Properly curing hay crucial for feed quality

Weather conditions across the Midwest have created challenges for hay making. Properly curing hay to the correct moisture level for baling is crucial to maintaining forage quality.

At baling, the moisture level should be a maximum of 20% for small square bales, 18% for round bales and 15% for large square bales. The larger the forage package, the lower the moisture should be at baling, according to a North Dakota State University Extension news release.

Exceeding those moisture levels can reduce dry matter and nutrient content of the hay, said James Rogers, NDSU Extension forage crops production specialist.

At harvest, hay naturally contains microbial content. Curing limits aerobic microbial growth. Baling hay at moisture levels greater than 25% creates an environment for aerobic microbial growth to occur.

Those microbes are living organisms that feed off of the nutrient content of the hay and generate heat. As heat increases, a chemical bond forms between proteins and carbohydrates, reducing dry matter and digestibility of the end product.

Although that reaction produces a more palatable hay, the loss of energy and digestible protein lessens its quality.

Several methods exist to accelerate drying time to prevent moisture-damaged hay. First, if possible, condition the hay at cutting. Conditioning crimps the stem, which hastens moisture loss and speeds drying.

Second, when cutting, spread the forage out into as wide a swath as possible. That increases the surface area exposed to sunlight.

Third, hay can be inverted or flipped over or if this is not possible rake the hay a couple of extra times to get hay moved from the bottom of a windrow to the top. However, be cautious with delicate crops such as alfalfa because mechanical handling can cause leaf loss.

Using a preservative can also accelerate the time from hay mowing to baling. Preservatives will not decrease the moisture content of hay, but they will lower anaerobic microbial growth, decreasing hay heating and thus dry matter and nutrient loss.

Preservatives allow baling at a hay moisture content of 25 to 30%. Beyond 30% moisture, they will not be effective.

Baleage is an option for hays with greater than a 30% moisture content. Another important point is that the effect will not last indefinitely. After about 30 days, the effect of a preservative treatment will begin to dissipate. If using a preservative, plan on feeding preserved hay early in the season and avoid storing preserved hay with untreated cured hay.

Three types of preservatives are available — organic acids, ammonia-based and microbial. Anhydrous ammonia is an effective anti-microbial preservative but requires extreme caution in handling and application to avoid personal injury. In addition it may produce toxicity in high-quality hay, potentially causing livestock death.

For those reasons, treating high-moisture hay with ammonia is not recommended.

Microbial products are available, but their effectiveness as a preservative is not supported by research.

Organic acids are reliable, effective and time-tested. Propionic acid is the most common of those, and though it is effective it can be corrosive. Buffers can be mixed with propionic acid to reduce the corrosiveness. Read and follow label directions with propionic acid use because the rates will vary based on moisture content of the hay.