Macro In Situ Results
from the University of Wisconsin - Trial 3
Compliments of Nutrition Department
What is Macro In Situ?
The macro in situ technique is a new method Mycogen Seeds is using to
estimate corn silage starch degradation in the rumen. Samples of silage are
placed as is – without drying or grinding – into polyester bags and
incubated in the rumen of cannulated dairy cows for a period of time (16 or 24
hrs). A rumen cannulated cow has an opening on her side used to reach inside her
rumen and introduce samples. Mycogen has been working on this new technique in
cooperation with some Universities. Researchers feel that the standard method of
drying and finely grinding silage samples before analysis for ruminal starch
degradation eliminates differences among hybrids due to kernel texture,
moisture, starch type or other factors. When the sample is finely ground, any
type of starch could potentially be degraded by the rumen microbes because of
the reduction in particle size of the grain and removal of barriers to
digestion, such as a harder seed coat or a harder endosperm.
Trial Results
The graph below summarizes starch degradation results. Various types of
hybrid were tested in this trial, including TMFÔ
Silage-SpecificÔ , dual purpose, high oil, Bt, waxy.
The TMF108 silage tended to have a greater starch degradation than the other
silages tested. Routine lab results do not include starch degradation, so TMF
and other silages will look similar on paper. The calculated energy value on the
report will not be corrected for this increased energy availability and more
grain than necessary might be pulled into the ration by the computer. This could
lead to less than optimal use of the silage and potential rumen health problems.
Please make sure your nutritionist is aware that you planted a silage-specific
TMF hybrid, so he/she can make the necessary adjustments to the ration. You can
contact our nutrition department at http://www.mycogen.com or 1-800-MYCOGEN
(1-800-692-6436) if you have any questions.
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