The relationship between the cell-wall constituents of roughages and the digestibility of the organic matter

Abstract

There is a strong correlation between the digestibility of the organic matter and the percentage crude fibre, percentage lignin, and percentage cellulose plus lignin in the foodstuffs examined.There is evidence that the holocellulose and xylan in grasses are different from those in legumes in the extent to which they are digested. It is suggested that this is due mainly to the xylans or hemicellulose fraction in the forages, and may be a reflexion of a different molecular structure for the xylans in either group.Within each group of plants both the holocellulose and xylan percentages are strongly correlated to the percentage digestible organic matter.Excessive heating of hay led to a marked rise in the percentage lignin. This is probably due to the xylans becoming horny and insoluble, therefore being determined as lignin. This also offers an explanation for the decrease in digestibility of the organic matter.