Most important is what market you will be selling in or what animal you are buying for. You have a choice of straight grass, straight alfalfa, or any mixture of the two. Oats cut when the grain is just starting to enter the milk stage make excellent hay. Oat hay is very palatable, medium in protein and higher in energy than most hay. Quality is controlled by many factors, no matter what type of hay we are dealing with.
Maturity influences the protein level.
As maturity increases, the protein level decreases. Grass hay should be cut when it first starts to head. Typical grass hay will run from 8 to 12 percent protein. Cutting alfalfa early will also increase palatability. Young, tender plants have a higher leaf to stem ratio, and more food value is in the leaves than in the stems.