Recently, research presented by Krishona Martinson of the University of Minnesota and Fred Hall of Iowa State University, stressed the importance of understanding how moisture can affect baling and mold formation, as well as how bale wrapping methods contribute to overall hay quality. They discussed how moisture content during baling is the most critical component, as this can impact mold formation. After multiple rounds of testing and baling at different moisture levels, Martinson’s team was able to track mold development and temperature rates. They found that higher moisture leads to more significant microbial respiration and heating, boosting mold formation within a bale.

Typically, mold counts under 500,000 colony-forming units (cfu/g) are considered to be low risk and safe to feed to animals. As counts over 1 million can affect cattle intake and overall health, feeding such hay should be done with caution. Round bales should ideally be baled at 15% moisture or lower to prevent spoilage and to help preserve nutrients. This is because bale wrap helps slow down the increase of neutral detergent fiber (NDF) and acid detergent fiber (ADF) over time by reducing further spoilage and nutrient loss.

While there are several types of bale wraps on the market to help bales keep longer, twine is the most affordable option — but it has the highest dry matter loss, between 12% and 35%, depending on storage and the environment around the bales. Net wrap is also a common option but has a dry matter loss of 7% to 11%. The B-wrap option, a new netwrap system compatible with John Deere balers, offers the best protection, preserving the best quality for up to a year with only minor losses. Although B-wrap is relatively more expensive, about $8 a bale, it may be worth the investment for long-term storage or high-value animals.

Cattle preference also varies with wrap type in feeding trials; it was recorded that cows consistently chose B-wrap over twine or net wrap, consuming an average of 17 more pounds per cow. Hall also emphasized the fire risk from improper baling and storage, noting that microbial activity can raise bale temperature above 200°F, which raises the risk of spontaneous combustion. He recommended monitoring bale moisture, separating wet bales, and communicating with fire departments about using a more environmentally safe spray of fire foam in case of emergencies.

Ultimately, hay management decisions have a direct impact on forage quality and livestock intake. Being an informed farmer can help make data-driven decisions that can reduce losses, improve health, and get the most out of every bale.