .39 .43 , 15 — — —

12 weeks:

WL . 9 .43±.. 10 .57±..08 .50 — — 105 300 23

WL - 9 .73±., 13 .58±,.09 .66 —. — 105 300 23

WL - 9 — — — .44 80 305 36

WL - 9 — — .35 —. — — 165

BIC . 9 — — — . 34 — — — 156

F - 9

. C

— — — . 54 — — — 156

Average .58 .58 .58 .41 .44 — — —

NH .38 , , , . 8 85 3

NH _ C .42 .60 .51 — — 8 29 106

RIR . c —, — .31 — — 24 71 126

SO . c .

.34±. 03 160 1, 150 12Jf.

SO . c —, — — — .07±. 05 160 1,150 124

so _ c — — —, — .45±. 03 240 1, 725 123

so _ c

_ c

— — — — .17±. 05 240 1,725 123

Average .40 .60 .41 — .26 — — —

16 weeks: Heavy Cross .47 — — 192 192 176

21 weeks: Ot* - cf — — .61 — — 240 675 130

24 weeks:

Heavy Cross . c —. — .52 — — 144 144 176

Pullet (light) : WL - 9 .67±. 03 — — — — 436 1,897 203

WL - 9 .40±. 09 .57±. 08 .48 — — 105 300 23

WL - 9 .69±. 13 . 56±. 09 .63 — — 105 300 23

WL - 9 .28±. 08 .64±. 09 .46 — — 105 300 23

WL - 9 .74+ . 13 .57±. 09 .65 —. — 105 300 23

WL . 9 — .48±.06 —. —, 230 2,270 AO

WL - 9 — ,—, — .43±. 04 115 1,135 AO

WL* . 9 .32 .52 . — 168 559 68

WL* - 9 .48 .89 — —, 300 1,500 H

WL* . 9 .86±. 11 —, — — 340 1,200 96

WL* - 9 .41±. 09 — — — 340 1,200 96

WL - 9 . 86±. 34 .17±. 38 — — 100 500 207

WLX's - 9 .29 ,41 — 464 3,036 31

WLX's - 9 .61 — .43 —. 501 4,769 73

BL - 9 .37±. 09 .34±. 14 — — 65 660 63

BLXS - 9 .71±. 13 . 45±. 12 — — 65 660 63

SXBL - 9 .55±. 12 .74±. 13 — —. 65 660 63

WLXRIR - 9 .69d=. 31 .06±. 30 — — 100 500 207

RIRXWL - 9 .78±. 32 .30±. 34 — — 100 500 207

Mix - 9 — .31 .18 159 609 197

Mix - 9 — -~ .43 .32 — — 101

Average .57 .48 .48 .25 .43 — — —

036-740—69-
8 AGRICULTURE HANDBOOK 36i3^ U.S. DEPT. OF AGRICULTURE

TABLE 1.—Reported heritabüity estimates of body weighty weight gain, jeed consumptiorij feed efficiencyy

conJormatioUf market quality traits, arid pigmentatiorij by age, breed, and sex of chickens—Continued

Trait, age, and breed of

chicken

Sex

Heritability estimate

D S-l-D ReaL

Degree of

freedom

S D

Ref.

BODY WEIGHT—Con.

24 weeks—Continued

Pullet (heavy):

WR -_. 9

WR 9

WR 9

WR 9

WR 9

NH 9

NH 9

NH 9

NH 9

RIR 9

RIR 9

RIR 9

WW 9

SO 9

SO 9

SO 9

SO 9

Ot* 9

SXS 9

Average —

Mature (light) : WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL* 9

WL* 9

WL* 9

WL* 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL 9

WL* 9

F 9

WLX's 9

WLX's 9

Inbreds 9

WLXA 9

WLXRIR 9

RIRXWL 9

Mix 9

Average —

— — .44 —

— — .43 —

— — .46 —

— — .38 —

35 .47 .41 .34±.04

51 .21 .36 .39±.04

47 .59 .53 .33±.06

58 .27 .39 .40±.04

68±. 08 — — —

85 — .71 .72±. 11

63±. 04 .35±. 41 — —

52±. 13 .70±. 10 .61±.07 —

43 .90 .67 .46±.04

34 .81 .58 .43±.08

57 .41 .49 .47±.04

45 .59 .52 . 40±.04

— — .64 —

41

41

55±. 11 .82±.12 —

64 384 80

64 380 167

64 380 167

32 192 168

64 384 80

10 129 51

12 131 51

12 140 51

15 158 51

547 3, 138 95

18 140 U9

100 500 207

46 232 62

8 87 51

8 67 51

9 86 51

10 96 51

240 675 130

65 660 63

.53 .56 .51 .44 .41 — — —

.82±.03 436 1,897 203

.29±.09 .64±.09 .49 — — 105 300 23

.67±. 12 .57±. 19 .62 — — 105 300 23

.25±.08 .62±.09 .43 — — 105 300 23

.63±. 12 .54±.09 .58 — — 105 300 23

.61 — — — — 36 190 77

. 52 — — ,—. 36 380 78

.47±. 18 .80±. 16 .63±. 10 — — 20 179 88

.93±.29 .69±. 15 .81±. 12 — — 18 156 88

.73±.23 .48±. 11 .60±. 11 —, — 18 180 88

.57±.28 .69±. 18 .63±. 13 — — 10 108 88

.62 .74 — — — 104 365 91

.44 .76 — — — 300 1,500 H

.85±.ll — — — — 340 1,200 96

.41±.09 — — — — 340 1,200 96

. 17 — .47 —. .80 42 218 108

.29 — — — — — .— 127

— — — — .53 140 1,400 142

— — .64db. 02 — — 85 404 143

.57±.31 .32±.37 — — 100 500 207

.25±.08 .58±.06 .41±. 08 — —, 245 994 161

.43 .73 — — 60 260 186

— — .53±. 04 — — 79 301 143

— — .36 — — — — 42

. 65 — .44 — — 501 4,769 73

— — — .75 — 98 751 162

.20 .56 — — — 19 152 11

.78±.32 .30±.34 — — — 100 500 207

.03±.33 .68±.43 — — — 100 500 207

.81 .39 ,69 .45 — 25 278 72

. 52 .59 .56 .60 .67 — ~ —
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 9

TABLE 1.—Reported heritability estimates q/ body weighty weight gain, jeed consumption, feed efficiency,

conformation, market quality traits, and pigmentation, by age, breed, and sex oj chickens—Continued

Trait, age, and breed of

chicken

Sex

Heritability estimate

D S+D Real.

Degree of

freedom

"S D~

Ref.

BODY WEIGHT—Con.

24 weeks—Continued

Mature (heavy) : WR 9

WR 9

NH 9

RIR 9

RIR 9

RIR* 9

RIR 9

S 9

S 9

Ot* 9

Mix 9

Mix 9

Mix 9

Syn 9

Syn 9

Average

WEIGHT GAIN

Oto 3 weeks: WL 9

3 to 6 weeks: WL 9

6 to 9 weeks: WL 9

9 to 12 weeks: WL 9

4 to 6 weeks: NH 9

4 to 8 weeks: Mix 9

6 to 8 weeks: NH 9

8 to 10 weeks: NH 9

Average

4 to 6 weeks: NH cf

4 to 8 weeks: Mix cf

6 to 8 weeks: NH cf

8 to 10 weeks: NH d'

Average —

4 to 6 weeks: NH C

6 to 8 weeks: NH C

8 to 10 weeks: NH C

Average —

— — .38 —

— — .36 —

73 . 27 .50 —

28 .36 — —

37±. 13 .86±. 13 .62±. 07 —

60±. 08 — — —

70±. 45 , 17±. 50 — —

00 .63 — —

70±. 21 .47±. 12 .59±.

.72

10 —

60 . 58

51±. 16 .59d=. 09 .64

.65

.58

.52

58±. 19 .69±. 11 .61±. 06 —

35 .63 .57 .67

49

— .49

— .35

,44

.65

.52

.42

,53

.52

01 .65

14 .03

00 -.05

15 . 18

90 .80

61 —

64 .66

63 .64

,42

52 .97

,66 —

. 50 1. 51

.09 .98

L 13

.75

.79

.51

.68

.56 .59 ,49

32 192 168

64 384 80

108 237 89

8

26 245 88

541 2,797 95

100 500 207

— — 8

22 194 88

240 675 130

59 457 46

44 481 72

159 609 197

109 769 U

19 243 72

4 40 u

4 40 u

4 40 u

4 40 u

56 218 183

—, — 74

56 218 188

56 218 183

56

56

56

56

56

56

218

218

218

218

218

218

18S

74

183

183

183

183

183

FEED CONSUMPTION

4 to 6 weeks: NH cf .75

6 to 8 weeks: NH cf .85

8 to 10 weeks: NH cf .53

Average — .73

56 218 183

56 218 183

56 218 183
10 AGRICULTURE HANDBOOK 3 6 3,, U.S. BEPT. OF AGRICULTURE

TABLE 1.—Reported heritability estimates of body weight, weight gain, feed consumption, feed efficiency,

conformation, market quality traits, and pigmentation, by age, breed, and sex of chickens—Continued

Heritability estimate Degree of

Trait, age, and breed of Sex freedom Ref.

chicken

D S+D bop Real. S D

FEED CONSUMPTION—Continued

4 to 6 weeks: NH 9 .76 — — — — 56 218 183

6 to 8 weeks: NH 9 .90 — — — — 56 218 183

8 to 10 weeks: NH ? . 95 — — -— — 56 218 183

Average — .87 — — — — — " '

4 to 6 weeks: NH C .73 .63

6 to 8 weeks: NH C .76 .70

8to lOweeks: NH C .60 .44

Average — .70 .59

FEED EFFICIENCY

4 to 6 weeks: NH d^ .32

6 to 8 weeks: NH d" .06

8 to 10 weeks: NH d" .05

Average — . 14

lto7days:WC C .66 —

8 to 14 days: WC C .19 —

15 to 21 days: WC C .14 —

22 to 28 days: WC C .32 —

lto28days:WC C .25 —

4to6weeks:NH C .48 .37

6to8weeks:NH C .03 .46

8tol0weeks: NH C .11 .35

Average — .27 .39

56 218 183

56 218 183

56 218 183

56 218 183

56 218 183

56 218 183

4 to 6 weeks: NH 9 . 65 — — — — 56 218 183

6 to 8 weeks: NH 9 —• 05 — — — — 56 218 183

8 to 10 weeks: NH 9-26 — — — — 56 218 183

Average — .29 — — — — —

16 96 119

16 96 119

16 96 119

16 96 119

16 96 119

56 218 183

56 218 183

56 218 183

FEATHERING

8 weeks: WR d — — . 38 — — 32 192 168

Back-10 days: WR cf — — — .35 — __ — 170

Breast-10 days: WR cT — — — .34 — -" '~ {12.

Back-5 weeks: WR ^ — — — .48 — — — 170

Back-7 weeks: WR d — — — .58 — _- — 170

Pins-10 weeks: WR d — — — .43 — — ^ 170

Down-10 weeks: WR & — — — -25 — __ __ 170

Average — — — .38 .41 — —

8 weeks: WR 9 — — .30 — — 32 192 168

Back-10 days: WR 9 — — — .46 — — — 170

Breast-10 days: WR 9 — — -— -29 — ^ ^ 170

Back-5 weeks: WR 9 — — — -50 — —^170

Back-7 weeks: WR 9 — — — -20 — —^170

Pins-10 weeks: WR 9 — — — .51 ~ -^-^170

Down-10 weeks: WR 9 — — — * 39 — --^170

Average — — — .30 .39 — — — —
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 11

TABLE 1.—Reported heritabUity estimates of body weight, weight gain, feed consumption^ jeed efficiency,

conformation, market quality traits, and pigmentation, by age, breed, and sex oj chickens—Continued

Trait, age, and breed of

chicken

Sex

Heritability estimate

D S-l-D Real.

Degree of

freedom Hef.

D

FEATHERIN G—Continued

10 days: NH C

8 weeks: WR C

8 weeks: BR C

8 weeks: NH C

8 to 12 weeks: NH C

Breast (broiler): WR C

Breast (broiler) : WR C

Average —

BREAST WIDTH

8 to 12 weeks: NH C

12 weeks:

NH C

NH C

Average —

BREAST ANGLE

8 weeks:

WR d*

WR d^

WR cf

_ d^

9 weeks:

SO cf

NH d^

Ot* d^

4á weeks: Ot* d^

Average —

8 weeks:

WR 9

WR 9

9

9 weeks:

SO 9

NH 9

Ot* 9

44 weeks: Ot* 9

Average —

8 weeks: WR C

9 weeks: Ot* C

10 weeks:

SO c

Mix C

NH C

NHXSO C

SOXNH C

12 weeks:

NH C

NH C

Average —

— — .36 .06 — — — 34

— — . 34 — — 32 192 168

— — .42 — — 18 85 79

— — . 33 — — 9 48 79

— — .16 .19 — — — 34

.50 .38 .44 — — 3 30 58

.02 .00 .01 — — 3 30 Ö8

.26 .19 .29 .13 — — — —

.21 .12 34

.20 8 85 S

. 13 .29 .21 — — 8 29 106

. 17 .29 . 21 . 12 — — — —

.48 .32 .40 36 161 171

.30 .39 .34 .26 .31 64 380 166

— —. — — .24 32 192 164

.30 — — — — 20 164 16

. 59 . 37 .48 .34±. 11 — 14 110 48

.20 .62 .41 .37±. 10 — 12 120 48

— — .— .45±. 03 — 395 1,128 129

— — .45 — — 240 675 ISO

.39 .43 .42 .36 .28 — — —

.23 .35 .30 .20 .31 64 380 166

—. — — — .21 32 192 164

.30 — — "— — 20 164 IS

.50 .22 .36 .42±. 11 14 110 48

.48 .66 .57 .50±. 11 — 12 120 48

—, — — .40±..03 — 395 1,128 129

— — .45 — — 240 675 ISO

.40 .41 .42 .38 .26 — — —

.26 .37 .32 .23 .31 64 380 166

— — .43±.02 — — 395 1,128 129

. 10 .79 .44 10 100 21

.46 — — — — 82 440 19

.35 .60 .47 — — 10 100 21

.68 .37 .52 — .— 10 100 21

.34 .47 .40 — — 10 100 21

.38 , 8 85 S

.50 .48 .49 —

— 8 29 106

.38 . 51 .44 .23 .31 —- — —-
12 AGRICXJLTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 1.—Beporied heritabUity estimóles oj body weighty weight gaiuy feed consumptiony feed efficiencyy

conformationj market quality traits^ and pigmentation, by age, breed, and sex oj cA-icÄreTis—Continued

Heritability estimate Degree of

Trait, age, and breed of Sex freedom Ref.

chicken

D S+D bop Real. S D

BODY DEPTH

10 weeks:

NH cT . 16 — .35 — — 8 66 5^

NH 9 .22 — .55 — — 8 66 55

Average — .19 — .45

KEEL LENGTH

8 weeks: cf . 59 — — —

9 weeks: Ot c?" — — — .56±.03

10 weeks: NH cf .27 — .52 —

44 weeks: Ot* & — — .55 —

8 weeks: 9 . 56 — — —

9 weeks: Ot 9 •— — — .56±.03

10 weeks: NH 9 .35 — .47 —

44 weeks: Ot* 9 — — .52 —

8 to 12 weeks: NH C — — .49 .48

9 weeks: Ot* C — — — .56±.02

12 weeks:

NH C .55 — — •—

NH C .50 .17 .34 —

Average — .47 .17 .48 .54

SHANK LENGTH

9weeks:0t* d^ _____ .50±.03

10 weeks: NH cf . 04 — .29 —

44 weeks: Ot* 6" — — .62 —

9 weeks: Ot* 9 — — — . 45±. 03

10 weeks: NH 9-23 — .56 —

Mature:

WL 9 — — .29 .33±.16

WL 9 — — .41 .54±.20

44 weeks: Ot* 9 — — .58 —

Average — .13 — .46 .45

SHANK DIAMETER

WEIGHT/SHANK LENGTH

8 weeks:

Average — .49

20 164 15

395 1,128 im

8 66 35

240 675 130

20 164 17

395 1,128 129

8 66 35

240 675 130

— — 34

395 1,128 129

8 85 3

8 29 106

395 1,128 129

8 66 35

240 675 130

395 1, 128 129

8 66 35

— 108 109

— 139 109

240 675 130

8 weeks:

cf .63 — — — — 20 164 Í5

9 .60 — — — — 20 164 Í5

Average — .61 — — — — — -— —

d' .44 — — — — 20 164: 15

Ç -54 — — — — 20 IM 15

BREAST BLISTERS

WR C .16 .24 .20 ~ - S BO 58

WR C .00 .00 .00 -^ — 3 30 55

Average — .08 .12 .10
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 13

TABLE 1.—Reported heritability estimates of body weighty weight gain, jeed consumption, jeed efficiency,

conformation, market quality traits, and pigmentation, by age, breed, and sex of chickens—Continued

Trait, age, and breed of

chicken

Sex

Heritability estimate

D S-hD Real

Degree of

freedom Ref.

D

DRESSING PERCENT

(BROILER)

WR & .69

AC* C .12

Average — .41

SHANK PIGMENT

8 weeks:

Meat cf

Meat .-_ cf

Meat 9

Meat 9

Average — . 36

.32

. 16

,24

,38

.50

. 14

.32

49 .30 .39

21 .69 .45

57 .28 .43

16 .23 . 19

,37

36

161

161

239

171

139

32 270 1S7

44 428 202

32 270 137

44 428 202

Table 2 summarizes the heritability estimates

of ^gg production and other traits associated with

egg production.

There appears to be little, if any, difference in

the average heritabilities of short, intermediate,

and long-term survivor production (0.22, 0.19 and

0.22, respectively) based on the paternal half-sib

correlation. However, the maternal half-sib average estimates are more than 30 percent higher

(0.32, 0.35 and 0.30, respectively), suggesting a

possible importance of either maternal or dominance effects, or both, for survivor production.

There are fewer heritability estimates of shortand long-term hen-housed production and apparently these differ according to paternal halfsib correlation estimates (0.33 and 0.15). However,

the average estimates from the maternal half-sib

correlation are similar for both short- and longterm hen-housed production (0.40 and 0.41), As

in survivor production, there is an apparent importance of either maternal or dominance effects,

or both. Short-term rate of production appears to

have a lower heritability (0.11) than short-term

survivor production or hen-housed production;

and again either maternal or dominance effects,

or both, appear to be considerable as evidenced

by the average maternal half-sib correlations

(0.45). Long-term, rate of production has an average heritability of 0.15 by the paternal half-sib

correlation, but there is only one estimate by the

maternal half-sib correlation (0.64). Winter rate

of production appears to have a higher heritability,

but all estimates were reported by a single investigator. There is no apparent importance of

either maternal or dominance effects indicated by

the meager data for this trait.

Eg^ mass appears to have a heritability of a

magnitude simdar to that of egg production.

There is no convincing evidence of either maternal

or dominance effects.

A great many estimates of the heritability of

sexual maturity have been reported. The average

of estimates tabulated for the paternal haK-sib

correlation indicates a heritability of approximately

0.39 for this trait in both light and heavy breeds.

There is limited information regarding broodiness, pauses, and persistency, but reports indicate

a low heritability for these traits.

The heritability estimates of egg traits are

reported in table 3.

There are a large number of reports of the heritability of early and mature ^gg weight. The

average estimates by the paternal half-sib correlation indicate a high heritability of early egg

weight for light and heavy breeds (0.45 and 0.57).

Similar average estimates of heritability of mature

egg weight for light and heavy breeds (0.46 and

0.58) suggest no difference in the heritability of

pullet and mature egg weight.

Either maternal or dominance effects, or both,

are suggested by the fact that the maternal halfsib estimates are about 15 percent higher than the

paternal half-sib estimates for early egg weight,

but there is no indication of these effects for

mature egg weight.

Average estimates of the heritability of specific

gravity for light and heavy breeds are 0.35 and

0.40 as estimated by the paternal half-sib córrela-
14 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

tion and there is no evidence of important maternal or dominance effects.

Egg shape appears to be quite highly heritable

in both light and heavy breeds (0.35 and 0.32)

as estimated by the paternal half-sib correlation.

Shell color is apparently quite highly heritable.

There is evidence of important dominance or

maternal influences, or both, as indicated by the

difference in average paternal and maternal halfsib correlations (0.35 and 0.56).

Haugh units and albumen height have similar

average paternal half-sib correlation estimates

(0.42 and 0.43), but the average for albumen

score is lower (0.27).

Reported estimates are too few to permit

meaningful connnents concerning the following

traits: yolk weight, yolk weight/egg weight, yolk

size, albumen weight, albumen weight/yo]k weight,

albumen percent, blood spots, meat spots, shell

thickness, shell strength, shell texture, shell defects, yolk color, mottling, Haugh units stored,

and quality loss.

Table 4 is a summary of fertility, hatchability,

mortality, aggressiveness, and physiological traits.

Based on estimates from only three reports,

fertility appears to have a low heritability.

Hatchability measured as a percentage of all eggs

set has a lower average heritabihty (0.09) than

hatchability measured on the probit scale (0.19).

However, hatchability of fertile eggs, measured in

percent, has a higher average heritabihty (0.14)

than hatchabiUty of fertile eggs measured on the

probit scale (0.07).

Aiortality up to 10 weeks of age, annual laying

house mortality, and mortality due to leucosis

are all apparently very lowly heritable (0.02,

0.08, and 0.09, respectively). There is also strong

evidence of important maternal or dominance

effects, or both, for early and laying house

mortality.

Aggressiveness as measured by the realized

heritabihty average is quite highly heritable (0.31).

There are so few estimates of heritability for all

traits reported in table 4 that any discussion of

the magnitude of the estimates does not seem

justified.

TABLE 2.—Reported heritability estimates of egg production and production traits ^ by age and breed of chickens

Trait, age, and breed of chicken

Heritability estimate

D S + D bo. Real.

Degree of

freedom .

S D

Ref,

SURVIVOR PRODUCTION

Short term

First 3 months: NH 0.31 0.19 0. 25

First 4 months:

NH .37 .21 .29 —

Syn — — — 0. 37

17 weeks > S.M.: S .02±. 05 .15±. 11 .09±. 05 —•

To Dec. 31: RIRXG .42 — —

To January : WL . 18 — —

WL .31 — —

WL .07 — —

WL . 16 .35 — —

WL .23 .61 — —

WL .18 .43 — —

WL . 21 .53 — —

WL — — .22 —

WL — — .48 —

WL — — .32 —

WL . 16 .12 . 14 —

WL . 14 .24 . 19 —

S .21±. 12 .29±. 10 .25±. 07 —

NH — — .25 —

May 31 (Australia):

WL .29 .36 .33±. 05 —

WL . 23±. 10 — — —

Average for short term .22 .32 .26 .37

— 108 237 89

108 237 89

145 735 117

12 144 187 — — 128

40 200 A

40 200 4

40 200 U

15 136 17

46 464 17

23 196 17

84 796 92

14 53 107

20 74 107 — — 111

48 604 146

100 904 198

12 144 187

— — 69

42 382 133

84 700 135
ESTIMATES OF HBRITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 15

TABLE 2.—Reported heritability estimates c^f egg prodv£tion and 'production traits, by age and breed oj

chickens—Continued

Trait, age^ and breed of chicken

Heritability estimate

S+D Real.

Degree of

freedom Ref.

SURVIVOR

PRODUCTION—Continued

Intermediate term

To 240 days of age: NH —

9 months of age: WL . 11

40 weeks of age: S . 16±. 10

42 weeks of age: WG* 28

44 weeks of age:

WL 27±. 07

WL . 13±. 07

46 weeks of age:

NH .._ —

WG* - . 28

WL —

11 months of age: WL . 16

350 days of age: WL —

365 days of age:

RIR 18

WL.__ _ - . 23±. 07

55 weeks of age: S 21±. 13

To March:

WL. 14

WL _ 14

WL . 20

WL 16

Average for intermediate

term , 19

Long term

32 weeks>maturity: S 14±. 10

250 days>maturity:

BLXBL- 18±. 08

BLXS . 18±. 06

SXBL 23±. 08

SXS,-_ - . 36±. 09

65 weeks of age: S . 31±. 07

319 days>housing: Mix —

300 days>maturity: WL », . 14

500 days of age:

WLXA__ - 44

Inbreds —

October to July: Mix . 24

72 weeks of age:

WL —

WL 32

WL . 21

WW - . 42±. 12

To May 1: S — 23±. 13

To May 31:

WL —

WL —

To June 1:

WL . 02

WL . 15

WL - 10

WL . 12

To June 30: WL —

To August: S - - 27±. 14

To September 30: WL —

15

16

23±.,11 .19

26±,

45±.

,07

09

.27

.29

05

.20

.17

.26

26

. 40±.08

.38±.13

.34

.61

.46

.52

13

, 31±.10

,29±.08

48 245 1Í7

— — 148

12 144 187

— — 86

105 300 S3

105 300 23

— 84

— — 66

— — 69

36 190 78

— — 117

31 121 66

245 994 161

12 144 187

15 136 17

46 464 17

23 196 17

84 796 92

,35 .23 .21

,35±.12

22±. 14 —

38±. 12 —

30±. 12 —

32±. 11 —

48±. 13 .40±.09

— .28

14 .14

.25±.07 —

17

,59

.29

.23

45 .33±. 06

14±. 09 .28±, 07

31±. 10 .27±,

.46

.15

07

33 .

40 —^

48 —

44

.24

41±. 11 .34±.

.26

08

12 144 187

65 660 63

65 660 63

65 660 63

65 660 63

12 144 187

— — 101

48 604 146

19 152 11

98 751 162

36 269 71

36 97 1

52 299 29

42 382 133

46 232 59

12 144 187

20 74 107

14 53 107

15 136 17

23 196 17

46 464 17

84 796 17

— — 111

12 144 187

— — 111

336_740—69-
16 AGRICULTURE HANDBOOK 3 6 S,; U.S. DEPT. OF AGRICULTURE

TABLE 2.—Reported heritability estimates of egg production and production traitsj by age and breed of

chickens—Continued

Trait, age, and breed of chicken

Heritability estimate Degree of

freedom Ref.

D S-hD Real. D

.57

, 22±.08 —

SURVIVOR

PRODUCTION—Gontinued

Long term—Continued

Annual:

WL -.05 .22 —

WL .09 .38 —

WL .11 .29 —

WL — — .34

WL — — .15

WL . 16±. 09 . 05±. 13 , 11±. 07

WL .23±.12 .30±.14 .26±.08

WL .23 .10 .17

WL . 30dr. 13 . 35±. 11 . 33±. 07

WL .16 .14 —

WL .45 .16 —

WL — .05 —

WL — — .15

WL._-- — — .50

WL ,38 — —

WL .16 .15 .15

WL — — .27±.ll

WL .18±.05 .74±.ll .46

NH .13 .11 ,12

F .16 .12 .14

S ,16 .68 —

A .25 — —

400 to 450 days>maturity:

S — — .45

BL — — .34

BLXBL .42±.12 . 14±. 09 .28±.07

BLXS .24±.08 .00dz.l3 —

SXBL .11±.06 ,36±.12 —

SXS .34±.09 ,30±. 12 —

500 days>maturity: WL .16 .15 .15

Average for long term .22 .30 .27

Month 1: NH TIs 721 TIs

Months 1 and 2: NH .32 .15 .24

November and December:

WL — — .34

BR — — .18

January and February : WL — — .59

BR — — .34

January through March : WL -.03 .41 —

WL- .03 .38 —

WL,_. .14 .33 —

Winter:

WL — — .27

WL-, — — .26

Marfsh and April:

WL — -^ .36

BR — — .27

March through June:

WL -.12 .37 —

WL .10 .30 —

WL .10 .25 —

May and June:

WL — ~ .49

WL — — .42

BR — — .09

.31

15 136 17

46 464 17

23 196 17

— : 39

36 190 77

20 179 88

18 156 88

— . — 28

18 180 88

130 1,000 no

130 1,000 no

130 1,000 no

4 53 107

20 74 107

— _ — 127

48 604 146

30 260 150

64 520 160

108 237 89

15 48 6

8

28 69 114

26 104 61

24 83 61

46 232 62

65 660 63

65 660 63

65 660 63

48 604 146

— — —

108 237 89

108 237 89

10 79 90

10 79 90

10 79 90

10 79 90

15 136 17

46 464 17

23 196 17

36 '97 1

40 137 2

10 77 90

10 78 90

15 136 17

46 464 17

23 196 17

10 '74 90

10 73 90

10 76 90
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 17

TABLE 2.—Reported heritability estimates oj egg production and production traits, by age and breed of

chickens—Continued

Trait, age, and breed of chicken

Heritability estimate

D S + D boD ReaL

Degree of

freedom Ref.

D

SURVIVOR

PRODUCTION-^Continued

July and August:

BR_"rriiii"iii"iiiii""ii — January 1 to 72 weeks of age: WL . 16±. 11

June to 365 days >S.M.:

WL -.19

WL . 24

WL . 24

250 to 450 days >S.M.:

BLXBL . 24±. 08

BLXS . 11±. 06

SXBL . 34±. 09

SXS . 29db. 08

Annual minus winter: WL —

September to February : WL —

To 28 weeks of age : WL . 26±. 07

WL . 23±. 08

28 to 36 weeks of age:

WL . 14±. 05

WL . 15±. 06

36 to 44 weeks:

WL . 20±. 06

WL . . 11±. 06

HEN HOUSED PRODUCTION

Short term

To December 31: WL —

To May 31 (Australia): WL . 27

To January: WL . 32

To March: WL . 39

To 46 weeks: NH —

Average for short term . 33

Long term

To May 31: WL . 23±. 11

To June 30: WL —

ToJime: WL .19

October to July: Mix —

To September 30: WL —

To 500 days of age:

WL* . 07

Ot* —

To 72 weeks of age:

WL . 00

WL . 19

Annual:

WL . 16

WL . 24±. 06

WLX's —

Average for long term .15

— . 17

06

35

18

—

22±.

39±.

21±.

09±.

14

12

12

10

.14

.55

39±.

44±.

07

09

.32

.33

18±.

23±.

06

08

. 16

.19

16±.

41d=.

06

09

. 18

.26

— .28 —

37 .32±.05 .10

35 — —

49 — —

— .12 .20

,40 ,24 15

10 73 90

10 69 90

84 700 1S5

15 136 17

46 464 17

23 196 17

65 660 63

65 660 63

65 660 63

65 660 63

40 137 2

5 73 16

105 300 23

105 300 23

105 300 23

105 300 23

105 300 23

105 300 23

— — 111

42 383 133

84 796 92

84 796 92 — — — u

37

20

.22

.22

—

—

84

84

36

700

796

269

135

111

92

71

111

59

.20

—

—

300

240

1,500

675

74

130

60

43 .31±. 05 .26

— 60

42

260

383

186

133

33

36±.08

—

.30±. 08

— 84

64

796

582

92

160

.13

41 22 .28
18 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 2.—Reported heritabüity estimates of egg production and production traits, by age and breed oj

chickens—Continued

Trait, age, and breed of chicken

Heritabüity estimate

D S+D bor Real.

Degree of

freedom

S D

Ref.

RATE OF PRODUCTION

Short term

To December 15:

Syn _- . 15±. 04 . 69±. 13

WL. 13±. 09 —

To January 1 :

Syn. - - . 18±. 12 —

WL. 14 .16

WL* - 06 .43

WR — —

WL — —

WL - — —

To 34 weeks of age: WL 07±. 05 —

To 9 months of age:

WL — —

F — —

To 260 days of age:

WL -. 03±.32 .73±.44

RIR.._. -. 10±.48 .92±.60

RIRXWL.. . 09±. 30 . 28±. 39

WLXRIR 19±. 27 -. 08±. 35

To 40 weeks of age:

WL*„_ . 15±. 07 —

WL* — . 21±. 07 —

RIR*.. 18±. 06 —

. 39±.05

15

, 23±.05

. 23±.04

.22

.21

.14

. 08±.02

. 10±.04

109 769 4Í

105 305 97

100 250 97

48 604 Ue

104 365 91

64 380 167

32 192 168

64 384 80

160 750 BOS

85 404 US

79 301 14s

100 500 ê07

100 500 207

100 500 207

100 500 207

340 1,200 96

340 1,200 96

562 3,089 95

Average for short term 11

Long term

To 55 weeks of age:

WL* 15d:. 07

WL. --. . Oôi. 07

To 64 weeks of age: WL. 04±. 06

22 to 64 weeks of age: WL . 18± 05

To 65 weeks of age: F —

To 70 weeks of age:

WL* 16±. 07

WL*. 11±. 07

To 72 weeks of age: WL 16

To May 31: Mix. —- —

Annual:

WL —

WL - 23

Average for long term .15

Winter:

Light . 02

Light . 36

Heavy .25

Heavy 1. 15

Mix . 17rb. 09

Mix . 85±. 20

Average .47

22 to 34 weeks of age: WL . 39±. 05

34 to 64 weeks of age: WL . 02±. 04

40 to 55 weeks of age:

WL*-. . 15±. 07

WL* . 06=t. 07

,45 18 23

64

. 25±.02

,51

18

00

12

— 340 1,200 96

— 340 1,200 96

— 160 750 208

— 160 750 203

— 79 301 14s

340 1,200 96

— 340 1,200 96

— 104 365 92

— 159 609 197

0.04 140

99

1,400

298

.64 .31 12 .04

38 .29 —

45 .41 .35±. 10

17 .27 . 15

55 .85 .35db. 10

29±. 09 .30 .07

52±,09 .68±. 09 .35±. 07

25

25

19

19

44

44

278

278

243

243

481

481

,40 .47 .25

160

160

750

750

340 1,200

340 1,200

190

72

96

96
ESTIMATES OF HERITABELITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 19

TABLE 2.—Reported heritabÜity estimates of^ egg production and production traits^ by age and breed of

chickens—Continued

Trait, age, and breed of chicken

Heritability estimate

D S+D bop Real.

Degree of

freedom

's D"

Ref.

RATE OF

PRODUCTION—Continued

55 to 70 weeks of age:

WL* 06±. 06

WL* . 10±. 07

December 1 to March 31: Mix..,

January to June: Inbreds

March to May 31: Mix

EGG MASS

To January: S-_ -.

To 17 weeks >S.M.: S

To 32 weeks >S.M.: S

To May: S

To 40 weeks of age: S

To 55 weeks of age: S

To 65 weeks of age: S

To August: S--

SEXUAL MATURITY

Light breeds:

WL

WL

WL's

WL

WL

WL

WL _„

WL

WL

WL.

WL*

WL*„_ _

WL

WL*

WL* _. 27±. 08

WL* 38±. 08

WL 21d=. 10

WL . 22±. 09

WL . 24

WL _- —

WL 29

WL 16

WL 48±. 31

WL -- . 31±. 06

WL*.._. 07

WLXX's . 22

WLX's 51

BL- .- —

BLXBL . 19±. 07

WLXA 90

RIRXWL . 65±. 30

WLXRIR 22±. 30

BLXS.-_ — 35±. 09

SXBL-. 25±. 08

Inbreds —

Average for light breeds . 39

— — .41 .11

— — — .31

" ~~" .38 .00

16±. 10 .25±.ll .20±.07

11±.08 .04±.09 . 08±. 06 —

27±. 14 . 24±. 11 .25±.08 —

28±.15 .30±.ll . 29db. 08 —

14±. 10 . 24±. 11 . 19±. 07 —

24±. 14 .41±.13 . 33±. 08 —

41±, 20 .49±. 13 .45±.10 —

42±. 20 .41±.21 .41±.10

.15

— — .12 —

48±.05 — — —

42 .55 — —

49 .48 —

24 .80 — —

27±.07 .28±.07 .27 —

17±.08 .47±.09 .32

26 — — —

— — .40 —

27 .27 — —

09 .45 — —

38 .55 — —

26 .57 — —

.31

.34

,35

, 38±.42

, 32±.06

,34

66±. 14

65

18±.31

, 25±.37

. 35±. 12

. 26±.12

. 31db.05 —

.31 —

.45 —

.43 —

.26

340 1,200 96

340 1,200 96

159 609 197

87 — 194

159 609 197

12 144 187

12 144 187

12 144 187

12 144 187

12 144 187

12 144 187

12 144 187

12 144 187

36 97 1

40 137 2

160 750 203

15 136 17

46 464 17

23 196 17

105 300 28

105 300 23

52 299 29

— — 39

168 559 68

300 1,500 74

84 796 92

104 365 91

340 1,200 96

340 1,200 96

25 729 100

25 1,058 100

42 218 108

111

— — 127

20 68 147

100 500 207

245 994 161

60 260 186

464 3,036 31

501 4,769 73

24 84 61

65 66 63

19 152 11

100 500 207

100 500 207

65 660 63

65 660 63

98 751 162

.44 ,42 .31
20 AGRICULTURE HANDBOOK 3'63„ U.S. DEPT. OF AGRICULTURE

TABLE 2,-^—Reported heritubility estimates of egg production and production traits, by a^e and breed of

chickens—Continued

Trait, age, and breed of chicken

Heritability estimate

D S+D bop Real.

Degree of

freedom

S D

Ref.

SEXUAL MATURITY—Con.

Heavy breeds:

WR — — .41

WR — — .28

WR — — .49

WR — — .38

RIR .14 .25 —

RIR* .33±.06 — —

RIR . 21

RIR . 45±. 37

NH ~

NH . 35

WW . 21±. 08

S . 30

S —

ot* — Syn .16±.09 — —

Syn .06±.ll — —

Mix , — — .07

SXS .40±.19 .31±.10 —

RIRXG .31 — —

Average for heavy breeds .39 .25 .32

BROODINESS

Nag.XWL .16 ,56

PAUSES

Long: Mix — —

Short: Mix — —

Winter:

RIR .08 .09 —

RIR .12 .20 —

Average .10 .15 .22

PERSISTENCY

S .20 .49 —

Mix — — .10

OVIPOSITION INTERVAL

WL .59 .74 .66

— .39 .40±.14

13±.38 — —

— .25 .33

23 .30 —

14±. 10 .18±.05 —

46

.41

—

— .34 —

11

23

21

20

.31

20

16

18

71 318 ^05

64 384 80

64 380 167

32 192 168

8

562 3,089 95

18 140 149

100 500 207

— — S4

108 237 89

46 232 62

8

27 107 61

240 675 130

110 320 97

105 265 97

— — 101

65

— 30

100

100

660

70

438

438

1Ô6

101

101

64

64

101

20 69
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS

TABLE 3,—Reported heritabUity estimates of egg traitsj by breed of chickens

21

Trait of egg and breed of chicken

Heritability estimate

D S+D Real.

Degree of

freedom

S D

Ref.

EARLY EGG WEIGHT

Light breeds:

WL

WL

WL

WL

WL

WL

WL

WL

WL

WL

WL

WL*

WL*

WL*

WL*

WL

WL

WL

WL

WL

WLX's

WLXA

WLXRIR

RIRXWL

Average for light breeds-..

Heavy breeds:

WR

WR

RIR

RIR

NH

S

S

S

WG* ___.

Syn

Average for heavy breeds..

_ 0.49

0. 62±.09

.30d=.07

.40±.09

. 54±.09

.29±.22

.27

.73

.64

.86±.44

.63±.09

.42

.53±.42

.72±.44

0.34

.49

.42

.50

.45±.

.50±.

.36

.50

.41±.

.49

,07

13

11

0.33

.61

.61

0. 40±.05

40

80

105

105

105

105

230

115

40

40

84

104

300

340

340

42

42

100

245

60

501

45

100

100

200

350

300

300

300

300

2,270

1,135

287

796

365

1,500

1,200

1,200

218

218

500

994

260

4,769

208

500

500

4

. 33±. 03 203

. .25±.08 ^3

.38±.08 23

.45±. 10 23

.47±.10 23

Iß

40

70

. .72±.19

. . 15

87

92

. 60 91

. 51 94

.53±.09 96

.51±.10 96

.48 WS

. .60 108

. .26±.36 207

. .20±.07 161

.72 186

. . 64 73

.45 136

. .41±.36 207

.20±.34 207

. .45 .53 .45 . 52 .40 — — —

'. .72±.09

.31±.77

.56

.72d=. 17

.80±.16

.76±.13

.76±.21

.63

.59

.73±.

.75±.

.82±.

.48±.

14

13

14

10

.62

—

64

32

544

100

108

12

12

12

109

380

192

2,692

500

237

144

144

144

769

167

168

96

. .01±.67

. .62

. .75±.31

. .70±.30

. 87±. 31

207

89

187

187

187

. .60

. .28±.28

86

4i

. .57 . 65 .67 .63 — — — —

MATURE EGG WEIGHT

Light breeds:

WL — — .51 —

WL — — .49 —

WL .47 — — —

WL .53 — — —

WL .61d=.05 — — —

WL — — .58 —

WL .44db.l0 .68±.(D9 .56 —

WL .45±. 10 .61±.,09 .53 —

WL .53±.ll . 60±. 09 .56 —

WL .61it.09 . 52±..09 .52 —

WL .32 .56 — —

WL .59 — — —

WL .37 — — —

WL — — .51 —

WL .68 .58 .63 —

WL — — — . 16

WL — — — . 14

36 97 1

40 137 2

40 200 4

40 200 4

80 350 203

5 73 16

105 300 23

105 300 23

105 300 23

105 300 23

16 77 24

52 299 29

52 299 29 — — 39 — — 69

40 — 70

40 — 70
22 AGBICULTURE HANDBOOK 3'63, U.S. DEPT. OF AGRICULTURE

TABLE 3.—Beported heritability estimates of egg traits, hy breed oj chickens—Continued

Trait of egg and breed of chicken

Heritability estimate

S+D Eeal.

Degree of

freedom

Ref.

MATURE EGG

WEIGHT—Continued

Light breeds—'Continued

WL —

WL . 51

WL _ . 36

WL 80±. 24

WL 35±. 16

WL 55±, 20

WL 45±. 24

WL- ._- . 14

WL*, , 53

WL* . 52±. 10

WL* . 41d:. 09

WL . 73

WL —

WL -»- - _ . 29

WL —

WL._ —

WL* —

WL* , —

WL 09±. 33

WL .. —

WL* . 67

WL 18

WL's -. — -. . 19

WL^s —

WLX's . 50

F - . 31

F ~

BL..- - —

BLXBL . 46±. 11

BLXLS . 42±. 10

LSXBL . 96±. 16

RIRXWL . 30±. 35

WLXRIR ,... . 54±. 38

Inbreds ^ —

Mix —

Mix . 36

Average for light breeds . 46

Heavy breeds:

WR—_ —

WE _ _ —•

BR-_. —

RIR . 38

RIR . 41±. 14

RIR . 78±. 10

RIR - 30±. 55

NH —

NH __ . 53

S 20

S —

S . 73±. 22

S . 81±. 33

S . 50±. 24

S ._ . 77±. 31

S 49±. 24

S . 76±. 31

A . 61

Ot* —

WG* . 60

WG* __. . 72

Mix _ ._ ___ . 72

Mix 1. 15

.41

,41

.18

26

.49±. 14

. 55±. 12

. 29±. 12

. 47±.41

. 06±. 43

.45

16 —

43±. 13

62±. 16

58±. 12

56±. 18

20

58

.61±.

.48±.

.57±.

.50±.

12

09

09

10

— —

— — —

—*

.47

.42

.39

—

—

.59±.

.67±,

.55±.

02

13

, 12

—

.61

86±. 45 —

.00

,10

,47

29

! 55±.06

.66

.50

.50

61 —

.44 —

49 .49 ,32 .61

.82

. 60±. 12

.55±.61

.25

.49

. 73±. 13

. 83±. 19

. 65±. 17

. 74±. 16

. 70±. 15

. 83±. 17

.43

.29

,55

66

,67

.33

1.07

,51±. 08 — —

.54

.39

.54

.73±. 10

,82±. 14

.58 ±.12

. 76±. 13

. 60±.ll

.79±.13

.67

.52

.50

40 — 70

36 190 77

36 380 78

20 179 88

18 156 88

18 180 88

10 108 88

84 796 9^

300 1,500 94

340 1,200 96

340 1,200 96

42 218 08

-— 4— 111

— ^— n7

140 1,400 14^

85 404 143

30 260 ISO

30 260 160

100 500 B07

5 58 167

60 260 186

10 75 200

— — 148

— -— 163

464 3,036 31

15 48 6

79 301 143

24 83 61

65 660 63

65 660 63

65 660 63

100 500 207

100 500 207

98 751 162

34 150 38

25 278 72

.89

,46 —

,42 —

71 318 205

64 384 80

4 50 167

8

26 245 88

545 2,2fel 96

100 500 207

13 60 167

— -— 69

— -— 8

26 104 61

22 194 88

12 144 187

12 144 187

12 144 187

12 144 187

12 144 187

28 69 114

240 675 ISO

— — 66

— — 66

59 457 45

19 243 72
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIO CORRELATIONS 23

TABLE 3.—Reported heritability estimates of egg traits^ by breed of chickens—Continued

Heritability estimate Degree of

freedom

Trait of egg and breed of chicken ——— ' — lí'^f.

S D S+D bop ReaL S D

ALBUMEN WEIGHT/YOLK

WEIGHT

WL._. * 78

WL . 34

WL —

NH —

BR —

.13 .46

.49 .41

— .12

— .00

— .02

Average .56 .31 .21

Average .13 .28 .26

S3 6-740—69 i

. .85±.20 .52±.09 .75 .43 — 44 481 72

— .52 .52 — 159 609 197

. .42±.10 — — 105 315 97

. .29±.08 — — — — 100 265 97

. .36±.ll .16dz. 11 .26±.09 — — 50 50 161

. .37 .02 .20 — — 50 50 151

. .58 .54 ,58 .46 L07 — — —

MATURE EGG

WEI GHT—Continued

Heavy breeds—Continued

Mix

Mix

Syn

Syn. ..__ -

Syn

Syn

Average for heavy breeds

YOLK WEIGHT

WL 43d=.15 .44±.23 .43±.13 — — 40 287 87

YOLK WEIGHT/

EGG WEIGHT

WL .20±.08 — — — — 40 287 87

WL .48 .04 — — — 10 75 200

YOLK SIZE

WL_ .39 .33 — — — 10 75 200

ALBUMEN WEIGHT

WL — — .02

WL .38 .23 —

NH — — .68

BR-... — -- .12

Average .38 .23 .27

5 58 157

10 75 200

13 60 157

4 50 167

11 45 102

10 58 102

5 58 167

13 60 167

14 50 157

ALBUMEN PERCENT

WL .38 .23 — — — 10 1h 200

BLOOD SPOTS

WL .23 — — -_ — 52 299 29

WL" ::::::"i:iiiiii"ii — — .32 — — — ^ 39

WL* .13 .28 — — — 300 1,500 94

WLX's" ' I .02 — .20 — — 464 3,036 31
24 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 3.—Reported heritabüity estimares of egg traits^ by breed of chickens—Oontinued

Heritability estimate

Trait of egg and breed of chicken

Average for heavy breeds

D S+D ReaL

Degree of

freedom

's D"

MEAT SPOTS

RIR 14

RIR —

RIR —

SPECIFIC GRAVITY

Light breeds:

WL . 26

WL . 35±. 15

WL_ . 14±. 09

WL . 24±. 16

WL* . 34

WL* . 62ih. 10

WL* . 30±. 09

WL . 45±. 42

WL* . 30

WUs —

WLX's . 38

WLX's _ 54

WLXA . 30

RIRXWL . 33±. 39

WLXRIR . 29±. 37

Average for light breeds . 35

Heavy breeds:

WR —

WR —

WR's —

BR's —

RIR . 55±. 11

RIR . 33±. 51

Syn . 35±. 13

RIR . 38

SHELL THICKNESS

WL

WL

Mix

.23

.68

26

52±. 15 .44±. 09

42±. 15 .28±. 08

70di. 19 .47±. 11

33

06±. 50

—

06

.04

.41

.26

49 it.

, 10±.

50

43

.34 .32

— .39

.44

— .44

— .05

~. 17±. 53

.15±. 07 .25±. 07

.10 .25

.40 03 .30

. 38±.09

.27

17 —

52

20

18

10

300

340

340

100

60

10

464

501

45

100

100

299

179

156

108

1,500

1,200

1,200

500

260

75

3,036

4,769

208

500

500

64

32

71

10

478

100

50

50

380

192

318

77

1,700

500

50

50

Ref.

42 316 118

119 721 1^0

119 721 1^0

88

88

88

H

96

96

207

186

90

31

73

136

207

207

167

168

206

90

96

207

151

loi

40 — 70

30 260 150

34 150 38

SHELL STRENGTH

WL- ,53 10 67 m

SHELL TEXTURE

Mix- 27 34 150

SHELL DEFECTS

WL's . 05 ,08 464 3,036 31
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS

TABLE 3.—Reported heritdbility estimates of egg traits, by breed oj chickens—Continued

25

Trait of egg and breed of chicken

Heritability estimate

D S+D Real.

Degree of

freedom

S D

Ref.

EGG SHAPE

Light breeds: WL . 55

WL —

WL's —

WL* . 74±. 10

WL . 61±. 09

WL --- -. 04±. 38

WL's —

WLX's . 27

RIRXWL . 18±. 37

WLXRIR . 16±. 34

Average for light breeds 35

— .73

— . 39

51±. 53

.22

.30

15±. 46 —

32±. 45 —

33 .41

52 299

— — 69

40 — 70

340 1,200 96

340 1,200 96

100 500 Î07

12 117 168

464 3,036 SI

100 500 207

100 500 207

eavy breeds:

NH — — .56

RIR 66±.53 .02±.55 —

WG* .11 .09 . 10

WG*__ _. __ .51 .18 .35

WG* .11 — —

Syn - — .28±.14 .26±.09 . 27±. 09

WG* 29

.28

.30 .30

Average for heavy breeds. _ . 32 17 32

— — 69

100 500 207

— — 55

— — 55

— — 86

50 50 151

50 50 151

— — 99

YOLK COLOR

WL_

MixOS

15

10

34

67

150

18Jt

38

SHELL COLOR

WL* . 48

WL* . 17

WL* . 54

WL . 51dz. 19

WL . 37±. 17

WL , 12±. 08

WL . 54±. 27

WLX's . 27

RIR . 89±. 22

S . 34±. 14

S . 24±. 17

S . 16±. 12

S . 17±. 12

S — . 18±. 10

Mix - . 30

Mix —

. 30±. 11

. 43

Average . 35

43 —

33 —

49 —

55±. 15 .53±. 10

72 + . 16 .54±. 10

57-t.,12 .34±, 06

63±. 18 .58±. 13

— .33

52±. 11 .70±. 10

77±. 21 .45±. 11

65±. 20 .45±. 11

56±. 15 .36±. 08

53±. 15 .35±. 08

78±. 14 .48±. 07

91

.58

25±. 14 .27±. 09

34 .38

.78 —

78 149 56

301 946 56

317 980 56

20 179 88

18 156 88

18 180 88

10 108 88

464 3,036 SI

26 245 88

12 144 75

12 144 75

12 144 76

12 144 75

22 194 88

12 97 12

34 150 38

50 50 151

50 50 161

.56 45 ,78

MOTTLING

WL* -. 01

WL* ~. 16

WL* . 00

, 10

,36

04

104 365 93

104 365 93

104 365 93
26 AGRICULTURE HANDBOOK 363, U^. DEPT. OF AGRICULTURE

TABLE 3.—Reported heritabUity estimates of egg traits, by breed of chickens—Continued

Trait of egg and breed of chicken

Heritability estimate

D S+D Real.

Degree of

freedom

S D

Eef.

HAUGH UNITS

WL _ . 30

WL_- _. —

WL _. . 55±. 20

WL . 54±. 20

WL. 70±. 23

WL . 68

WL —

WL —

WLXV —

WLXA . 57

WR —

WR_ —

WR's —

NH . , 35

RIR . 47±. 14

S 50±. 17

Syn . -. 04±. 03

Syn -. 05

Average .42

11 —

23±. 13 .41±. 11

43±. 14 .48±. 11

53i. 11 .62±. 11

55 —

— .60±. 15

— .21

— .32

— .37

.43

— .44

34±. 11 .40±. 08

55±. 13 .52±. 09

08 dr. 07 .02±. 08

12 .04

52 299 3S

40 — 70

20 179 88

18 156 88

18 180 88

104 365 93

30 260 150

— — 199

— — 199

45 208 136

64 380 167

32 192 168

71 318 206

12 125 49

26 245 88

22 194 88

50 50 151

50 50 161

35 ,37 11 —

HAXJGH UNITS — STORED

2 weeks:

WL

WLXA

ALBUMEN SCORE

.66

.28

WL . . 29

WL* , 10

WL* . 29

WL* .38±.09

WL* . 23±. 09

WL . 67±. 40

WL —

WL* .__. . 25

WLX's. 40

RIRXWL . 08±. 39

WLXRIR . 16±. 38

RIR . . 28±. 10

RIR . 11±. 51

Average .27

ALBUMEN HEIGHT

WL .68±.22

WL . 56±. 21

WL —

WL —

WL —

WLX's —

BR.^ —

WG* - 05

Mix —

Average _ . 43

57

71 —

40 —

21±.47 z

— .59

06 —

— .42

15±. 49

04±.45 —

. 62±. 56 —

.31 .51

29±.13 .48±. 11

48±. 15 .52±.

.55

11

— .56±. 14

— .36

— .23

— .55

22

104 365 93

45 208 136

52 299 ê9

104 365 91

300 1,500 94

340 1,200 96

340 1,200 96

100 500 207

10 67 184

60 260 186

464 3,03« 31

100 500 207

100 5(K) 207

478 1,700 96

100 500 207

20 179 88

18 156 88

10 n 90

30 260 160

— -^ 199

— — 199

10 76 90

— -^ 86

34 150 38

.39 .43
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 27

TABLE 3.—Reported heritabüity estimates of egg traits, by breed of chickens—Continued

neritability estimate

Trait of egg and breed of chicken

S

QUALITY LOSS

Haugh units, 14 days:

WL* .._ - .22

WL 25

Stored Haugh units/fresh Haugh

units:

WL 28

Albumen height loss, 12 days:

WL -.01

WL -.56

D S+D bor Real.

Degree of

freedom

S D

Ref.

,23

,58

23

04

18

104

50

365

250

93

IOS

104 365 93

20

20

173

165

121

in

TABLE 4.—Reported heritabüity estimates ojfertility, hatchability, mortality, aggressiveness, and

physiological traits, by breed and sex of chickens

Trait and breed of chicken Sex

Heritability estimate

D S+D Real.

Degree of

freedom Ref.

D

FERTILITY

NH 9 —

NH 9 0.02

Inbreds $ —

Average _ — . 02

HATCHABILITY

All eggs-percent:

NH _ 9 .13

NH 9 .04

Mix 9 .11

NHXSO 9 .11

SOXNH 9 .08

Average — ,09

All eggs-probit:

NH 9 .27

SO 9 .12

Mix__ 9 .20

Mix 9 .20

NHXSO 9 .19

SOXNH 9 .13

Average — . 19

0.21

0.01 0. 02±.04 — 43 79 26

.14 — — 40 280 47

— .06 — 87 — 194

,21 .08 .04

07±.04 —

,07

10 100 20

43 79 26

— — 18

10 100 20

10 100 20

10 100 20

10 100 20

— — 18

10 100 20

10 100 20

10 100 20
28 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 4.—Reported heritability estimates ojfertility^ hatchabüity, mortality, aggressivenessj and

physiological traits, by breed and sex oj chickens—Continued

Heritability estimate Degree of

Trait and breed of chicken Sex freedom Ref.

Average — .14 — .06 .16

Fertile eggs-probit:

NH 9 . 14 — — -—

NH 9 . 02 — — .04±.04

SO 9-23 — — —

NHXSO 9 .07 — — —

SOXNH 9 -. 14 — — —

Mix 9 .08 — —- —

Average — .07 — — .04

.36 .56

.21 .51

D S+D bop ReaL S D

HATCHABILITY—Con.

Fertile eggs-percent:

WL 9 . 16 .23 — —

NH 9 . 06 — — —

NH 9 .65 — — —

NH 9 . 29 — — —

NH 9 . 04 .22 .10 —

SO 9 . 12 — — —

Inbreds 9 — — — .16

Inbreds 9 — — .02 —

NHXSO 9 .04 — — —

SOXNH 9 -.05 — — —

Mix 9 . 08 — -— —

Mix 9 . 05 — — —

16 77 U

10 100 20

47 730 27

47 730 27

40 280 47

10 100 20

84 396 162

87 813 196

10 100 20

10 100 20

36 269 71

— — 18

10 100 20

43 79 26

10 100 20

10 100 20

10 100 20

— — 18

Fertile eggs at 30% hatch:

WL 9-42 .57 — — — 16 77

Fertile eggs at 50% hatch:

WL 9 .36 .56 — — — 16 77

Fertile eggs at 70% hatch:

WL 9 .21 .51 — — ~ 16 77 ^4

HATCHING TIME

WL 9 .49 .58 — — — 16 77

MORTALITY

Embryonic :

1 week: Inbreds C —• — .01

2 weeks: Inbreds C — — .01

3 weeks: Inbreds C — — .01

Growing:

Chick: Inbreds C — — .05

0 to 3 weeks:

WL C .03±.01 .36±.05 —

A C .02±.02 .37±.07 —

3 to 6 weeks:

WL C .02±.02 .18±.04 ~

A C .OOi.OO .07±.07 —

0 to 6 weeks:

WL C .03d=.02 .28±.04 — — — 108 968 134

A C .01±.02 .36±.07 — — — 43 372 134

To 10 weeks: WL+X's C .02 — .13 — — 464 3,036 31

Average of growing

mortality.-- — ,02 .27 .04 — — _ __. —

87

87

87

813

813

813

195

195

195

87 813 195

108

43

968

372

134

134

108

43

968

372

134

134
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 29

TABLE 4.—Reported heritabUity estimates ojfertility, hatchabUity, mortality, aggressiveness, and

physiological traits, by breed and sex of chickens—Continued

Trait and breed of chicken Sex

Heritability estimate

D S+D ReaL

Degree of

freedom Ref.

D

MORTALITY—Continued

11 to 20 weeks: WL+X's C

21 to60weeks: WL-fX's C

61 to 70 weeks: WL+X's C

0to72weeks: WL+X's C

Annual:

WL 9

9

In laying house:

WL+X's 9

Mix 9

WLX's 9

Average annual —

From leucosis: WW 9

WL 9

From lymphomatosis:

S 9

RIR 9

9

Resistance RIR 9

Resistance RlR 9

Resistance RIR 9

Average —

From other diseases:

WL 9

~— 9

From reproduction disorders 9

LIVEABILITY

Brooder: WW C

To 10 weeks of age:

Mix C

Mix___. C

Laying: Mix 9

To 365 days of age: RIR 9

To 72 weeks of age: WL 9

RESISTANCE TO ROUS

SARCOMA VIRUS

WC —

J C

ADRENAL WEIGHT

Left: WR cf

Right: WR &

Both: WR cf

02

05

00

05 —

.04

.08

. 07

. 10

08

08 . 11

.08

. 09±. 03

08±.06

06

.27d=. 16 . 10±.05

.05

08

,09

464

464

464

464

3,036

3,036

3,036

3,036

Si

81

31

SI

100

8 40

113

1Ô4

23

36

67

269

60

71

19 .08

03±. 04 .15±. 14 .04±. 04

07 — .08

00±. 00 .04±. 01 .01±. 00

04±. 02 . 16±. 05 .05±. 02

05 .03 .05±. 02

12 — .22

14 — .20

24 — . 12

23 67 60

>100 — 113

40 248 Ul

46 281 m

8 40 164

9 135 196

9 135 196

9 135 196

10 10

03 — .03

07 .06 .07±.02

02 .06 .03±.02

07±.01 .14±.01 .lOi.Ol

>100

54

11

20

.03

.08

,28

. 12

78

,77

.42

.53

.57

13

10

40

40

363

59

43

US

154

154

59

— — 18

— — 18

—, — 101

42 48 66

52 299 29

u

152

50 109 112

50 109 172

50 109 172
30 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 4.—Reported heritabUity estimates ojjertüity, hatchahüity, mortality, aggressiveness, and

physiological traits, by breed and sex of chickens—Continued

Triut and breed of chicken Sex

HeritabUity estimate

D S+D Heal.

Degree of

freedom Ref.

D

AGGRESSIVENESS

Domination:

WL C

AC cT

WL _. 9

WL- - 9

WL 9

WE - - 9

A -_. 9

RIR 9

Average —

Encounters won : WL C

Matings completed:

AC cf

AC _ - -_.. d^

BLOOD

Albumen, 8 weeks: WL, RIR, C . 60

Alkaline phospliatase:

WL* 9 —

WL 9 .40

WL cf .03

Alpha 1 globulin, 8 weeks:

WL, RIR .,_ C .42

Alpha 2 globulin, 8 weeks:

WL, RIR-- C . 28

Alpha 3 globulin, 8 weeks:

WL, RIR-.,. C . 11

Beta-f Gamma globulin, 8

weeks: WL, RIR C . 58

Hemoglobin, 1 day: WL, RIR. C . 21

Hemoglobin, 2 weeks: ARB* C >1. 0

Hemoglobin, 4 weeks: ARB* C , 31

Hemoglobin, 6 weeks: ARB*«.. C . 36

Hemoglobin, 10 weeks: ARB*,. C . 36

Hemoglobm, 12 weeks: ARB*.. C . 83

Hemoglobin, 14 weeks: ARB*., C . 36

Hemoglobin, 17 weeks: ARB*. .0 .16

Red blood cell volume — .39

Carotinoid concentration

Syn meat c?' • 21

Sjmmeat 9 .32

Sfâ'um cholesterol, 6 weeks:

WL* 9 .34

Serum cholesterol, 9 weeks:

WL- - 9 .19

Pressure, mature:

.,- c — Pressure, 19 weeks:

WR cf —

WR 9 —

Protein, total: WL, RIR G . 00

Prothrombin time:

WR cf —

WR 9 —

0.22

.57

-.27

.39

.70

.01

.24

.88

36

,52 .33 .31

18

.52 ,33

.36

35

,00

.27 35 .27

84

54 —

17 ,25

41 .30

,05

,04

,53

.03

36

43

43

Ô7

163

98

98

98

98

98

98

67

. 18±.05 60 240 169

.31di.ll 60 240 169

—— 12 159 104

, 52 119 192

13 42 181

— 13 66 181

-- 12 159 104

— 12 159 104

— 12 159 104

__ 12 159 104

19 .¿— 104

— 19 — 104

— 19 -— 104

19 .— 104

— 19 .— 104

— 19 .— 104

— 19 ,—. 104

_ 19 104

— 51 207 188

_ 20 . 179

— 20 -— 179

— 52 116 191

— 49 114 n

.15 63 190 180

.09 63 190 180

.13 63 190 180

^ . 189

— — 189

— 12 159 104

.47 132

.38 — -:— 132
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 31

TABLE 4.—Reported heritabUity estimates ojjertüity^ hatchabüity, mortalityj aggressiveness, and

physiological traits, by breed and sex of chickens—Continued

Trait and breed of chicken Sex

Heritability estimate

D S-fD Real.

Degree of

freedom Ref.

S D

BURSA WEIGHT

Hatching: WG C — —

11 days: WG C — —

27 days: WG* C .30 —

62 days: WR d^ ~ —

COMB WEIGHT RESPONSE

To testosterone propionate:

High — — —

Low — — —

To Pregnant mare serum — — —

HEAT TOLERANCE

WL* C .44±.26 .47±.26

HEMAGGLÜTINATION

TITER

For Newcastle virus:WL C — —

SEMEN VOLUME

6 to 7 months:

WR c?" — —

WR cf ,41±.30 —

SPERM CONCENTRATION

WR d" .46±.30 —

WR. d" — —

SPERM MOTILITY

WR-— cf — —

WR - cf .87±.40 —

SPLEEN WEIGHT

lday:WG* C — —

11 days: WG* C — —

27 days: WG* C .57 —

TESTES WEIGHT

lday:WG*-_ _ çP — —

11 days: WG* c^ — —

62 days: WG* & — —

11 weeks: NH _. cf . 47 —

.32

.48

.33

14

,01

,29

.78

50

70

60

18

43

.44±.08

.27±.08

.42±. 11

45±.15 —

.77

— ~ 5-Í

50 109 Í7S

— 160 Î40

— 160 140

— 160 140

42 157 Í9S

10 43 1S2

64 380 Î67

24 — Î77

24 — 177

64 380 167

64 380 167

24 — 177

H

82

— 221 S4

— 221 84

50 109 172

8 66 So
32 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 4.—Reported heritabUity estimates o^ fertilityj hatchahility, mortality, aggressiveness, and

physiological traits, by breed and sex of chickens—Continued

Trait and breed of chicken Sex

Heritability estimate

D S+D ReaL

Degree of

freedom Ref.

D

TESTES WEIGHT

RESPONSE

100 mg. LH injected: WR cf . 24

200 mg. LH injected: WR cf —

5 mg. FSH injected : WR. cf 0. 00

10 mg. FSH injected: WR d^ . 04

20 mg. FSH injected: WR <J^ . 16

64 mg. FSH injected: WR & . 64

THYROID WEIGHT

4weeks:NH C —

62 days: WR d' —

11 weeks:

NH cf .04

NH 9 .07

THYROXINE SECRETION

2 to 15 weeks: NH — —

.24

.92

.33

.58

.62

8 : 174

8 174

5 . 174

5 174

5 174

5 174

5 74 169

50 109 172

8 ^6 36

8 66 36

,68 L 18 83 42 178

VISUAL STIMULUS

RESPONSE

24-hour chicks: WL — .59 74 ,66 15 176

Genetic and Phenotypic Correlations

Estimates

The reported estimates of genetic and phenotypic correlations are summarized and reported

in table 5. The number of estimates reported for

many different traits is so large that it precludes

the possibihty of a reasonable discussion of all of

them. In addition, as pointed out in the introduction, the estimates reported vary greatly. For this

reason the discussion will be generalized and

limited to those genetic correlations for which

several estimates have been reported and for

which a reasonable estimate of the average can

be given.

Body weights taken before sexual maturity show

a rather high positive genetic correlation with mature body weights (in the range of 0.52 to 0.68) ;

a positive correlation with pullet egg weight (0.15)

and with mature egg weight (0.37) ; and a small

negative correlation with sexual maturity (—0.10),

measures of egg production (short-term) (—0.12),

and specific gravity (—0.03).

Pullet body weights are positively correlated

with both pullet and mature egg weights (0.34

and 0.40), page 34, as are mature body weight

(0.29 and 0.36), page 34.

Most estimates of the genetic correlation between sexual maturity and different measures of

production are negative but range fram —0.96 to

+0.58. The correlation of sexual maturity with

egg weight is small and positive (0.06 to 0.08),

whereas the correlation of sexual maturity with

specific gravity is quite high (0.29).

When all measures of egg production are considered, an average of genetic correlations between

the traits indicates that egg production shows a

small negative correlation with egg weight (about

—0.05) but considerably larger negative correlations with Haugh units (about — 0.33)j specific

gravity (about —0.31), and shell thickness (about

-0.26).

Egg weight is negatively correlated with albumen quality of pullet eggs (—0.32) and positively

correlated with albumen height of eggs of mature

hens (0.26); with fresh Haugh units for eggs of

mature hens (0.04); and with average specific

gravity (0.13) and average shape of eggs of pullets

and mature hens (0.19).

Albumen quality shows small negative correlations with specific gravity and egg shape (—0.04

and —0.07). Specific gravity appears to be positively correlated with egg shape (0.12).
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 33

TABLE 5.—Reported estimates oj genetic and phenotypic correlations among traits in chickens, by age oj

chickens

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

BODY WEIGHT

3 weeks and—

6 weeks 0.91 0.83

9 weeks .83 .74

12 weeks .70 .68

4 weeks and—

8 weeks .84 .93

8-week breast angle . 22 —

Cumulative number of

matings .31 .07

6 weeks and—

9 weeks .95 .93

12 weeks .92 .62

9-week breast angle .16 —

9-week keel length .71 —

9-week shank length . 77 —

Serum cholesterol level

at 6 weeks — —. 09

8 weeks and—

PuUet body weight .68

Mature body weight . 52

126

126

126

168

167

169

126, 129, 130

126, 126

129

129

129

191

8-week feather score .51

8-week breast angle .28

Age at first egg —. 10

Rate of production:

Short term —.12

34 to 64 weeks of age« . 65

41 to 55 weeks of age_ . 14

56 to 70 weeks of age_ . 01

64 weeks of age —.76

70 weeks of age .11

Survivor production:

To 8 months of age . 05

To 46 weeks of age .15

To 500 days of age. _ _ . 09

Pullet egg weight . 15

Mature egg weight . 37

Haugh units . 12

Albumen height .13

Albumen quality—

USDA score -.21

Specific gravity —. 03

Shape index .23

Aggressiveness . 34

Semen volume .21

Sperm concentration —.16

Sperm motility —.29

Number of matings . 07

Serum cholesterol level

at 6 weeks -.37 .00

. 56 81, 95, 96,

168, 203

.43 41,45,81,

86, 95, 96,

145, 168,

203

. 39 79

.35 164, 173

.07 81, 94, 96,

97, 168, 203

-.07 41, 81, 95,

96, 97,

168, 203,

207

-.02 203

— 96

— 96

-.04 203

— 95,96

117

-.07 86

-.02 62

. 11 95, 96, 203

. 21 45, 81, 95,

96, 97,

168, 203

.32 168

.02 86

95,96

-.08 95, 96, 168

— 95,96

.39 173

.51 168

-1.05 168

-.36 168

-.01 169

191

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

BODY WEIGHT—Con.

8 weeks and—Continued

Shank pigmentation at

8 weeks —.54 —.07

9 weeks and—

12 weeks . 98

Pullet body weight .69

Mature body weight .62

9-week breast angle . 33

308-day breast angle .20

308-day keel length .73

9-week shank length . 79

308-day shank length .83

Age at first egg —.05

Hen housed production—annual .09

Mature egg weight .17

62-day adrenal weight.. _ —. 37

62-day bursa weight . 18

62-day thyroid weight... —. 33

Semen concentration at

6 to 7 months . 04

Sperm motility at 6 to 7

months —.21

Semen quantity at 6 to

7 months . 08

10 weeks and—

Mature body weight . 78

10-week breast angle . 65

Age at first egg .35

Survivor production to

319 days >S.M . 13

Persistency . 26

11-week thyroid

weight .68

11-week testes weight . 35

12 weeks and—

Pullet body weight .79

Mature body weight . 65

12-week breast width . 16

12-week keel length . 74

12-week shank length . 87

Age at first egg —.26

Pullet egg weight .25

Mature egg weight .32 .12

Survivor production:

To 28 weeks of age. __ .22 —

28 to 36 weeks of age. . 08 —

36 to 44 weeks of age.

To 46 weeks of age

Annual

Hen housed production

to 46 weeks of age

Rate of production—

annual

93 126

58 62, 130

— 130

31 48,130

— 102

— 102

— 102

— 105

26 62, ISO

130

38 62, 130

47 172

07 172

26 172

— 177

— 177

— 177

40 127

16 11

18 101,149

— 101

— 101

58 35

40 35

_ 23

— 23

13 3, 34, 106

80 3,106

66 3,106

03 23, 125

23, 125

Pullet and—

Mature body weight

8-week breast angle

06

20

11

— 23

34

— 23

17 — 34

- . 03 125

91

15

. 43 23,

95, 96, 197, 203,

. 18 167
34 AGRICULTUKE HANDBOOK 3'6»3, TJ.S. DEPT. OF AGRICTJIJTURE

TABLE 5.—Reported estimates of genetic arid phenotypic correlations among traits in chickens, by age of

chickens—Continued

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

BODY WEIGHT—Con.

Pullet and—Continued

Age at first egg .03 -.17 7, 23, SO, 62,

63, 68, 96,

96, 203

Survivor production:

To 250 days of age .06 — 63

To 28 weeks of age— .10 — 23

28 to 36 weeks of age, .05 — 23

36 to 44 weeks of age- -.03 — 23

To 46 weeks of age .09 .03 86

250 to 450 days -.30 — 63

To 450 days -. 16 , ., 63

Airn^ial^ . -^ ^ x^T- .06 — 23

Rate of production:

Short term —. 15 .01 95, 96, 203

Dec. 1 to March 1 .68 197

March 2 to May 31 .54 — 197

34 to 64 weeks of age- -.58 -.05 203

41 to 55 weeks of age- .15 — 96

56 to 70 weeks of age- -.09 — 96

To May 31 .56 197

To 64 weeks of age— -.16 -.03 203

To 70 weeks of age -.09 — 95,96

Pullet egg weight .34 .25 7,23, Ifi, 95,

96, 203

Mature egg weight .40 .17 23, SO, 62, 63,

86, 95, 96,

197, 203

Albumen quality—

USDA score -.05

-.05 .05

95,96

Albumen height 86

Specific gravity ^ -.02 — 95,96

Shape index .06 -.01 86, 95, 96

Persistency .67 — 7

Mating frequency .17 -.01 169

Mature and—

8-week breast angle .13 .16 167

Aire at first eetr ,06 . 12 7, 23,89, 91,

95, 96,101,

149,161,

203

Survivor production:

1 month -.29

—.43

-.42

-.12

-.08

-.06

89

2 months - - 89

3 months 89

28 weeks .06

.01

23

28 to 36 weeks of age- 23

36 to 44 weeks of age« .09 — 23

Short term -.51

-.01

-.10

.06

89

To 11 months of age.- 2S,88

To 319 day>maturity. .07 — 101

Annual .03 .11 89,161

Hen housed production

to 44 weeks of age .12 -.11 78

Rate of production:

Dec. 1 to Mar. 1 -.31 — 197

Mar. 2 to May 31 .71 — 197

Short term .00 . 05 4U 91, 96,

96, 203, 207

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

BODY WEIGHT—Con.

Mature and—Continued

Rate of production—

Continued

34 to 64 weeks of age- —. 44

41 to 55 weeks of age- —, 04

56 to 70 weeks of age- . 00

Winter —. 12

64 weeks of age —. 06

To 70 weeks of age —, 11

Annual , 16

Persistency , 16

Pullet egg weight .29

Mature egg weight .36

Albumen quality—

USDA score _— —.03

Albumen height .06

Haugh units . 01

Haugh units—afresh . 17

Haugh units—stored —. 13

Haugh unit loss in 2

weeks . 69

Specific gravity .09

Shape index .05

Shell color —.06

Serum cholesterol level:

At 6 weeks —.37

At 8 months —

WEIGHT GAIN

0 to 3 weeks and—

3 to 6 weeks , 87

6 to 9 weeks —

9 to 12 weeks —.20

3 to 6 weeks and—

6 to 9 weeks —

9 to 12 weeks . 47

6 to 9 weeks and—

9 to 12 weeks —.48

FEATHERING

10-day back and—

10-day breast feathering- —

5-week back feathering— —

7-week back feathering— —

10-week pinfeathers —

10-week down score —

10-day breast and—

5-week back feathering.- —

7-week back feathering., —

10-week pinfeathers —

10-week down score —

5-week back and—

10-week pinfeathers —

10-week down score —

-.04

,39

.22

,09

.25

.24

.01

96

03 72

05 203 — 95,96

17 91 — 101

08 23, 95, 96,

161, 203

23 23,41,45,72,

78, 88, 89,

91,95,96,

U^y 146,

197, 203

— 95,96, 207

12 88

16 88

28 93

93 93

26 98

01 88, 95, 96 — 95, 96

03 88

03 191

02 191

u

u

u

u

u

u

53 170

28 170

28 170

08 170

12 170

30 170

29 170

17 170

09 170

10 170

21 170
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 35

TABLE 5.—Reported estimates oj genetic and phenotypic correlations among traits in chickens, by age of

chickens—Continued

Traits correlated

Correlation

Ge- Phenonetic typic

BREAST ANGLE

8-week and—

59-day live weight .27 .38

59-day eviscerated

weight .06

8-week feathering .08

Age at first egg .04

Rate of production—

annual . 02

Mature egg weight .11

Haugh unit loss in 2

weeks .00

Specific gravity —.32

Semen volume .15

Sperm concentration . 86

Sperm motility . 35

Number of matings —. 12

9-week and—

Broiler weight .21

9-week keel length .22

9-week shank length —. 12

12-week breast width and—

12-week shank length— .35 .38

KEEL LENGTH

SEXUAL MATURITY

Age at first egg and—

Survivor production:

To 28 weeks of age —.96

28 to 36 weeks of age. -. 32

36 to 44 weeks of age_ —.10

To 44 weeks of age —.58

To 46 weeks of age —. 58

Winter -.72

Short term —.59

To 500 days of age —. 65

Annual —. 23

Hen housed production:

To 46 weeks of age___ —. 22

Short term —.62

-.48

-.20

-.34

Ref.

FEATHERING—Con.

7-week back and—

10-week pinfeathers

10-week down score

— -. 23

-. 29

170

170

10-week pinfeathers and—

10-week down score — . 13 170

Breast feathering and—

Breast blisters in

broilers .50 .70 58

171

38 171

07 167

01 167

02 167

16 167

04 167

15 167

13 167

22 167

27 167

01 169

__ 131

— 129, 131

— 129, 131

3,106

12-week and—

12-week shank length .55 .52 3,106

12-week breast width --.35 -.07 3,106

23

23

34

2

17, 34, 63

7

17, 30, 39, 63,

89, 101, 161

34

186

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

SEXUAL MATURITY—

Continued

Age of first egg and—Con.

Rate of production:

Short term —.79

34 to 64 weeks of age- —. 34

41 to 55 weeks of age. —. 04

56 to 70 weeks of age. —. 03

To 60 weeks of age__- -.33

To 64 weeks of age .58

To 70 weeks of age . 04

Annual —. 50

Pullet egg weight .06

Mature egg weight .10

Albumen quality—

USDA score .00

Haugh units—fresh .37

Haugh units—stored

2 weeks .35

Haugh units loss in

2 weeks —.09

Specific gravity . 29

Egg Shape . 16

Percent blood spots —. 10

Serum cholesterol level:

Atôweeks .33

At 8 months —

Persistency —. 15

SURVIVOR

PRODUCTION

To 28 weeks of age and—

28 to 36 weeks of age. __ . 43

36 to 44 weeks of age . 20

To 44 weeks of age . 70

Pullet egg weight . 17

Mature egg weight —. 04

28 to 36 weeks of age

and—

36 to 44 weeks of age .67

To 44 weeks of age . 86

PuUet egg weight .27

Mature egg weight —.31

36 to 44 weeks of age

and—

To 44 weeks of age . 80

Pullet egg weight . 13

Mature egg weight —. 15

Short term and—

400 to 450 days of age__ . 77

300-day production .56

Too 500 days of age .67

Annual . 43

Rate of production—

short term .30

Egg mass to January . 91

Pullet egg weight .24

Mature egg weight —.15

10 46,91,95,96,

97, 203, 207

01 203 — 96 — 96 — 30

07 203 — 95,96

27 91,92

23 7, 23, 95,

96, 161

01 2, 7,23,39,89,

95, 96, 203

30, 95, 96

32 93

31 93

04 93 — 95, 96 — 95, 96

02 39

04 191

02 191 — 7

23

— 63

42 146

50 146

55 17, 107, 146

22 146

94 187 — 23

04 23, 29, 63, 69,

78, 89, 187
36 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 5.—Reported estimates oj genetic and vhenotypic correlations among traits in chickens, by age of

chickens—^Continued

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

SURVIVOR PRODUCTION—Continued

Short term and—Con.

Albumen quality—

USDA score „_ -.20

Specific gravity .09

Egg shape —.29

Annual and—

Winter . 85

To 500 days of age .96

AnnuaU .73

Rate of production to

60 weeks of age .83

Pauses >6 days .59

Pauses <6 days —. 59

Persistency . 38

Pullet egg weight —. 02

Mature egg weight —.04

Percent blood spots .08

Percent meat spots .01

Albumen quality—

USDA score -.37

Albumen height —. 04

Haugh units —.28

Specific gravity —. 30

Shell thickness -.26

Egg shape —.18

Yolk color -.21

Viability . 67

Serum cholesterol level

at 6 weeks .37

Serum alkaUne

phosphatase .50

HEN HOUSED

PRODUCTION

Short term and—

First month .69

Second month .69

Third month .89

Annual 1.21

RATE OF

PRODUCTION

34 to 64 weeks of age

and—

To 64 weeks of age_

41 to 55 weeks of age

and—

56 to 70 weeks of age.

Annual

Short term and—

34 to 64 weeks of age_

41 to 55 weeks of age.

56 to 70 weeks of ageTo 64 weeks of age_ » _

.58

88

.87

.67

.76

.45

.19

22 29

30 29

07 29,69

73 29

94 146

61 146

— 30

— 101

— 101

— 101

11 161

03 7, 29, 62, 63,

69, 88, 89,

150,187

03 39

— 118

14 29,150,184

02 88

21 50, 88, 139,

150

13 29, 88,136

05 50,150,184

05 29,69

— 184

— 101

06 191

01 192

01

,05

,04

35 185

93 185

78 185

65 185

96

203

96

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

RATE OF PRODUCTION—Continued

Short term and—Con.

Annual .90

Pullet egg weight .45

Mature egg weight —.03

Albumen quality—

USDA score . 08

Specific gravity *-.41

Shapeindex —.10

Annual and—

Rate of production to 60

weeks of age .91

Mature egg weight .01

Albumen quality—

USDA score . 00

Haugh umts—afresh —. 38

Haugh tmits—stored 2

weeks —.50

Haugh unit loss in 2

weeks^_, .36

Specific gravity —.23

Shapeindex .17

Persistency . 65

EGG WEIGHT

Pullet and—

Rate or production:

34 to 64 weeks of age_ —. 04

41 to55 weeks of age__ —.17

56 to 70 weeks of age. _ —. 09

Shorti^erm —.49

To 64 weeks of age —. 23

AnnuaL —.42

Mature egg weight .83

Albumen quality—

USDA score -.32

Specific gravity .09

Mature and—

Survivor production:

To 46 weeks of age —.16

Winter —.38

Rate of production:

34 to 64 weeks of age- . 07

41 to 55 weeks of age, —. 20

56 to 70 weeks of age_ —. 37

Short term —.31

To 64 weeks of age . 09

Annual —. 36

Albumen quality—-

USDA score . 14

Albumen height .26

Haugh units —.04

Haugh units—fresh . 04

Haugh units—stored 2

weeks- . 02

10

01

95,96

203

91, 203, 207

—

' 95, 96, 207

95, 96, 207

95, 96, 207

11

30

91

02

03

91, 94, 96

93

77 93

07 93

94,96

94,96

7

04

04

96

96

95,96,151

— 95,96

29 7, ^3, 95, 96,

203

— 95,96

— 95,96

.01

02

86

96

— 95,96,207

. 05 203

— 95, 96

. 05 29, 30, 95, 96,

136

.31 86, 88, 150,

199

,05 88

, 22 93,150,199

34 93
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 37

TABLE 5.—Reported estimates oj genetic and phenotypic correlations among traits in chickens^ by age of

chickens—Continued

Traits correlated

Correlation

Ge- Phenonetic typic

Ref.

EGG WEIGHT—Con.

Mature and—Continued

Haugh unit loss in 2

weeks . 79

Specific gravity .16

Shell thickness .25

Percent blood spots —. 04

Percent meat spots ~. 04

Egg shape . 07

Shell color —.02

Yolk weight . 83

Yolk weight/egg weight. — 1. 00

Serum cholesterol level:

At 6 weeks —.35

At 8 months —

BLOOD SPOTS

Percent and—

Rate of production to

60 weeks of age —.13

Shell thickness .44

Serum cholesterol level

at 6 weeks .00

MEAT SPOTS

Percent and—

Shell thickness

Serum cholesterol level

at 6 weeks

.43

.00

ALBUMEN

Quality and—

Rate of production:

41 to 55 weeks of age_ . 00

56 to 70 weeks of age. —. 48

Albumen quality—

stored . 94

Specific gravity —.04

Egg shape —.07

Serum cholesterol level

at 6 weeks .23

Height and—

Survivor production:

In March -. 13

To 46 weeks of age . 00

Percent meat spots —. 16

Haugh units .96

Specific gravity —.37

Shell thickness .14

Egg shape . 20

Hatching date .13

Haugh units and—

Survivor production in

March —.24

Percent meat spots —. 19

Albumen quality—

USDA score -.85

43 98

00 29, 88, 95, 96,

136

24 160

00 39

— 118

06 29, 69, 86, 96,

96

06 76,88

55 63

42 63

07 191

18 191

05

08

74

17

12

,04

30

115

191

118

191

96

96

136

29, 95, 96,131

29, 30, 95, 96

191

24 199

03 86

— 118

94 88, 199

27 90

15 150, 199

20 86

08 199

23 199

— 118

55 93

Traits correlated

Correlation

Ge- Phenonetic typic

ALBUMEN-^Continued

Haugh units and—Con.

Haugh units—stored 2

weeks .96

Shell thickness .18

Specific gravity . 21

Shell color -.01

Percent hatch:

Of fertile eggs .45

Of all eggs -.39

Hatching date —.23

Serum cholesterol level:

At 6 week;s —

At 8 months —

Haugh unit loss in 2 weeks

and—

Albumen quality—

USDA score -.14

Haugh units—fresh —. 15

Haugh units—stored

2 weeks —.38

Haugh units—stored/

Haugh units—afresh —. 89

SHELL QUALITY

Specific gravity and—

Rate of production:

41 to 55 weeks —.44

56 to 70 weeks -.25

Egg shape .12

Shell color -.09

Shell thickness and—

Percent hatch:

Of fertile eggs —.13

Of all eggs —.20

Shell strength and—

Serum cholesterol level:

At 6 weeks . 00

At 8 months —

Egg shape and—

Survivor production to

46 weeks . 12

Rate of production :

41 to 55 weeks . 37

56 to 70 weeks . 25

HATCHABILITY

Percent hatch of fertile

eggs and—

Survivor production—

October to July .30

Hen housed production—October to July« . 23

Hen day production—

October to July .31

Current egg production.- . 96

Weeks in production . 22

Weeks of age —

Percent inbreeding —

Fertmty . 36

Percent hatch of all eggs _ —

. 11

,07

,06

,03

,03

. 19

.05

.23

02

.36

.42

.96

07

. 16

.25

. 13

.05

.04

.06

.01

. 18

.78

Ref.

116

50, 199

88

88

50

60

199

191

191

93

93

93

03

04

96

96

29, 96, 96

88

05

08

60

60

08

02

191

191

86

96

96

71

71

71

25

3,145
38 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

TABLE 5.—Reported estimates oj genetic and phenotypic correlations among traits in chickens, by age oj

chickens—Continued

Traits correlated

Correlation

Ge- Phenonetic typic

HATCHABILITY—Con.

Percent hatch of all eggs

set and—

Fertility

COMB WEIGHT

Single and—

Testes weight -.03

69

07

THYROID

Weight and—

11-week testes weight-.

62-day adrenal weight.

62-day bursa weight--.

BURSA

62-day weight and—

62-day adrenal weight.

MATIN GS

Number of completed

and—

40 .37

09 -.02

25 -.00

-. 18 ,05

APPROACHES

Number of normal and—

Number of abnormal

approaches

Number of crouches

Mild avoidances

Strong avoidances

Ref.

84

36

172

172

172

Number of courts .36 .54 20A

Number of courts .36 .60 169

Number of mounts .71 .94 169

Number of treads .82 .97 169

Relative aggressiveness_ .08 .09 169

Number of normal

approaches — .91 204

Number of abnormal

approaches — .30 204

Semen appearance score. — . 13 204

1. Sperm motility .23 .03 204

2. Sperm motility .23 .01 169

3. Semen volume -.38 .07 204

4. Semen volume -.38 -.04 169

5. Sperm concentration- — . 15 204

6. Sperm concentration. -.67 .01 169

Number of crouches — .68 204

Mild avoidances — .48 204

Strong avoidances — .23 204

Percent fertility — .35 204

COURTS

Number and—

Number of normal approaches — .44 204

Number of abnormal

approaches — .17 204

Number of crouches — .59 204

Mild avoidances — .94 204

Strong avoidances — .43 204

22 204

63 204

44 204

39 204

Traits correlated

Correlation

Ge- Phenonetic typic

APPROACHES—Con.

Number of abnormal and—

Number of crouches

Mild avoidances

Strong avoidances

CROUCHES

Number and—

Mild avoidances

Strong avoidancesSEMEN

Appearance score and—

Motility score —

Volume —

Optical density —

Sperm count —

Percent fertility —

Volume and—

Optical density score —

Sperm motility .04

Sperm count —

Percent fertility —

Optical density and—

Sperm count —

Percent fertility —

Quantity and—

Sperm concentration —. 04

Sperm motility .04

SPERM

Motility and—

Volume —

Optical density —

Sperm count —.04

Percent fertility —

Count and—

Sperm motiUty .51

Percent fertility —

Concentration and—

Sperm motility .51

25

, 12

.26

51

, 16

, 12

,57

,38

31

04

Ref.

204

204

204

59 204

21 204

87 204

39 204

22 204

26 204 — 177

12 204

15 204

48 204

20 204

177 — 177

204

204

177, 204

177

204

177

Adult and—

Hen housed production—October to July- -.56 -.22 71

Hen day production—

October to July -.27 -.67 71

Hen day production to

365days>S.M .42 . 14 144

Total leucosis mortality. .90 — 113

Total nonleucosis

mortality .83 •— 113

Total mortality .54 — 113

Broodiness .03 . 11 145

Percent hatch of fertiles _ -.33 -.05 71
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 39

GENERAL CONCLUSIONS

The extreme variability of reported estimates is

perhaps one of the most obvious features of a

summary of reported heritability and of genetic

or phenotypic correlation estimates. Standard

errors of estimates are usually large, even where

estimates are made from large populations. For

this reason, the value of estimates of these parameters in a specific population is questionable to

one interested in a genetically different population.

Another feature that is obvious from a review

of the literature on genetic parameter estimates

is lack of information regarding the importance of

genotype environment interactions and maternal,

dominance, epistatic, or other effects that may or

may not be important in the genetic study of

various traits. These effects have been expeditiously handled in many cases simply by assmning

that they are negligible or do not exist. It seems

that more studies designed to estimate the importance of these effects would be well justified.

It seems reasonable to conclude that suflBcient

estimates oí the heritability of body weights, egg

weights, sexual maturity, and measures of egg

production have been reported so that averages

provide meaningful estimates of expected values

of this parameter. For most other traits reported

estimates are too few to provide meaningful

approximations of the heritability. Additional

estimates would be of some value. However, it

does not seem that studies designed to estimate

heritability are justified unless they are a byproduct of a selection experiment or some other

genetic study.

For reasons discussed earlier, individual estimates of genetic or phenotypic correlations are of

little value except as they relate to a specific

genetic study. If a very large number of these are

reported for any two traits, averages would provide an expected value for the parameters but

these approximations would be quite unreliable.

Thus, although reported estimates of genetic or

phenotypic correlations are of some general interest, they are of principal value as they relate to

specific populations and should be recognized as

such.

REFERENCES

(1) ABPLANALP, HANS.

1956. SELECTION PROCEDURES FOR POULTRY FLOCKS WITH MANY HATCHES.

Poultry Sei. 35: 1285-1304.

(2)

1957. GENETIC AND ENVIRONMENTAL CORRELATIONS AMONG PRODUCTION

TRAITS OF POULTRY. Poultry

Sei. 36: 226-228.

(3) AsMUNDSON, V. S., and LERNER,

1. M.

1960. EXPERIMENTAL TESTS OP A SELECTION INDEX. Poultry Sei. 39:

151-160.

(4) LowRY, D. C, LERNER, I. M.,

and DEMPSTER, E. R.

1964. SELECTION FOR EGG NUMBER WITH

X-RAY INDUCED VARIATION. Genetics 50: 1083-1100.

(5) AMER, M. F,

1965. HERITABILITY OF BODY WEIGHT

IN FAYOUMI. Poultry Sei. 44:

741-744.

(6)

1967. HERITABILITY OF EGG PRODUCTION

AND EGG WEIGHT IN THE

FAYOUMI. Poultry Sei. 46: 32-

35.

(7) BACZKOWSKA, H., and KAMINSKA, B.

1964. GENETIC ENVIRONMENTAL AND

PHENOTYPIC CORRELATIONS BETWEEN SOME ECONOMIC CHARACTERS IN LAYING HENS. (Abstract) Anim. Breeding Abs.

33: 3772.

(8) KAMINSKA, B., and FREUNDLICK,

1963. STUDIES ON THE HERITABILITY OF

SOME CHARACTERS OF ECONOMIC

IMPORTANCE IN LAYING HENS

BASED ON MATERIAL FROM TWO

BREEDING FARMS. (Abstract)

Anim. Breeding Abs. 32: 3412.

(9) BECKER, W. A.

1964, HERITABILITY OF A RESPONSE TO

AN ENVIRONMENTAL CHANGE IN

CHICKENS. Genetics 50: 783-

788.

(10) and BERG, L. R.

1960. THE RELATIONSHIP BETWEEN THE

NUTRITIONAL ENVIRONMENT AND

SELECTION FOR BODY WEIGHT.

(Abstract) Poultry Sei. 39: 1234.
40 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

(11) BEILHARZ, R. G., and MCDONALD, M. W. (21)

1961. A COMPARISON OP WHITE LEGHORNS,

AUSTRALORPS AND THEIR RECIPROCAL CROSSES. Austral.

Jour. Agr. Ees. 12: 539-546.

(12) BLOW, W, L., BOSTIAN, C. H., and GLAZENER, E. W.

1950. THE INHERITANCE OF EGG SHELL (22)

COLOR. Poultry Sei. 29: 381-

385.

(13) BOHREN, B. B., HILL, W. G., and ROBERTSON, A,

1966. SOME OBSERVATIONS ON ASYMMET- (23)

RICAL CORRELATED RESPONSES

TO SELECTION. Genet. Res. 7:

44-57.

(14) BOWER, R. K.

1962. A QUANTITATION OP THE INFLUENCE (24)

OP THE CHICK EMBRYO GENOTYPE ON TUMOR PRODUCTION BY

ROUS SARCOMA VIRUS ON THE

CHORIOALLANTOIC MEMBRANE.

Virology 18:372-377.

(15) BOYER, J. P., DELAAGE, X., and CALET, C. (25)

1963. INFLUENCE OF PEED ON THE HERITABILITY OP SOME CHICKEN

TRAITS. (Abstract) 11th Internatl. Cong. Genet. I, Proc, p.

262.

(16) BRANDSCH, H.

1961. HERITABILITY AND SELECTION IN

PREDIGREE POULTRY BREEDING

IN AN AGRICULTURAL PRODUCTION COOPERATIVE. (Abstract)

Anim. Breeding Abs. 29: 2363,

(17) BRAY, D. F., KING, S. C, and ANDERSON,

V. L.

1960. SEXUAL MATURITY AND THE MEASUREMENT OP EGG PRODUCTION.

Poultry Sei. 39:590-601.

(18) BRUNSON, C. C, GODFREY, G. F., and

GOODMAN, B. L.

1955, HERITABILITY ESTIMATES OF HATCHABILITY AND RESISTANCE TO

DEATH TO TEN WEEKS OF AGE.

(Abstract) Poultry Sei. 34:1182.

(19) GODFREY, G.F., and GOODMAN,B-L1955. TYPES OF GENE ACTION IN THE

INHERITANCE OF TEN WEEK BODY

WEIGHT AND BREAST ANGLE IN

BROILERS. (Abstract) Poultry

Sei. 34: 1183.

(20) GODFREY, G. F., and GOODMAN,

B. L.

1956. HERITABILITY OP ALL-OR-NONE (30)

TRAITS. HATCHABILITY AND RESISTANCE TO DEATH TO TEN

WEEKS OF AGE. Poultry Sei.

35:516-523.

(26)

(27)

(28)

(29)

GODFREY, G. F., and GOODMAN,

B.L,

1956. TYPES OP GENE ACTIOl^ IN THE

INHERITANCE OF TEN-WEEK BODY

WEIGHT AND BREAST ANGLE IN

BROILERS. Poultry Sei. 35: 524-

532.

CHERMS, F. L., JR., WILCOX, F. H., and

SHOPFNER, C. S.

1960. GENETIC STUDIES OP SERUM CHOLESTEROL LEVEL IN THE CHICKEN. Poultry Sei. 39: 889-892.

CLAYTON, G. A., and ROBERTSON, A.

1966. GENETICS OP CHANGES' IN ECONOMIC TRAITS DURING THE LAYING YEAR. Brit. Potiltry Sei.

7:143-151.

CRITTENDEN, L. B., and BOHREN, B. B.

1961. THE GENETIC AND ENVIRONMENTAL

EFFECTS OF HATCHING TIME, EGG

WEIGHT AND HOLDING TIME ON

HATCHABILITY. Poultry Sei. 40:

1736-1750.

and BOHREN, B. B.

1962. THE EFFECTS OP CURRJENT EGG

PRODUCTION, TIME IN PRODUCTION, AGE OF PULLET AND INBREEDING ON HATCHABILITY AND

HATCHING TIME. Poultry Sei.

41:426-433.

BOHREN, B. B., and ANDERSON,

V.L.

1957. GENETIC VARIANCE AND COVARIANCE OP THE COMPONENTS OP

HATCHABILITY IN NEW HAMPSHIRES. Poultry Sei. 36: 90-

103.

DAVIS, G. T.

1955. INFLUENCE OF OXYGEN CONCENTRATION ON HATCHABILITY AND

ON SELECTING FOR HATCHABILITY. Poultry Sei. 34: 107-113.

DEMPSTER, E. E., LERNER, I. M., and

LOWRY, D. C.

1952. CONTINUOUS SELECTION FOR EGG

PRODUCTION IN POULTRY. Genetics 37: 693-708.

DiCKERSON, G. E.

1955. GENETIC SLIPPAGE IN RESPONSE

TO SELECTION FOR MULTIPLE

OBJECTIVES. Cold Spring Harbor Symp. Quantitative Bid.

20:213-224.

1957. GENETIC COVARIATION AMONG SOME

ECONOMIC CHARACTERS OP LEGHORN-TYPE CHICKENS. (Abstract) Poultry Sei. 36: 1112.
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 41

(31)

(32)

(33)

(34)

1957.

1960.

GENETIC VAHIATION IN SOME ECONOMIC CHAEACTEES OP LEGHOENTTPE CHICKENS. (Abstract)

Poultry Sei. 36: 1113.

(35)

(36)

(37)

(38)

(39)

(40)

(41)

TECHNIQUES FOR RESEARCH IN

QUANTITATIVE ANIMAL GENETICS.

TECHNIQUES AND PROCEDURES

IN ANIMAL PRODUCTION RESEARCH, pp. 56-105. New York.

and LAMAREAUX, W. F.

1954. REPEATABILITY AND HERITABILITY

OF ALBUMEN QUALITY IN WHITE

LEGHORNS. (Abstract) Poultry

Sei. 33: 1053.

DILLARD, E. U., DICKERSON, G. E., and

LAMAREAUX, W. F.

1953. HERITABILITIES OF EGG AND MEAT

PRODUCTION QUANTITIES AND

THEIR GENETIC AND ENVIRONMENTAL RELATIONSHIPS IN NEW

HAMPSHIRE PULLETS. (ABstract) Poultry Sei. 32: 897.

EL-IBIARY, H. M., and SHOFFNER, C. S.

1951. THE EFFECT OF INDUCED HYPOTHYROIDISM ON THE GENETICS

OF GROWTH IN THE CHICKEN.

Poultry Sei. 30: 435-444.

ERASMUS, J. E.

1965. SELEKSIE VIR 12-WEKE LIGGAAMSGEwiG BY KUIKENS. Soutb African

Jour. Agr. Sei. 8: 831-837.

FALCONER, D. S.

1960. INTRODUCTION TO QUANTITATIVE

GENETICS. 370 pp., illus. New

York.

FARNSWORTH, G. M. and NORDSKOG, A. W.

1955. BREEDING FOR EGG QUALITY, 3.

GENETIC DIFFERENCES IN SHELL

CHARACTERISTICS AND OTHER

EGG QUALITY CHARACTERISTICS.

Poultry Sei. 34: 16-26.

and NORDSKOG, A. W.

1955. ESTIMATES OF GENETIC PARAMETERS INFLUENCING BLOOD

SPOTS AND OTHER ECONOMIC

TRAITS OF THE FOWL. (Abstract)

Poultry Sei. 34: 1192.

FESTINO, M. F., and NORDSKOG, A. W.

1967. RESPONSE TO SELECTION FOR BODY

WEIGHT AND EGG WEIGHT IN

CHICKENS. Genetics 55: 219-

231.

FRIARS, G. W., BOHREN, B. B., and

MCKEAN, H. E.

1962. TIME TRENDS IN ESTIMATES OF GENETIC PARAMETERS IN A POPULATION OF CHICKENS SUBJECTED TO

MULTIPLE OBJECTIVE SELECTION.

Poultry Sei. 41: 1773-1784.

(42) FUCHS, M. H., and KRUEGER, W. F.

1957. A COMPARISON OF THE GENETIC

VARIANCE OF PUREBRED AND

STRAIN CROSS WHITE LEGHORNS.

(Abstract) Poultry Sei. 36: 1120.

(43) GAFFNEY, L. T.

1964. STUDIES ON GROWTH RATE AND

ESTIMATES OF THE HERITABILITY

OF BODY WEIGHT IN BROILER

STOCK. Austral. Poultry Sei.

Conv. Proc., pp. 74-78.

(44) GARBER, M. J., and GODBEY, C. B.

1952. THE INFLUENCE OF SIRE, DAM AND

HATCHING DATE ON SPECIFIC

RATE OF GROWTH OF SINGLE

COMB WHITE LEGHORN PULLETS

FROM HATCHING TO TWELVE

WEEKS OF AGE. Poultry Sci.

31: 945-955.

(45) GHOSTLEY, J. E., and NORDSKOG, A. W.

1956. EFFICIENCY OF INDEX SELECTION

FOR EGG WEIGHT AND FOR

GROWTH RATE. (Abstract)

Poultry Sei. 35: 1144.

(46) GiESBRECHT, F. G., and NORDSKOG, A, W.

1963. ESTIMATING AGE AT SEXUAL MATURITY FROM FLOCK RECORDS.

Poultry Sei. 42: 83-87,

(47) GiLBREATH, J. C, WELCH, Q. B., and

MORRISON, R. D.

1962. EFFECTS OF SELECTION AND OUTBREEDING ON HATCHABILITY IN

CHICKENS. Okla. Agr. Expt.

Sta. Tech. Bui. T-96, 12 pp.

(48) GODFREY, G. F., and GOODMAN, B. L.

1956. GENETIC VARIATION AND COVARIATION IN BROILER BODY WEIGHT

AND BREAST WIDTH. Poultry

Sei. 35: 47-50.

(49) GOODMAN, B. L., and NEWELL,

G. W.

1954. REPEATABILITY AND HERITABILITY

ESTIMATES OF ALBUMEN QUALITY. (Abstract) Poultry Sei.33 :

1056.

(50) GOODMAN, B. L., and GODFREY, G. F.

1955. GENETIC, PHENOTYPIC AND ENVIRONMENTAL CORRELATIONS BETWEEN SOME EGG QUALITY TRAITS

AND EGG PRODUCTION AND

HATCHABILITY. (Abstract)

Poultry Sei. 34: 1197.

(51) and GODFREY, G. F.

1956. HERITABILITY OF BODY WEIGHT IN

THE DOMESTIC FOWL. Poultry

Sei. 35: 50-53.

(52) GRIMES, J. F., and JAAP, R. G.

1957. REPEATABILITY ESTIMATES OF

GENETIC VARIANCE WITHIN TWO

CLOSED-FLOCK STRAINS. (Abstract) Poultry Sei. 36: 1121.
42 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

(53)

(54)

(55)

(56)

(57)

(58)

(59)

(60)

(61)

GOODMAN, B. L., and JAAP, R. G.

1960. IMPROVING ACCURACY OF HERITABILITY ESTIMATES FROM DIALLEL

AND TRIALLEL MATINGS IN POULTRY. 1. EIGHT-WEEK BODY

WEIGHT IN CLOSED FLOCK

STRAINS. Poultry Sei. 39: 938-

943.

and JAAP, R. G.

1960. IMPROVING ACCURACY OF HERITABILITY ESTIMATES FROM DIALLEL

AND TRIALLEL MATINGS IN

POULTRY. 2. WEIGHT OF SPLEEN

AND BURSA OP FABRICIUS IN A

RANDOMBRED POPULATION.

Poultry Sei. 39: 944-949.

and JAAP, R. G.

1961. NON-ADDITIVE AND SEX-LINKED

GENETIC EFFECTS ON EGG PRODUCTION IN A RANDOMBRED POPULATION. Poultry Sei. 40: 662-

668.

GowE, R. S., BuDDE, H. W., and MCGANN,

P. J.

1965. ON MEASURING EGG SHELL COLOR

IN POULTRY BREEDING AND SELECTION PROGRAMS. Poultry

Sei. 44:264-270.

GUHL, A. M., CRAIG, J. V., and MUELLER,

CD.

1960. SELECTIVE BREEDING FOR AGGRESSIVENESS IN CHICKENS. Poultry

Sei. 39: 970-980.

GYLES, N. R., KAN, J., and SMITH, R. M.

1962. THE HERITABILITY OP BREAST

BLISTER CONDITION AND BREAST

FEATHER COVERAGE IN A WHITE

ROCK BROILER STRAIN. Poultry

Sei. 41: 13-17.

HALE, R. W.

1954. HERITABILITY OF CHICK VIABILITY

IN A WHITE WYANDOTTE FLOCK.

Jour. Agr. Sei. 44: 221-226.

1959. HERITABILITY OF LAYING-HOUSE

VIABILITY IN A WHITE WYANDOTTE FLOCK. Poultry Sei. 38:

471-474.

(62)

1961. GENOTYPE-ENVIRONMENT INTERACTIONS IN A COMPARISON OF THE

CAGE AND SEMI-INTENSIVE SYSTEMS FOR LAYING HENS. Brit.

Poiütry Sei. 2: 145-157.

1961. HERITABILITIES AND GENETIC CORRELATIONS OP EGG PRODUCTION

AND OTHER CHARACTERS IN A

WHITE WYANDOTTE FLOCK.

Anim. Prod. 3: 73-87.

(63)

(64)

(65)

(66)

(67)

(68)

(69)

and CLAYTON, G. A.

1965. A DIALLEL CROSSING EXPERIMENT

WITH TWO BREEDS OP LAYING

FOWL. Brit. Poultry Sei. 6:

153-174.

HAYS, F. A.

1951. FURTHER STUDIES ON ENVIRONMENTAL AND HEREDITARY

FACTORS AFFECTING WINTER

PAUSE INCIDENCE AND DURATION. Poultry Sei. 30:100-105.

1954. TESTING FOR OVERDOMINANCE AND

EPiSTASis. Poultry Sei, 33:

1105-1106.

(70)

(71)

(72)

(73)

1954. INHERITANCE OP VIABILITY OP PULLETS IN THE LAYING HOUSE.

Poultry Sei. 33: 1107-1108.

HAZEL, L. N.

1943. THE GENETIC BASIS FOR CONSTRUCTING SELECTION INDEXES.

Genetics 28: 476-490.

and LAMAREAUX, W. F.

1947. HERITABILITY OP MATERNAL EFFECTS AND NICKING IN JIELATION

TO SEXUAL MATURITY AND BODY

WEIGHT IN WHITE LEGHORNS.

Poultry Sei. 26: 508-514.

HICKS, A. F., JR.

1958. HERITABILITY AND CORRELATION

ANALYSES OF EGG WEIGHT, EGG

SHAPE AND EGG NUMBER IN

CHICKENS. Poultry Sei. 37:

967-975.

Buss, E. G., and MAW, A. J. G.

1961. THE HERITABILITIES 0¥ SEASONALLY DETERMINED EGG QUALITY

TRAITS. Poultry Sei. 40: 821-

822.

HILL, J. F., DICKERSON, G. E., and

KEMPSTER, H. L.

1954. SOME RELATIONSHIPS BETWEEN

HATCHABILITY, EGG PRODUCTION

AND ADULT MORTALITY. (ABstract) Poultry Sei. 33: 1059.

HoGSETT, M. L., and NORDSKOG, A. W.

1958. GENETIC-ECONOMIC VALUE IN SELECTING FOR EGG PRODUCTION

RATE, BODY WEIGHT AND EGG

WEIGHT. Poultry Sei. 37: 1404-

1419.

VON KROSIGK, C. M., and

MCCLARY, C. F.

1964. GENETIC AND PHENOTYPIC VARIANCE-COVARIANCE ESTIMATES

AND THEIR APPLICATION TO

INDEX-RECIPROCAL RECURRENT

SELECTION FOR EGG PRODUCTION. (Abstract) Poultry Sei.

43: 1329.
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 43

(74)

(75)

(76)

(77)

(78)

(79)

(80)

HoRTON, I. F., and MCBRIDE, G.

1964. GENETIC FACTORS AFFECTING SEX

DIMORPHISM IN BODY WEIGHT OF

MEAT CHICKENS. Austial. Poultry Sei. Conv. Proc. pp. 79-81.

HUNTON, P.

1962, GENETICS OF EGG SHELL COLOUR

IN A LIGHT SUSSEX FLOCK. Blit.

Poultry Sei. 3: 189-193.

(84)

1964. GENETICS OF EGG SHELL COLOUR:

COVARIANCE WITH EGG NUMBER

AND EGG SIZE. Brit. Poultry

Sei. 5:45-^8.

HURNIK, J.

1963. THE HERITABILITY OF SOME PRODUCTIVE CHARACTERS IN POULTRY. (Abstract) Anim. Breeding Abs. 32: 577.

1965. CORRELATIONS BETWEEN ECONOMIC

CHARACTERS IN POULTRY. (Abstract) Anim. Breeding Abs. 33:

2858.

HURRY, H. F., and NORDSKOG, A. W.

1953. A GENETIC ANALYSIS OP CHICK

FEATHERING AND ITS INFLUENCE

ON GROWTH RATE. Poultry Sei.

32:18-25.

IDETA, G., and SIEGEL, P. B.

1966. SELECTION FOR BODY WEIGHT AT

EIGHT WEEKS OF AGE. 3. REALIZED HERITABILITIES OF UNSELECTED TRAITS. Poultry Sci.

45:923-932.

and SIEGEL, P. B.

1966. SELECTION FOR BODY WEIGHT AT

EIGHT WEEKS OF AGE. 4. PHENOTYPIC, GENETIC AND ENVIRONMENTAL CORRELATIONS BETWEEN

SELECTED AND UNSELECTED

TRAITS. Poultry Sei. 45: 933-

939.

(82) JAAP, R. G.

1960. HERITABILITIES, GENE INTERACTION AND CORRELATIONS FOR

GROWTH OF GLANDS ASSOCIATED

WITH ANTIBODY FORMATION IN

THE YOUNG CHICKEN. Poultry

Sei. 39:557-560.

(81)

(83)

1962. RATES OF PROGRESS FROM INTRAPOPULATION SELECTION TO INCREASE GROWTH RATE IN

CHICKENS. (Abstract) Poultry

Sei. 41: 1653.

(85)

(86)

(87)

(88)

MURRAY, M. W., and TEMPLE,

R. W.

1961. THE GENETIC CONTROL OP VARIANCE IN COMB AND TESTES

WEIGHT OF YOUNG MALE

CHICKENS. Poultry Sei. 40:354-

363.

and SMITH, J. H.

1959. SELECTION FOR RAPIDITY OF

GROWTH. (Abstract) Poultry

Sei. 38: 1215.

SMITH, J. H., and GOODMAN, B. L.

1962. A GENETIC ANALYSIS OF GROWTH

AND EGG PRODUCTION IN MEATTYPE CHICKENS. Poultry Sei.

41: 1439-1446.

JAFFE, W. P.

1964. THE RELATIONSHIP BETWEEN EGG

WEIGHT AND YOLK WEIGHT.

Brit. Poultry Sei. 5: 295-298.

(89)

(90)

(91)

(92)

(93)

1966. EGG PRODUCTION, BODY WEIGHT

AND EGG QUALITY CHARACTERS,*

THEIR HERITABILITY AND THE

CORRELATIONS BETWEEN THEM.

Brit. Poultry Sei. 7: 91-98.

JEROME, F. N., HENDERSON, C. R., and

KING, S. C.

1956. HERITABILITIES, GENE INTERACTIONS AND CORRELATIONS ASSOCIATED WITH CERTAIN TRAITS

IN THE DOMESTIC FOWL. Poultry

Sei. 35:995-1013.

JOHNSON, A. S., and MERRITT, E. S.

1955. HERITABILITY OF ALBUMEN HEIGHT

AND SPECIFIC GRAVITY OP EGGS

FROM WHITE LEGHORNS AND

BARRED ROCKS AND THE CORRELATIONS OF THESE TRAITS

WITH EGG PRODUCTION. Poultry

Sei. 34: 578-587.

KING, S. C.

1961. INHERITANCE OF ECONOMIC TRAITS

IN THE REGIONAL CORNELL CONTROL POPULATION. Poultry Sei.

40: 975-986.

and HENDERSON, C. R.

1954. HERITABILITY STUDIES OF EGG PRODUCTION IN THE DOMESTIC FOWL.

Poultry Sei. 33: 155-169.

MITCHELL, J. D., KYLE, W. H.,

and STADELMAN, W. J.

1961. EGG QUALITY GENETIC VARIATION

AND COVARIATION. Poultry Sei.

40: 965-975.
44 AGRICULTURE HANDBOOK 363, U.S. DEPT. OF AGRICULTURE

(94)

(95)

(96)

(97)

(98)

(99)

(100)

(101)

(102)

(103)

1965.

(105)

(106)

(107)

(108)

KING, S. C, VAN VLECK, L. D., and (104)

DOOLITTLE, D. P.

1963. GENETIC STABILITY OF THE CORNELL RANDOMBRED CONTROL

POPULATION OP WHITE LEGHORNS. Genet. Res. 4: 290-

304.

KiNNEY, T. B., JR., and LOWE, P. C.

1968. GENETIC AND PHENOTYPIC VARIATION IN THE REGIONAL RED

CONTROLS OVER NINE YEARS.

Poultry Sei. 47: 105-110.

LOWE, P. C, BOHREN, B. B., and

WILSON, S. P.

1968. GENETIC AND PHENOTYPIC VARIATION IN RANDOMBRED WHITE

LEGHORN CONTROLS OVER SEVERAL GENERATIONS. Poultry

Sei. 47: 113-123.

and SHOFFNER, R. N.

HERITABILITY ESTIMATES AND GENETIC CORRELATIONS AMONG

SEVERAL TRAITS IN A MEAT

TYPE POULTRY POPULATION.

Poultry Sei. 44: 1020-1032.

KoMAi, T., CRAIG, J. V., and WEARDEN, S,

1959. HERITABILITY AND REPEATABILITY

OF SOCIAL AGGRESSIVENESS IN

THE DOMESTIC CHICKEN. Poultry Sei. 38: 356-359.

KosiN, I. L.

1957. A GENETIC ANALYSIS OF EGG SHAPE

IN CHICKENS AND TURKEYS.

(Abstract) Poultry Sei. 36:

1134.

KRAUSE, E., YAMADA, Y., and BELL, A. E.

1965. GENETIC PARAMETERS IN TWO POPULATIONS OF CHICKENS UNDER

RECIPROCAL RECURRENT SELECTION. Brit. Poultry Sei. 6:

197-206.

KRUBGER, W. F., DICKERSON, G. E.,

KJNDBR, Q. B., and KEMPSTER, H. L.

1952. THE GENETIC AND ENVIRONMENTAL

RELATIONSHIP OF TOTAL EGG

PRODUCTION TO ITS COMPONENTS

AND TO BODY WEIGHTS IN THE

DOMESTIC FOWL. (Abstract)

Poultry Sei. 31: 922.

HILL, A. T., MALIK, D. D., and

WARD, N. C.

1963. THE HERITABILITY OF THE ALBUMEN-YOLK RATIO IN LEGHORNS.

(Abstract) Poultry Sei. 42:1283.

KYLE, W. H., and MITCHELL, J. D.

1958. HERITABILITY OF THE CHANGE IN

EGG QUALITY DURING STORAGE.

(Abstract) Poultry Sei. 37:1219.

(109)

(110)

(111)

(112)

(113)

(114)

LEPORE, P. D.

1965. HERITABILITY ESTIMATES FOR

HEMOGLOBIN AND SERUM PROTEIN CONCENTRATION IN GROWING CHICKENS. (Abstract)

Poultry Sei. 44: 1393.

LERNER, I. M.

1958. THE GENETIC BASIS OF SELECTION.

298 pp., illus. New York.

AsMUNDsoN, V. S., and CRUDEN,

D.M.

1947. THE IMPROVEMENT OP NEW HAMPSHIRE FRYERS. Poultry Sei. 26 :

515-524.

and CRUDEN, D. M,

1948. THE HERITABILITY OP ACCUMULATIVE MONTHLY AND ANNUAL EGG

PRODUCTION. Poultry Sei. 27:

67-78.

— and CRUDEN, D. M.

1950. THE HERITABILITY OF EGG WEIGHT.

THE ADVANTAGES OP MASS SELECTION AND OP EARLY MEASUREMENTS. Poultry Soi. 30:

34-41.

and DEMPSTER, E. R.

1951. ATTENUATION OP GENETIC PROGRESS UNDER CONTINUED SELECTION IN POULTRY. Heredity 5:

75-94.

and HAZEL, L. N.

1947. POPULATION GENETICS OF A POULTRY FLOCK UNDER ARTIFICIAL

SELECTION. Genetics 32: 325-

339.

LOWRY, D. C, LERNER, I. M., and

TAYLOR, L. W.

1956. INTRA-PLOCK GENETIC MERIT

UNDER FLOOR AND CAGE MANAGEMENTS. Poultry Soi. 35:

1034-1043.

LUSH, J. L.

1948. THE GENETICS OP POPULATIONS.

381 pp. Ames, Iowa. [Mimeo.

book, Iowa State College.]

LAMAREAUX, W. F., and HAZEL,

L. N.

1948. THE HERITABILITY OF RESISTANCE

TO DEATH IN THE FOWL. Poultry ScL 27:375-388.

MCBRIDE, G.

1962. THE INTERACTIONS BETWEEN GENOTYPES AND HOUSING JîNVIRONMENTS IN THE DOMESTIC HEN.

Austral. Soc. Anim. Piod. Proc.

4:95-102.
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 45

(115)

(116)

(117)

(118)

MCCLART, C. F., and BEARSE, G. E.

1954. AN APPARENT GENETIC CORRELATION BETWEEN EGG SHELL THICKNESS AND BLOOD SPOT INCIDENCE

IN CHICKEN EGGS. (Abstract)

Poultry Sei. 33: 1070.

and BEARSE, G. E.

1956. THE GENETIC CORRELATION OF ALBUMEN QUALITY IN FRESH AND

STORED EGGS. (Abstract) Poultry Sei. 35: 1157.

MCCLUNG, M. R.

1958. HERITABILITY OF AND GENETIC CORRELATIONS BETWEEN GROWTH

RATE AND EGG PRODUCTION IN

MEAT TYPE CHICKENS. (ABstract) Poultry Sei. 37: 1225.

(119)

(120)

(121)

(122)

1963. SELECTION FOR LOW MEAT SPOT

INCIDENCE. (Abstract) Poultry

Sei. 42: 1288.

1965. HERITABILITY OF FEED CONVERSION

IN BROILERS. (Abstract) Poultry Sei. 44: 1398.

and DuRFEE, W. K.

1964. SELECTION FOR LOW MEAT SPOT

INCIDENCE IN A BROWN EGG

BREED. Poultry Sei. 43: 1515-

1525.

MILLAR, R. I., and DURFEE, W. K.

1959. HERITABILITY OF THE CHANGE IN

ALBUMEN HEIGHT DURING STORAGE. (Abstract) Poultry Sei.

38: 1227.

MAHMOUD, H. M., KRUEGER, W. F.,

BRADLEY, J. W., and QUISENBERRY,

J. H.

1965. HERITABILITY OF EIGHT-WEEK BODY

WEIGHT UNDER TWO ENVIRONMENTS AND RELATED GENE ENVIRONMENT INTERACTIONS. (Abstract) Poultry Sei. 44: 1395.

(123) MALONEY, M. A., JR., and GILBREATH,

J. C.

1966. SELECTION FOR DIFFERENTIAL BODY

WEIGHT AT TWELVE WEEKS OF

AGE IN THE DOMESTIC FOWL.

(Abstract) Poultry Sei. 45: 1102.

(124) GILBREATH, J. C, and MORRISON,

R. D.

1963. TWO-WAY SELECTION FOR BODY

WEIGHT IN CHICKENS. 1. THE

EFFECTIVENESS OF SELECTION

FOR TWELVE-WEEK BODY WEIGHT.

Poultry Sei. 42: 326-334.

(125) GILBREATH, J. C, and MORRISON,

R. D.

1963. TWO-WAY SELECTION FOR BODY

WEIGHT IN CHICKENS. 2. THE

EFFECT OF SELECTION FOR BODY

WEIGHT ON OTHER TRAITS. Poultry Sci. 42: 334-344.

(126) MARTIN, G. A., GLAZENER, E. W., and

BLOW, W. L.

1953. EFFICIENCY OF SELECTION FOR

BROILER GROWTH AT VARIOUS

AGES. Poultry Sei. 32: 716-720.

(127) MAZANOWSKI, A.

1965. INVESTIGATIONS ON THE INFLUENCE OP THE HERITABILITY INDEX ON BREEDING PROGRESS IN

A POPULATION OF LEGHORN.

(Abstract) Anim. Breeding Abs.

33: 3797.

(128) MERAT, P.

1960. HERITABILITJY OF WINTER LAYING

IN PULLETS WITH AND WITHOUT

SUPPLEMENTARY LIGHTING.

(Abstract) Anim. Breeding Abs.

29: 2369.

(129) MERRITT, E.'S.

1966. ESTIMATES BY SEX OP GENETIC

PARAMETERS FOR BODY WEIGHT

AND SKELETAL DIMENSIONS IN A

RANDOM BRED STRAIN OF MEAT

TYPE FOWL. Poultry Sei. 45:

118-125,

(130) and GOWE, R. S.

1962. DEVELOPMENT AND GENETIC PROPERTIES OF A CONTROL STRAIN OF

MEAT-TYPE FOWL. XII World's

Poultry Cong. Proc, pp. 66-70.

(131) ZAWALSKY, M., GORRILL, A. D. L.,

and others.

1963. CORRELATED CHANGES IN SKELETAL DIMENSIONS OF BROILER

CHICKENS SELECTED FOR WIDTH

OF BREAST. (Abstract) Canad.

Jour. Genet, and Cytol. 5: 104.

(132) MoHAPATRA, S. C, and SIEGEL, P. B.

1966. GENETIC VARIATION OF PROTHROMBIN TIME IN CHICKENS.

(Abstract) Poultry Sei. 46:1294.

(133) MORRIS, J. A.

1956. GENETIC PARAMETERS ASSOCIATED

WITH CHARACTERS AFFECTING

EGG PRODUCTION IN THE DOMESTIC FOWL. II. HERITABILITY

OF EGG PRODUCTION FOR TWO

PART-ANNUAL PERIODS OF

MEASUREMENT AND THE GE-

^ NETIC CORRELATION BETWEEN

THEM. Austral. Jour. Agr. Res.

7: 630-639.
46 AGRICULTURE HANDBOOK 3 63, U.S. DEPT. OF AGRICULTURE

(134)

(135)

(136)

(137)

(138)

MORRIS, J. A.

1959. HERITABILITY OF CHICK VIABILITY

FOR TWO BREEDS OP DOMESTIC

FOWL. Poultry Sei. 38: 481-

485.

1963.

1964.

CONTINUOUS SELECTION FOR EGG

PRODUCTION USING SHORT TERM

RECORDS. Austral. Jour. Agr.

Res. 14: 909-925.

(139)

(140)

(141)

(142)

(143)

(144)

ESTIMATES OF GENETIC PARAMETERS RELEVANT IN SELECTION

FOR CERTAIN ASPECTS OF EGG

QUALITY. Austral. Jour. Agr.

Res. 15: 719-727.

MoYER, S. E., and COLLINS, W. M.

1960. HERITABILITY OF INTENSITY OF

YELLOW SHANK PIGMENTATION IN

CROSS-BBED BROILER PROGENY.

Poultry Sei, 39: 662-663.

COLLINS, W. M., and SKOGLUND,

W. C.

1962. HERITABILITY OF BODY WEIGHT AT

THREE AGES IN CROSS-BRED

BROILER CHICKENS RESULTING

FROM TWO SYSTEMS OF BREEDING. Poultry Sei. 41: 1374-

1382.

MUIR, P. V., and GOODMAN, B. L.

1964. HERITABILITY OF DRESSING PERCENTAGE IN BROILERS. Poultry Sei. 43: 1605-1606.

NESTOR, K. E., and JAAP, R. G.

1965. SELECTION FOR COMB WEIGHT WITH

ANDROGEN AND GONADOTROPHIN STIMULATION. Poultry Sci.

44: 1441-1451.

NiGHTALL, E. W.

1956. A STUDY OF THE INCIDENCE OF

LYMPHOMATOSIS IN POULTRY

KEPT AT THE UNIVERSITY OF

NOTTINGHAM SCHOOL OF AGRICULTURE. Poultry Sei. 35:109-

125.

NoRDSKOG, A. W., and FESTING, M.

1962. SELECTION AND CORRELATED RESPONSES IN THE FOWL. XII

World's Poultry Cong. Proc.,

pp. 25-29.

FESTING, M., and VERGHESE, M. W.

1967. SELECTION FOR EGG PRODUCTION

AND CORRELATED RESPONSES IN

THE FOWL. Genetics 55: 179-

191.

and HILL, J. F.

1958. CORRELATION BETWEEN EGG PRODUCTION AND ADULT VIABILITY

IN HYBRID FLOCKS. Poidtry Sci.

37: 1265-1273.

(145)

(146)

(147)

(148)

(149)

(150)

(151)

(152)

(153)

(154)

SMITH, L. T., and PHILLIPS, R. E.

1959. HETEROSIS IN POULTRY. : 2. CROSSBREDS VERSUS TOP-CROSSBREDS.

Poultry Sci. 38: 1372^1380.

OLIVER, M. M., BOHREN, B. B., and

ANDERSON, V. L.

1957. HERITABILITY AND SELECTION EFFICIENCY OP SEVERAL MEASURES

OF EGG PRODUCTION. Poultry

Sei. 36: 395-402.

ONISHI, N.

1954. ON THE INHERITANCE OF SEXUAL

MATURITY IN SINGLE COMB

WHITE LEGHORNS. X World's

Poultry Cong. Proe., pp. 30-33.

OROZCO, P. F.

1962. COEFFICIENTS OF HERITABILITY FOR

TWO TRAITS IN TWO STRAINS OF

WHITE LEGHORNS. (Abstract)

Anim. Breeding Abs. 31: 1557.

PEELER, K. J., GLAZENER, E. W., and

BLOW, W. L.

1955. THE HERITABILITY OF BROILER

WEIGHT AND WEIGHT AND AGE

AT SEXUAL MATURITY AND THE

GENETIC AND ENVIRONMENTAL

CORRELATIONS BETWEEN THESE

TRAITS. Poultry Sei. 34: 420-

426.

QUINN, J. p.

1963. ESTIMATES OF SOME GENETIC PARAMETERS OP EGG QUALITY.

Poultry Sei. 42:792-795.

REDMAN, C. E., and SHOFFNER, R. N.

1961. ESTIMATES OF EGG QUALITY PARAMETERS UTILIZING A POLYALLEL CROSSING SYSTEM. Poultry Sci. 40: 1662-1675;

RETA, G., BOHREN, B. B., and MOSES,

H. E.

1963. SIRE AND DAM EFFECTS ON HEMAGGLUTINATION TITERS IN AVIAN

EGGS FOLLOWING INOCULATION

WITH NEWCASTLE DISEASE VIRUS.

Poultry Sei. 42: 1182-1187.

RICO, M.

1962. INHERITANCE OF QUANTITATIVE

CHARACTERS IN THE SPECIES

GALLUS DOMESTICUS. 1. HERITABILITY OF EGG PRODUCTION,

EGG WEIGHT AND BODY WEIGHT.

(Abstract) Anim. Breeding

Abs. 32: 2453.

ROBERTSON, A., and LERNER, I. M.

1949. THE HERITABILITY OF ALL-OR-NONE

TRAITS: VIABILITY IN POULTRY.

Genetics 34: 395-411.
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 47

(155) RODERO, A., and MARTINEZ DE MIGUEL, R.

1961. HERITABILITY OP BODY WEIGHT IN

BLACK CASTILIÀN, FRANCISCAN

UTRERA AND WHITE LEGHORN

PULLETS. (Abstract) Anim.

Breeding Abs. 31:703.

(156) SAEKI, Y.

1957. INHERITANCE OF BROODINESS IN

JAPANESE NAGOYA FOWL WITH

SPECIAL REFERENCE TO SEXLINKAGE AND NOTICE IN BREEDING PRACTICE. Poultry Sei. 36 :

378-383.

(157) SCHEINBERG, S. L., WARD, H., and NORDSKOG, A. W.

1953. BREEDING FOR EGG QUALITY, i.

HERITABILITY AND REPEATABILITY OP EGG WEIGHT AND

ITS COMPONENTS. Poultry Sei.

32: 504-510.

(158) SCHULTZ, F. T.

1953. ANALYSIS OP EGG SHAPE OF

CHICKENS. Biometrics 9: 336-

353.

(159) SHAKLEE, W. E., and KNOX, C. W.

1956. SELECTION FOR THYROID WEIGHT

IN NEW HAMPSHIRE CHICKENS.

Jour. Hered. 47: 211-212.

(165)

(160)

(161)

(162)

(163)

(164)

SHELDON, B. L.

1956. GENETIC PARAMETERS ASSOCIATED

WITH CHARACTERS AFFECTING

EGG PRODUCTION IN THE DOMESTIC FOWL. 1. HERITABILITY

OF TOTAL EGG PRODUCTION DURING THE PULLET YEAR. Austral.

Jour. Agr. Kes. 7: 625-629.

SHIBATA, K.

1965. GENETIC CORRELATIONS AMONG

SOME ECONOMIC TRAITS IN A

WHITE LEGHORN CLOSED FLOCK.

Jour. Agr. Sei. (Tokyo) 2: 18.

SHOFFNER, K. N., and SLOAN, H. J.

1948. HERITABILITY STUDIES IN THE DOMESTIC FOWL. VIII World's Poultry Cong. Proc., pp. 269-281.

SIEGEL, P. B.

1960. A METHOD FOR EVALUATING AGGRESSIVENESS IN CHICKENS.

Poultry Sei. 39: 1046-1048.

1962. A DOUBLE SELECTION EXPERIMENT

FOR BODY WEIGHT AND BREAST

ANGLE AT EIGHT WEEKS OF AGE

IN CHICKENS. Genetics 47:

1313-1319.

(166)

(167)

(168)

(169)

(170)

(171)

(172)

(173)

(174)

1962. SELECTION FOR BODY WEIGHT AT

EIGHT WEEKS OF AGE. 1. SHORT

TERM RESPONSE AND HERITABILITIES. Poultry Sei. 41: 954-

962.

1962. SELECTION FOR BREAST ANGLE AT

EIGHT WEEKS OF AGE. 1. GENE

INTERACTIONS AND HERITABILITiEs. Poultry Sei. 41: 1177-

1185.

1963. SELECTION FOR BREAST ANGLE AT

EIGHT WEEKS OF AGE. 2. CORRELATED RESPONSES OF FEATHERING BODY WEIGHTS AND REPRODUCTIVE CHARACTERS. Poultry

Sei. 42: 437-449.

1963. SELECTION FOR BODY WEIGHT AT

EIGHT WEEKS OF AGE. 2. CORRELATED RESPONSES OF FEATHERING, BODY WEIGHTS AND REPRODUCTIVE CHARACTERISTICS. Poultry Sci. 42: 896-905.

1965. GENETICS OF BEHAVIOR: SELECTION

FOR MATING ABILITY IN CHICKENS. Geneties 52: 1269-1277.

CRAIG, J. V., and MUELLER, C. D.

1957. HERITABILITIES, SEX DIFFERENCES

AND PHENOTYPIC CORRELATIONS

FOR SIX FEATHERING CHARACTERISTICS. Poultry Sei. 36:

621-628.

and EssARY, E. O.

1959. HERITABILITIES AND INTERRELATIONSHIPS OF LIVE MEASUREMENTS AND EVISCERATED WEIGHT

IN BROILERS. Poultry Sei. 38:

530-532.

and SIEGEL, H. S.

1960. GENETIC PARAMETERS OF GLAND

AND BODY WEIGHTS IN WHITE

ROCK COCKERELS. Jour. Hered.

51: 59-62.

and SIEGEL, H. S.

1963. THE CORRELATED RESPONSES OP

RELATIVE AGGRESSIVENESS TO

SELECTION FOR BODY WEIGHT

AND BREAST ANGLE IN CHICKENS.

Poultry Sei. 42: 1208-1211.

and SIEGEL, H. S.

1964. GENETIC VARIATION IN CHICK BIOASSAYS FOR GONADOTROPINS. 1.

TESTES WEIGHT AND RESPONSE.

Va. Jour. Sei. 15: 187.
48 AGRICULTURE HANDBOOK 36-3, U.S. DEPT. OF AGRICULTURE

(175) SMITH, F. V., and TEMPLETON, W. B.

1965. GENETIC ASPECTS OF THE RESPONSE

OF THE DOMESTIC CHICK TO

VISUAL STIMULI. Anim. Behaviour 14: 291-295.

(176) SMITH, J. H., AND JAAP, R. G.

1957. NON-ADDITIVE GENETIC EFFECTS

ON GROWTH IN A FLOCK CLOSED

FROM CROSSBRED PARENTS. (ABstract) Poultry Sei. 36: 1158.

(177) SoLLER, M., SNAPER, N., and SCHINDLER,

H.

1965. HERITABILITY OF SEMEN QUANTITY,

CONCENTRATION AND MOTILITY

IN WHITE ROCK ROOSTERS AND

THEIR GENETIC CORRELATION

WITH RATE OF GAIN. Poultrj

Sei. 44: 1527-1529.

(178) STAHL, P., PIPES, G. W., TURNER, C. W.,

and STEPHENSON, A. B.

1962. MODE OF INHERITANCE OF THYROXINE SECRETION RATE IN

LINES OF NEW HAMPSHIRE CHICKENS. Poultry Sei. 41: 570-572.

(179) STONE, H. A., and COLLINS, W. M.

1966. HERITABILITY OF BLOOD GAROTINOID CONCENTRATION AND ITS

GENETIC RELATIONSHIP TO BODY

WEIGHT IN THE CHICKEN. (Abstract) Poultry Sei. 45: 1128.

(180) STURKIE, P. D., WEISS, H. S., RINGER,

R. K., and SHEAHAN, M. M.

1959. HERITABILITY OF BLOOD PRESSURE

IN CHICKENS. Poultry Sei. 38:

333-337.

(181) STUTS, E. C, BRILES, W. E., and KUNKEL, H. O.

1957. PLASMA ALKALINE PHOSPHATASE

ACTIVITY IN MATURE INBRED

CHICKENS. Poultry Sei. 36:

269-276.

(182) TARER, R. W., MCCLUNG, M. R., and

HYRE, H. M.

1967. HERITABILITY OF INTERVAL BETWEEN OVIPOSITION IN THE HEN.

(Abstract) Poultry Sei. 46:1326.

(183) THOMAS, C. H., BLOW, W. L., COCKERHAM, C. C, and GLAZENER, E. W.

1958. THE HERITABILITY OF BODY

WEIGHT, GAIN, CONSUMPTION

AND FEED CONVERSION IN BROILERS. Poultry Sei. 37: 862-869.

(184) ToRGEs, H. G.

1963. INVESTIGATIONS ON THE DEGREE

OF INHERITANCE IN EGG QUALITY

CHARACTERS, EGG ALBUMEN INDEX, BREAKING STRENGTH OF

THE SHELL AND YOLK COLOUR.

(Abstract) Anim. Breeding Abs.

32:2457.

(185)

(186)

(187)

(188)

(189)

(190)

(191)

(192)

(193)

(194)

(195)

VAN VLECK, L. D., and DOOLITTLE, D. P.

1964. GENETIC PARAMETERS OF MONTHLY

EGG PRODUCTION IN THE CORNELL CONTROLS. Poultry Sei.

43: 560-567.

KING, S. C, and DOOLITTLE, D. P.

1963. SOURCES OF VARIATION IN THE

CORNELL CONTROLS AT TWO

LOCATIONS. Poultry Sei. 42:

1114-1125.

WARING, F. J., HUNTON, P., and MADDISON, A. E.

1962. GENETICS OF A CLOSED POULTRY

FLOCK. 1. VARIANCE AND COVARIANCE ANALYSIS OF EGG PRODUCTION, EGG WEIGHT AND EGG

MASS. Brit. Poultry Sei. 3:151-160.

WASHBURN, K, W.

1967. HERITABILITY OF PACKED RED

BLOOD CELL VOLUME IN THE

DOMESTIC FOWL. Poultry Sei.

46: 1025-1026.

and SIEGEL, P. B.

1963. INFLUENCE OF THIOURACIL ON

CHICKENS SELECTED FOR HIGH

AND LOW BODY WEIGHTS. Poultry

Sei. 42: 161-169.

WHEAT, J. D., and LUSH, J. L.

1961. ACCURACY OF PARTIAL TRAPNEST

RECORDS. 2. RATES OF LAY FOR

SPECIFIC PERIODS OF THE YEAR

AND HERITABILITY OP YEARLY

PRODUCTION. Poultry Sei. 40:

402-406.

WiLCox, F. H., CHERMS, F. L., JR., VAN

VLECK, L. D., and others.

1963. ESTIMATES OF GENETIC PARAMETERS OF SERUM CHOLESTEROL

LEVEL. Poultry Sei. 42: 37-42.

VAN VLECK, L. D., and SHOFFNER,

C. S.

1962. SERUM ALKALINE PHOSPHATASE

AND EGG PRODUCTION. X World's

Poultry Cong. Proc., pp. 19-21.

WILSON, H. R., ARMAS, A. E., Ross, I. J.,

and others.

1966. FAMILIAL DIFFERENCES OF SINGLE

COMB WHITE LEGHORN CHICKENS IN TOLERANCE TO HIGH

AMBIENT TEMPERATURE. Poultry Sei. 45: 784-788.

WILSON, W. O.

1948. EGG PRODUCTION RATE AND

FERTILITY IN INBRED CHICKENS. Poultry Sei. 27: 719-726.

1948. VIABILITY OF EMBRYOS OF CHICKS

IN INBRED CHICKENS. Poultry

Sei. 27: 727-735.
ESTIMATES OF HERITABILITIES AND OF GENETIC AND PHENOTYPIC CORRELATIONS 49

(196) WOOD, B. M., and GARREN, H. W.

1958. A STUDY OF THE RESISTANCE OF

RHODE ISLAND REDS TO IMPLANTS OF LYMPHOID TUMOR

STRAIN RPL~12. Poultiy Sci.

37: 321-326.

(197) WYATT, A. J.

1954. GENETIC VARIATION AND COVARIATION IN EGG PRODUCTION AND

OTHER ECONOMIC TRAITS IN

CHICKENS. Poultry Sei. 33:

1266-1274.

(198) YAMADA, Y., BOHREN, B. B., and CRITTENDEN, L. B.

1958. GENETIC ANALYSIS OF A WHITE LEGHORN CLOSED FLOCK APPARENTLY

PLATEAUED FOR EGG PRODUCTION. Poultry Sei. 37: 565-580.

(199) YAO, K. T. S.

1958. EGG INTERIOR QUALITY OF PUREBRED, INBRED, INCROSS AND

iNCRoss-BRED CHICKENS. (Abstract) Poultry Sei. 37: 1254.

(200) and SKINNER, J. L.

1959. HERITABILITY AND GENETIC CORRELATIONS OF ALBUMEN WEIGHT

AND YOLK SIZE IN CHICKEN EGGS.

(Abstract) Poultry Sei. 38:1262.

(201) ZERVAS, N. P., and COLLINS, W. M.

1965. GENETIC VARIATION IN 14-DAY

CHICK EMBRYO WEIGHT. Poultry Sci. 44: 631-636.

(202) COLLINS, W. M., and SKOGLUND,

W. C.

1962. GENETIC VARIATION AND COVARIATION IN YELLOW SHANK PIGMENTATION INTENSITY AND EIGHTWEEK BODY WEIGHT OF CHICKENS.

Poultry Sei. 41: 1247-1254.

UNPUBLISHED MATERIALS

(203) ANDREWS, L. D.

1966. RECURRENT SELECTION AND GENETIC PARAMETERS OF ECONOMIC

IMPORTANCE IN THE DOMESTIC

FOWL. Unpublished Ph. D.

thesis. Copy on file, Univ. of

Mo. Libr., Columbia.

(204) ARZE, G. C.

1964. SELECTION FOR MATING ABILITY

AND ITS RELATIONSHIP TO FERTILITY IN THE DOMESTIC FOWL.

M.S. thesis. Copy on file, Univ.

of Ga. Libr., Athens.

(205) HAWKES, B. W.

1963. GENETIC PARAMETERS OP QUANTITATIVE CHARACTERISTICS IN DIVERGENT LINES OF CHICKENS.

M.S. thesis. Copy on file. Va.

Polytech. Inst. Libr., Blacksburg.

(206) LANKFORD, L. T.

1952. HERITABILITY OF GROWTH RATE IN

WHITE WYANDOTTE CHICKENS.

M.S. thesis. Copy on file, Univ.

of Ark. Libr., Fayetteville.

(207) SAADEH, H. K.

1967. RECIPROCAL RECURRENT SELECTION

VERSUS FAMILY INDEX SELECTION, HERITABILITIES AND CORRELATIONS ASSOCIATED WITH

QUANTITATIVE TRAITS IN THE

DOMESTIC FOWL. Unpublished

Ph. D. thesis. Copy on file,

Kans. State Univ. Libr., Manhattan.

U.S. GOVERNMENT PRINTING OFFICE: 1969