Feed resources are very important for livestock production,
especially during the dry season in the tropical area. The
scarcity of feed has been critically exerting in terms of
quantity and quality, particularly protein sources which
result in low productivity. Rice straw is the main cropresidue
which farmers usually store for use as ruminant feed
in tropical areas, especially in Asia. However, rice straw is low in nutritive value with low level of protein (2–5%DM), high
fiber and lignin content (NDFN50%), low DM digestibility
(b65%) thus resulting in low voluntary feed intake (1.5–2.0%)
(Wanapat et al., 1985). Of the chemical treatment procedures
available generally for improving cereal straws, Fadel Elseed
et al. (2003) show that when using urea combined with
calcium hydroxide, it could improve rumen degradability.
Furthermore, Wanapat et al. (2009) suggested that using 2%
urea and 2% calcium hydroxide treated rice straw could
improve rumen fermentation and milk production. The
concentrated alkaline agents can chemically break the ester
bonds between lignin and hemicellulose and cellulose, and