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SEASONAL VARIATION IN REACTION TIME
[Vol. XXII, Part II,
in sperm concentration. McKenzie and Berliner [1937] also found that the
normal ejaculates, of rams with sperm concentration higher than 1000 millions
per c.c. were usually acidic and sometimes gave a value as low as 5.9 and
never above 7.3. Comstock and Brady [1937] gave the pH. of normal semen
of ram as 6.9 and abnormal as over 7.0, Terril [1937] observed that ejaculates
giving an acid reaction to litmus were definitely superior to those giving
an alkaline reaction. In the present investigation, although it has been found that
rams with higher pH of semen had lower sperm concentration, the correlation was
not directly proportional. Determination of pH in semen has been recognised
by various workers on semenology as one of the methods of evaluating semen quality
as it indirectly gives an indication of sperm concentration in semen. Higher pH
of semen in generally associated with lower sperm concentration, and vice versa.
This was found to be true between years and between seasons. In autumn and
summer when the air temperature was higher than in winter and spring the pH
value of semen was higher associated with lower sperm concentration. This observa-
tion is confirmatory to the results obtained by McKenzie and Berliner [1937] in
rams under heat treatment. They observed that semen in rams under heat treat-
ment became more and more alkaline. Gunn and his co-workers [1942] also observed
that semen of rams whose tests were subject to scrotal insulation always became
alkaline.
Sperm concentration. Result of analysis of data on sperm concentration showed
that it was highly variable among rams between years and among seasons. Highly
significant variation between rams within breeds and between seasons have also
been observed by Phillips et al. [1943]. They found the highest sperm concentration
in winter and lowest in fall. McKenzie and Berliner [1937] observed a low level
of sperm concentration in the Shorpshire during August and September and a sudden
increase in October, which lasted till December. In this experiment highest sperm
concentration was observed in spring and lowest in autumn. This result is in'
complete agreement with that obtained in bulls by Mukherjee and Bhattacharya
[1947]. Berliner and Werbritton [1937] made histological studies of the organs
•and glands of the rams which were used in the experiment of McKenzie and Berliner
[1937]. They also made histological studies of organs and glands of thyroidecto-
mised rams and rams treated with thyroxine and gonadotrophins. Their results
indicated that the change in level of thyroid -secretion due to high environmental
temperature might be the cause of lowered fertility in rams. Bogart and Mayer
[1946] found that thyroid is of major importance in the reproductive physiology
of the rams and that environmental temperatures produce variations in rams in-
directly through the thyroid gland. High environmental temperatures produce
variations in rams indirectly through the thyroid gland. High environmental
temperature decrease thyroid secretion and consequently decrease the spermato-
genesis.
Total number of spermatozoa. The result of analysis of the data on total
number of spermatozoa showed that autumn was the worst season and spring
the best season for total number of spermatozoa. In winter and summer
there was no significant variation. This result differs from the observation of
McKenzie and Berliner [1937] and Phillips et al. [1943, b]. According to McKenzie