Development and evaluation of prediction equations for methane emission from Nellore cattle

Abstract

ABSTRACT. Dry matter intake (DMI), nutrient intake and enteric CH4 emission were evaluated in 48 Nellore cattle (392 ± 27 days of age). Equations were generated from intake data and evaluated using root mean square prediction error (RMSPE), and validated by cross-validation. Equations that included DMI and hemicellulose intake (HEMI) [C H4 M Jd- 1 = 4.08 ± 1.65 + 11.6 ± 2.34 D M I k gd- 1 - 33.4 ± 7.21 H E M I ( k gd- 1 ) ]; DMI and total carbohydrate intake (TCHI) [ C H4 M Jd- 1 = 5.26 ± 1.69 - 6.3 ± 1.47 D M I k gd- 1 + 8.8 ± 1.81 T C I k gd- 1 ]; metabolizable energy intake (MEI) and cellulose intake (CELI)[ C H4 M Jd- 1 = 5.16 ± 1.72 - 0.13 ± 0.048 M E I M Jd- 1 + 7.37 ± 1.53 C E L I k gd- 1 ], and non-fiber carbohydrate intake (NFCI) [ C H4 M Jd- 1 = 3.14 ± 1.48 + 3.65 ± 1.05 N F C I k gd- 1 ] resulted in the lowest RMSPE (14.3, 14.1, 14.3 and 14.7%, respectively). When literature equations were evaluated using our database, the most accurate predictions were obtained with equations that included DMI and lignin intake (RMSPE = 15.27%) and MEI, acid detergent fiber intake and lignin intake (RMSPE = 15.7%). The mean error of predicting enteric CH4 emission with the equations developed in this study based on DMI and nutrient intake is 17% and the most accurate predictions are obtained with equations including DMI, carbohydrate intake and MEI.