Roughages and Concentrates

25.4.1 Roughages and Concentrates Some animal nutrition workers divide animal feeds into two general kinds: roughages and concentrates.

Roughages are bulky foods that contain lots of fiber and small amounts of nutrients. Roughages are important for grass-eating livestock to stimulate the digestive system and keep it functioning properly. Some roughage (like tender, green forage and well-made hay) are quite nutritious because they are digestible. Roughages from mature dry plants are mostly fiber and are not very digestible or nutritious. These poorly digested roughages include straw, very mature grass, corn stalks, poor rice bran and poor silage.

Concentrates contain large amounts of nutrients in a small amount of food. There are energy concentrates - (containing a high quantity of energy) such as cereal grains or cereal by-products, high quality rice bran, or mustard seed cake. There are also protein concentrates (containing a high quantity of protein) such as soybean meal, fish meal, or blood meal. Concentrates often have vitamins and minerals mixed in them. Non-grass eaters (like pigs, birds, dogs, cats, and people) require concentrates in their diet.

Summary of Digestibility 1. Grass-eating animals can digest more roughage because of the bacteria and protozoa in their stomachs and intestines. Animal health agents must be careful not to give medicines by mouth that may harm these beneficial bacteria and protozoa.

2. Non-grass eating, simple-stomached animals (like man, chickens and pigs) cannot digest roughage feeds. They require more concentrates to stay healthy.

3. The more young and tender a grass is, the more nutritious and digestible it is. Young, tender, green, digestible forages supply most of the nutrients needed by grass-eating livestock (except for salt).

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