March, 1954] S. S. PRABHU AND P. BHATTACHARYA 49
and anoestrus teaser cows at intervals of few minutes, 24-48 hours and seven days,
between changes, no effect in either reaction time and quality and quantity of
semen .collected which could be attributed as due mainly to the physiological state
of the teaser cows, could be detected. Since the only stimulus provided was the
olfactory one and collections were taken in all cases in the artificial vagina, the
possible effect of natural service cannot be ruled out. Our results show that in case
of buffalo bulls there is no harm if occasional additional stimuli in the form of teaser
cows on heat are shown to the artificial insemination bulls for short periods to over-
come impaired sex-drive. It is interesting to find out whether significant differences
are produced, if the treatment is continued for fairly long period before change-
over is effected. Experience in training older bulls used to natural service to serve
in artificial vagina seems to suggest expectation of positive results. It was observed
that as a rule bulls used to natural service took on an average longer time to serve
in artificial vagina. Here again species difference was noticed suggesting the exis-
tence of differing threshold reaction values for B. indicus and B. bubalis. Records
collected over the past ten years show that buffalo bulls as a class can be trained
to serve in the artificial vagina earlier than bulls of the B. indicus breeds, especially
those of the milk breeds. The exception to this general observation are the bulls
transferred from one climatic stress to another, which come in a class by themselves.
Finally, the possible role of training on the normal sex behaviour of bulls needs
consideration. In this connection reference is invited to the reports of Milovanov
[1934] and of McKenzie and Berliner [1937] on the effect of training on the normal
mating behaviour of rams. Whether such an effect is present in buffaloes, and if
present whether it has influenced the results got by us since only artificial insemina-
tion trained bulls were used is difficult to say without further work.
SUMMARY
1. Using a ' switch back' design, three sets of experiments were run on the
common water buffalo bulls normally found in Uttar Pradesh to investigate the effect
of short term stimuli in the form of a teaser cow ' on heat' on the reaction time and
semen production.
2. In the first experiment, which was replicated, an interval of about 24-48 hours,
in the second experiment an interval of seven days and in the third experiment
an interval of 15-20 minutes were given before changing over of ' treatments '.
3. The first two experiments were conducted on six bulls, while for the third
experiment 12 bulls were used. Results show that there was no statistically signifi-
cant difference in either the reaction time or semen production between the bulls
in the two groups, in all the experiments. In addition, no residual effect of one
treatment on the next subsequent treatment could be detected.
4. It has been concluded that as far buffalo bulls are concerned a short-term
addition to normal service condition, such as providing a teaser cow on heat for
making collection from artificial insemination trained bulls, is not attended by any
bad effects, either immediate or subsequent, and as such may be safely introduced
in suitable cases to provide additional sex-stimuli.