Fermentation Balance Approach to Estimate Extent of Fermentation and Efficiency of Volatile Fatty Acid Formation in Ruminants

Abstract

A fermentation balance equation was used to estimate the extent of fermentation of rations fed at or near voluntary intake to lactating dairy cows. The rations varied in hay to concentrate ratio from 100 :0 to 20 :80 and in four trials the high concentrate ration was fed completely pelleted. The extent of fermentation varied from 71% on the hay ration to 40% on the completely pelleted high concentrate ration. The factors affecting extent of fermentation were: 1) The hay to concentrate ratio, 2) fineness of particles, and 3) level of intake. The residual heat of fermentation was 6.4% of fermented substrate, and the theoretical CO2/CH4 ratio increased with increasing concentrate in the diet. The assumptions involved in these computations and the implications of the results obtained on efficiency of fermentation and feed efficiency for ruminants were discussed. © 1968, American Dairy Science Association. All rights reserved.