June, 1952] D. P. MUKHERJEE AND P. BHATTACHARYA 121
and Berliner a distinct increase in total number of spermatozoa was observed from
October to January in Shorpshire and August to November in Hampshire. According
to Phillips and his associates, total spermatozoa was highest in winter and lowest
in fall. Both the above groups of workers found spring to be the second best season.
Abnormal spermatozoa. The result obtained in this respect show that ram 3
varied significantly from the rest of the rams. Regarding the effect of seasons,
it was found that in autumn and spring the average percentage of abnormal sper-
matozoa was significantly more than in spring and summer. It has been stated
before that in autumn the tailless spermatozoa and in winter the bent-tail ones were
more than in other seasons. Autumn was marked for its high temperature, humidity
and rainfall. During this season the semen quality was also poorer than in other
seasons. Phillips and McKenzie [1934] observed that there was a marked increase
in the production of abnormal spermatozoa following heat treatment of rams and
within three weeks practically no spermatozoa were present. McKenzie and Berliner
[1937] also found that heat applied to scrotum either experimentally or by local
inflammation decreased spermatogenesis and increased abnormal spermatozoa.
The predominance of tailless spermatozoa in autumn as found in this experiment
might be due to high environmental temperature. The increase in the percentage
of tail abnormalities in winter as observed in this experiment was also reported in
bulls and rams by Phillips et al. [1943, a and 1943 b]. But they did not mention
the types of the tail abnormalities. This experiment showed that the predominant
tail abnormality in winter was the bent-tail one. Mukherjee and Bhattacharya
[1947] also observed the increase in bent-tail spermatozoa in the ejaculates of bulls
in winter. They have further shown that the bent-tail spermatozoa in the ejaculates
of farm animals are really immature ones and have suggested that in winter, when
the rate of spermatogenesis was comparatively higher than in autumn, more of
immature spermatozoa like bent-tail ones were carried along with normal spermatozoa
in the male reproductive tract before they came to ampullae for final ejectment.
SUMMARY
Seasonal variation in 'reaction-time' and semen characteristics of nine rams
were studied for two consecutive years.
Highly significant variation was observed among rams in average 'reaction-time'
and all attributes of semen studied except in the initial motility.
'Reaction-time' did not show any definite seasonal trend and bore no relationship
with the quality of semen produced.
Between years highly significant variations were found in 'reaction-time'; pH
of semen, sperm concentration and total number of spermatozoa.
Between seasons highly significant variations were found in all characterisitcs
of semen except in 'reaction-time'. The semen quality in autumn was poorer than
in other seasons. Spring was found to be the best season for semen quality.
Between months within seasons highly sigificant variation was found in intial
motility of spermatozoa, sperm concentration, total number of spermatozoa and
percentage of abnormal spermatozoa.
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