Exam from 2023
A common quality measure for silage is pH. However, at high dry matter content this is
not considered a useful measure. What is the reason for that?
The PH in silage with a high DM content desn´t have to be as low as in wet silage since
there is less water and fermentation in dryer silage. Less lactic bacteria.
What is the main principle for the conservation of those very high dry matter silages,
i.e. which prerequisites become more and more important the higher the DM gets?
Higher DM wilting to get higher sugar content !!
Airthight sealing and pack it densly (in tower silo put below and better for bales than bunker
silo); Speed (not too fast, not too low)
Avoid having a lot of concurrence for the LAB
1
, Aerobic stability of silage.
a) What does the term “aerobic stability” of silage mean?
How long can the silage be opened until it ”gets bad” (air comes in, if there is e.g a lot
yeast left heating)
b) Which microorganisms are most important when it comes to negative effects on
the aerobic stability of silage?
Yeast
Clostridia
c) Which substrates do these microorganisms use?
Glucose, acids
d) How can you measure aerobic stability?
Measure Temperature (heating yeast)
Measure how much oxygen goes into the silage
(Smell it)
2
A common quality measure for silage is pH. However, at high dry matter content this is
not considered a useful measure. What is the reason for that?
The PH in silage with a high DM content desn´t have to be as low as in wet silage since
there is less water and fermentation in dryer silage. Less lactic bacteria.
What is the main principle for the conservation of those very high dry matter silages,
i.e. which prerequisites become more and more important the higher the DM gets?
Higher DM wilting to get higher sugar content !!
Airthight sealing and pack it densly (in tower silo put below and better for bales than bunker
silo); Speed (not too fast, not too low)
Avoid having a lot of concurrence for the LAB
1
, Aerobic stability of silage.
a) What does the term “aerobic stability” of silage mean?
How long can the silage be opened until it ”gets bad” (air comes in, if there is e.g a lot
yeast left heating)
b) Which microorganisms are most important when it comes to negative effects on
the aerobic stability of silage?
Yeast
Clostridia
c) Which substrates do these microorganisms use?
Glucose, acids
d) How can you measure aerobic stability?
Measure Temperature (heating yeast)
Measure how much oxygen goes into the silage
(Smell it)
2
