Why is dwarf ness desired in cereals and profuse branching and tallness in fodder crops

Fodder crops are grown to feed farm animals so if they are tall their leaves can be easily cut and utilized for feeding (hay or silage). Whereas branching in fodder crops for example in grasses, makes it desirable for grazing instead of hay.

Dwarfness in cereal so that less nutrients are consumed for growth and instead these nutrients are used to increase yield of grains.