Skip to main content Accessibility help

Effects of dietary neutral detergent fibre to protein ratio on duodenal microbial nitrogen flow and nitrogen losses in lactating cows fed high-concentrate total mixed rations with different forage combinations

  • Q. C. REN (a1) (a2), X. JIN (a1), Z. H. ZHANG (a1), H. J. YANG (a1) and S. L. LI (a1)...


The objective of the present study was to investigate the effect of dietary neutral detergent fibre (NDF) : crude protein (CP) ratio on duodenal microbial crude protein (MCP) flow and nitrogen (N) losses. The study was completed in a 5 × 5 Latin square design with five lactating Holstein dairy cows and 5 high-concentrate total mixed rations (TMR) with different forage combinations, typical for Northern China. The rations with a fixed forage-to-concentrate ratio (39 : 61) resulted in different dietary NDF : CP ratios: TMR1 3·03 : 1 (428·2 g NDF/kg : 141·4 g CP/kg); TMR2 2·74 : 1 (392·7 g NDF/kg : 143·2 g CP/kg); TMR3 2·55 : 1 (368·3 g NDF/kg : 144·4 g CP/kg); TMR4 1·84 : 1 (304·8 g NDF/kg : 165·8 g CP/kg); TMR5 1·60 : 1 (285·0 g NDF/kg : 178·0 g CP/kg). Rumen content, milk, blood, urine and faeces were sampled on the last 3 days of five 18-day periods. Purine derivatives in the urine samples were determined to estimate rumen MCP flow into the small intestine. Milk yield and milk protein yield increased linearly with decreasing dietary NDF : CP ratio although slight differences in dry matter intake were observed due to feed intake restriction. Diurnal ammonia N in the rumen and duodenal MCP flow increased linearly, but blood urea N, urinary N and faecal N linearly decreased with decreasing dietary NDF : CP ratio. The enhanced N utilization in the maize-silage-based TMRs (TMR4–5) in comparison with maize-stover-based TMRs (TMR1–3) increased milk yield and the synthesis of milk protein instead of milk fat in the lactating cows, probably due to high transfer of ammonia N into rumen MCP with a considerable increase of dietary non-fibre carbohydrate content and the decrease of NDF : CP ratio. The present results indicate that not only increasing dietary non-structural carbohydrate content but also adjusting the ratio of structural carbohydrate to CP ratio are important diet formulation strategies for mitigating N losses in lactating cows.


Corresponding author

*To whom all correspondence should be addressed. Email: and


Hide All
Allen, M. S. (2000). Effects of diet on short-term regulation of feed intake by lactating dairy cattle. Journal of Dairy Science 83, 15981624.
Allen, M. S. & Mertens, D. R. (1988). Effect of dietary fiber level and forage source on intake and milk production of Holstein cows (abstract). Journal of Dairy Science 71(Suppl. 1), 179.
Aldrich, J. M., Muller, L. D., Varga, G. A. & Griel, L. C. (1993). Non-structural carbohydrate and protein effects on rumen fermentation, nutrient flow, and performance of dairy cows. Journal of Animal Science 76, 10911105.
AOAC (1999). Official Methods of Analysis. 16th edn.Arlington, VA, USA: AOAC International.
Cabrita, A. R. J., Bessa, R. J. B., Alves, S. P., Dewhurst, R. J. & Fonseca, A. J. M. (2007). Effects of dietary protein and starch on intake, milk production, and milk fatty acid profiles of dairy cows fed corn silage-based diets. Journal of Dairy Science 90, 14291439.
Cao, Z. J., Ma, M., Yan, X. Y., Li, S. L. & Zhang, X. M. (2009). A simple urine-collecting apparatus and method for cows and heifers. Journal of Dairy Science 92, 52245228.
Chen, X. B., Chen, Y. K., Franklin, M. F., Ørskov, E. R. & Shand, W. J. (1992). The effect of feed intake and body weight on purine derivative excretion and microbial protein supply in sheep. Journal of Animal Science 70, 15341542.
Dewhurst, R. J., Davies, D. R. & Merry, R. J. (2000). Microbial protein supply from the rumen. Animal Feed Science and Technology 85, 121.
Firkins, J. L. (1997). Effects of feeding nonforage fiber sources on site of fiber digestion. Journal of Dairy Science 80, 14261437.
Grings, E. E., Roffler, R. E. & Deitelhoff, D. P. (1991). Response of dairy cows in early lactation to additions of cottonseed meal in alfalfa-based diets. Journal of Dairy Science 74, 25802587.
Herrera-Saldana, R., Gomez-Alarcon, R., Torabi, M. & Huber, J. T. (1990). Influence of synchronizing protein and starch degradation in the rumen on nutrient utilization and microbial protein synthesis. Journal of Dairy Science 73, 142148.
Hoover, W. H. & Stokes, S. R. (1991). Balancing carbohydrate and protein for optimum rumen microbial yield. Journal of Dairy Science 74, 36303644.
Hristov, A. N. & Broderick, G. A. (1996). Synthesis of microbial protein in ruminally cannulated cows fed alfalfa silage, alfalfa hay, or corn silage. Journal of Dairy Science 79, 16271637.
Hristov, A. N. & Ropp, J. K. (2003). Effect of dietary carbohydrate composition and availability on utilization of ruminal ammonia nitrogen for milk protein synthesis in dairy cows. Journal of Dairy Science 86, 24162427.
Huhtanen, P. & Shingfield, K. J. (2005). Grass silage: factors affecting efficiency of N utilization in milk production. In Silage Production and Utilization. Proceedings of the XIVth International Silage Conference, Belfast, Northern Ireland, July 2005 (Eds Park, R. S. & Stronge, M. D.), pp. 3550. Wageningen, The Netherlands: Wageningen Academic Publishers.
Johnson, R. R. (1976). Influence of carbohydrate solubility on non-protein nitrogen utilization in the ruminant. Journal of Animal Science 43, 184191.
Khorasani, G. R., Okine, E. K., Corbett, R. R. & Kennelly, J. J. (2001). Nutritive value of peas for lactating dairy cattle. Canadian Journal of Animal Science 81, 541551.
Koenig, K. M., Beauchemin, K. A. & Rode, L. M. (2003). Effect of grain processing and silage on microbial protein synthesis and nutrient digestibility in beef cattle fed barley-based diets. Journal of Animal Science 81, 10571067.
Kuoppala, K., Yrjänen, S., Jaakkola, S., Kangasniemi, R., Sariola, J. & Khalili, H. (2004). Effects of increasing concentrate energy supply on the performance of loose-housed dairy cows fed grass silage-based diets. Livestock Production Science 85, 1526.
Leng, R. A. & Nolan, J. V. (1984). Nitrogen metabolism in the rumen. Journal of Dairy Science 67, 10721089.
Linn, J. G. & Olson, J. D. (1995). Using milk urea nitrogen to evaluate diets and reproductive performance of dairy cattle. In Proceedings of the 4-State Applied Nutrient Management Conference, August 2-3 1995, La Crosse, WI, pp. 155167. Madison, WI, USA: University of Wisconsin.
Martin, O. & Sauvant, D. (2002). Meta-analysis of input/output kinetics in lactating dairy cows. Journal of Dairy Science 85, 33633381.
Maynard, L. A., Loosli, J. K., Hintz, H. F. & Warner, R. G. (1979). Animal Nutrition. 7th edn.New Delhi: Tata McGraw-Hill Publishing Company Ltd.
Meng, Q., Kerley, M. S., Ludden, P. A. & Belyea, R. L. (1999). Fermentation substrate and dilution rate interact to affect microbial growth and efficiency. Journal of Animal Science 77, 206214.
Moorby, J. M., Dewhurst, R. J., Evans, R. T. & Danelón, J. L. (2006). Effects of dairy cow diet forage proportion on duodenal nutrient supply and urinary purine derivative excretion. Journal of Dairy Science 89, 35523562.
Nocek, J. E. & Russell, J. B. (1988). Protein and energy as an integrated system: relationship of ruminal protein and carbohydrate availability to microbial synthesis and milk production. Journal of Dairy Science 71, 20702107.
NRC (2001). Nutrition Requirements of Dairy Cattle. Washington, D.C.: National Academy Press.
Rinne, M., Jaakkola, S., Kaustell, K., Heikkila, T. & Huhtanen, P. (1999). Silages harvested at different stages of grass growth v. concentrate foods as energy and protein sources in milk production. Animal Science 69, 251263.
Rodríguez, C. A., González, J., Alvir, M. R., Repetto, J. L., Centeno, C. & Lamrani, F. (2000). Composition of bacteria harvested from the liquid and solid fractions of the rumen of sheep as influenced by intake level. British Journal of Nutrition 84, 369376.
Rodríguez, L. A., Stallings, C. C., Herbein, J. H. & McGilliard, M. L. (1997). Diurnal variation in milk and plasma urea nitrogen in Holstein and Jersey cows in response to degradable dietary protein and added fat. Journal of Dairy Science 80, 33683376.
Russell, J. B., O'Connor, J. D., Fox, D. G., Van Soest, P. J. & Sniffen, C. J. (1992). A net carbohydrate and protein system for evaluating cattle diets: I. Ruminal fermentation. Journal of Animal Science 70, 35513561.
Russell, J. B., Sniffen, C. J. & Van Soest, P. J. (1983). Effect of carbohydrate limitation on degradation and utilization of casein by mixed rumen bacteria. Journal of Dairy Science 66, 763775.
SAS (2004). SAS/STAT User's Guide Statistics, Version 9.1. Cary, NC: : SAS Inst., Inc.
Tamminga, S. (1992). Nutrition management of dairy cows as a contribution to pollution control. Journal of Dairy Science 75, 345357.
Tyrrell, H. F., Moe, P. W. & Flatt, W. P. (1980). Influence of excess protein intake on energy metabolism of the dairy cow. In Energy Metabolism of Farm Animals (Eds Schurch, A. & Wenk, C.), pp. 6972. EAAP Publication no. 13. Zurich, Switzerland: Juris Verlag.
Tyrell, H. F. & Reid, J. T. (1965). Prediction of energy value of cow's milk. Journal of Dairy Science 48, 12151223.
Valadares, R. F. D., Broderick, G. A., Valadares Filho, S. C. & Clayton, M. K. (1999). Effect of replacing alfalfa silage with high moisture corn on ruminal protein synthesis estimated from excretion of total purine derivatives. Journal of Dairy Science 82, 26862696.
Van Soest, P. J., Robertson, J. B. & Lewis, B. A. (1991). Methods for dietary fibre, neutral detergent fibre, and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74, 35833597.
Verbic, J., Chen, X. B., MacLeod, N. A. & Ørskov, E. R. (1990). Excretion of purine derivatives by ruminants: effect of microbial nucleic acid infusion on purine derivative excretion by steers. The Journal of Agricultural Science, Cambridge 114, 243248.
Verdouw, H., Van Echteld, C. J. A. & Dekkers, E. M. J. (1978). Ammonia determination based on indophenol formation with sodium salicylate. Water Research 12, 339402.
Wang, C., Liu, J. X., Yuan, Z. P., Wu, Y. M., Zhai, S. W. & Ye, H. W. (2007). Effect of level of metabolizable protein on milk production and nitrogen utilization in lactating dairy cows. Journal of Dairy Science 90, 29602965.
Wattiaux, M. A. & Armentano, L. E. (2006). Carbohydrate metabolism in dairy cows. In Dairy Essentials (Ed. Wattiaux, M. A.), pp. 912. Madison, WI, USA: Babcock Institute for International Dairy Research & Development/University of Wisconsin.
Wright, T. C., Moscardini, S., Luimes, P. H., Susmel, P. & McBride, B. W. (1998). Effects of rumen-undegradable protein and feed intake on nitrogen balance and milk protein production in dairy cows. Journal of Dairy Science 81, 784793.


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed