|Abstract or Summary
- Chemical and biological evaluations were conducted to provide
chemical composition and digestibility information, in addition to
yield data, for silage corn varieties produced on poorly drained
Dayton soil series. Each variety was subjected to a Kjeldahl nitrogen,
acid detergent fiber, acid detergent lignin, cell wall, and
residual ash test. Subsequently cell contents, cellulose, and hemicellulose
were calculated by difference.
The objectives of this study were to determine if significant
differences in nutrient composition and digestibility existed among
silage corn varieties grown under similar cultural conditions, and
whether such differences could be detected by the detergent analysis
scheme in a non-pasture forage. Finally, a comparison of in vitro
(artificial rumen) and summative equation digestibility coefficients
would indicate the possibility of using the latter for estimating nutritive
value in forage crop experimental work. In addition, grass and
legume samples, varying widely in nutritive value, were subjected
to detergent analysis to ascertain the systems capabilities for
assessing differences in chemical composition between forage types.
Statistical analysis of the data for chemical composition of the
silage corn varieties showed that no significant differences among
varieties existed at the five percent probability level.
Biological availability of the nutrients of the silage corn varieties
was measured by the in vitro (artificial rumen) technique. No
significant differences were noted in the 24-hour trials. However,
in the 12-hour trials varieties two and four gave coefficients that
were significantly (P < .05) greater than varieties one, five, six,
seven, or ten. Calculated correlations of the 12 and 24-hour in
vitro (artificial rumen) dry matter digestibility and of coefficients
estimated by the summative equation were not highly significant.
Relationships of chemical constituent data of grass and legume
samples from detergent analysis provided evidence that this feed-stuff
fractionation accurately reflects differences in chemical composition
between species. Hemicellulose values of the grass were
four times as great as those of the alfalfa, but the cellulose content
was similar for the two forage types. Comparison of silage corn
data with that of the alfalfa gave a relationship analogous to that of
Residual ash values of the grass were ten times larger than those of the alfalfa. However, it was not an important factor limiting
nutritive value in either the alfalfa or the silage corn.
Alfalfa cell wall level and its digestibility were lower than that
of the grass. But cell wall material of the grass was twice the
amount contained in the alfalfa, and its digestibility was also higher
which reflects its lower degree of lignification.