Dr. Bill Weiss, Dairy Nutrition Specialist, The Ohio State University
In Ohio, the first cutting of alfalfa and cool season grasses usually makes up about 45% of the total annual yield. Therefore, the quality of first cutting will affect your cows for a substantial period of time. Milk production and income over feed costs are almost always better when good forages are fed.
1. Cut the forage at the correct maturity because quality doesn't improve after the crop is cut; it only gets worse. The best single index of hay crop forage quality is NDF. We found that with alfalfa, milk production decreases about 0.3 lb/day for every 1 unit increase in NDF concentration above about 37%. A good compromise between yield, quality, and stand longevity is to cut alfalfa so that the resulting hay or silage has about 40% NDF. A useful tool to determine when to cut alfalfa is an Alfalfa Quality Stick (if interested in purchasing contact Mark Sulc, firstname.lastname@example.org ). You go out into a field and measure the height of the longest stem with the stick, and it will tell you the approximate NDF concentration. Because NDF concentration increases during hay and silage making, cut alfalfa when it is about 38% NDF and the resulting feed will have about 40% NDF. Cool season grasses with an NDF concentration of about 50% is nutritionally equivalent to alfalfa with 40% NDF. To obtain that concentration, grasses need to be cut before they head (probably too late by the time you read this)
2. Get the crop to the correct dry matter as soon as possible. Mow early in the day to take advantage of sunlight and lower humidity during the entire afternoon. Wide swathing helps increase drying rate, but the swath has to be really wide (swath width at least 70% as wide as the cutter) to see a big effect. Tedding increases drying rate, but it should be done soon after alfalfa is mowed so that leaf shatter is minimal, and labor and fuel costs must be considered. With wide swathing, tedding is probably unnecessary. Mechanical conditioning greatly increases drying rate of first cutting alfalfa, especially under good drying conditions. Responses are much less for subsequent cuttings.
3. Chop at the correct dry matter (DM) concentration. For hay crop silages, DM percentages should be in the low 30's for bunker silos and around 40 for uprights and bags. At the DM that alfalfa is chopped for silage, the moisture concentration can decrease by several percentage units in an hour. If you have a lot of acres, chopping should start when the crop is slightly wetter than desired so that when you are finished, it will not be too dry.
4. A good lactic acid bacterial inoculant is often profitable (reduces fermentation losses) when applied to first cutting hay crops. If you use them, make sure they are well-distributed during application (either at the chopper or at the blower).
5. Fill the silo quickly, pack well, and cover or seal the silo as soon as possible. Delaying sealing by 24 hours causes a measurable decrease in fermentation quality and a measurable increase in fermentation losses.