6
THE EFFECT OF FEEDING THYROPROTEIN ON SEMEN. (I) [Vol. XXIII, Part I,
be used to distinguish a very good sample from a very bad one. Grading of
samples with small differences is almost impossible by this method.
The dosage of thyroprotein administered to the animals was found to have
a deleterious effect on semen volume. The total volume of semen of the experi-
mental group was found to be much lower than that of the control group. A conse-
quential effect of such reduction in volume was that the total number of sperma-
tozoa failed to show any significant difference between the two groups, in spite of
the higher sperm concentration of the experimental group. According to Bogart
and Mayer [1946] ' the results of a concentration count are indicative of the sperma-
togenic activity of the male, but do not give a true evaluation unless the semen
volume is also considered and a calculation of the total spermatozoa per ejaculate
is made. To gain any degree of insight into the effect of high temperature and
thyroxine upon spermatogenesis the data on total spermatozoa per ejaculate and
the semen volume must be considered.' Judged on the basis of these factors, the
present investigation shows that thyroprotein feeding has little effect on spermato-
genesis. Bogart and Mayer [1946] found that thyroactive protein fed at the daily
dosage level of 1 gm. per ram failed to maintain or raise semen volume during periods
of high temperature. But the decrease in volume due to high environmental
temperature was less in the treated group than in the control group. This obser-
vation is contrary to what has been found in the present experiment. The reason
for the decrease in semen volume might be due to the high dosage of thyroprotein
administered to the animals.
The percentage of abnormal spermatozoa was found to be uninfluenced by
thyroprotein feeding. This result is not in agreement with those of some previous
workers. Bogart and Mayer [1946] found that by feeding 1 gm. of thyroprotein
per day per ram for a period of 30 days during the summer, the percentage of abnor-
mal spermatozoa decreased considerably. Berliner and Warbritton [1937] reported
that two intact and one thyroidectomised Hampshire rams with high abnormality
counts returned to normality after the administration of two doses (2 mg.) of thy-
roxine in August. In contrast to these results Eaton et al., [1948] observed that
feeding of thyroprotein to rams for 15 weeks, increased the percentage of abnormal
spermatozoa. In the present experiment, some of the animals of the experimental
group after four weeks of thyroprotein feeding produced semen containing 30
to 40 per cent beaded spermatozoa. These were included as abnormal spermatozoa
although such spermatozoa have been identified by Mukherjee and Bhattacharya
[1949] as immature forms. The increase in the percentage of beaded spermatozoa
in some of the animals and their inclusion as abnormal sperm in the computation of
results might have masked the beneficial effect of thyroprotein feeding on other
true abnormalities. But in a study from the point of view of semen utility, the
beaded spermatozoa cannot be excluded from the computation of results because
they, like the other abnormalities, reduce the fertilising capacity of semen.
' Recation time ' is an indications of sex vigour. Reineke [1946] found de-
finite improvement in sex drive and vigour by oral administration of thyroprotein
to 14 bulls which were sluggish, lethargic and showed lessened libido before treatment.
Turner et al. [1943] found that a Toggenburg buck, which showed a definite lack of
interest in oestrous does, displayed sexual interest after the feeding of one gram of