A California group is leading the nation in efforts to make forage-test results more reliable.
Three years ago, the California Hay Testing Consortium started the "California Recognized" program for testing labs' ability to accurately analyze alfalfa hay. Fourteen of the 24 labs that operate in the state are participating in the stringent program, and more are expected to complete entry requirements by next year.
More reliable hay-test results are needed, says Peter Robinson, University of California extension dairy nutritionist. Too often, says Robinson, hay samples from the same stack come back from different labs showing substantial differences in nutritional ratings.
"We need to come up with a single standard that all labs follow so that both the hay producer and the dairy operator can read these test results with confidence," he says. "We also need to develop better lab techniques for predicting animal performance from forage."
Agreeing with him is Doug Gisi, manager of the University of California, Davis 100-cow experimental herd. Gisi, who also managed his own dairy in California's central valley, says dairymen should use hay testing as a matter of course.
"The small amount of money that is spent on a hay sample test is insignificant when compared to what the dairyman will lose in milk production if his feed does not meet the nutrition levels needed by his cows," he says.
University of California extension forage specialist Dan Putnam is on the board of the National Forage Testing Association (NFTA), which aims to improve hay testing techniques in the U.S. He was also instrumental in forming the California Hay Testing Consortium in 1995. The consortium of labs, hay growers and dairy nutritionists has objectives similar to NFTA, but focuses on California.
Putnam points out that reliability of lab results is of tremendous economic importance in California, and that there are frequent disagreements between buyers and sellers as to which lab results to believe.
"Often, a sale will either go through or be denied based on a half point or a point of ADF or TDN," he says. "You can easily have variation between labs that is greater than that."
Sampling variation is sometimes responsible for differing lab results. In some cases, different people pull samples from the same stack for testing. At other times, unground samples are split and sent to different labs - an unfair test of their abilities because unground samples are usually genuinely different.
"However, some portion of the variation of hay test values between labs may be due to labperformance and lack of method standardization between labs," says Putnam. "The labs themselves are very aware of this and have been very active in trying to address this issue."
The California Recognized program judges labs on six alfalfa hay samples (including four NFTA samples) for ADF, NDF and crude protein. Participation in NFTA is required.
"This is a vigorous program, but most of the labs think it's fair," says Putnam. "Most of them do pretty well on the ADF and crude protein tests, but there has been some difficulty with NDF. Both ADF and NDF are used in Midwestern states to calculate relative feed value, and in California, ADF is used to calculate TDN. TDN is used for hay trading in California."
He adds: "I'm encouraged by the labs' willingness to join in this program to help standardize hay testing. It's certainly not perfect, but the NFTA and the California Recognized programs have made progress toward greater standardization over the last few years."