Methods of predicting properties of a feedstuff sample
Various embodiments disclosed relate to methods of predicting neutral detergent fiber digestibility (NDFD) properties of a feedstuff sample. A method of predicting neutral detergent fiber digestibility (NDFD) properties of a feedstuff sample includes collecting a near-infrared spectrum of the feedstuff sample to provide NIR data of the feedstuff sample. The method also includes predicting NDFD of the sample at an elapsed time, NDFD rate of the sample, and/or NDFD extent of the sample from the NIR data using a NIR/NDFD calibration model. Various embodiments provide a method of developing the NIR/NDFD calibration model using in vitro gas production (IVGP). Various embodiments provide a method of predicting digestibility of the feedstuff sample for an animal at a rumen passage rate (eNDF).
1. A method of developing a near-infrared (NIR)/neutral detergent fiber digestibility (NDFD) calibration model comprising:
converting gas pressure per mass of isolated NDF or whole sample from in vitro gas production of a calibration sample to NDFD using an IVGP/NDFD correlation algorithm,
measuring NIR data from the calibration sample, and
correlating the NIR data from the calibration sample to the NDFD of the calibration sample.
2. The method of claim 1 , wherein the gas pressure per mass of the isolated NDF or whole sample from in vitro gas production is measured at multiple elapsed times; and
the gas pressure per mass of the isolated NDF or whole sample at two or more of the elapsed times is converted to a predicted NDFD at the two or more elapsed times using the IVGP/NDFD correlation algorithm.
3. The method of claim 1 , further comprising collecting a near-infrared spectrum of a feedstuff sample to provide NIR data of the feedstuff sample; and
predicting NDFD of the feedstuff sample at an elapsed time, NDFD rate of the feedstuff sample, and/or NDFD extent of the feedstuff sample from the NIR data using the NIR/NDFD calibration model.
4. A method of developing a near-infrared (NIR)/neutral detergent fiber digestibility (NDFD calibration model comprising an NIR/NDFD extent calibration model and an NIR/NDFD rate calibration model, the method comprising:
developing a NIR/NDFD extent calibration model and developing a NIR/NDFD rate calibration model, comprising
converting gas pressure per mass of isolated NDF or whole sample from in vitro gas production of a calibration feedstuff sample to NDFD using an IVGP/NDFD correlation algorithm,
determining NDFD rate and NDFD extent from the NDFD using an equation that relates at least NDFD, time, the NDFD rate, and the NDFD extent,
measuring NIR data from the calibration sample,
correlating the NIR data from the calibration sample to the NDFD rate of the calibration sample to develop the NIR/NDFD rate calibration model, and
correlating NIR data from the calibration sample to the NDFD extent of the calibration sample to develop the NIR/NDFD extent calibration model.
5. The method of claim 4 , wherein the gas pressure per mass of the isolated NDF or whole sample from in vitro gas production is measured at multiple elapsed times; and
the gas pressure per mass of the isolated NDF or whole sample at two or more of the elapsed times is converted to a predicted NDFD at the two or more elapsed times using the IVGP/NDFD correlation algorithm.
6. The method of claim 4 , further comprising collecting a near-infrared spectrum of a feedstuff sample to provide NIR data of the feedstuff sample; and
predicting NDFD of the feedstuff sample at an elapsed time, NDFD rate of the feedstuff sample, and/or NDFD extent of the feedstuff sample from the NIR data using the NIR/NDFD calibration model.