ORIGINAL PAPER
Effects of type of grass silage and level of concentrate on the flow of soluble non-ammonia nitrogen entering the omasum of dairy cows
C. W. Choi 1, 2  
,   A. Vanhatalo 1,   P. Huhtanen 1
 
More details
Hide details
1
Animal Production Research, MTT Agrifood Research Finland, FIN-31600 Jokioinen, Finland
2
Department of Nutritional Physiology, National Livestock Research Institute, R.D.A. Suweon, South Korea
CORRESPONDING AUTHOR
C. W. Choi   

Department of Nutritional Physiology, National Livestock Research Institute, R.D.A. Suweon, South Korea
Publication date: 2003-01-02
 
J. Anim. Feed Sci. 2003;12(1):3–22
 
KEYWORDS
ABSTRACT
Four ruminally cannulated Finnish-Ayrshire dairy cows were used to study effects of type of grass silage (primary vs secondary) and level of concentrate supplementation on concentration and the flow of soluble non-ammonia N (SNAN) in the liquid phase of digesta entering the omasum. The treatments in a 4 x 4 Latin square design consisted of either primary growth of grass silage (PG) or secondary growth of grass silage (SG) each with either 8.1 or 12.1 kg/d of concentrate (air dry basis). Digesta entering the omasum was collected, and SNAN fractions (free amino acids, peptides and soluble protein) in the digesta were assessed using ninhydrin. The microbial contribution to SNAN was estimated using 15N as a microbial marker. Concentrations of free amino acids, peptides and soluble protein N averaged 22.3, 59.8 and 23.1 mg N/l, respectively. PG diets tended (P=0.09) to increase peptide N concentration in omasal digesta compared with SG diets, whereas level of barley concentrate did not affect concentrations of SNAN fractions. Peptide N constituted the largest proportion of SNAN in omasal digesta, supporting the previous observation that hydrolysis of peptides to AA is the most limiting step in rumen proteolysis. The microbial contribution to SNAN averaged 0.71, indicating that a substantial proportion of the SNAN was of microbial origin. Soluble dietary NAN flow averaged 9.1 g N/d, accounting for approximately 0.05 to 0.08 of total dietary NAN flow.
 
CITATIONS (4):
1.
Chemical and ruminal in vitro evaluation of Canadian canola meals produced over 4 years 1
Glen A. Broderick, Stefania Colombini, Sara Costa, Mehmet A. Karsli, Antonio P. Faciola
Journal of Dairy Science
 
2.
Changes in ruminal fermentation and blood metabolism in steers fed low protein TMR with protein fraction-enriched feeds
Chang Weon Choi
Korean Journal of Agricultural Science
 
3.
Effect of quantifying peptide release on ruminal protein degradation determined using the inhibitor in vitro system1
S. Colombini, G.A. Broderick, M.K. Clayton
Journal of Dairy Science
 
4.
Omasal Flow of Soluble Proteins, Peptides, and Free Amino Acids in Dairy Cows Fed Diets Supplemented with Proteins of Varying Ruminal Degradabilities
S.M. Reynal, I.R. Ipharraguerre, M. Liñeiro, A.F. Brito, G.A. Broderick, J.H. Clark
Journal of Dairy Science
 
ISSN:1230-1388