Investigate the Magnitude of Differences on Total Metabolizable Protein among Different Genotypes of Barley Grown for Three Consecutive Years


Several genotypes of barley have been developed by Crop Development Center. However, no quantitative evaluation of true protein supply to ruminants has been done in terms of protein degradation balance (PDB) and total metabolizable protein supply (or total truly absorbed protein in the small intestines). The objective of this study was to determine the magnitude of difference in terms of total metabolizable protein supply of five CDC feed-type barley cultivars in comparison to Canada’s most widely grown malting cultivar AC Metcalfe. Six, two row cultivars of spring sown barley, included AC Metcalfe, CDC Cowboy, CDC Dolly, CDC Helgason, CDC Trey and McLeod were grown in the research field of University of Saskatchewan, Saskatoon, SK, Canada for three consecutive years. The quantitative predictions were made in terms of: 1) Rumen synthesized microbial protein truly absorbed in the small intestine (AMCP); 2) Rumen undegraded protein truly absorbed in the small intestine (ARUP); 3) Endogenous protein in the digestive tract (AECP); 4) Total metabolizable protein supply in the small intestine. The results showed that CDC barley variety differed (P < 0.05) in AMCP ranging from 34 to 40 g/kg DMand AECP, but had no difference (P > 0.05) in ARUP with average of 48 g/kg DM. Total metabolizable protein ranged (P < 0.05) from 85 to 92 g/kg DM. In conclusion, CDC barley variety affected total predicted metabolizable protein supply, but not to large extend. All the barley varieties had negative degraded protein balance value.



Acid detergent insoluble crude protein


Endogenous protein in the digestive tract


Rumen synthesized microbial protein truly absorbed in the small intestine


Rumen undegraded protein truly absorbed in the small intestine


Crude Protein


Potentially degradable fraction in situ


Endogenous protein


Effective degradability of crude protein in situ


Protein degradation rate in situ


Protein passage rate in situ


Potential Rumen synthesized microbial protein based on effective degradability of crude protein


Potential Rumen synthesized microbial protein based on total digestible energy


Rumen synthesized microbial protein supply


Metabolizable protein


Neutral detergent insoluble crude protein


Non-protein nitrogen


Fraction of CP that is instantaneously solubilized at time zero


Fraction of CP that is soluble in borate-phosphate buffer and precipitated with trichloroacetic acid


Calculated as total CP minus the sum of fractions PA, PB1, PB3 and PC


Calculated as the difference between the portions of total CP recovered with NDF and ADF


Fraction of CP recovered with ADF and is considered to be undegradable. It contains proteins associated with lignin and tannins and heat-damaged proteins such as the Mailard reaction products


Protein degradation balance calculated based on data from NRC 2001 model


Rumen undegradable feed protein


Rumen undegradable feed protein estimated according to the DVE/OEB system


Soluble fraction in situ


Soluble crude protein


True Protein


Undegradable fraction in situ


  1. AOAC 1990. Official Methods of Analysis (15th Ed.). Association of Official Analytical Chemists, Arlington, VA, USA.

    Google Scholar 

  2. Hart, K.J., Rossnagel, B.G., Yu, P. 2008. Chemical characteristics and in situ ruminal parameters of barley for cattle: Comparison of the malting cultivar AC Metcalfe and five feed cultivars. Can. J. Animal Sci. 88:507–513.

    Article  Google Scholar 

  3. Licitra, G., Hernandez, T.M., Van Soest, P.J. 1996. Standardization of procedures for nitrogen fractionation of ruminant feeds. Animal Feed Sci. Technol. 57:347–358.

    Article  Google Scholar 

  4. NRC 2001. Nutrient Requirement of Dairy Cattle (7th Ed). National Research Council, National Academy Press, Washington, D.C., USA.

    Google Scholar 

  5. Ørskov, E.R., McDonald, I. 1979. The estimation of protein degradability in the rumen from incubation measurements weighted according to the rate of passage. J. Agric. Sci. (Cambridge) 92:499–503.

    Article  Google Scholar 

  6. Sniffen, C.J., O’Connor, J.D., Van Soest, P.J., Fox, D.G., Rusell, J.B. 1992. A net carbohydrate and protein system for evaluation cattle diets. II. Carbohydrate and protein availability. J. Animal Sci. 70:3562–3577.

    CAS  Article  Google Scholar 

  7. Tamminga, S., Van Straalen, W.M., Subnel, A.P.J., Meijer, R.G.M., Steg, A., Wever, C.J.G., Block, M.C. 1994. The Dutch protein evaluation system: The DVE/OEB-system. Livestock Production Sci. 40:139–155.

    Article  Google Scholar 

  8. Tamminga, S., Brandsma, G.G., Duinkerken, G.v., Vuuren, A.M.v., Blok, M.C. 2007. Protein evaluation for ruminants: the DVE/OEB 2007-system. CVB documentation report 53.

  9. Yu, P., Christensen, D.A., McKinnon, J.J. 2003a. Comparison of the National Research Council-2001 model with the Dutch system (DVE/OEB) in the prediction of nutrient supply to dairy cows from forages. J. of Dairy Sci. 86:2178–2192.

    CAS  Article  Google Scholar 

  10. Yu, P., Meier, J., Christensen, D.A., Rossnagel, B., McKinnon, J.J. 2003b. Using the NRC-2001 model and the DVE/OEB system to evaluate nutritive values of Harrington (Malting-Type) and Valier (Feed-Type) barley for ruminants. Animal Feed Sci. Technol. 107:45–60.

    CAS  Article  Google Scholar 

  11. Yu, P. 2005. Prediction of protein supply to ruminants from concentrates: comparison of the NRC-2001 model with the DVE/OEB system. J. of the Science of Food and Agric. 85:527–538.

    CAS  Article  Google Scholar 

  12. Yu, P., Hart, K., Du, L. 2009. An investigation of carbohydrate and protein degradation ratios, nitrogen to energy synchronization, and hourly effective rumen digestion of barley: effect of variety and growth year. J. of Animal Physiol. and Animal Nutrition 93:555–567.

    CAS  Article  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Peiqiang Yu.

Rights and permissions

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Reprints and Permissions

About this article

Cite this article

Hart, K.J., Rossnagel, B.G. & Yu, P. Investigate the Magnitude of Differences on Total Metabolizable Protein among Different Genotypes of Barley Grown for Three Consecutive Years. CEREAL RESEARCH COMMUNICATIONS 40, 405–412 (2012).

Download citation


  • total metabolizable protein
  • barley
  • genotypes
  • plant protein
  • ruminants