Methods of predicting properties of a feedstuff sample

1. A method of predicting neutral detergent fiber digestibility (NDFD) properties of a feedstuff sample, the method comprising:

collecting a near-infrared spectrum of the feedstuff sample to provide NIR data of the feedstuff sample; and

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.

2. The method of claim 1 , wherein the NDFD is a Daisy Jar NDFD, an in vitro filtration NDFD, an in situ NDFD, or an in vivo NDFD.

3. The method of claim 1 , wherein the NDFD is a Daisy Jar NDFD.

4. The method of claim 1 , wherein the feedstuff sample is a forage sample.

5. The method of claim 1 , wherein the in vitro gas production from the forage sample comprises gas pressure generated from a sealed container comprising a rumen fluid and isolated NDF or whole sample from the forage sample, wherein the sealed container is heated and agitated during the in vitro gas production.

6. The method of claim 1 , wherein the NIR/NDFD calibration model comprises an NIR/NDFD extent calibration model and an NIR/NDFD rate calibration model.

7. The method of claim 1 , wherein predicting the NDFD at the elapsed time from the NIR data comprises predicting NDFD extent and NDFD rate from the NIR data using the NIR/NDFD calibration model, and predicting NDFD at the elapsed time using an algorithm that relates at least NDFD, time, the NDFD extent, and the NDFD rate.

8. The method of claim 7 , further comprising predicting digestibility of the feedstuff sample for an animal at a rumen passage rate (eNDF) using an equation that relates at least the NDFD rate, the NDFD extent, the rumen passage rate, and the eNDF.

9. The method of claim 1 wherein predicting the NDFD at the elapsed time from the NIR data comprises predicting NDFD extent from the NIR data using an NIR/NDFD extent calibration model, predicting NDFD rate from the NIR data using an NIR/NDFD rate calibration model, and predicting NDFD at the elapsed time using an algorithm that relates at least NDFD, time, the NDFD extent, and the NDFD rate.

10. The method of claim 1 , further comprising developing the NIR/NDFD calibration model.

11. The method of claim 10 , wherein developing the NIR/NDFD calibration model comprises developing a NIR/NDFD extent calibration model and developing a NIR/NDFD rate calibration model.

12. The method of claim 10 wherein developing the NIR/NDFD calibration model comprises measuring NIR data from a calibration feedstuff sample and correlating the NIR data from the calibration feedstuff sample to NDFD of the calibration feedstuff sample.

13. The method of claim 12 , further comprising predicting the NDFD data of the calibration sample that is correlated to the measured NIR data, wherein predicting the NDFD of the calibration sample comprises converting gas pressure per mass of isolated NDF or whole sample from in vitro gas production of the calibration sample at an elapsed time to NDFD using an IVGP/NDFD correlation algorithm.

14. The method of claim 10 , wherein developing the NIR/NDFD calibration model comprises 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 a NIR/NDFD rate calibration model, and correlating NIR data from the calibration sample to the NDFD extent of the calibration sample to develop a NIR/NDFD extent calibration model.

15. A method of predicting digestibility of a feedstuff sample for an animal at a rumen passage rate (eNDF) comprising:

collecting a near-infrared spectrum of the feedstuff sample to provide NIR data of the feedstuff sample;

predicting NDFD rate of the sample from the NIR data using an NIR/NDFD rate calibration model;

predicting NDFD extent of the sample from the NIR data using an NIR/NDFD extent calibration model; and

predicting eNDF of the sample using an equation that relates at least the NDFD rate, the NDFD extent, the rumen passage rate, and the eNDF.

16. A method of predicting neutral detergent fiber digestibility (NDFD) properties of a feedstuff sample, the method comprising:

determining a gas pressure per mass of isolated NDF or whole sample from in vitro gas production of the isolated NDF or whole sample of the feedstuff sample at one or more elapsed times; and

converting the gas pressure per mass of the isolated NDF or the whole sample at the elapsed time to a predicted NDFD at the elapsed time using an IVGP/NDFD correlation algorithm.

17. The method of claim 16 , wherein the determining of the gas pressure per mass of the isolated NDF or whole sample from in vitro gas production of the feedstuff sample comprises performing the in vitro gas production and measuring the gas pressure per mass of the isolated NDF or whole sample.

18. The method of claim 16 , further comprising predicting NDFD rate and NDFD extent from the predicted NDFD with an equation that relates at least the NDFD rate, the NDFD extent, and the NDFD at time t.

19. The method of claim 18 , further comprising predicting digestibility of the feedstuff sample for an animal at a rumen passage rate (eNDF) using an equation that relates at least the NDFD rate, the NDFD extent, the rumen passage rate, and the eNDF.

20. The method of claim 16 , wherein the method is a method of developing an NIR/NDFD calibration model.