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Variation and correlations of the organs of single comb white leghorn cockerels.

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AUTHOR'S ABSTRACT OF THIS PAPER ISSUED B Y
THE BIBLIOGRAPHIC SERVICE. NOVEMBER 19
VARIATION AND CORRELATIONS O F T H E ORGANS
O F SINGLE COMB WHITE LEGHORN COCKERELS'
ARTHUR JOHN SOUBA
Section of Animal Nutrition, Division of Agricultural Biochemistry,
University of Minnesota, St. Paul
ONE PLATE
The writer, having collected considerable data on the size
of organs of single comb white Leghorn cockerels in connection with a nutrition study, deems it advisable to make a brief
report because extensive data on the subject are lacking. Two
hundred cockerels of uniform weight and appearance were
selected at the age of 34 days from a hatch of 609 chicks.
These cockerels were of line bred ancestry for several generations back and the data of only those birds that showed
a normal growth to the age of 100 to 120 days are reported
here.
The data which are presented here, comprise the data of
pens A and B of a previous publication (Souba, '23). Pel1
A formed a group of fifty birds receiving a regular poultry
ration of grain, grain mash, and green roughage. Pen B
formed a group of fifty birds receiving a synthetic diet of
starch, casein, butterfat, lard, salt mixture, and yeast product.
That the rations were of approximately relative equal value
was shown in the publication of the above reference, for
there existed no significant difference in the mean, standard
deviation or coefficient of variation of the weights of the
birds of these two pens. The slight differences which were
not significant and which were observed in the mean, standard
deviation and co-efficient of variation of the weight and size
The writer wishes to express his indebtedness to the Minnesota Agricultural
Experiment Station for the privilege of collecting the data presented in this paper.
291
THE ANATOMICAL RECORD, VOI..
26, NO. 4
292
A R T H U R J O H X SOUBA
of organs may be attributed to the fact that the data werz
collected on a small number of individuals and to randoiri
sampling.
Po r t e r ('05) observed a coefficient of variation of 10.8 to
17.8 per cent in the weight of boys between the ages of 1 2 to
16 years, which corresponds to the age of puberty in boys.
This is a period of life in which the variation of growth is
the greatest f o r inost organisms. White Leghorn cockerels
between the ages of 100 to 120 days show a coefficient of variation of 19.6982 1.203. Latimer ( '22) has already ~ 1 1 0 ~ ~ 7 1 1
that a 100 to 120 day old white Leghorn cockerel falls in tlie
period of greatest growth, ancl accounts thus for the relative
variation in the weight of these cockerels. Jackson ( '13) reports a coefficient of variation in the body weights of albino
rats of 13.6k0.99 at birth, 28.4t3.00 a t twenty (lays of age
and 18.5t2.0 a t five montlis.
Tlie coefficient of variations given in table 1 is in fair
agreement with the corresponding coefficients that Jackson
('13) found f o r rats twenty days of age. I n all cases his coefficients are larger with the exception of weight of testes, in
which lie also found the largest variation. I n the data for
the testes, tlie cockerels showed the greatest coefficient of variation, which was extremely high, ancl doubtless due to the age
a t which the birds were Billed ancl autopsied. A t the age of
100 to 120 days, not only do we find a large coefficient of variation due to the fact that the birds grow the fastest during
this period, but it is also during this period that the testes of
wliite Legborn cockerels begin to grow very rapidly.
Tlie coefficient of variation in the length and heiglit of combs
of single comb white Leghorn cockerels is less than the coefficient of variation for the absolute weight of the comb. Tlie
observed coefficients were as follows : Length of combs,
18.68721.141 ; height of combs, 24.787k1.513 ; and weight of
combs, 57.221 k3.490.
On account of the large coefficient of variation in tlie weight
of rats and the weight of their organs, Jackson ('13) pointed
1
I
I
Grams
ST.~NDAKD
DEVIATIOS
i
1
j
Per rent
CO~FFIC,RNT
i
,
,
I
'
1
___--
-
--
3 0 . 1 7 t 2 . 9 4 to 4 3 . 4 7 ~4.32
14.72 c 1.404 to 23.74 T 2.36
11.70+-1.16 to 19.40-c 1.85
l t i . 2 6 t 1 . 0 1 to 2 0 . 9 4 t 2.04
15.10 i1.41 to 23.30 _c 2.31
8 3 . 7 0 ~ 7 . 9 8t o 1 2 2 . 9 0 t 1 2 . 2 2
iRAXkE OF COEFFICIENTS OF VARIATION
1 s CilWUPS OF COCKEREIS OF PENS
A AND B 2
1
The various statistical constants-mean, standard deviation, coefficient of variation and probable errors-were obtained by employing the usoal formnlas (Pearson's) as given by Ynle ('11)
'The various groups consisted of 25 individunls.
. . . . ...
1
1
0.47 t .023 ! 3 5 . 8 7 8 2 1.i56
5.128 t 251
21.858 & 1.069
.083
1.205- .059
19.185tO.V39
.@B 0 . 4 1 6 t .0"0
18.705t0.916
.N9
0.709 1
. .03j
20.32i & 0.994
.024 I 3.48 t .017 111.182t5.438
164.22 I8.04
19.N t 0 . 9 3 2
-1-
Grams
1.31 C .033
23.46 L .355
Kidneys ....... G.281=
Pancreas ...... 2 . 2 2 4 t
Hearts
. I 3.488 1.
Testes .........! 3 . 1 3 O t
Spleen . ... ....1
-
TABLE I
Variation in the weight of organs of single comb white Leghorn c~wkerrl~
100 observations
u?
P
B
m
M
w
0
3
0
9
Z
u
294
ARTHUR J O H N SOUBA
out a ‘spurious correlation’ factor in connection with his
work with albino rats and f o r this reason said that the coeffjeients of correhtion were too high. In most cases he found
a much higher coefficient of correlation in albino rats than I
have found in single comb white Leghorn cockerels. However, with the large coefficient of variation in the weight of
birds and the weights of the various organs, especially the
testes, one is suspicious of any correlation as being due to
heterogeneity of material. Theref ore, in working up t.hese
data it seemed desirable first t o correlate the various groups
of cockerels which were of the same age or the same weight.
F o r these preliminary calculations, the weight of the birds
and the weight of the testes were used, and correlation coefficients ranging from .4335 to .8002 were obtained f o r pen
A, pen B, groups of cockerels 100 and 120 days old, and
groups of cockerels which varied only within 100 grams in
weight. This is likewise true f o r the other organs. This has
lead me to conclude t h a t a n actual correlation exists between
the weight of the testes or other organs and the weight of the
bird, though the value of the coefficient may not be the exact
or true coefficient, because of the cockerels’ unequal growth
and the scatter of the body weights and organ weights.
TABLE 21
of birds and the weight of
COEFFICIENT OF
organs. 100 observations
COP.REI.ATION
Weight of bird and weight of testes.. .............................
.521 +- ,050
.671 _t .038
Weight of bird and weight of spleen.. .........................
Weight, of bird and weight of liver.
................. 2301 r+ .024
Weight of bird and weight of kidneys.. ......................
.568
.047
Weight of bird and weight of pancreas ............................
.523 c .050
Weight of bird and weight of heart ...............................
.776 i- .027
(b) Correlations between the weight of organs and the length of
organs. 61 observations
Weight of comb and length of comb.. ........................
Weight of testes and length of testes. ..........................
(c) Correlations between the weight of organs and the cuhe of the
length of organs. 61 observations
....... .9289 c .0119
Weight of comb and length of comb cubed.. .....
Weight of testes and length of testes cubed .......
. . . . . . . .9816i- .W32
(a) Correlations between the weight
The statistical constantcoefficient of correlation-was
ing the formulas given by Yule (’11).
obtained by employ-
VARIATION A N D C O R R E L A T I O N S IN C O C K E R E L S
295
Correlation coefficients of larger magnitude a r e further
noted i n the weight of the organs and the length of the organs. Theoretically, if the shape of the organ remained constant there should be a perfect correlation between the weight
of the organs and the cube of one of the linear dimensions.
Any difference should be an index of the change in the shape
of the organ. It would appear therefore that the comb
changed its shape more than the testes.
The comb of a bird has been known for some time to be a
secondary sex-character. Capons do not develop combs like
those of normal male birds, showing that some relation exists
between the comb and sex organs, and this has been attributed
to the internal secretion. The comb of a hen has been used by
poultrymen as a character indicative of the hen’s reproductive activity. I n fact both fancy and utility judges pay considerable attention to the size and shape of combs. However,
in my search of the literature no statement regarding the correlation between comb and testes has been found.
I n the following table (p. 6) a r e given the simple, partial,
and multiple correlation coefficients between the weight of the
birds, weight and length of the testes and the weight and
length of the combs.
It is very interesting to note the correlation coefficient between the weight of testes and weight of combs as corrected f o r
the weight of the birds, as well as the correlation coefficient
between the length of testes and length of combs corrected for
the weight of the birds. A study of the standard deviation
of the second order and the regression equations justifies
the statement that such a correlation exists. It is also interesting to note the relationship of the development of the
testes upon the development of the comb and growth or increase in body weight. Thus from a knowledge of the body
weight and development of the comb one can predict the sexual clevelopment of single comb white Leghorn cockerels.
'796
ARTHUR J O H N SOUBA
TABLE 3'
(a) Sitttple, partial, and multiple correlations betqeen the weight of birds, the
ileiglit of testep, and tlie weight of combs
Kninber of obscrrations, 61
\ AIIIABI
F.
\\'eight of bird
Wcight of testes
IYcight of comb
Y
S1
s2
s3
5 T 4 S I ) A K D DE\'IATION
WF.4N
8R2.200 c 15.174
3.204t
11.950 -c
0.336
0.590
175.730 c 10.732
3.877 & 0.236
6.838 Z!Z 0.418
(1)) Pimplc, partial, and multiple correlations between the \wiglit of birds, the
length of testes, and the length of combs
Kiunibrr of observations, ti1
V,\ K I A B1.E
]\'right of bird
Length of testes
I m g t l i of comb
Y
S1
x2
ss
>"AN
892.800 c 15.174
2 . 1 4 6 c 0.067
8.594 + 0.139
ST.\SI).\I:L)
I)I?vixrios
175.750 t 10.732
O.773f 0.047
1.rjoii t 0.098
The statistical constants were obtained by employing the forninlae gircn b y
Tlllc ( ' 1 1 ) .
LITERATURE CITED
C . M. 1913 Postnatal growth in the albino rat. Anier. Jonr. h a t . ,
vol. 15.
LATIMER,
€I. B. 1922 The postnataI growth of body, systems and organs of tlie
single comb white Leghorn chicken. Thesis, Univ. of Alinn. Lib.
PORTER,
W. T. 1905 Growth of St. Louis children. Trans. St. Louis Acad. of
Sciences, vol 6.
SOUBA,
A. J. 1923 Influence of the antineuritic vitamin upon the internal organs
of single comb white Leghorn cockerels. Am. Jo. of Physiol., vol. 44.
PULE,
G . U. 1911 An Introduction t o the Theory of Statistics. London and
Philadelphia.
JACKSOS,
VARIATION AND CORRELATIONS I N COCKERELS
PLATE 1
ARTHUR JORK SOUBA
This plate shows the combs and testes of a group of white Leghorn cockerels
which were of the same age, approximately the same weight and differing in the
size of combs.
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