Agriculture News: Cutting, baling hay is intricate, and sometimes lucky, process

By Keenan Bishop, Published:

While this spring hasn’t been as bad as last year, baling hay between rain showers in May and June is difficult. We’ve even missed some rains that were predicted so some farmers with hay down actually got lucky. About the only sure way of getting that first cutting up successfully is to ensile it as balage. Otherwise you take a chance of getting it wet.

One fellow here in our county who frequently has the highest alfalfa test results in the state works around this by cutting before a rain to extend his window of opportunity. Green hay will leach out a lot less nutrients than dried hay will if rained on. If hay is going to get wet make it on the front end, not the tail end of the process, if possible.

Still, many are forced to bale hay to try and beat a rain and end up doing so before the ideal 18-20 percent moisture level. Still more will guess that the hay is ready to bale without realizing that the moisture level is still too high.

Some get lucky, those that don’t risk moldy hay or hay that heats up enough to caramelize, which makes it tasty for the livestock but nutritionally void.

Others suffer a worse fate and that’s a hay fire. Now that many have structures just for hay storage there is more to lose than just your hay. Every couple of years here in Franklin County someone will lose a barn to a hay fire.

According to a Virginia Tech Extension publication (
442-105.html), freshly cut forage is not dead yet; respiration (the burning of plant sugars to produce energy) continues in plant cells and a small amount of heat is released in the bale. Many producers refer to this elevation in bale temperature as “sweating” or “going through a heat.” In hay baled at the proper moisture concentration, plant cell respiration has slowed dramatically and will eventually cease.

Heat is normal

The heat generated in hay bales is normal and generally of little consequence. However, if bale moisture levels are too high (greater than 20 percent), the heat and moisture will provide a suitable environment for the growth and multiplication of bacteria that are present on forage crops.

The respiration of mesophilic bacteria releases additional heat in the bale and interior bale temperatures can reach 130-140 degrees. At this temperature range, most mesophilic bacteria die and interior bale temperatures start to decline.

This cycle of heating and cooling may occur several times during the weeks after baling as the microbial population increases and decreases. However, the maximum temperature decreases during each subsequent cycle. The interior bale temperature will eventually stabilize near the ambient temperature. Hay that has sustained these heat cycles has lost much of its quality as a feeding source, but is unlikely to catch fire.

Baled hay becomes a potential fire hazard when the interior bale temperature does not cool after the first heating cycle. This occurs when the respiratory heat created by the mesophilic bacteria provides an environment favorable for the growth and multiplication of thermophilic (heat loving) bacteria.

The thermophilic organisms multiply and the heat produced by their respiration can raise the interior bale temperature to 170 degrees before microbial activity ceases.

The thermophilic bacteria and their respiration heat convert the hay to a form similar to a carbon sponge with microscopic pores. This damaged material combines readily with oxygen at high temperatures and can self-ignite in the presence of oxygen.

One way to avoid this worry is to check the moisture of hay before you bale. There is a simple procedure that can be done in your microwave ( or you can borrow our moisture meter, which can check windrows or bales.

Another form of insurance is a temperature probe. We have a couple of 3-foor thermometers here at the office that can be inserted into a bale to monitor the temperatures to see if the bale is heating up, cooling down or stable.

Third Thursday Thing

Kentucky State University’s Sustainable Agriculture Workshop, or “Third Thursday Thing,” is Thursday with the focus on pastured poultry. The workshop begins at 10 a.m. For complete information email The farm is at 1525 Mills Lane off U.S. 127 South.

Farm-City Field Day

The 56th annual Franklin County Farm-City Field Day, claimed by some to be “the best day of the summer,” is July 10 at the Willis farm on Mt. Zion Road. Educational tours begin at 9 a.m. with lunch at 11:45.

Free tickets are available at the Farm Bureau Office, 1212 Wilkinson Blvd., or upon arrival at the Field Day.

Want to leave your comments?

Sign in or Register to comment.