Learning objectives forages part 1
Differences between structural and non-structural carbohydrates
Nonstructural carbohydrates: starch and sugars
Structural carbohydrates: pectin, hemicellulose, cellulose
Definition of fiber as related to its structural components
Fiber is a dietary carbohydrate that contains substances such as cellulose, lignin, and pectin.
Neutral detergent fiber (NDF) = fraction that quantifies the cell wall concentrations of
feedstuffs
● Included cellulose, hemicellulose, and lignin
● NDF reflects the bulkiness of a feed
Acid detergent fiber (ADF) = fraction that quantifies cellulose and lignin concentrations of
feedstuffs
● ADF negatively associates with the energy content of a feed
Lignin is normally found in grasses and legumes; it's completely indigestible
Factors that affect forage nutritive value
Maturity → which has the most effects on nutritive value
Soil fertility
Fertilization
Weather
Harvesting
Storage methods
Differences between legumes and grasses
Grasses use soil N (nitrogen) in the form of nitrate or ammonium ions
In legumes, rhizobia organisms (bacteria) in legume root nodules “fix” atmospheric N. The N is
reduced to ammonium, which is used for the synthesis of amino acids
High amounts of Legumes in pastures can also cause bloat
How to avoid bloat in grazing animals
● Plant mixtures of legumes and grasses
● Plant non-bloating legumes such as birdsfoot trefoil, sainfoin, etc.
● Fill animals with hay or grass pasture before turning them on pastures with high
proportion of legumes
● Never turn hungry livestock into pasture with high proportion of legumes
Differences between structural and non-structural carbohydrates
Nonstructural carbohydrates: starch and sugars
Structural carbohydrates: pectin, hemicellulose, cellulose
Definition of fiber as related to its structural components
Fiber is a dietary carbohydrate that contains substances such as cellulose, lignin, and pectin.
Neutral detergent fiber (NDF) = fraction that quantifies the cell wall concentrations of
feedstuffs
● Included cellulose, hemicellulose, and lignin
● NDF reflects the bulkiness of a feed
Acid detergent fiber (ADF) = fraction that quantifies cellulose and lignin concentrations of
feedstuffs
● ADF negatively associates with the energy content of a feed
Lignin is normally found in grasses and legumes; it's completely indigestible
Factors that affect forage nutritive value
Maturity → which has the most effects on nutritive value
Soil fertility
Fertilization
Weather
Harvesting
Storage methods
Differences between legumes and grasses
Grasses use soil N (nitrogen) in the form of nitrate or ammonium ions
In legumes, rhizobia organisms (bacteria) in legume root nodules “fix” atmospheric N. The N is
reduced to ammonium, which is used for the synthesis of amino acids
High amounts of Legumes in pastures can also cause bloat
How to avoid bloat in grazing animals
● Plant mixtures of legumes and grasses
● Plant non-bloating legumes such as birdsfoot trefoil, sainfoin, etc.
● Fill animals with hay or grass pasture before turning them on pastures with high
proportion of legumes
● Never turn hungry livestock into pasture with high proportion of legumes
