Doktorarbeit Endversion - Stiftung Tierärztliche Hochschule Hannover

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Chart 7.1: Percentual increase of ammonia concentrations at days 10 to 14
(addition of Clostridia) and days 15 to 18 (ending of addition of
Clostridia till the end of addition of silage) respectively, compared to
controlling phase (days 7 to 8)
Percentual increase compared to controlling phase
Addition Day 10-14 Day 15-18
K-01, C. perfringens, 1 mL 25,2 -3,15
K-01, C. botulinum, 1mL 43,1 20,6
K-01, C. perfringens, 2mL 2,56 -14,6
K-01, C. botulinum., 2mL 8,67 2,74
S-11, C. perfringens, 1 mL 72,2 45,6
S-11, C. botulinum, 1mL 76,6 61,4
S-11, C. perfringens, 2mL 36,8 37,4
S-11, C. botulinum, 2mL 35,9 73,0
S-05, C. perfringens, 1 mL 109 83,3
S-05, C. botulinum, 1mL 110 119
S-05, C. perfringens, 2mL 47,2 53,0
S-05, C. botulinum, 2mL 68,8 155
Varying effects of ruminal bacteria especially proteolytic ruminal bacteria and HAB
(Hyper Ammonia producing Bacteria) might be the reason for the different effects of
diverse strains and amounts of Clostridia on ammonia concentrations. An alternative
explanation for the increasing ammonia concentrations could be ammonia production
by Clostridia strains themselves. Furthermore, a combination of both effects cannot
be excluded.
Except the ammonia concentrations other parameters of fermentation like pH, production
of volatile fatty acids, bacterial protein, production and composition of gas
and the activity of ruminal protozoa were not affected by the addition of Clostridia.
In summary, the results of the present study show that Clostridium botulinum as well
as Clostridium perfringens induce changes of ammonia concentrations in bovine
ruminal fluid when grass silage is fed, while other parameters of fermentation stayed
constant. Kind of Clostridia strain as well as amount of Clostridia affected the grade
of ammonia increase. Furthermore it has been shown that grass silages with
conspicuously low true protein amplify these effects.