Introduction

• In ruminants, feed is fermented in the rumen before gastric and intestinal digestion. 
  • This process is called rumination. 
• The rumen is essentially a fermentation vat. 
• The rumen allows the beneficial and symbiotic rumen microbe relationship, by hosting microbial fermentation. 
• The rumen environment is anerobic.
• The rumen functions at 39°C, with a changeable but healthy pH of around 6.0.
• The process of rumination and microbial fermentation produce bi-products, such as:
  • Carbon dioxide.
  • Methane.
  • Hydrogen sulphide.
• These gases are not harmful to the ruminant but are problematic to the environment. 
• This article outlines the processes involved in rumen function and microbial protein synthesis.

The rumen

Rumination

Rumen microorganisms and microbial protein synthesis

Optimizing ruminal conditions for microbes

The rumen microorganisms

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• Ardnt C, Powell J M, Aguerre M J, Crump P M & Wattiaux M A (2015) Feed conversion efficiency in dairy cows: Repeatability, variation in digestion and metabolism of energy and nitrogen, and ruminal methanogens. J Dairy Sci 88, 3938-3950 PubMed.
• Contreras-Govea F E, Cabrera V E, Armentano L E, Shaver R D et al (2015) Constraints for nutritional grouping in Wisconsin and Michigan dairy farms. J Dairy Sci 98, 1336-1344 PubMed.
• Fatehi F, Krizsan S J, Gidlund H & Huhtanen P (2015) A comparison of ruminal or reticular digesta sampling as an alternative to sampling from the omasum of lactating dairy cows. J Dairy Sci 98 (5), 3274-3283 PubMed.
• Golder H M, Celi P, Rabiee A R & Lean I J (2014) Effects of feed additives on rumen and blood profiles during a starch and fructose challenge. J Dairy Sci 97, 985-1004 PubMed.
• Anantasook N, Wanapat M, Cherdthong A & Gunun P (2013) Changes of Microbial Population in the Rumen of Dairy Steers as Influenced by Plant Containing Tannins and Saponins and Roughage to Concentrate Ratio. Asian Australas J Anim Sci 26 (11), 1583-1591 PubMed.
• Schirmann K, Chapinal N, Weary D M, Heuwieser W & von Keyserlingk M A G (2012) Rumination and its relationship to feeding and lying behavior in Holstein dairy cows. J Dairy Sci 95, 3212-3217 PubMed.
• Krausse K M & Oetzel G R (2005) Inducing Subacute Ruminal Acidosis in Lactating Dairy Cows. J Dairy Sci 88 (10), 3633-3693.

Other sources of information

• AHDB (2014) Feeding improvement programme. [online] Available at: http://dairy.ahdb.org.uk/.
• Grant R (2009) Stocking Density and Time Budgets. Proc. Western Dairy Management Conference. pp 7 – 17.
• Sejrsen K, Hvelplund T & Nielsen M O (2006) Ruminant Physiology- Digestion,metabolism and impact of nutrition on gene expression, immunology and stress. Wageningen academic publishers. ISBN-10:90-76998-64-7.
• Ungerfeld U M & Kohn R A (2006) The role of thermodynamics in the control of ruminal fermentation. Animal and avian science, University of Maryland, College park, MD USA 20742.
• Chamberlain A T & Wilkinson J M (1996) Feeding the dairy cow, Chalcombe publications ISBN 0 94861732 2