How do roughages differ from concentrates in reference to cattle feed?

Roughage contains more fibre and cellulose and less energy as well as protein in most cases than concentrates. Roughages are hay, straw and pasture grasses. Concentrates are grain-type feeds, beet-pulp, waste bread, etc. Roughages are the standard feed for all cattle operations; concentrates are used for fattening up cattle for slaughter. They can also be for older animals that are not going to slaughter but need the extra nutrient to gain weight or as a supplement if the roughage feed is low in nutrient itself.