Zur Schätzung der Menge an nutzbarem Rohprotein am Duodenum von Milchkühen

Abstract

Zusammenfassung Maßgeblich für die Proteinversorgung von Wiederkäuern ist die Menge an nutzbarem Rohprotein (nXP) am Duodenum. Um diese aus Rationsparametern abschätzen zu können, wurden anhand von 532 Einzeltiermessungen aus Braunschweig‐Völkenrode und Dummerstorf‐Rostock an fistulierten Milchkühen Regressionsgleichungen zur Bestimmung des nutzbaren Rohproteins am Duodenum abgeleitet. Als wichtigste Einflußfaktoren auf den Fluß an nutzbarem Rohprotein bestätigte sich die Aufnahme an umsetzbarer Energie (ME) oder verdaulicher organischer Substanz (DOS) und an nativem Futterrohprotein. Eine gewisse Verbesserung der Schätzgenauigkeit ergab sich durch Einbeziehung der in 335 Messungen bestimmten Menge an ruminal nicht abgebautem Futterrohprotein (UDP). Noch etwas geringer wurde der Schätzfehler bei Berücksichtigung der Wechselbeziehung zwischen mikrobieller Proteinsynthese und Abbaubarkeit des Futterrohproteins (XP) im Pansen. Die Schätzgleichungen mit dem höchsten Bestimmtheitsmaß (r2 = 0,91) und dem geringsten Variationskoeffizienten (cv = 8,9) lauteten: g nXP = [11,93 ‐ (6,82 (UDP/XP))]ME + 1,03 UDP, und g nXP = [187,7 ‐ (115,4 (UDP/XP))]DOS + 1,03 UDP

Calculation of utilizable crude protein at the duodenum of cattle by two different approaches

“…Formulating equations for predicting the amount of utilizable crude protein (uCP, in German: nXP) at the duodenum, Lebzien et al (1996) showed that most of the variation in uCP could be explained by differences in metabolizable energy (ME) or digestible organic matter (DOM) and non-urea feed protein (CP). Some improvements in predicted values were obtained when taking into account the in vivo measured flow of undegraded feed crude protein (UDP) and the relationship between microbial protein synthesis and crude protein degradation in the rumen are shown by Voigt and Piatkowski (1987).…”

“…Utilizable crude protein was defined as total crude protein at the duodenum minus endogenous protein. Further details concerning the experimental design, the animals, the diets, the sampling procedures, the marker techniques and the analytical procedures are given elsewhere (Lebzien et al, 1996).…”

“…The 327 measured amounts of utilizable crude protein at the duodenum were compared with values calculated by multiple regression (Lebzien et al, 1996) and by addition of microbial protein and undegraded feed protein estimated separately. The regressions and the measurements for microbial protein synthesis as well as the feed protein degradation and the organic matter fermentation in the rumen were based on the same experimental data set.…”

“…Measurement (uCP) 2096 ± 607 g Calculation by regression (Lebzien et al, 1996) Figure 1 shows the differences between amounts of utilizable crude protein at the duodenum as measured or calculated using regression equation 2 or by addition of microbial crude protein B (MCP B ) and undegraded feed protein.…”

Investigations on the influence of duodenal histidine infusion on nitrogen and amino acid turnover of growing German holstein bulls

“…III). This proportion varied between 70 and 85%, and therefore corresponded to a typical cattle ration as shown by Lebzien et al (1997). The NAN fraction disappearing from the intestine was utilised with an efficiency of between 0.4 and 0.5 and no apparent effects due to L-His supply were detected.…”