Effective rumen degradation of dry matter, crude protein and neutral detergent fibre in forage determined by near infrared reflectance spectroscopy

Abstract

The objective of the present study was to examine if near infrared reflectance spectroscopy (NIRS) could be used to predict degradation parameters and effective degradation from scans of original forage samples. Degradability of dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF) of 61 samples of perennial ryegrass (Lolium perenne L.) and orchardgrass (Dactylis glomerata L.) was tested by using the in situ technique. The grass samples were harvested at three different stages, early vegetative growth, early reproductive growth and late reproductive growth. Degradability was described in terms of immediately rumen soluble fraction (a fraction, for DM and CP only as NDF does not contain a soluble fraction), the degradable but not soluble faction (b fraction) and the rate of degradation of the b fraction (c value). Overall effective degradability of DM, CP and NDF was also calculated. Near infrared reflectance spectroscopy was examined for its ability to predict degradation parameters and to make a direct prediction of effective degradation from scans of the original samples of perennial ryegrass and orchardgrass. Prediction of effective degradation of the different feed fractions showed different accuracy. The coefficients of determination (R(2)) from regressions of predicted vs. measured effective degradation, using a cross-validation method, were 0.92 for DM, 0.78 for CP and 0.61 for NDF. The attempt to predict the degradation parameters (a, b and c) by NIRS was less successful as the coefficients of determination for the degradation parameters were low. Concentrations of CP and NDF in the original samples were predicted by using NIRS and the validated R(2) value was 0.98 for CP and 0.92 for NDF. It is concluded that using NIRS predictions from scans of original samples is a promising method to obtain values for the effective degradation of DM, CP and NDF in ruminant feeds, but that larger calibration sets are necessary for obtaining improved accuracy.

Prediction of rumen degradability parameters of a wide range of forages and non-forages by NIRS

“…Several studies reported the inability of NIRS to predict the rate of degradation of nutrients (Andrés et al, 2005b;Nordheim et al, 2007;Ohlsson et al, 2007). Herrero et al (1997) related this difficulty to the exponential nature of the models used in parameterization of the degradation rate.…”

“…Recently, Belanche et al (2013 and2014) used Fourier transformation mid-IR spectroscopy (FTIR) to estimate degradability parameters of CP, dry matter (DM) and NDF, and results suggested that mid-IR can be used for screening purposes but not for estimating dynamic parameters of degradability. Similarly, several efforts using NIRS to predict rumen degradation parameters have been reported (Todorov et al, 1994;De Boever et al, 2003;Andrés et al, 2005b;Ohlsson et al, 2007). However, most of these studies are feedstuff specific, predicting degradation parameters of a particular feedstuff or a specific category of feedstuffs, mainly forages or compound feeds and not byproducts or grains.…”

Quantification of bovine immunoglobulin G using transmission and attenuated total reflectance infrared spectroscopy

“…[41][42][43] Methods employing IR spectroscopy have been successfully used to determine nutrient contents of milk, 36,37 colostrum IgG concentration, 33 feed composition, and the kinetics of nutrient degradation in the rumen. 20,31 It has also been utilized in screening for metabolic diseases such as ketosis 18 and foodborne pathogens. 7 However, there are a number of IR spectroscopic sampling techniques.…”

Empirical Attributes and Limitations of Methodologies for Predicting the Degradability of Ruminal Protein

“…Although these methods are robust and can be applied to a wide variety of feeds, some limitations have been observed. This type of analysis provides chemical-structural information about the feed, allowing the chemical composition of and the kinetic processes that degrade ruminal food to be inferred (Andrés et al, 2005;Ohlsson et al, 2007). The FTIR technique has recently been developed; it is more sensitive than traditional methods, and data can be obtained more quickly (Belanche et al, 2013).…”

“…Another interesting conclusion of this study was that the majority of FTIR-based predictions show a similar level of accuracy as the NIRS method, suggesting that FTIR should be considered as a low-cost alternative method for the nutritional evaluation of feeds. Although NIRS has demonstrated some capability for directly predicting the degradability of forage components in situ (Nordheim et al, 2007;Ohlsson et al, 2007), approximately 12,000 dacron bags would need to be processed for calibration purposes (Hoffman et al, 1999). Given this complexity, NIRS is proposed as a reliable technique for predicting the composition of incubation residues for which calibration requires fewer observations (Reeves et al, 1991;Berzaghi et al, 1997;Andrés et al, 2005).…”