Purdue University
Agricultural Experiment Station
Lafayette, Indiana
Mimeo DH-59
July, 1956
SILAGE IS WHAT YOU MAKE IT
D. L. Hill and B. J. Walker Dairy Department
The notion that "silage is silage” just isn't so. A great variety of green forage crops are being made into silage under many different circumstances, and there are tremendous differences in the resulting silages. As a feed, silage can be no better than the crop from which it is made. Many dairymen are referring to the forage crop in terms of "tons per acre” with little regard for the quality or nutritive value. Dairymen must begin to think of their winter roughages in terms of their feeding value rather than as sources of bulk. Putting the forage crop into the silo will not miraculously restore what has been lost. The
feeding of silages which vary so greatly in quality has resulted in animal performances ranging from very satisfactory to unsatisfactory.
The basic objective in harvesting the forage crop is to effectively save and preserve the crop when it makes the best feed. Experiments comparing ordinary hay making and ensiling have shown that nutrient losses may be reduced from 1/3 to 1/2 by making good silages.
Quality Grass Silage
The evaluation of quality in silages is best made by taking into account the nutrient content and the type of fermentation which takes place in the silo. These factors in turn influence the rate at which the silage is consumed by the animal.
The stage of maturity at which the crop is harvested influences the nutritive value very significantly. As the plant matures, the chemical composition and the nutritive value change markedly. The crude protein content of alfalfa cut pre bud may be over 25% on a dry basis, but it decreases to about 14% if harvested when in full bloom. At the same time the crude fiber content increases from about 20% to over 30%, Associated with the increase in crude fiber is a notable increase in lignin or the "woody” component. The lignin cannot be used by the animal and should be regarded as a culprit, since its presence may interfere with the utilization of the feedstuffs.
The maturity of alfalfa may be described as vegetative (pre-bud and in bud), flowering (1/10 bloom, 1/4 bloom, 1/2 bloom, full bloom) and mature. First cutting alfalfa has the highest nutritive value if cut before it flowers. For those who choose to cut during the flowering stage when the nutritive value is somewhat lower, the alfalfa should not be harvested any later than 1/10 bloom. Second cutting is not as critical and the alfalfa may be permitted to reach  1/2 bloom without a serious decrease in nutritive value.
The meadows usually consist of alfalfa and some species of grass. In alfalfa grass mixtures the grass matures more rapidly than the alfalfa. Harvesting the crop at the proper stage of maturity may affect the nutritive value more change of species. The age of grasses may be described as leafy, in boot , heading, flowering, and seed stage. Brome grass makes the best silage vested when in the "boot." Some sort of compromise must be reached in deciding when to cut alfalfa-grass mixtures.