You can find a lot of help from FAO website.

this could help you

https://apps.icarda.org/wsInternet/wsInternet.asmx/DownloadFileToLocal?filePath=Tools_and_guidelines/Animal_nutrition.pdf&fileName=Animal_nutrition.pdf

@ Stalin Vedamanickam, Thank you very much, It is very interesting manual!

I think you should read the article of Dr HPS Makkar "on IVOMD"and for the VFA estimation you can go for GLC gas chromatorgraphic method used to estimate the vfas in rumen liquor 

Dear Demissie Chanie,

   Please go with following calculation:

               Ruminally degraded N in proportion to the intake of dietary

               N = (x - f) × 100 ÷ x

Regards:

Mahesh

Dear Chanie,

      50 g difference is due to ruminal proteolysis by microbes releasing ammonia for microbial protein synthesis.

     In your case, RDN (% N)= (450-100)*100/450=77.78%.

    Pl. note 400 g of duodenal N includes combined contribution from both microbial N flow (300 g) plus those escaping rumen degradation (100 g).

Regards:

Mahesh

Dear M. S. Mahesh,

Thank you very much once again. This was what I need!

Kind regards