Table 3.

Measures of predictive ability of MollyRum14 for methane production (g CH₄/d) from sheep fed varying forages (sole diet), and the effect of substrate degradation rate (SLOW, MOD or FAST) and fermentation stoichiometry (FS = 0 favors a more acetogenic fermentation, FS = 0.5 intermediate, FS = 1.0 favors a more propionogenic fermentation)

Variable				Substrate degradation rate			FAST
				MOD
	SLOW			FS
	0.0	0.5	1.0	0.0	0.5	1.0	0.0	0.5	1.0
Mean observed	19.2	19.2	19.2	19.2	19.2	19.2	19.2	19.2	19.2
Mean predicted	18.3	17.5	16.6	19.0	18.2	17.4	19.2	18.4	17.6
Mean bias	−0.9	−1.7	−2.6	−0.1	−0.9	−1.7	0.1	−0.7	−1.5
RPE1	20.5	21.4	23.3	18.8	18.9	20.1	18.5	18.5	19.5
Error decomposition:
% bias	4.9	17.0	32.7	0.1	6.5	20.1	<0.1	4.3	17.0
% slope	12.4	7.4	3.6	15.0	10.2	5.7	15.5	10.8	6.3
% random	82.7	75.5	63.7	84.9	83.4	74.2	84.4	84.9	76.7
R 22	0.56	0.56	0.56	0.62	0.62	0.62	0.64	0.63	0.63
CCC3	0.74	0.71	0.67	0.79	0.78	0.74	0.80	0.79	0.76
RSR4	0.72	0.75	0.82	0.66	0.67	0.70	0.65	0.65	0.69

N = 43.

¹Relative prediction error = (Root mean square prediction error: RMSPE)/mean observed) × 100. An RPE value of <10% indicates good predictive ability, between 10% and 20% reasonable predictive ability and >20% poor predictive ability.

² R ² of the regression predicted vs. observed.

³Lin’s concordance correlation coefficient (closer to 1 is better).

⁴Ratio of RMSPE to standard deviation of observed values: <0.5, very good prediction; 0.5–0.75, good prediction; 0.75–1, moderate prediction; and >1.0, model needs improvement.