AMTS and Dairy One Forage Laboratory hosted a joint meeting/webinar at the DFA Syracuse Headquarters on May 4. The purpose was to get some discussion going about what field people are seeing and understanding about the aNDFom time points for measuring fiber digestibility. In recent years research in the model has focused on better understanding and predicting how the cows are digesting fiber. The published research has measured the disappearance over time of NDF in in vitro digestion establishing a rate of digestion that then appears to correlate to Dry Matter Intake. Time points for measuring aNDFom were established for forage fiber sources (30, 120, 240) and non-forage fiber sources (12, 90, 120) and incorporated into the CNCPS model. The major forage labs quickly developed analyses for forages and non-forages to help implement the results. The alphabet soup of initialisms has been complicated and further confused because everyone is not sure what the time point designations mean.
Lynn Gilbert and Sally Flis presented a morning session where the terminology was explained and an afternoon session where numbers were inputted into the model demonstrating the difference between using the library lignin x 2.4 values and the uNDF (aNDFom 240–forages and aNDFom 120–non-forages) values as a measure of undigestible fiber. They demonstrated the effect these can have on predicted milk production. Both sessions can be watch below.