28
INFLUENCE OF FACTORS AFFECTING SEX-DRIVE
[Vol. XXVI, Part II,
Experiment VI
There was no significant change in the time taken when collections were made
at night under the artificial light instead of during the day under sunlight. In semen
quality, however, a significant difference in variation was observed in respect of
sperm concentration of the first ejaculates. The average over bulls for day collections
was 520 millions per c.c. as compared with 814 millions per c.c. of night collections.
Sex-drive and short term change in sex stimuli. Using the average over bulls
and over experiments as an estimate of the intensity of sex-drive inherently present
in the bulls of our experiments, the results obtained when different stimuli were
applied, were re-arranged in the descending order of reaction time values and the
figures are presented in Table III.
Out of the 14 bulls in the experiments, No. 23 had the highest average reaction
time and bull No. 16, the lowest. It was noticed that while the latter jumped at
once and gave a thrust, the former took time to explore the dummy and gave a
thrust only after one or two attempts. A comparison of the reactions of these
two extreme types to the new sexual stimuli would give an indication of their relative
behaviours. If we take only the experiments involving the change of dummies and
leave out of consideration the experiments like giving bath and changing the time of
collection since they deal with effects other than sex ones, marked reaction could be
observed in bull No. 23 to the change in sex stimuli and small or negligible in the case
of bull No. 16. Similar also is the case with bull No. 40 which came near to bull No. 23
in sex-drive and bull Nos. 19 and 21 which had sex-drives nearer to bull No. 16.
In the intervening cases the effects were rather not clear cut. If we divide all the
bulls into two broad groups depending upon their level of sex-drive, viz. those with
sex-drive of 60 and less seconds and those having sex-drives above 60 seconds,
then the first five bulls namely, Nos. 23, 40, 24, 26 and 25 fall in the latter category,
while the remaining 9 bulls fall in the former. If now we consider their behaviour
in experiments I (a) and (b), II and IV, we find that in the above 60 seconds
group, out of 9 cases only in one case the results were different from the
expected rest, while in one it was equal. In the below 60-seconds group, out of 30
cases there were 9 cases in which the results were different and two cases in which
they were equal. This appears to suggest that bulls having higher reaction time
are more susceptible to change in sex stimuli than bulls with lower reaction time
Considering now the experiments in which cold shower bath was given prior to
collection or collections taken during evening or at night and retaining again the
two broad divisions in respect of sex-drive, we find that in the group with longer
reaction time, out of 9 instances in two cases they behaved differently; while in
the group with shorter reaction time, out of 17 cases in 7 cases the results were
different from the others. This also shows that the bulls with reduced reaction
time are less likely to notice any change than bulls with higher reaction times.