NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
294
CHANGES IN THE HISTOLOGY OF THE THYROID [ Vol. XXV, Part IV,
The thyroid sections were studied for changes in (i) the diameters of the
lobules and (ii) the heights of their epithelial cells. To study the diameter of the
lobule, at least 50 lobules cut transversely were selected at random from the slides
prepared from the material obtained from each animal. In each selected lobule,
the two diameters at right angles to each other were measured by means of an
ocular micrometer and the mean of the two was taken as the diameter of the
lobule. The height of the epithelial cells lining the lobules was determined by
means of an ocular micrometer and oil immersion lens.
The testicular sections were studied for the diameters of the seminiferous
tubules. To study the diameter of the tubules, at least 70 tubules which were
cut transversely were selected at random from slides prepared from the materials
obtained from each animal and the mean diameter was determined as in the case
of the thyroid lobule.
During the months the materials were collected, daily maximum and
minimum air temperatures and relative humidity were recorded in a well-ventilated
shed situated in the Institute area at a distance of about a mile from the slaughter
house.
RESULTS
For the purpose of this study, the year was generally divided into four seasons
as described by Mukherjee and Bhattacharya [1952], namely, (i) May to July,
summer, (ii) August to October, autumn, (iii) November to January, winter and (iv)
February to April, spring. As stated before, the materials were collected at the peak
of the seasons except in autumn (see below). The collections were made in summer,
from middle of May to end of June; in autumn from middle of July to middle of
August; in winter from middle of December to middle of January and in spring
from middle of February to middle of March. Mukherjee and Bhattacharya [1952]
characterised autumn as a season with highest humidity and almost as high air
temperature as in summer. In this experiment highest humidity associated with
high air temperature was observed between middle of July to middle of August.
The materials for autumn were, therefore, collected during this period.
Table I shows the range of variation and average of air temperature, relative
humidity, diameter and height of the epithelial cells of the thyroid lobule and the
diameter of the testicular tubule in different seasons. It will be seen from the Table
that during summer, when average air temperature was highest with lowest relative
humidity, the diameter of the thyroid lobule was more than in any other season.
In autumn when average air temperature was almost as high as in summer with
highest relative humidity, the height of the epithelial cells and the diameter of the
testicular tubule were lower than in the remaining three seasons. The measurements
showed reverse trend during spring when the average air temperature was moderate
(neither so low as in winter nor so high as in summer) associated with moderate
relative humidity.
December, 1955 ] D. S. BHATNAGAR, D. P. MUKHBEJEE AND P. BHATTACHARYA 295
TABLE I
Range and average variation in the air temperature, relative humidity, diameter of the thyroid lobule, height of the
epithelial cells and the diameter of the testicular tubule in four seasons
Season
Summer
Autumn
Winter
Spring
Air temperature (ºF)
Range
69 to 113
73 to 108
42 to 76
48 to 88
Average
93.6
87.2
58.6
67.9
Relative humidity (per cent)
Range
25.0 to 96.8
50.0 to 96.0
49.0 to 94.5
45.0 to 89.0
Average
49.0
72.0
70.5
64.2
Diameter of the thyroid
lobule (u)
Range
66.64 to 516.46
83.3 to 332.2
49.98 to 474.81
83.3 to 383.18
Average
236.4
187.65
209.06
202.32
Height of the epithelial
cells of lobule (u)
Range
1.66 to 6.64
1.66 to 6.64
1.66 to 6.64
1.66 to 6.64
Average
3.69
3.09
4.47
4.79
Diameter of the testicular
tubule (u)
Range
99.96 to 316.54
108.29 to 266.56
141.61 to 316.54
116.62 to 274.89
Average
187.95
168.27
192.85
195.91
TABLE II
Statistical analysis of the difference in means between the diameter of the thyroid lobules, height of the epithelial cells
and the diameter of the testicular tubules
Seasons
Summer
Autumn
Winter
Spring
Thyroid Lobule Diameter
Mean (u)
236.40±3.84
(490)
187.65±2.89
(562)
209.06±3.43
(545)
202.32±3.23
(560)
P7
Dif 1-2 <0.01
Dif 1-3 <0.02
Dif 3-2 = 0.01
Dif 1-4 <0.01
Dif 4-2 <0.02
Dif 3-4 <0.50
Height of the epithelial cell
Mean (u)
3.69±0.006
(570)
3.09±0.07
(300)
4.47±0.08
(470)
4.79±0.08
(480)
P7
Dif 1-2 <0.05
Dif 3-1 <0.01
Dif 3-2 <0.01
Dif 4-1 <0.01
Dif 4-2 <0.01
Dif 4-3> 0.10
Diameter of the Testicular Tubule
Mean (u)
187.95 ±3.02
(570)
168.27 ± 2.71
(560)
192.85±3.07
(561)
195.91±3.12
(564)
P7
Dif 1-2 <0.50
Dif 3-1 <0.50
Dif 3-2 <0.01
Dif 4-1 <0.10
Dif 4-2 <0.01
Dif 4-3 <0.50
* Probability of chance occurrence of the difference between means from Fisher's table of t value
* Underlined differences are significant
Figures in brackets show the number of observations made
December, 1955 ] D. S. BHATNAGAR, D. P. MUKHERJEE AND P. BHATTACHARYA 297
TABLE III
Partial correlation coefficients between atmospheric factors and the various measure-
ments of the two glands
Diameter of the thyroid lobule
Height of the opithelial cells of the thyroid lobule
Diameter of the testicular tubule
Air
temperature
—0.345
—0.808**
—0.617**
Relative
humidity
—0.596**
—0.541**
—0.488**
**Significant at 1 per cent level
TABLE IV
Correlation coefficients between the various measurements of the two glands
Relation
Diameter of the thyroid lobule and height of the epithelial cell
Diameter of the thyroid lobule and diameter of the testicular tubule
Height of the epithelial cell and diameter of the testicular tubule
Correlation
Coefficient
+0.118
+0.171
+0.488**
** Significant at 1 per cent level
December, 1955 ] D. S. BHATNAGAR, D. P. MUKHERJEE AND P. BHATTACHARYA 299
the stored hormone was discharged into the blood due to lower air temperature
caused by high relative humidity but the production of hormone was lowest of all
seasons.
Partial correlation coefficients between the atmospheric factors, the diameter
and the height of the epithelial cells of the thyroid lobules indicated that in buffaloes
increase in humidity may cause the thyroid to discharge more of its stored hormone
into the blood, as a result of which the lumina of the follicles become smaller. The
production of hormone, however, as indicated by the height of the epithelial cells,
depends on both air temperature and relative humidity. Increase in either of the
two atmospheric factors when the other was held constant decreased the production
of the thyroid hormone. That the thyroid hormone is controlled by the environ-
mental temperature has been found in rats [Dampsy and Astwood, 1943; Hurst
and Turner, 1947; Maqsood and Reineke, 1950], in birds [Reineke and Turner,
1945] and in sheep [Berliner and Warbritton, 1937 ; Bogart and Mayer,
1946].In
influence on the thyroid activity.
Testes differ from the thyroid in the sense that they cannot store their product
and as such the increase in the diameter of the tubule may be an indication of their
higher activity and vice versa. Thus in winter and spring when the diameter of the
tubules in buffaloes was more in comparison to that in autumn, it indicated that the
activity of the testes in the two seasons was more than in autumn. Although there
was no significant difference between winter, spring and summer with regard to the
diameter of the testicular tubule, the histological study of the tubules indicated
that in winter and spring the rate of spermatogenesis was more. As the correlation
coefficient between the height of the epithelial cells of the thyroid lobule and the
diameter of the testicular tubule was positive and highly significant, it indicates that
greater the thyroid activity the greater is the testicular activity. But, as stated
before, this action of the thyroid may not be direct but indirect.
SUMMARY
The thyroid and the testicular materials from 32 adult buffalo-bulls slaughtered
at the peak of four different seasons, viz. summer, autumn, winter and spring were
studied. The thyroid materials were studied for seasonal variation in the diameter
of the thyroid lobule and the height of the epithelial cells of the lobule and the
testicular materials for the diameter of the tubules. The study revealed the following:
(1) In autumn, the diameter of the thyroid lobule was significantly lower
than in other season. In summer, the diameter of the thyroid lobule
was significantly more than in winter and spring.
(2) In autumn, the height of the epithelial cells was significantly lower than
in any other season. In summer, the height of the epithelial cells was
significantly lower than in the rest of the three seasons.
(3) The mean diameter of the testicular tubule in autumn was significantly
lower than in the rest of the three seasons. The diameter of the testicular
tubule in summer was in between that of autumn and winter.
300
CHANGES IN THE HISTOLOGY OF THE THYROID [ Vol. XXV, Part IV,
(4) No significant difference between winter and spring with regard to the
variations in the thyroid and the testicular materials has been found.
(5) The height of the epithelial cells of the thyroid lobules seems to have an
indirect effect on the diameter of the testicular tubule.
(6) Partial correlation coefficients between air temperature and the height of
the epithelial cells of the thyroid lobule and between air temperature
and the diameter of the testicular tubule was negative and highly
significant.
(7) Highly significant negative partial correlation coefficients between the
relative humidity and the two diameters and the height of the epithelial
cells have been obtained.
(8) The height of the epithelial cells of the thyroid lobule has been found to be
most sensitive to changes in air temperature and relative humidity than
the two diameters studied. Of the two diameters, the one of the testi-
cular tubule was comparatively more sensitive than that of the thyroid
lobule to variations in air temperature and relative humidity.
REPERENCES
Barker, S. B. (1949). J. Endocrinol., 6(2), 137
Berliner, V. and Warbritton, V. (1937). Proc. Amer. Soc. Anim. Prod., 137
Bogart, R. and Mayer, D.T. (1946). Amer. J. Physiol. 147, 320
Cameron, A.T. (1945). Recent advance in endocrinology. 5th Edn., Blackstone Co., London
Dampsey, E.W. and Astwood, E.B. (1943). Endocrinology 32, 509
Holm, E.O. (1949). Amer. J. Physiol., 158, 337
Hurst, V. and Turner, W. (1947). Amer. J. Physiol. 150, 686
Lerman, J. (1942). Amer. Med. Assn. 335N. Dearborn St., Chicago
Maqsood, M. and Reineke, E.P. (1950). Amer. J. Physiol. 162, 24
Moore, C.R. (1939). Biology of testes—Sex and Internal Secretion. Williams and Welkins Co., Baltimore
Mukherjee, D.P. and Bhattacharya, P. (1952). Indian J. vet. Sci. 22(2), 73, 1951
Oloufa, M.M., Bogart, R. and McKenzie, F.F. (1951). Fertile and Sterile 2, 223
Reineke, E.P., and Turner, C.W. (1945). Poult. Sci. 24, 499
Schneider, B.A. (1939). Quart. Rev. Biol. 14, 289
Shukla, D.D. and Bhattacharya, P. (1952a). Indian J. vet. Sci. 32(2), 109
—(1952b).
Indian J. vet. Sci. 22(2), 179
Watzka, M. (1938). Tierazte Mill. 19, 323 (citation from Vet. Bull. 9, 431)
ENVIRONMENTAL CAUSES OF VARIATION IN THE
LENGTH OF GESTATION OF BUFFALOES
By Y. S. GHANEM,1 A. ABUL-FADL, A. ZAHER2 and F. A. SOLIMAN, Department of
Zoology and Physiology, Faculty of Veterinary Medicine, Cairo University
(Received for publication on 16th December 1954)
(With one Text figure)
T HE Egyptian farmer has learned through years of experience that his buffalo is
expected to calve 10 months and 10 days after service, which is approximately
310 days. Levine [1920] found the average length of gestation in buffaloes to be
312 days. Ragab and Asker [1951] gave an estimate of 316.7 days. Kanneth
[1953] cited estimates of gestation period in the buffalo ranging from 310 to 316
days.
The scientific study of the various factors influencing the length of gestation in
farm animals has stimulated the interest of many investigators. Some of these
factors are the season and month of parturition, sex of young, age of dam, etc.
The season of calving has been found by Herman and Spalding [1947] and Alexander
[1950] to affect gestation length in cattle. They observed that cows calving during
the winter had the longest gestation and those calving during the summer had the
shortest. Other investigators [Knapp et al., 1940; Jafar et al., 1950] did not
observe any influence of season of calving on gestation length. Many studies
indicate that males are carried for a longer duration than females in cattle [Knoop
and Hayden, 1934; Jafar et al., 1950]; however, in buffaloes, Ragab and Asker
[1951] and Weaver et al. [1947] failed to show any effect of the sex of calf on the
duration of pregnancy. The age of dam has been found to affect gestation period
by some investigators [Knoop and Hayden, 1934; Herman and Spalding, 1947],
while others did not observe such an effect [Knapp et al., 1940; Weaver et al.,
1947; Jafar et al., 1950; Ragab and Asker, 1951].
In the present study, it was intended to investigate the effects of the different
environmental factors discussed above on the duration of pregnancy in the Egyptian
buffalo.
MATERIAL AND METHODS
The data used in this study were obtained from the breeding records kept on
Bahteem farm of the Egyptian Agricultural Society from 1935 to 1951. They
included 424 gestations, which terminated in the birth of living normal calves, from
126 buffaloes. These buffaloes were kept for milk production and were given dry
ration during the summer and autumn, while in the winter and spring they were
allowed to graze in clover fields. The length of gestation was computed from the
day of service to the day of calving, both days inclusive.
1 Present address: Zoology Dept., Faculty of Science, Cairo University
2 Present address: Animal Production Dept., Faculty of Agriculture, Heliopolis University
301
36 AR/55
7
302
VARIATION IN THE LENGTH OF GESTATION [ Vol. XXV, Part IV,
The data was examined statistically, using the 'analysis of variance' method
[Snedecor, 1946]. The method of expected subclass numbers [Snedecor, 1934]
and the method of unweighted means [Yates, 1934] were used in those cases of
multiple classification where the numbers in the subclasses were disproportionate.
RESULTS AND DISCUSSION
The average length of gestation in all the data was found to be 316.4 days, with
a standard deviation of ±7.86 days. This estimate is close to that reported by
Ragab and Asker [1951]. Figure 1 shows the frequency distribution of gestation
lengths, which seems to be slightly skewed [Sk=—0.08]. The mode of the distribu-
tion is 317 days.
Month and season of calving
Table I shows the average gestation lengths during the different months and
seasons of the year. It may be noticed that gestations ending in winter calving
are the longest, while those ending in autumn are the shortest, the other seasons
occupying a medium position. This effect of calving season was found to be highly
significant [Table II]. The effect of months within seasons was not significant.
Herman and Spalding [1947] and Alexander [1950] also observed that gestations
ending in winter calvings are the longest. The seasonal effect may be due to some
unknown nutritional or climatic factors which need further investigation.
TABLE I
Average length of gestation according to month and season of calving
Month of calving
December
January
February
March
April
May
June
July
August
September
October
November
TOTAL
Number
of
gestations
44
27
20
25
18
37
35
38
47
45
41
47
Average
length
in days
318.4
318.5
318.5
317.6
318.8
315.3
316.4
316.9
316.6
314.5
313.2
315.7
Season
of
calving
Winter
Spring
Summer
Autumn
Number
of
gestations
91
80
120
133
424
Average
length
in days
318.5
316.8
316.6
314.5
316.4
December, 1955 ] Y. S. GHANEM, A. ZAHER, A. A. FADL AND P. A. SOLIMAN 303
Fig. 1. Frequency distribution of gestation period in buffaloes
304
VARIATION IN THE LENGTH OF GESTATION [ Vol. XXV, Part IV,
TABLE II
Analysis of variance of gestation length for month and season of calving
Source of variation
Seasons
Months within seasons
Within months
Degrees of
freedom
3
8
412
Mean
square
290.7**
38.9
60.5
** P <0.01.
Year and season of calving
The gestations obtained from the year 1944 to 1950 were used to study the
effect of year and season of calving, since there were sufficient number of gestations
during each of these years. The analysis of variance did not show a significant
effect of year of calving on gestation length, while the season effect was highly
significant [Table III].
TABLE III
Analysis of variance of gestation length for year and season of calving
(method of expected subclass numbers)
Source of variation
Years
Seasons
Interaction
Within subclasses
Degrees of
freedom
6
3
18
361
Mean
square
125.2
253.3**
76.0
59.9
** P <0.01.
TABLE IV
Average length of gestation according to sex of calf and season of calving
Season of calving
Winter
Spring
Summer
Autumn
TOTAL
Male
Number
57
50
59
61
227
Average
318.2
316.0
315.7
313.2
315.7
Female
Number
34
30
61
72
197
Average
318.8
318.1
317.6
315.7
317.2
Total
Number
91
80
120
133
424
Average
318.5
316.8
316.6
314.5
316.4
December, 1955 ] Y. S. GHANEM, A. ZAHER, A. A. FADL AND F. A. SOLIMAN 305
Sex of calf and season of calving
Table IV shows the average gestation lengths ending by the birth of male and
female calves during the different seasons. Female calves were carried 1.5 days
longer than males. This difference was found significant [Table V], and was
responsible for 2.2 per cent of the total variance. The variation due to season of
calving was highly significant and was responsible for 4.1 per cent of the total
variance. Other investigators, however, [Knoop and Hayden, 1934; Jafar et al.,
1950; Ragab and Asker, 1951] observed that male calves are carried longer than
females. No satisfactory explanation for this controversy could be suggested.
TABLE V
Analysis and estimates of variance of gestation length for sex of calf and season of
calving
(Method of unweighted means)
Source of variation
Sexes
Seasons
Within subclasses
Degrees
of
freedom
1
3
416
Mean
square
358.5*
334.9**
59.7
Expected
value of
mean square
210.9ΣX 2 +Σ 2
104.6σ x
2 +σ 2
σ 2
Variance
component
1.4
2.6
59.7
Per cent
of total
variance
2.2
4.1
93.7
* P <0.05.
**P <0.01.
Age of dam
The lengths of 159 gestations from buffaloes of known ages were available for
studying the effect of age of dam on gestation length. They were adjusted for
season of calving and sex of calf; then they were divided into two groups according
to the age of the dam. The older buffaloes (above six years of age) carried their
calves 319 days, while the younger ones (2 to 6 years old) carried their calves 316
days. The difference was highly significant, and was responsible for 8.0 per cent
of the total variance [Table VI]. The age effect may be due to the slowing down
of physiological processes, including the control of pregnancy, in older buffaloes.
TABLE VI
Analysis and estimates of variance of gestation length for age of dam
Source of variation
Between ages
Within ages
Degrees
of
freedom
1
156
Mean
square
340.3**
47.4
Expected
value of
mean square
71.7σ a
2 +σ 2
σ 2
Variance
components
4.1
47.4
Percent
of total
variance
8.0
92.0
** P <0.01.
36 AR/55
8
306
VARIATION IN THE LENGTH OP GESTATION
[Vol. XXV, Part IV,
SUMMARY
The data relating to the length of 424 gestations in Egyptian buffaloes were
used in the study of the effects of certain environmental factors on pregnancy dura-
tion:
1. The average length of gestation was found to be 316.4,±7.86 days.
2. Differences due to season of calving were found highly significant. Gesta-
tions ending in winter calvings were found to be the longest, and those
ending in autumn calvings were the shortest.
3. The year of calving did not influence the length of gestation.
4. Female calves were carried in utero for a significantly longer period than
males.
5. Old buffaloes (above six years of age) carried their calves for significantly
longer periods than younger ones (2 to 6 years old).
ACKNOWLEDGMENT
The authors are indebted to the Egyptian Agricultural Society for providing
the breeding records, which were necessary for carrying out this investigation.
REFERENCES
Alexander, M. H. (1950). Length of Gestation in the Five Major Breeds of Dairy Cattle, Abstr. J.
Dairy Sci., 33 : 377
Herman, H. A. and Spalding, R. W. (1947). A Study of Factors Affecting the Length of Gestation in
Dairy Cattle. J. Dairy Sci., 30 : 545-546
Jafar, S. M., Chapman, A. B. and Casida, L. E. (1950). Causes of Variation in Length of Gestation in
Dairy Cattle. J. Anim. Sci., 9 : 593-599
Kenneth, J. H. (1953). Gestation Periods, a Table and Bibliography. Commonwealth Bureau of
Animal Breeding and Genetics, Tech. Commu., 5, third edition Edinburgh
Knapp, Jr., B., Lambert, W. V. and Black, W. H. (1940). Factors Influencing Length of Gestation
and Birth Weight in Cattle. J. agric. Res., 61 : 277-285
Knoop, C. E. and Hayden, C. C. (1934). A Study of the Length of Gestation and Service Record of
Dairy Cows. Ohio Agric. Exp. Sta. Bull., 19 : 8-14
Levine, C. O. (1920). The Water Buffalo, A Tropical Source of Butterfat. J. Heredity, 11 : 51-64
Ragab, M. T. and Asker, A. A. (1951). Factors Influencing Length of Gestation Period in Egyptian
Cattle and Buffaloes. Indian J. Dairy Sci., 4 : 159-169
Snedecor, G. W. (1934). The Method of Expected Numbers for Tables of Multiple Classification with
Disproportionate Subclass Numbers. J. Amer. Stat. Ass., 29 : 389-393
——(1946).
Statistical Methods, fourth edition. Iowa State College Press, Ames, Iowa.
Weaver, E., Wettstein, E. D. and Horwood, R. E. (1947). The Length of Gestation Period in Brown
Swiss. The Quart. Bull. Michigan. State College, 30 : 180-185
Yates, F. (1934). The Analysis of Multiple Classifications with Unequal Numbers in the Different
Classes. J. Amer. Stat. Ass., 29 : 51-66