Interactions among breed, farm intensiveness and cow productivity on predicted enteric methane emissions at the population level

Figures & data

Figure 1. Number of herds, cows and spectra collected by breed, herd intensiveness level class (HL) and cow production level class (CL). Five classes of daily milk energy output (dMEO, MJ/d) for each factor: HL-1 and CL-A <-1.5σ; HL-2 and CL-B -1.5σ to -0.5σ; HL-3 and CL-C -0.5σ to +0.5σ; HL-4 and CL-D + 0.5σ to +1.5σ; HL-5 and CL-E > +1.5σ.

Table 1. Analysis of variance of milk yield and of the predicted informative fatty acids content: F-values of the factors included in the model of analysis (all the effects are highly significant for p < 0.001).

Trait	DF	Milk yield, kg/d	Predicted informative fatty acids, %:
			4:0	16:0iso	18:1t10	18:1t11	18:1c9	18:2c9c12
Mean	–	23.20	3.40	0.32	0.29	1.21	18.13	2.02
SD	–	7.40	0.59	0.06	0.11	0.43	2.54	0.44
Year of calving	7	19,078	3,952	2,799	790	809	2,709	3,104
Month of the year	11	1,061	308	593	659	355	784	560
Parity	4	41,237	687	6,558	3,568	5,891	6,497	2,438
Stage of lactation	11	130,812	29,666	17,690	895	3,982	26,647	8,661
Breed	3	372,766	966	433	240	1,147	176	159
Herd level	4	246,646	554	4,110	1,135	5,283	3,967	8,064
Cow level	4	131,360	1,222	933	300	3,708	2,723	357
Herd level by breed	12	214	153	268	262	519	60	427
Cow level by breed	12	170	46	27	51	54	27	28
RMSE	1,759,637	4.0	0.54	0.05	0.10	0.41	2.23	0.41

DF: degrees of freedom; SD: standard deviation.

Table 2. Analysis of variance of the enteric CH₄ yield, intensity and production predicted directly from milk FTIR spectra or through prediction of informative fatty acids: F-values of the factors included in the model of analysis (all the effects are highly significant for p < 0.001).

Trait	DF	CH4 yield, g/kg DMI:		CH4 intensity, g/kg milk:		Daily CH4 production, g/d:
		Direct-IR	Indirect-IR	Direct-IR	Indirect-IR	Direct-IR	Indirect-IR
Mean	–	21.3	21.3	14.2	14.2	357	333
SD	–	1.3	1.1	1.3	1.2	77	100
Year of calving	7	5,030	2,957	6,830	6,266	6,249	10,575
Month of the year	11	145	196	91	360	1,193	726
Parity	4	1,917	2,148	1,944	3,515	9,051	43,591
Stage of lactation	11	19,233	18,016	46,397	65,960	17,553	39,948
Breed	3	1,108	918	1,168	1,442	686	343,342
Herd level	4	3,537	4,506	196	114	6,378	278,162
Cow level	4	368	148	25	21	4,350	139,400
Herd level by breed	12	614	158	64	97	677	405
Cow level by breed	12	34	18	11	31	57	323
RMSE	1,759,637	1.2	1	1	1	70	58

DF: degrees of freedom; SD: standard deviation.

Figure 2. Average daily milk production by breed of cows (kg/d).

Figure 3. Milk fat, butyric acid (4:0) and iso-palmitic acid (16:0 iso), in % of total fatty acids (LSM ± CI), by breed, herd intensiveness class level or cow production class level plotted against actual cow yield (kg/d).

Figure 4. Milk isooleic acid (18:1 trans10), vaccenic (18:1 trans11), oleic (18:1 cis9), and linoleic acid (18:2 cis9,cis12), in % of total fatty acids (LSM ± CI), by breed, herd intensiveness class level or cow production class level plotted against actual cow yield (kg/d).

Figure 5. Predicted enteric CH₄ yield (LSM ± CI, CH₄/DMI, g/kg dry matter intake) predicted directly from milk FTIR spectra or indirectly from predictive informative milk fatty acids by breed, herd intensiveness class level or cow production class level plotted against actual cow yield (kg/d).

Figure 6. Predicted enteric CH₄ intensity (LSM ± CI, g/kg of corrected milk) predicted directly from milk FTIR spectra or indirectly from predictive informative milk fatty acids by breed, herd intensiveness class level or cow production class level plotted against actual cow yield (kg/d).

Figure 7. Predicted daily enteric CH₄ production (LSM ± CI, dCH₄, g/d) predicted directly from milk FTIR spectra or indirectly from predictive informative milk fatty acids by breed, herd intensiveness class level or cow production class level plotted against actual cow yield (kg/d).

Data availability statement

The results and analyses presented in this paper freely available upon request.