166 APPLICATION OF ARTIFICIAL INSEMINATION IN CATTLE [Vol. XXII, Part III,
'possible' number of collections works out at 1456. The number of collections
actually made were 533, i.e., less than one per bull per week. The low number
was due mainly to the lack of adequate demand for semen, and also in some measure
to the inherent defect in the bulls themselves, and their inconsistent behaviour
after being in use for sometime. The actual number of bulls maintained at each
centre could have been reduced considerably, if it had been possible to select more
active and pretrained bulls.
Average Volume of Ejaculum per Collection
The average volume of semen per collection varied according to species and
breed, and within a breed, from animal to animal. Bos bubalis bulls on an average
gave 2.63±0.07 c.c. of semen as compared to 3.10±0.05 c.c. given by the Bos indicus
bulls. The difference is statistically significant. In Bos bubalis, the average for
the Nili breed was 2.41±0.06 c.c. and for the Murrah breed 3.54±0.06 c.c. per
collection. In both the breeds within breed differences, however, are not significant.
In the Bos indicus breeds, the Sahiwal topped the list with 3.72±0.11 c.c.; next
came the Tharparker with 3.10±0.07 c.c. followed by the Nagori and Indo-European
Cross-bred with 2.84±0.11 c.c., 2.43±0.19 and 2.35±0.13 c.c. per collection res-
pectively. Differences amongst breeds are statistically significant. The bull
to bull differences amongst Sahiwal and Tharparker are also statistically significant.
The highest average volume was given by a Sahiwal Bull (M 12/1.2) stationed at
Montgomery centre (4.11±0.19 c.c.), the lowest by the Indo-European Cross-bred
bull No. 1 from Calcutta with 2.35±0.13 c.c.
With the B. bubalis bulls, Ayyar [1944] observed an average volume of 3.00 c.c.
per collection in the 16 collections made from 2 bulls, while Shukla and Bhattacharya
[1949] found the average volume from 24 collections to be 1.84±0.99 c.c. The
results reported herein are from 162 collections made from 5 bulls. The average
worked out is slightly higher than that reported by Ayyar [1944] and significantly
higher than the figure reported by Shukla and Bhattacharya [1949]. In case of
Bos indicus bulls, the average volume for Sahiwals is given as 3.80±0.35 c.c. per
collection by Shukla and Bhattacharya [1949]. This figure is not significantly
different from 3.72±0.11 c.c. found in our study. The former figure is an average
of 18 collections made from a single bull, while the latter is from 95 collections made
from 4 different bulls. Data regarding Tharparker and Nagori and Indo-European
Cross-bred bulls are new and have not been reported previously. No attempt is
made here to compare the results with those of foreign breeds. In view of the small
number of bulls studied under each breed, the conclusions drawn above should be
taken as tentative subject to confirmation on the basis of further observations
on a larger number of bulls.
Month to month variation in average volume in the different breeds is brought
out in Table II.
Preservation of Semen
In the early stages of the work at the centres, the ejacula were preserved 'neat'
and used as such. Diluted semen was used in two centres later on. At Patna,
neat semen had been used throughout.