Farm Progress

Proper hay harvest and storage retain quality

Jeffrey Stapper

September 1, 2009

4 Min Read

The ongoing drought has resulted in many livestock producers looking for hay in Texas, and at the same time resulted in new folks getting into the hay making business. It seems that there will be a good hay market in most of Texas for a while as pastures and rangelands simply lack viable forage to sustain livestock and wildlife.

Hay varies in quality more than any other field crop and special attention should be given to the production of good-quality hay because animal performance is directly related to hay quality. One should note that of all the factors that affect hay quality, the growth stage when it is harvested usually has the greatest effect. As grasses mature from the vegetative to the reproductive (seed) stage, they become higher in fiber and lower in crude protein, digestibility and palatability.

For example, it is generally recommended to harvest bermudagrass at a15-inch to 18-inch height for the first cutting and then about every four weeks thereafter to make the best quality hay.

After mowing, poor weather and handling conditions can lower hay quality. Rain can cause leaf loss and nutrient leaching from plants during curing. Raking dry, brittle hay can cause excessive leaf loss. Since leaves contain the best nutrients in a hay sample, retaining as many leaves as possible in the hay sample should be a goal of every hay producer. The goal is to take forage plants from an initial moisture content of 70-80 percent down to about 15 percent for safe baling and storage.

Freshly cut forage is not dead; 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."

The heat generated by plant cell respiration 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 mesophilic (warm temperature) 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 degrees to 140 degrees Fahrenheit. At this temperature range, most mesophilic bacteria die and interior bale temperatures start to decline.

Baled hay becomes a potential fire hazard when the interior bale temperature does not cool after the first heating cycle. Fire is imminent if interior bale temperatures exceed 175 degrees Fahrenheit and fire is present at temperatures greater than 200 degrees.

When hay is baled, it should not be higher than 18 to 22 percent moisture. At higher moisture levels, bales lose large amounts of dry matter from excessive heating and molding. In severe cases, spontaneous combustion is possible. Moisture levels for safe storage of hay vary with size and density of the bale and type of hay. In general, hay in small rectangular bales should be baled at less than 22 percent moisture to keep molding and heating to a minimum. Large round bales retain internal heat much longer than conventional bales. Therefore, hay should be less than 18 percent moisture before baling in large bales.

If you are buying or producing hay, you know you have a significant investment, so storage becomes an important, yet often overlooked issue. If bales cannot be stored in a barn, careful consideration into the storage location should be considered. Bales stored outside will suffer variable losses, depending upon a combination of factors, including: moisture of the hay at baling time, amount of rain during the storage period, internal drainage of the soil on which bales are stored, amount of space between the bales, type of hay (grass or grass-legume), and the skill of the operator making the bales.

Store bales on well drained areas. Consider placing bales on poles or crushed rock to minimize losses on the bottom. Some research has shown that these techniques reduce storage losses by 15 percent. Always place bale rows in the same direction as the prevailing winds.

If you need hay, the Texas Department of Agriculture has a link on their web site at:,1911,1848_0_0_0,00.html that lists both in state and out-of-state hay suppliers.

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