Usually, forages are grown on the farm. They may be grazed directly or harvested and preserved as hay or silage. The energy intake and the milk production of a cow may be limited by too much forage in a ration. However, bulky feeds are essential to stimulate rumination and maintain the health of the cow. In general, the higher the fiber in a forage, the lower the energy content of the forage.
Cows usually eat more legumes than grasses at similar stages of maturity.
However, good quality forages fed in balanced diets will supply much of the protein and energy needed for milk production. Soil and climate conditions usually determine the type of forage that is most commonly grown in a region. Grasses need nitrogen fertilizers and moisture conditions to grow well. However, legumes are more resistant to drought. The feeding value of forages is greatly influenced by the growth stage when harvested or grazed.