No matter how hard you try there will be a loss in dry matter and quality when harvesting hay. But, looking at the right places ahead of time can limit the loss in the long run. Baling hay at the proper moisture, using hay preservatives, and ensuring the proper baler adjustments are ways to reduce the loss to hay which occur during baling.

When mowing hay, cut after the dew is gone in humid areas and when the topsoil is dry to reduce soil compaction and to hasten hay drying. In drier climates, a dew may be needed to produce higher quality hay and lessen leaf loss. During damp seasons, a long stubble may be needed to keep the windrow off the soil surface and aid drying by allowing air to pass around the bottom and top of the hay. Yield may be lost, but higher quality hay may be worth the trade-off when facing a wet or damp season.

Conditioning – Conditioning of alfalfa speeds drying by crimping and opening the waxy layer surrounding the stem. Large or coarse stemmed hays tend to respond to conditioning better than fine stemmed hays. For grasses a flail conditioner may be useful to condition the hay. Flail conditioner on alfalfa can lead to greater leaf loss.

Raking – In alfalfa more leaf loss can be caused by raking dry alfalfa than by any other harvest operation.

Respiration Losses – Hay that dries quickly will lose 2 to 6 percent dry matter (DM) due to respiration. Hay that dries very slowly may lose 15 percent DM due to respiration. Cutting hay when good drying weather is expected will reduce respiration losses considerably and lead to higher quality hay.

Weathering Losses – Rain (leaching) can cause up to 20 percent nutrient loss. Carbohydrates, B vitamins, and some soluble minerals are readily leached from dry hay.

Time of Cutting – Natural physiological processes in plants cause the concentrations of soluble carbohydrates and other highly digestible nutrients to peak in the evening. Recent research suggests that hay cut at or near sundown is higher in energy than hay harvested at sunup.

Baling Losses – Studies have showed that field losses of 1 to 5 percent have been measured for small rectangular balers operating in typical conditions for alfalfa hay. Under these same conditions, field losses of 3 to 30 percent have been measured for large round balers.

Hay Moisture Content – Hay moisture content is the largest single factor contributing to leaf loss. Hay baled at a moisture content above 15 percent has much less leaf loss than hay baled below 15 percent moisture. The upper moisture limit to prevent mold growth and other hay deterioration for large round alfalfa bales is typically 18 to 20 percent. Hay baled above 25 percent moisture will usually spoil unless chemical preservatives are added to the hay. Hay that is put up too wet also increases the chance of fire, especially when stored indoors.

When the hay becomes too dry and brittle and losses become excessive, stop baling and resume in the evening or morning when the leaf moisture level increases. This dew-moistened hay can be baled at a slightly higher moisture level than when it was drying down because dew moisture in the hay is more easily released during curing than internal moisture. In addition, moisture gauges tend to read higher than the actual moisture content in dew-moistened hay.

A number of commercial moisture testers are available for use in determining hay moisture levels. Some operate using a sample of hay, while others operate using a probe. Generally, the probe models are simpler to use since they do not require taking a sample. A number of readings should be taken and averaged to get the most accurate moisture determination. Probe several bales at different locations in the field to account for field variations. Square bales should be probed from their ends while round bales should be probed through their diameter.

Hay preservatives – Hay preservatives allow harvesting of hay at higher moisture content. Advantages of hay preservatives include: 1) allowing hay to be baled at higher moisture levels, which may reduce the risk of rain damage, 2) baling at higher moisture levels reduces dry matter and nutrient losses caused by leaf shatter, and 3) lengthening the potential baling period by allowing hay to be baled at higher moisture levels. Disadvantages of hay preservatives include: 1) some preservatives, such as propionic acid, are corrosive and can damage machinery and injure workers, 2) some preservatives have not been tested thoroughly under a wide variety of haying conditions, and 3) some preservatives may not be cost effective.

Hay preservatives have been classed into several types: organic acids, acid salts, salt (NaCl), anhydrous ammonia, urea, fermentation products, anaerobic bacterial inoculants and aerobic bacterial inoculants. The organic acids (propionic, acetic, citric) are very effective in preventing mold and heating. As hay moisture content increases, the amount of acid needed increases

Baler Pickup – The pickup mechanism of large round balers may cause losses as high as 12 percent, although losses more typically range from one to three percent. Field speed, size of windrow, hay moisture content, and mechanical condition of the pickup influence this loss. Higher moisture content reduces pickup loss. Lowering field speed in general, and synchronizing field speed to pickup rotational speed in particular, reduces pickup loss. Heavy windrows reduce pickup loss by reducing field speed and contact with pickup components.