This year has been a challenge for forage producers due to the wet weather this summer. A few years ago we ran into this same issue of low quality forages. UGA Extension Forage Scientist Dr. Dennis Hancock is encouraging cattlemen and producers to sample their hay and baleage to assess the nutritive value of it. Below are some commens from Dennis on this issue.
Dr. Saha at the Feed and Environmental Water Lab to summarize the samples received from this growing season so far (April 1-current). He has provided the attached summary, which can be seen below. If you compare the values to the means shown in the long-term summary found in Figure 11 of the “Understanding and Improving Forage Quality” Extension Bulletin, you will see that the average values from 2018 compare favorably to these long-term data. BUT (and I strongly emphasize this BUT), there is tremendous variability this year. He kindly provided the ranges in values for these forage categories, as well as the standard deviation. These summary statistics alert us to the real risks out there: There are many samples that are extremely low quality. For reference, wheat straw generally has a TDN value of ~45% or less. Note the range in the quality on some of these samples.
The final column in the attached is one that I calculated which is the coefficient of variation (standard deviation as a percent of the mean). Normally, we see a CV of ~10%. This year, the we have a LOOOOTTTTT more variability. Some categories are showing as much as 38% CV!
Forage Sampling
Obtaining a representative forage sample is critically important. The first step is to identify a single lot (forage taken from the same farm, same field, and cut under the same conditions within a 48-hour time period). Once a lot is defined, sub-samples should be obtained from at least 20 different bales (hay, baleage) or areas (silage) that are selected at random. Avoid taking grab samples from the bale or stack, as this may cause leaf loss and result in a sample that is not a fair representation of the lot. It is best to use a clean, sharp, forage probe. Detailed sampling procedures from the National Forage Testing Association can be obtained here.
For information on selecting and purchasing forage probes, see the frequently asked question (FAQ) page entitled “What hay probe do you recommend and where can I get one?” on the University of Georgia’s Forage Extension
If you have any questions about forage quality or sampling please contact your local county agent.