Incorporation of ammonia into microbial protein was enhanced due to supplementation of yeast which was confirmed by greater microbial yield and microbial true protein reaching the duodenum (Erasmus, 1991). Erasmus et al. (1992) reported
higher flow of non-ammonia nitrogen (NAN),microbial-N and dietary-N to the duodenum by addition of yeast culture in the
diet of lactating dairy cows.