For the second year in a row, Chris Parker, the Morgan County Extension ag educator, cored sample sof champion hay slices and other selected samples from the Morgan County Fair.. Then he sent the results to Litchfield Labs for forage analysis. He's a firm believer in the premise that the only way to know the feeding value of a forage is to have it analyzed in a lab.
The lab analyzes for many things including these key factors: crude protein, with the higher the number, the more protein can supply to the animal, crude fiber, with lower numbers meaning the forage is more digestible in most cases, the total digestible nutrients or TDN, and the relative feed value, or RFV. The first three are based on percentages, and are usually reported on a 100% dry matter basis, since moisture content of hay sent to the lab can vary. The RFV value is a calculated number based on several other factors, intended to signify what feed value the forage has for certain classes of animals. It does not represent a percentage. The RFV value of 100 is the base point, meaning samples scoring above that point are generally above average in supplying nutrients, and samples scoring below are below average.
All three samples of grass have, including two champions in various levels, based on age of the 4-H'er, and a second place sample to one of the division champions, tested below 90 in RFV. All three were very close together, although one of the champions only tested just above 9% in crude protein, while the other two samples tested above 13%. Grass hay samples testing above 13% are good for that category, Parker notes. However, higher crude fiber content compared to mixed hay and legumes helped pull down the TDN percentage and the bottom line RFV value.
The exercise on the grass hays indicates that sight and smell alone aren't always 100% accurate at judging from one hay form another. It can get you in the ballpark, with greener hay with lots of leaves or hay cut at a young stage of maturity typically testing higher in protein, and often carrying a higher RFV value. However, sometimes looks can be deceiving. Especially when differences are small, it's hard to separate one hay form another if the RFV is only a point or two apart.
Once you know forage values, you can determine how the forage could best be fed, and how much you can afford to pay for it if you're buying it, Parker notes. For example, the three hay samples with RFVs below 90 still have value. They would be ideally suited to helping beef cows on maintenance make it through the winter. However, they wouldn't be the choice of a dairyman who's after top milk production, or even someone feeding any animal that is nursing during the lactation period.
For more information, see the September issue of Indiana Prairie Farmer.