Optimierung der Effizienz der Stickstoff-Verwertung bei Rindern.
Abstract
The Cornell Net Carbohydrate and Protein System (CNCPS) model was used to formulate a corn-based diet that would meet the rumen requirements for 410 kg large-frame steers with an estrogen implant and fed an ionophore. A highly undegradable intake protein (UIP) mixture was formulated from meat and bone meal, blood meal, fish meal and hydrolyzed feather meal that provided the amino acids needed to supplement those derived from microbial protein. Four Holstein steers weighing 406.8 kg were fed at 95 % of ad libitum intake a 90:10 concentrate-forage diet at hourly intervals. The steers were injected with 500 mg estradiol 17-beta at 12-h intervals, mimicking the effects of an estrogenic implant. Treatments consisted of inclusion of UIP mixture at 0, 2.6, 5.2, and 7.8% of the diet on a DM basis, and the diets contained 11.3, 12.5, 13.8 and 14.9% CP on a DM basis, respectively. Diet DM intake was fixed at 6.4 kg/d and although DM digestibility was not significantly affected by amount of UIP addition, it increased from 75.3 in the control diet to 76.2, 77.2, and 77.8% with the three levels of UIP. N digestibility increased (P .011) from 63.8 to 65.8, 70.7 and 71.5% with each level of UIP addition. As the amount of N absorbed increased (P .001) from72.8 to 84.0, 100.0 and 106.3 g/d, N balance increased (P .003) from 19.6 to 30.5, 33.3 and 39.3 g/d when UIP was fed at 0, 2.6, 5.2 and 7.8% of the diet. The maximum biological value (N retained in % of N absorbed) was achieved when 2.6% UIP was added to the diet, a 36.4% improvement compared to the diet with no inclusion of UIP. Adding 7.8% UIP to the diet enhanced efficiency of N use (N retained in % of N intake) by 47.7% (P = .047). Circulating concentrations of plasma urea N (PUN) were increased (P = .017) from 4.5 for the control diet to 5.7, 6.2 and 6.1 mg/dL when the UIP mixture was added at 2.6, 5.2 and 7.8%.
Schlagworte Rind Aminosäuren Proteinaufnahme Stickstoff Stoffwechsel
Publikationen
Potential improvement of the efficiency of dietary nitrogen utilization in Holstein steers through the use of animal by-products.
Autoren: Knaus, W F; Beermann, D H; Guiroy, P J; Boehm, M L; Fox, D G Jahr: 1999
Originalbeitrag in Fachzeitschrift
Mitarbeiter*innen
Wilhelm Friedrich Knaus
Ao.Univ.Prof. Dipl.-Ing. Dr.nat.techn. Wilhelm Friedrich Knaus
wilhelm.knaus@boku.ac.at
Tel: +43 1 47654-93235
Projektleiter*in
01.09.1995 - 31.08.1996
BOKU Partner
Externe Partner
Cornell University
Prof. Dr. Donald H. Beermann
Koordinator