Rain that occurs between the time forage is cut and baled causes both yield and quality losses that reduce the value of the crop as an animal feed and a marketable commodity. Leaching of soluble carbohydrates, protein, and certain minerals. Leaf shattering and loss, removing the highly digestible and high protein portion of the forage. Microbial activity that metabolizes soluble carbohydrates, reduces forage energy content, and possibly produces harmful mycotoxins. Several research studies have addressed the effects of rainfall on cut alfalfa.
Losses appear to be greatest after partial drying of the forage has occurred.
Several different Michigan studies on field cured alfalfa were reported. In a second study, rainfall intensity was kept constant at 0.7 inch but spread over periods of 1 to 7 hours. The big losses in quality and yield come when the hay is almost ready to bale. A light shower on hay that has just been cut causes little or no damage. The best, well-tested, alfalfa varieties for Oklahoma are listed below.