Spent coffee grounds (SCG) was incorporated in the urea-wheat straw mixture (UWS) and it was stacked for 12 d with 3 d turning at 70 per cent moisture. Compared to the UWS alone the stacking of UWS-SCG mixture resulted in altered microbial and chemical changes during open stacking. Comparative evaluation of the UWS or UWS-SCG as such or after open stacking showed that in adult buffaloes the digestibilities of nutrients were lower (P < 0.01) in the stacked preparation than their respective original preparations. Further stacked UWS-SCG preparation had resulted in the maximum faecal-N loss with negative N balance. The results showed that even natural fermentation process did not improve the nutritive value of SCG and is thus unsuitable as a feed ingredient.
