Fütterungsbedingte mikrobielle Zusammensetzung von Rinderkot ...

8. Summary 85
ratio, which differed significantly, at 9.1 and 7.0 for ND and NB, respectively.
Digestibility was also significantly affected by the feeding regime. Undigested dietary
N, fibre fractions (NDF) and hemicellulose were significantly higher in ND compared
with the NB treatment. There were parameters showing only an effect of the sampling
days. However, with the methods applied, clear feeding effects on microbial parameters
in cattle faeces were confirmed.
Further feeding effects on fecal quality were investigated for cattle of different
performance levels. A study was carried out to investigate first the effects of different
diets for heifers, low and high lactation cows on their faeces and subsequently the
effects of these different cattle faeces types on N2O emissions, N mineralisation and
plant N uptake. A low N and high ADF diet given to heifers resulted in a faeces
dominated by fungi, which was low in microbial biomass C in combination with a wide
microbial biomass C/N ratio and a high ergosterol concentration, especially in
comparison with the diet of high lactating cows. Added to soil, heifer faeces led to the
lowest microbial CO2 production and strongest N immobilisation but also to lowest N2O
emissions during a 14-day incubation at 22 °C. Also, the rye grass yield and plant N
uptake was lowest in the soil amend with heifer faeces in a 62-day pot experiment. N
uptake by rye grass correlated positively with the faecal N concentration and negatively
with its crude fibre concentration, but also negatively with the microbial biomass C/N
ratio and the fungal C to bacterial C ratio. Faecal microbial properties revealed closer
relationships to plant N uptake than soil microbial properties.