Performance of animals fed crop residues

Ruminants can utilize crop residues as sources of energy, but productivity is low because of the high level of cell walls and lignin. Chemicals, especially sodium hydroxide, have been used to increase the digestibility of crop residues. Hemicellulose is solubilized and the extent and rate of cellulose and hemicellulose digestion are increased. Two systems have been developed for chemical treatment. The first involves pelleting finely ground residue in combination with sodium hydroxide treatment. A dense, easily transported feed-stuff is produced. The second method is an "on-the-farm" method that utilizes a minimum amount of equipment. In vitro and in vivo digestibilities have been increased from 10 to 20 percentage units by sodium hydroxide treatment. While lamb and cattle gains have generally been increased by feeding chemically treated residues, the level of performance often has not been as great as would be predicted from in vitro digestibilities. Sodium residues following chemical treatment have been shown to increase rate of passage from the rumen and reduce rumen fiber digestion. The use of alfalfa with sodium hydroxide-treated residues and the use of ammonium or calcium hydroxides for treatment have good potential.