December, 1955 ]     P. BHATTACHARYA AND S. S. PRABHU                    275

No data beyond 78 hours was available at the Calcutta and Patna centres.
Considering only the average rates over all centres and also those rates which includ-
ed figures from all centres, it appears that no marked drop in conceptions occurred
when semen stored for 72 hours outside the body in an extender was used for breed-
ing. The average rate over these periods was 64.54±1.15 per cent (Range 59.14
to 68.89 per cent). Pooling the data into age periods of 12 hours, statistical analysis
was carried out on figures of all centres upto the age of 60 hours. Though figures
for all centres were available in the 60.1 to 72 hours period, due to small number of
inseminations on which the Patna figure was based, this period was not included
in the analysis. The results of the analysis are summarised in Table XIII.

                             TABLE XIII

                     Analysis of variance

**Significant at 1 per cent level

It will be seen from the above analysis that though the difference in concep-
tion rates among centres was highly significant, the variation in rates between age
groups of semen was not significant.

                                             SUMMARY

The data gathered during the calendar year 1948 at the Calcutta, Patna and
Bangalore field artificial insemination centres, operated by the Animal Genetics
Division of the Indian Veterinary Research Institute, and comprising 6758 insemina-
tions made from 737 ejaculates drawn from 23 Bos indicus, one Bos taurus and
seven Bubalus bubalis bulls of the centres are analysed and discussed.

                                    ACKNOWLEDGMENT

The authors are thankful to Shri D. B. Mukherjee, Ch. Chetram and Shri S. V.
Chandiramani, respective officers-in-charge of the Calcutta, Patna and Bangalore
artificial insemination centres, for their help in introducing the new technique in
the field. The basic data collected by these officers of the centres were freely drawn
in preparing this article. Thanks are also due to Major J. M. Lahiri, Principal,
Bengal Veterinary College, Shri S. K. Sen, Director, Animal Husbandry Depart-
ment, Bihar, and Dr. K. C. Sen, Director, Indian Dairy Research Institute, Banga-
lore, for their keen personal interest and for providing all facilities for work. To
the Director, Indian Veterinary Research Institute, the authors are grateful for
help and advice at all stages during the operation of the scheme.

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