Effects of Physically Effective Neutral Detergent Fiber Content on Intake, Digestibility, and Chewing Activity in Fattening Heifer Fed Total Mixed Ration

  • Oh, Mi Rae ;
  • Hong, Heeok ;
  • Li, Hong Liang ;
  • Jeon, Byong Tae ;
  • Choi, Cheong Hee ;
  • Ding, Yu Ling ;
  • Tang, Yu Jiao ;
  • Kim, Eun Kyung ;
  • Jang, Se Young ;
  • Seong, Hye Jin ;
  • Moon, Sang Ho
  • Received : 2016.05.02
  • Accepted : 2016.07.25
  • Published : 2016.12.01


The objective of this study was to determine the effects of physically effective neutral detergent fiber (peNDF) content in total mixed ration (TMR) on dry matter intake, digestibility, and chewing activity in fattening Hanwoo (Bos taurus coreanae) heifers. The experiment was designed as a replicated $3{\times}3$ Latin square using 12 heifers. Fattening heifers were offered one of three diets [high (T1), medium (T2), and low (T3) peNDF] obtained by different mixing times (3, 10, and 25 min) for the same TMR feed. The peNDF content of TMR was determined by multiplying the proportion of dry matter retained by a 1.18 mm-screen in a Penn State Particle Separator by the dietary NDF content. The $peNDF_{1.18}$ content was 30.36%, 29.20%, and 27.50% for the T1, T2, and T3 diets, respectively (p<0.05). Dry matter intake was not affected by peNDF content in TMR. Total weight gain in T1 group was significantly higher (p<0.05) than in T2 and T3 groups. However, weight gain did not differ between T2 and T3 groups. The feed conversion ratio decreased with an increase in the peNDF content (T1: 12.18, T2: 14.17, and T3: 14.01 g/g). An increase in the peNDF content of TMR was associated with a linear increase in the digestibility of dry matter, crude protein, crude fiber, neutral detergent fiber, and acid detergent fiber (p<0.05). Also, an increase in peNDF content of the TMR resulted in a linear increase in the number of chews in eating and ruminating (p<0.05), and consequently in the number of total chews (p<0.05). These results indicate that peNDF content affects digestibility and chewing activity. Consequently, the peNDF content of TMR should be considered for improving feed efficiency, digestibility, body weight gain, and performance in fattening heifers.


Physically Effective Neutral Detergent Fiber;Chewing Activity;Digestibility;Dry Matter Intake;Fattening Heifer;Total Mixed Ration


  1. Allen, M. S. 1997. Relationship between fermentation acid production in the rumen and the requirement for physically effective fiber. J. Dairy Sci. 80:1447-1462.
  2. AOAC (Association of Official Analytical Chemists) International. 1990. Official Methods of Analysis. 15th edn. Association of Official Analytical Chemists, Washington, DC, USA.
  3. ASAE (American Society of Agricultural Engineers). 1998. S424: Method of Determining and Expressing Particle size of Chopped Forage Materials by Sieving Screening. ASAE Standards. Am. Soc. Agric. Eng., St. Joseph, MI, USA.
  4. Beauchemin, K. A., W. Z. Yang, and L. M. Rode. 2003. Effects of particle size of alfalfa based dairy cow diets on chewing activity, ruminal fermentation, and milk production. J. Dairy Sci. 86:630-643.
  5. Buckmaster, D. M. 2000. Particle size in dairy cows. In: Recent Advances in Animal Nutrition (Eds. P. C. Garnsworthy and J. Wiseman). Nottingham University Press, Nottingham, UK. pp. 109-128.
  6. Brouk, M. and R. Belyea. 1993. Chewing activity and digestive responses of cows fed alfalfa forages. J. Dairy Sci. 76:175-182
  7. Calberry, J. M., J. C. Plaizier, M. S. Einarson, and B. W. McBride. 2003. Effects of replacing chopped alfalfa hay with alfalfa silage in a total mixed ration on production and rumen conditions of lactating dairy cows. J. Dairy Sci. 86:3611-3619.
  8. Einarson, M. S, J. C. Plaizier, and K. M. Wittenberg. 2004. Effects of barley silage chop length on productivity and rumen conditions of lactating dairy cows fed a total mixed ration. J. Dairy Sci. 87:2987-2996.
  9. Grant, R. J. and V. F. Colenbrander. 1990. Milk fate depression in dairy cow: role of silage particle size. J. Dairy Sci. 73:1834-1842.
  10. Kononoff, P. J. and A. J. Heinrichs. 2003a. The effect of reducing alfalfa haylage particle size on cows in early lactation. J. Dairy Sci. 86:1445-1457.
  11. Kononoff, P. J. and A. J. Heinrichs. 2003b. The effect of corn silage particle size and cottonseed hulls on cows in early lactation. J. Dairy Sci. 86:2438-2451.
  12. Lammers, B. P., D. R. Buckmaster, and A. J. Heinrichs. 1996. A simple method for the analysis of particle sizes of forage and total mixed rations. J. Dairy Sci. 79:922-928.
  13. Mertens, D. R. 1988. Balancing carbohydrates in dairy rations. In: Proceedings of the Large Herd Dairy Management Conference, Syracuse, NY, USA. 150 p.
  14. Mertens, D. R. 1997. Creating a system for meeting the fiber requirements of dairy cows. J. Dairy Sci. 80:1463-1481.
  15. Mertens, D. R. 2002. Measuring fiber and its effectiveness in ruminant diets. Proceeding Plains Nutrition Council Spring Conference. San Antonio, TX, USA. pp. 40-66.
  16. Michalet-Doreau, B., I. Fernandez, and G. Fonty. 2002. A comparison of enzymatic and molecular approaches to characterize the cellulolytic microbial ecosystems of the rumen and the cecum. J. Anim. Sci. 80:790-796.
  17. Poppi, D. P., D. J. Minson, and J. H. Ternouth. 1981. Studies of cattle and sheep eating leaf and stem fractions of grasses. I. The voluntary intake, digestibility and retention time in the reticulorumen. Crop. Pasture Sci. 32:99-108.
  18. Soita, H. W., D. A. Christensen, and J. J. McKinnon. 2000. Influence of particle size on the effectiveness of the fiber in barley silage. J. Dairy Sci. 83:2295-2300.
  19. Schwab, E. C., R. D. Shaver, J. G. Lauer, and J. G. Coors. 2003. Estimating silage energy value and milk yield to rank corn hybrids. Anim. Feed Sci. Technol. 109:1-18.
  20. Teimouri Yansari, A., R. Valizadeh, A. Naserian, D. A. Christensen, P. Yu, and F. Eftekhari Shahroodi. 2004. Effects of alfalfa particle size and specific gravity on chewing activity, digestibility, and performance of Holstein dairy cows. J. Dairy Sci. 87:3912-3924.
  21. Yang, W. Z. and K. A. Beauchemin. 2006. Effects of physically effective fiber on chewing activity and ruminal pH of dairy cows fed diets based on barley silage. J. Dairy Sci. 89:217-228.
  22. Yang, W. Z., K. A. Beauchemin, and L. M. Rode. 2001. Effects of grain processing, forage to concentrate ratio, and forage particle size on rumen pH and digestion by dairy cows. J. Dairy Sci. 84:2203-2216
  23. Yang, W. Z., K. A. Beauchemin and L. M. Rode. 2002. Effects of particle size of alfalfa-based dairy cow diets on site and extent of digestion. J. Dairy Sci. 85:1958-1968.


Grant : Cooperative Research Program for Agriculture Science & Technology Development

Supported by : Rural Development Administration