Development of NIRS calibrations to estimate fecal composition and nutrient digestibility in beef cattle.

Feces from cattle fed 65 different diets and from 23 digestibility studies were used to develop near infrared spectroscopy (NIRS) calibrations to predict fecal composition [organic matter (OM), starch, nitrogen (N), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), and crude fat (CF)] and digestibility [DM, OM, starch, crude protein (CP), NDF, ADF, and gross energy (GE)]. The prediction of these parameters in feces collected from cattle fed wheat or barley grain (89% of diet DM) with barley silage (study 1), or barley grain diets containing varying levels of barley silage (study 2) was assessed. Validations for feces composition displayed moderate to excellent linearity (R2val>0.70) for OM, starch, N, NDF, and ADL, and poor linearity for ADF and CF (R2val =0.25). When both digestibility and feedlot datasets were combined, cross-validation for fecal composition found accurate predictions (R2CV > 0.90, SECVThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author