THE CHEMICAL COMPOSITION OF STAR GRASS (CYNODON
PLECTOSTACHYUM) AT DIFFERENT STAGES OF GROWTH
AND THE NUTRITIVE VALUE OF MATURE STAR
GRASS HAY
By N. L. MATHUR and S. C. RAY, Animal Nutrition Section, Imperial Veterinary Research
Institute, Izatnagar
( Received for publication on 12 December 1942)
SEN [1942] drew attention to the possibilities
of star grass (Cynodon plectostachyum) as a fodder
for the cattle in India. Sometime ago, through
the courtesy of this worker, the writers received a
consignment of star grass hay for determination
of the digestibility coefficient and the nutritive
value of this material. They also received four
samples of star grass, cut at three, four, six and
seven months of age, for complete chemical
analysis.
In this note are reported the results of (1) the
chemical analysis of the grass at the four different
stages of progressive maturity, and of (2) the feed-
ing experiment with the hay obtained from the
last cut (seven months' growth).
CHEMICAL COMPOSITION
The samples of star grass cut at different stages
were analysed for their organic and inorganic
constituents. The results of the analysis are
shown in Table I.
TABLE I
Composition of star grass at different stages of growth
Sample
1st cut . .
2nd cut . .
3rd cut . .
4th cut . .
Approxi-
mate
age
(months
3
4
6
7
Organic
matter
88.14
88.79
91.78
89.18
Percentage expressed on dry matter basis
Crude
protein
12.19
9.44
7.19
5.44
Ether
extract
1.65
0.90
0.86
0.90
Crude
fibre
26.60
30.36
32.72
37.60
N-free
extract
47.70
48.09
51.01
45.24
Total
carbo-
hydrates
74.30
78.45
83.73
82.84
Ash
11.86
11.21
8.22
10.82
Cal-
cium
0.97
0.75
0.52
0.53
Phos-
phorus
0.36
0.33
0.30
0.24
Up to the third cut the organic matter pro-
gressively increased. In the last cut, however,
the value of the organic matter slightly decreased
owing to a proportionate rise in the ash content.
The percentage value of crude protein moiety
significantly decreased with advancing maturity.
The decrease in protein content was over 22 per
cent between the first and the second cut, about
24 per cent between the second and the third cut
and over 24 per cent between the third and the
last cut. A comparatively high value of ether
extract was recorded in the sample from the first
cut. This value fell abruptly by almost 50 per
cent in the second cut and remained at much the
same low level in subsequent cuts. With pro-
gressive maturity, as expected, the crude fibre
content showed a steady increase. The other
fraction of the carbohydrate moiety, namely the
nitrogen-free extract, showed a similar tendency
to increase up to the third cut, but thereafter
there was an abrupt drop in this value.
The analytical data presented in Table I also
show that for a non-leguminous forage, star grass
is richly provided with such essential minerals as
calcium and phosphorus. The percentage value
of calcium showed a gradual decrease with ad-
vancing maturity up to the third cut. The cal-
cium contents of the comparatively mature grass
in the third and in the last cut were much the same.
The phosphorus value of the grass progressively
decreased with the increasing maturity of the
plant. As compared with a less than 10 per cent
decreased in the value during each of the first two
intervals, the phosphorus content dropped by 20
per cent in the interval between the third and the
last cut.
It is of interest to note that though the interval
between the third and the last cut was only one
month, during this short period the quality of the
grass suffered significantly owing to a decrease in
the percentage values of such important consti-
tuents as crude protein, nitrogen-free extracts and
phosphorus.
DIGESTIBILITY AND NUTRITIVE VALUE
For the purpose of this experiment, two hill
bulls of 3 and 4 years of age respectively were used.
The weights of these animals were 244 and 252
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