It may be calculated chemically or mathematically by using the ADF value. A reference value of 100 is used, based on full bloom alfalfa. Prime hay will have an RFV of greater than 151 while poor hays will have an RFV of less than 75. Comparing RFV values between cool season and warm season forages is not a valid comparison. As-Fed Basis lists forage nutrient contents including water as you would normally feed it.
Moisture is the water content of the feed.
Fed values as water acts to dilute nutrient content. For comparing feeds always use the dry matter basis. Use old round bales or hang secured nylon shade cloth vertically. Cows should be protected from the wind for 30 minutes after milking to allow teats time to dry off and blood circulation to reestablish. For example, if a bale is 5 feet in diameter, a one-foot distance should be left between bales for the windbreak to be effective.