Why does hay quality vary?

Hay is hay. Right?

Most people understand that the package of dry forage we bind up and call “hay” is not created equal in terms of nutrient content. In fact, hay is subject to extreme variation in the production phase and then additional potential forage quality variation when it is tested in the lab.

Rocky Lemus, extension forage specialist at Mississippi State University, documented the points of variation during a presentation at the National Hay Association’s 124th Annual Conference held in Acme, Mich., last week. Those points of variation include:

In the field:

• Forage species
• Plant maturity at harvest
• Fertilization (soil fertility)
• Leaf and stem variation in different parts of the bale, the presence of weeds, and baling conditions
• Storage methods
• Forage sampling methodology, including number of cores, hay lot separation, uniformity of sample, sample size, and sample processing

In the lab:

• Grinding protocol (not subsampling)
• Sample particle size and homogeneity
• Sample moisture and drying method
• Near infrared reflectance spectroscopy (NIRS) standardization and lamp quality
• Robustness of NIRS equations
• Wet chemistry protocols

Lemus’ point was simply this: There is ample opportunity to produce hay of various qualities due to uncontrollable factors. Let’s not make it even more variable by poor techniques both in the field and the lab.

“Our dilemma in the hay industry is that hundreds of thousands of pounds of highly variable plant material must be represented in a single, tiny-sized sample,” Lemus said. “Proper sampling of hay and forage is of tremendous importance to ensure an accurate forage test.”