Mike Addy

It was recognized that when animals are offered a low-nitrogen, high fiber roughage such as rice straw (RS), one of the critical nutrients is fermentable nitrogen (N) available to rumen microbes (ARC, 1984). The use of urea/molasses blocks is a convenient way for avoiding excessive intake of urea, and will ensure an almost continuous supply of ammonia-N (PJG Kunju & Leng 1981; Preston, 1986).

Actually, this varies with animal. Animals like pig will benefit greatly from yellow grease while it may not really be good for other animals