In Situ Assessment of Degradability of Organic Matter in the Rumen of the Dairy Cow

A. Arieli*, S. J. Mabjeesh, Z. Shabi, I. Bruckental, Y. Aharoni, S. Zamwel, H. Tagari

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This study analyzed the relationships among the effective degradabilities of organic matter (OM) in feedstuffs, which were assessed separately by an in situ method and a direct in vivo measurement of the rumen degradation of OM in the diets of Holstein dairy cows. For this comparison, 80 individual data points were used from studies of dairy cows that were in midlactation and that had been cannulated in the rumen and abomasum. In vivo evaluation of the true degradability of OM in the rumen was based on rare earth digesta markers. Purine N served as a microbial marker. Feed samples were incubated in the rumens of dairy cows for 3, 6, 9, 12, 24, 48, and 72 h, and effective rumen degradation was calculated from the percentage of residual OM for rumen outflow rates of 4, 6, and 8%/h. Evaluations of rumen degradability of OM by the in situ method were correlated with actual in vivo measurements of rumen degradability of OM (r2 = 0.31, 0.34, and 0.37; SE of the estimate = 4.1, 4.0, and 3.9%, respectively). We concluded that the in situ method is a useful tool for providing reliable estimates of rumen degradability of OM in dairy cows.

Original languageAmerican English
Pages (from-to)1985-1990
Number of pages6
JournalJournal of Dairy Science
Issue number7
StatePublished - Jul 1998

Bibliographical note

Funding Information:
Received October 20, 1997. Accepted March 12, 1998. 1This research was partially supported by Research Grant Award Number US-2155-92R from the United States-Israel Binational Agricultural Research and Development Fund (BARD). 2Corresponding author.


  • In situ
  • Organic matter
  • Rumen degradability


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