December, 1955] N. S. KUSHWAHA, D. P. MUKHERJEE AND P. BHATTACHARYA 325
and spring nor between spring and summer. It is apparent from Table IV that
among the two atmospheric factors which may be responsible for this peculiar seaso-
nal variation in sperm concentration, air temperature may be an important factor as
it varied significantly between seasons. To make a comparative study of this pattern
of variation from that of bull, monthly variations in sperm concentration of the two
species together with air temperature are given in Fig. 2. It may be seen from the
figure that in autumn both in buffalo and bull, sperm concentration showed a down-
ward trend from summer. With the advent of winter the curve took an upward
trend. The trend was slow in buffalo, whereas in bull it was marked and rapid.
Throughout winter, the sperm concentration in bull was maintained at higher level
than in summer and autumn. The concentration reached its peak at the middle
of spring, after which with the increase in air temperature it began to decrease.
In buffalo the increase initiated at the advent of winter continued slowly throughout
winter and spring and began to decrease slowly with the advent of summer. It
might be that due to this slow change there was no significant difference between
autumn and winter, between spring and summer and between autumn and spring.
Bhatnagar, Mukherjee and Bhattacharya [1954] studied seasonal variation in the
histology of the thyroid and the testis of buffalo at the peaks of the four seasons.
The periods during which the activity of the two glands were studied are shown in
Fig. 2 by circle marks. It was observed that the testicular activity in spring and
winter was more than in autumn ; between autumn and summer, the activity was
more in summer. As the quality of semen is dependent on the testicular acivity,
it seems from the results obtained from the histological study of the gland that the
effect of climate on semen quality was the same as in the case of other farm animals
like bulls, sheep and goats. This result is contrary to what has been obtained in the
present experiment. The apparent contradictory results obtained may be explained
from Fig. 2 which shows that in summer and autumn when the gland was studied,
the trend of sperm concentration was towards decrease while in winter and spring
it was towards increase. This was reflected in the histological structure of the gland.
In spring, although the level of sperm concentration was lower than in summer, it
is apparent from the figure that during spring it was towards increase as against
summer when it was towards decrease. This may be the reason why the gland
showed hyperactivity in spring in comparison with summer.
From the above discussion it seems that climate influences the semen quality
in buffalo in the same way as in other farm animals. The difference in the trend of
seasonal variation in sperm concentration of the buffalo from that of other species
of farm animals may be due to the reason that in buffalo the fluctuation in sperm
concentration due to the fluctuation in air temperature is not so rapid and marked
as in other species. This may be due to the reason that in buffalo the thermo-re-
gulatory mechanism is not so much developed as in bulls, sheep and goats.
Total number of spermatozoa
The result of analysis of data on total number of spermatozoa showed that there
was highly significant variation between seasons. This result is contrary to those
obtained in bulls by Mukherjee and Bhattacharya [1952] but is in agreement with
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