Since the quality of forage directly impacts the production success, there are many ways to test forage. The first term to be understood is dry matter (DM). When forage is harvested by machine, the amount above the leftover stubble can be dried, since 70-90% of the herbage is water, and weighed to determine the amount of dry matter, usually referred to per acre. Testing can be done on representative samples. But if the forage is consumed by grazing animals there are still other ways to test for quality. Forage quality can be determined by many ways but the three main methods are discussed below:
Feed Trial Evaluations
Organoleptic observations means using the sense organs (eyes, nose, taste, ears, touch) to evaluate the quality of the forage. This method is practical because it can be easily done, requires no special equipment, and is readily applied. It is the simplest method but it provides the least information. Organoleptic observation can be useful in some ways but cannot determine chemical composition. Visually, high-quality forage should show leafiness, vivid color, little foreign material, an appropriate stage of maturity, and no molds. The smell should be fresh and in the case of silage sweet; a specific odor that you can learn to recognize. Livestock use their sense of smell in selection. Some producers can even taste the right flavors, especially in good silage. Touch can also be used to check for the right consistency. Good hay should not be too brittle. Good silage will not be slimy.
The stage of maturity at cutting or grazing influences quality more than the species, variety, production location, soil fertility, or seasonal influences. Early harvested alfalfa hay (cut at pre-bud or early bud stage) or grass harvested at boot or head emergence will have the highest nutritive value for livestock. The right time for harvest also makes the forage more palatable and digestible. Both decrease as the crop grows older. But yield continues to improve as the plants mature so there is a constant balancing act for producers between getting the best quality and the best yield. However, on a yearly basis, early cut hay yields as much feed (digestible dry matter) per acre as later-cut hay. Livestock will eat more of it because it is so palatable and digestible. Harvesting at the best times also wisely utilizes the regrowth potential of grasses and legumes.
Two-thirds of the protein (the desired portion of food) is found in leaves of forages. Livestock will naturally select the leafy portions when grazing but retaining leaves is more difficult in hay and silage making. Leaf shatter during raking and baling greatly reduces hay quality, especially of legumes. Look for lots of leaves in a bale to indicate good quality.