Broschüre 2004 zum Download (pdf | 1994,28 KB) - H. Wilhelm ...

HANS STEINHART
Diskussion
SCHWARZ
Coming to your last conclusions: What would you
recommend the farmers to interrupt this problem
with BAB-spores and so on?
DRIEHUIS
We see this relation with aerobic instability, and
also notice that in these poor layers the consolidation
was very poor. It was loose material. It seems that the
poor compaction of these silages is simply the reason
why at least these layers are so instable, and probably
also the reason that these Butyric Acid Bacteria start
to grow. Probably this does not only occur in the
endphase, I mean, the feed out phase, but probably
already earlier during the storage phase. During the
storage phase we have some oxygen penetration into
the silage already. That gives these Butyric Acid Bacteria,
these Clostridia, more time to grow, because
they need time. They need a high pH, they need the
lack of oxygen, but they also need time, because they
are very slow growers. The other organisms involved
in aerobic instability grow much faster. So, we have
calculated, that you need about 2 weeks or so to go
from 100 spores to 1 Million spores. There must be
a long incubation period.
What can farmers do? Now we think that the poor
consolidation, the poor compaction, the low density
of the grass- and of the maize-silage in particular
forces this, and what we wonder is, whether this has
changed in the recent years. Is the situation that we
experience now, different from 5 –10 years ago? We
think so. We think that this may be the reason why
the percentage of milk deliveries with to much spores
goes up again.
We think that trends taking place in agriculture,
with a higher and higher capacity of machinery, result
in less and less attention in silage making, less and less
intention to good compaction and taking enough time
for compaction and good sealing, and that might be a
reason why this is now occuring more and more.
ROTH-MAIER
You spoke about the penalty system you have in
the Netherlands. Could you just shortly explain how
this penalty system works, that you can identify the so
called bad farmers who had contaminated milk?
DRIEHUIS
The system works so that farmers are tested six
times during the winter period. Samples were taken
from the milk tank, the milk that they delivered to
the milk industry, and it was analysed for butyric acid
bacteria with a very simple method. This just gives
an indication of »higher« or »lower« than a certain
value. If they are higher than that limit value, they
get a penalty. If it is just at that critical value, then the
analysis will be repeated. And if it is high again, they
get a penalty. But it is a very rough analysis for this.
Since this year, the system will be changed, and they
will analyse it through the whole year, not only in the
winter period, but also in the summer period, which
is quite logical, if you see this.
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