Chemical analyses of eighty-three grasses, calculated on the wet and dry basis, are reported. Their composition is discussed from a nutritional point of view. Scientific, English and Spanish common names of the grasses are also given

Axtmayer, Joseph H.

Cook, D. H.

Rivera Hernández, G.

English

Portal de Revistas Académicas Universidad de Puerto Rico

T H E JOURNAL OF' AGHICIXTURE OP T H E UNIVERSITY OP PUERTO RICO 
CHEMICAL ANALYSES OF GRASSES2 
By Joseph H. Axtmayer, 0. Rivera Hernández and D. H. OooTc -with, tne 
technical assistance of José A. Goyco and M. G. de Fernández^ 
From the Department of Chemistry of the School of Tropical Medicine, San 
Juan, Puerto Rico and the Department of Chemistry of the Agricultural , 
Experiment Station, Río Piedras,-Puerto Rico. 
The object of this study- was to find through the medium oí 
a systematic survey, grasses which would be worthwhile a trial 
in our studies of the nutritive values of forage crops of Puerto 
Rico. Although the findings from a chemical analysis of a grass 
do not yield all the data necessary for judging its nutritive value, 
nevertheless, some.light is shed upon its possibilities. Grasses of 
good nutritive qualities with root systems capable of reducing soil 
erosion would be of double value to the agricultural economics of 
the Island. 
Puerto Rico imports large quantities of mixed feed concen-
trates used by the dairy industry. Even so, the milk production 
is insufficient to meet the needs of the inhabitants of the Island, 
were each individual to receive the daily amount considered ade-
quate by our present knowledge of optimum nutritional require-
ments. I t is also expensive, considering the income of the lower 
class of people. We see no reason why uncultivated regions could 
not be used to produce crops which could be used as forage, not 
only for grazing, but for cutting and mixing with other crops in 
the preparation of concentrates. 
MATERIALS 
All the grasses analyzed had been cut during the blooming 
stage with the exception of sample 64, same grass as sample 63, 
i Cooperative project between the School of Tropical Medicine and the 
Agricultural Experiment Station. 
2 Mr. G. Ii. Crawford, Chief, Soil Conservation Service in Puerto Rieo, and 
Dr. H. W. Alberts cooperated by furnishing samples of varieties and species and 
also valuable agronomic data. 
- j r * -
CHEMIOAL ANALYSES OF GBASSES 33 
which was cut during the after-blooming stage. Our reason for 
collecting the grasses for analysis during the blooming stage was 
to obtain comparable samples. Although it is known tha t an act-
ively growing immature grass, contains more.protein and more 
total digestible nutrients than the more mature plants, the flower-
ing stage was selected for the sake of uniformity. 
METHODS OP ANALYSIS 
The samples were brought to the laboratory as soon as cut. 
They were then eleaned, cut into smaller sizes, weighed and placed 
in a large horizontal flow, forced-air oven for the moisture deter-
minations. When dry, they were ground in a Wiley mill, and the 
powder stored in air-tight bottles for the determinations of the 
other constituents. The analyses were performed according to 
the methods of the Official Agricultural «Chemists. All analyses 
for a given constituent' were performed in duplicate. 
DISCUSSION 
The analyses of the grasses as reported on the dry basis show 
that some are quite rich in total crude protein, and would yield 
a hay of some nutritional value. Those yielding a percentage of 
protein above ten (10) could be used for this purpose. 
They are low in ether-soluble extract (fat) and high in crude 
fiber, as is to be expected. The nitrogen-free extract (carbo-
hydrates) averages around 45-50% and is a good source of energy. 
The most favorable ratio of calcium to phosphorus for growth 
and bone formation is between 2 and 1 and 1 and 2. With the 
amount of ultraviolet radiation available throughout the year in 
the sunshine of Puerto Eico, an abundance of vitamin D for the 
mobilization of the calcium and phosphorus is assured. The calcium 
and phosphorus ratios of the grasses studied are all narrow and 
within the limits of profitable utilization. 
Abundance of all the other vitamins is also a certainty in the 
fresh grasses but may be reduced when these are dried. 
Nutritional studies which have been planned include some of 
these grasses, to be used either fresh, as cut, or as hay, in the 
experimental rations. The formulation of a cheap ration, nutri-
tionally adequate, consisting of crops grown in Puerto Eico would 
be of great help in the production of cheap milk which is of such 
great importance in human dietaries. 
34 THE JOTJBNAL OF AGKICUI/TUBE OF THE UNTVEBSITY OF PUERTO BICO 
SUMMARY 
Chemical analyses of eighty-three grasses, calculated on the 
wet and dry basis, are reported. Their composition is discussed 
from a nutritional point of view. 
Scientific, English and Spanish common names of the grasses 
are also given. 


CHEMICAL ANALYSES OF GRASSES

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CHEMICAL ANALYSES OF GRASSES

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