Chemical treatment of roughage has been the aim of studies for a long time. However, until nowadays, many questions are arisen due to the efficiency of additives used in relation to the variation of answers, either in nutritive value of treated roughage or in performance of animals feed with diet containing such roughage. This revision will approach the main and most used products, which are anhydrous ammonia, urea, sodium hydroxide and calcium oxide. It has been noticed that ammonization (both for anhydrous ammonia and urea) has presented more efficient result in animal's performance when compared with sodium hydroxide or calcium oxide. However, regarding its nutritive value, both sodium hydroxide and calcium oxide have presented a higher efficiency in the decreasing of cell wall and in the increase of treated roughage' digestibility.
ammonia; calcium oxide; sodium hydroxide; urea
