Extension Ag Update
November/December 2003
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Hay Analysis: Improved Test

Dr. Gavin Meerdink Beef and Feed Safety Extension Veterinarian University of Illinois College of Veterinary Medicine; Source: Christine A. Beuoy, University of Illinois College of Veterinary, 217-244-1562

Relative Feed Value (RFV) has been used for some time as a single-value indication of hay value relative to “average.” An improvement, the Relative Forage Quality (RFQ) test, has been developed by Dan Undersander, from the University of Wisconsin, along with John Moore, from the University of Florida, and Randy Shaver, Wisconsin Extension dairyman. The new test is being adapted by test laboratories, and hay growers and buyers are slowly becoming aware of it and learning how to interpret the test results.

In order to more accurately predict how forages will perform in a ration, changes were made to better estimate the digestibility of the forage. In the RFQ test, TDN (total digestible nutrients) is incorporated into the formula, which includes the estimate for NDF (neutral detergent fiber). Another plus for the new method is that grasses (because of their high NDF) will be measured more accurately. Forages raised in cooler weather should outperform those grown under hotter conditions. Therefore, first-cutting hay might outscore second and third cuttings.

The RFQ test is expected to cost $5 to $10 more per sample than RFQ. The improved estimate might help producers more accurately gauge how to supplement hay to best maintain condition of beef cattle through the winter.