First Cut: Time for a change

By Mike Rankin

Sometimes doing nothing is easier than making a change. That’s currently where things stand with our hay marketing and grading standards.

The USDA Agricultural Marketing Service revised its present hay market guidelines in 2003. These are widely used by market reporters and others to describe hay quality and report price values. Largely driven by the fiber-based metrics of RFV (relative feed value) and TDN (total digestible nutrients), the standards also include the likes of ADF (acid detergent fiber), NDF (neutral detergent fiber), CP (crude protein) and visual description guidelines.

In addition to the USDA grading scale, there is also another standard that was developed by the American Forage and Grassland Council’s hay quality task force nearly 30 years ago. It is based primarily on RFV, and this is still the market scale of choice in some U.S. regions. Using this scale, Prime alfalfa hay (the highest grade) is defined as being greater than 151 RFV. That same hay would qualify as (barely) Good in the USDA standard, which tops out with a Supreme grade of over 185 RFV.

The current fiber-based systems founded on RFV and TDN have served us well. Prior to their arrival, hay was often judged solely on crude protein at best; or by kicking the wagon tires at worst. In the past 30 years, forage testing has moved from the research lab to routine use on most farms. Near infrared spectroscopy (NIRS) has made testing forages faster and affordable. And though there are still forage testing mountains to scale, we’ve come a long way in relatively few years.

Every forage specialist I’ve talked to from around the country agrees that fiber digestibility needs to be brought into the hay grading and value equation. This was done from an animal feeding standpoint years ago. Some specialists have been vocal about a change; at least one got tired of waiting and just developed his own grading scale.

The importance of digestibility is why we currently measure not just NDF, but the digestibility of NDF (NDFD). It’s one reason why RFV got flushed for RFQ (relative forage quality), which also more accurately assesses the value of grass species. Even though NDFD and RFQ are not perfect from a rate of digestion standpoint, they are still a whole lot more predictive of animal performance than the fiber-based ADF, NDF, RFV or TDN metrics. Maybe Wisconsin’s Dave Combs has the answer with his total-tract NDFD analysis, which accounts for both degree and rate of digestion.

A new system of grading and valuation will have to be relatively simple, but yet defendable from a science perspective. It will need to be robust for different forage species and for different regions of the country; a Michigan buyer needs to talk the same language as a Montana or Kentucky seller.

To make this happen, we need a champion or champions to move the issue forward. It will have to involve a variety of players: university specialists, USDA personnel, The National Hay Association, American Forage and Grassland Council and interests from all U.S. regions. Will it be easy? No. Is it possible? Yes, because there are a lot of very smart people in this industry. I know the ideas are out there, now we just need to have the discussion. This editorial appeared in the January issue of Hay & Forage Grower on page 4.

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