April's Ag Advice by April Borders Excessive rainfall has been a problem for us this spring. It has been a problem in all of our crops but we want to look at the problem that it has created for us in our alfalfa fields.
Because fields were too wet to get into, producers were forced to harvest their hay later then normal. As a result, some producers were cutting alfalfa that was over-mature and could no longer be considered as dairy forage.
Research has shown that each day alfalfa harvest is delayed we see a loss of 5 points Relative Feed Value (RFV) or $9 per acre less in revenue. According to SDSU Extension Forage Specialist Peter Jeranyama, the loss is even greater in terms of quality effect on milk performance of dairy animals.
"These economic considerations should be kept in mind when considering whether or not to cut if rain is threatening," said Jeranyama. "Forage quality will continue to decline while waiting for good weather. In many situations, it may be better to cut alfalfa and take some risk of rain rather than wait and realize the certainty of forage quality decline."
Another problem that producers are dealing with is the fact that some of the hay that was baled wet is now beginning to heat up. Not only does hay lose its quality as it grows hot but it also poses a danger of spontaneous combustion.
"A rule of thumb is to check baled hay four or five days after baling for its initial temperature rise level," said Jeranyama.
Iowa State University Extension Forage Agronomist Steve Barnhart has developed these general guidelines on how to monitor the temperature of stored hay when baled a little wet.
* Temperatures up to 120 degrees F: Caused by normal respiration by fungi and bacteria. The process is referred to as normal sweating during hay curing. This temperature rise occurs when hay is baled at 15 to 20 percent moisture. These temperatures generally do not cause serious concerns in forage quality loss. However, mold may develop at this temperature range.
* Temperatures 110-150� F: Caused by fungi able to grow at this temperature. Chemical reactions during heating will denature some protein and cause some fiber to be less digestible.
* Temperatures 135-160� F: Caused by fungi respiration. At 150� F check temperature every day. At temperatures above 160� F, chemical reactions dominate the heating process. If the temperature continues to rise, check temperature every four hours. At this stage the situation may become dangerous.
* Temperature of 175� F: Continue to check the temperature every few hours and notify your local fire department. Do not attempt to move the hay without fire department assistance.
* Temperature of 190� F or hotter: At this stage spontaneous combustion is possible. Ask your fire department to assist you.
Make sure that you are out monitoring your wet hay for heating problems. It could save you some serious problems in the future. For more information contact the Clay County Extension Office at 677-7111.