1. Prediction of enteric methane emissions by sheep using an intercontinental database
- Author
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Agencia Estatal de Investigación (España), CSIC - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), European Commission, National Institute of Food and Agriculture (US), Belanche, A., Hristov, A. N., van Lingen, H.J., Denman, Stuart E., Kebreab, E., Schwarm, A., Kreuzer, M., Niu, M., Eugène, M., Niderkorn, V., Martin, C., Archimède, H., McGee, M., Reynolds, C.K., Crompton, L. A., Bayat, A.R., Yu, Z., Bannink, A., Dijkstra, J., Chaves, A. V., Clark, H., Muetzel, S., Lind, V., Moorby, J.M., Rooke, J.A., Aubry, A., Antezana, W., Wang, M., Hegarty, R., Hutton Oddy, V., Hill, J., Vercoe, P.E., Savian, J.V., Abdalla, A.L., Soltan, Y.A., Gomes Monteiro, A.L., Ku-Vera, J.C., Jaurena, G., Gómez-Bravo, C.A, Mayorga, O.L., Congio, G.F.S., Yáñez Ruiz, David R., Agencia Estatal de Investigación (España), CSIC - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), European Commission, National Institute of Food and Agriculture (US), Belanche, A., Hristov, A. N., van Lingen, H.J., Denman, Stuart E., Kebreab, E., Schwarm, A., Kreuzer, M., Niu, M., Eugène, M., Niderkorn, V., Martin, C., Archimède, H., McGee, M., Reynolds, C.K., Crompton, L. A., Bayat, A.R., Yu, Z., Bannink, A., Dijkstra, J., Chaves, A. V., Clark, H., Muetzel, S., Lind, V., Moorby, J.M., Rooke, J.A., Aubry, A., Antezana, W., Wang, M., Hegarty, R., Hutton Oddy, V., Hill, J., Vercoe, P.E., Savian, J.V., Abdalla, A.L., Soltan, Y.A., Gomes Monteiro, A.L., Ku-Vera, J.C., Jaurena, G., Gómez-Bravo, C.A, Mayorga, O.L., Congio, G.F.S., and Yáñez Ruiz, David R.
- Abstract
Enteric methane (CH) emissions from sheep contribute to global greenhouse gas emissions from livestock. However, as already available for dairy and beef cattle, empirical models are needed to predict CH emissions from sheep for accounting purposes. The objectives of this study were to: 1) collate an intercontinental database of enteric CH emissions from individual sheep; 2) identify the key variables for predicting enteric sheep CH absolute production (g/d per animal) and yield [g/kg dry matter intake (DMI)] and their respective relationships; and 3) develop and cross-validate global equations as well as the potential need for age-, diet-, or climatic region-specific equations. The refined intercontinental database included 2,135 individual animal data from 13 countries. Linear CH prediction models were developed by incrementally adding variables. A universal CH production equation using only DMI led to a root mean square prediction error (RMSPE, % of observed mean) of 25.4% and an RMSPE-standard deviation ratio (RSR) of 0.69. Universal equations that, in addition to DMI, also included body weight (DMI + BW), and organic matter digestibility (DMI + OMD + BW) improved the prediction performance further (RSR, 0.62 and 0.60), whereas diet composition variables had negligible effects. These universal equations had lower prediction error than the extant IPCC 2019 equations. Developing age-specific models for adult sheep (>1-year-old) including DMI alone (RSR = 0.66) or in combination with rumen propionate molar proportion (for research of more refined purposes) substantially improved prediction performance (RSR = 0.57) on a smaller dataset. On the contrary, for young sheep (<1-year-old), the universal models could be applied, instead of age-specific models, if DMI and BW were included. Universal models showed similar prediction performances to the diet- and region-specific models. However, optimal prediction equations led to different regression coefficients (i.e. interc
- Published
- 2023