The majority of the damage from untimely rains is the loss of soluble nutrients from the hay (the sugars). | Photo: iStock

The majority of the damage from untimely rains is the loss of soluble nutrients from the hay (the sugars). Even before rain damage, we lose some sugar during plant respiration that occurs from the time forage is cut until it reaches about 50% moisture content. Rainfall will extend the length of time that the hay is wetter than 50% moisture, leading to more loss of sugars from respiration.

Rainfall also leaches the soluble sugars from hay. The amount of leaching depends on the forage type, the hay moisture content when it rains, the concentration of soluble sugars and the number, amount and intensity of rainfall event(s). Leaf shatter can also be significant in legumes, especially on nearly dry forage.

Hay that has been rained on during curing will also have greater levels of dirt as well as higher numbers of microorganisms that will cause molding in the bale. Finally, the extra tedding and raking that may be needed to cure the crop can lead to further losses, especially in legume hay