September, 1953] S.S PRABHU, S. GUHA AND P. BHATTACHARAY 177
The quantity of bhusa fed to bulls 1, 2 and 8 was subsequently raised to four
pounds, as it was observed that three pounds allowance was insufficient.
The experiment was started on 29 June, 1949 and concluded on 9 November,
1949. Due to the non-availability of wheat bran, it had to be excluded from the
mixture from 31 July, 1949. The rations were weighed as per schedule drawn up
and fed individually to the animals. The blood-meal was added prior to feeding.
Blood-meal was increased slowly and brought up to the desired level to enable the
animals to get used to it. Within 4 to 8 days all were readily taking blood-meal
mixed in the concentrates.
Semen was collected at weekly intervals from all the bulls, and on each day
of collection two ejaculates were taken and completely analysed with regard to
colour and consistency, volume, initial motility, sperm density, percentage of abnor-
mal sperm and initial pH. In addition, reaction time for each ejaculate and records
of daily body weight of the animals were maintained.
RESULTS
In Table II are brought out the averages of the various semen characteristics,
observed in the two ejaculates of the control and blood-meal fed animals. In addition
the averages of the reaction time, body weights, rates of gain and rates of change
in rates of gain of the different bulls are also given in the same table. The figures
given in columns 13, 14 and 15 of the table are respectively the values of co-efficients
A, B and C obtained by fitting orthogonal polynomials as described by Fisher [1943]
to the daily live-weight data. The co-efficients give respectively (i) average weight,
(ii) average gain in weight and (iii) average rate of change in gain of weight.
For analysing the data on semen characteristics and reaction time, two different,
methods were adopted. In the first method, the figures under each criterion for the
different bulls in the two groups were separately averaged out and the averages so
obtained used in conducting a straight-forward analysis of variance. The variance
due to treatment differences were tested using the 'between bulls within feeds'
variance as the error. The results are given in Table III. In none of the criteria
were the treatment differences found to be significant.
This method at best provides a rough and ready way of testing overall group
differences. Besides, the use of averages smooths out random variation between
collections giving more stable figures for carrying out the analysis. The analysis,
however, does not take into account the possible effect of the time factor on semen
production and reaction time. In the present experiment, a certain amount of
seasonal effect on the results might reasonably be expected as the experiment had
lasted for over four months—of which the initial period of about one month and a
few days had fallen in summer and the major portion in autumn. Correction for
initial observation might, therefore, be necessary. These points were taken care
of in the second method wherein the technique of analysis of co-variance was em-
ployed. In live weight data analysis of residual variance was carried out after
adjustment of initial weight. The items so studied were (i) final weight (ii) average
weight (iii) average rate of gain and (iv) average rate of change in rate of gain.