DETERMINATION OF DIGESTIBILITY CO-EFFICIENTS               315

The values obtained from the graph drawn for each of the food components are
set forth in the following Table :—

                                                TABLE VII.*

Components

Ordinate at
x=o
(consumed) C
gems.

Ordinate at
x = o
(digested) D

Digestibility
of
roughage
D
C

Slope of the
curve
(Digestibility
of
concentrate)

1

2

3

4

5

Dry matter ....

3,862

1,751

.4507

.701

Organic matter ....

3,326

1,687

.5073

.7216

Crude protein ....

147

13

.0873

.8475

Ether extract ....

45

19

.4316

.9636

Crude fibre.....

1,302

803

.6165

.2729

Nitrogen free extract ...

1,830

845

.4617

.6730

* The original data are reproduced in Appendix II.

It will be seen that the straight line in the graph has given a very close fit
to the observed values except in the case of crude fibre †. This evidently points
out that the interaction during the course of digestion is probably negligible and the
digestibility is more or less constant for the three sets of combinations. This
would suggest a fair order of reliability for the estimates of digestibility co-efficients.

THE DIRECT ESTIMATION OF DIGESTIBLITIES (OF STRAW AND CAKE) BY THE AID
                            OF MULTIPLE REGESSION EQUATIONS.

We have no direct way of ascertaining whether there is any or no interaction
taking place during the course of digestion of cake and straw. The same state-

† In the case of fibre the range of variation of the observed values and the deviations from the
straight line will be seen to be of the same order and hence the fit cannot be considered satisfactory.