A hemicellulose can be any of several heteropolymers (matrix polysaccharides) present in almost all cell walls along with cellulose. Their molecular weights are usually lower than that of cellulose and they have a weak undifferentiated structure compared to crystalline cellulose. But the chains form a 'ground' - they bind with pectin to cellulose to form a network of cross-linked fibres. Hemicelluloses include xylan, glucuronoxylan, arabinoxylan, glucomannan, and xyloglucan. As percent content of hemicellulose increases in animal feed the voluntary feed intake decreases. Hemicellulose is represented by the difference between NDF and ADF.