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

Pires Sobrinho, Tatiana Lucila; Branco, Renata Helena; Magnani, Elaine; Berndt, Alexandre; Canesin, Roberta Carrilho; Mercadante, Maria Eugênia Zerlotti

doi:10.4025/actascianimsci.v41i1.42559

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) [ $C H_{4} (M J d^{- 1}) = 4.08 (\pm 1.65) + 11.6 (\pm 2.34) D M I (k g d^{- 1}) - 33.4 (\pm 7.21) H E M I (k g d^{- 1})]$ ; DMI and total carbohydrate intake (TCHI) $[C H_{4} (M J d^{- 1}) = 5.26 (\pm 1.69) - 6.3 (\pm 1.47) D M I (k g d^{- 1}) + 8.8 (\pm 1.81) T C I (k g d^{- 1})]$ ; metabolizable energy intake (MEI) and cellulose intake (CELI) $[C H_{4} (M J d^{- 1}) = 5.16 (\pm 1.72) - 0.13 (\pm 0.048) M E I (M J d^{- 1}) + 7.37 (\pm 1.53) C E L I (k g d^{- 1})]$ , and non-fiber carbohydrate intake (NFCI) $[C H_{4} (M J d^{- 1}) = 3.14 (\pm 1.48) + 3.65 (\pm 1.05) N F C I (k g d^{- 1})]$ 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.

Keywords:
beef cattle; dry matter intake; greenhouse gas; prediction; sulfur hexafluoride

[1] *Author for correspondence. E-mail: mercadante@iz.sp.gov.br; mezmercadante@gmail.com

Item¹	Ingredients			Total diet
Item¹	Hay	Corn	Cottonseed meal
DM, g kg^-1	894	857	886	868
OM, g kg^-1 DM	944	979	948	941
Ash, g kg^-1 DM	55.6	20.7	52.6	42.0
CP, g kg^-1 DM	57.7	102	315	139
EE, g kg^-1 DM	12.2	78.8	17.1	34.5
NDF, g kg^-1 DM	774	451	609	620
NDFap, g kg^-1 DM	743	416	569	587
ADF, g kg^-1 DM	444	57.4	336	288
Lignin, g kg^-1 DM	68.1	6.50	111	56.2
Cellulose, g kg^-1 DM	376	50.9	225	232
Hemicellulose, g kg^-1 DM	330	394	273	332
TDN, g kg^-1 DM	535	807	489	602
TCH, g kg^-1 DM	875	799	615	784
NFC, g kg^-1 DM	131	383	45.6	198
GE, Mcal kg^-1	4.18	4.5.2	4.50	4.28
DE, Mcal kg^-1	2.36	3.6.4	2.28	2.71
ME, Mcal kg^-1	1.93	3.22	1.85	2.29

Source	Equation
Ellis et al. (2009Ellis, J. L., Kebreab, E., Odongo, N. E., Beauchemin, K., McGinn, S., Nkrumah, J. D., ... McBride, B. W. (2009). Modeling methane production from beef cattle using linear and nonlinear approaches. Journal of Animal Science, 87(4), 1334-1345. doi: 10.2527/jas.2007-0725. https://doi.org/10.2527/jas.2007-0725.... ) Eq. A	$C H_{4} (M J d^{- 1}) = 2.29 + 0.670 D M I (k g d^{- 1})$
Ellis et al. (2009Ellis, J. L., Kebreab, E., Odongo, N. E., Beauchemin, K., McGinn, S., Nkrumah, J. D., ... McBride, B. W. (2009). Modeling methane production from beef cattle using linear and nonlinear approaches. Journal of Animal Science, 87(4), 1334-1345. doi: 10.2527/jas.2007-0725. https://doi.org/10.2527/jas.2007-0725.... ) Eq. B	$C H_{4} (M J d^{- 1}) = 3.05 + 3.71 C E L I (k g d^{- 1})$
Ellis et al. (2009Ellis, J. L., Kebreab, E., Odongo, N. E., Beauchemin, K., McGinn, S., Nkrumah, J. D., ... McBride, B. W. (2009). Modeling methane production from beef cattle using linear and nonlinear approaches. Journal of Animal Science, 87(4), 1334-1345. doi: 10.2527/jas.2007-0725. https://doi.org/10.2527/jas.2007-0725.... ) Eq. D	$C H_{4} (M J d^{- 1}) = 6.01 + 0.345 N F C I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 1b	$C H_{4} (M J d^{- 1}) = 4.38 + 0.0586 M E I (M J d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 2b	$C H_{4} (M J d^{- 1}) = 3.96 + 0.561 D M I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 4b	$C H_{4} (M J d^{- 1}) = 5.26 + 6.93 L I G I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 5b	$C H_{4} (M J d^{- 1}) = 5.58 + 0.848 N D F I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 6b	$C H_{4} (M J d^{- 1}) = 5.70 + 1.41 A D F I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 7b	$C H_{4} (M J d^{- 1}) = 3.05 + 0.0371 M E I (M J d^{- 1}) + 0.801 N D F I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 8b	$C H_{4} (M J d^{- 1}) = 3.31 + 0.0382 M E I (M J d^{- 1}) + 1.05 A D F I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 11b	$C H_{4} (M J d^{- 1}) = 2.30 + 1.12 D M I (k g d^{- 1}) - 6.26 L I G I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 12b	$C H_{4} (M J d^{- 1}) = 2.70 + 1.16 D M I (k g d^{- 1}) - 15.8 E E I (k g d^{- 1})$
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 14b	$C H_{4} (M J d^{- 1}) = 2.94 + 0.0585 M E I (M J d^{- 1}) + 1.44 A D F I (k g d^{- 1}) - 4.16 L I G I (k g d^{- 1})$
Axelsson (1949Axelsson, J. (1949). The amount of produced methane energy in the European metabolic experiments with adult cattle. Annals of the Royal Agricultural College of Sweden, 16, 404-419.)	$C H_{4} (M J d^{- 1}) = 2.07 + 2.64 D M I (k g d^{- 1}) - 0.105 D M I^{2} (k g d^{- 1})$
Mills et al. (2003Mills, J. A. N., Kebreab, E., Yates, C. M., Crompton, L. A., Cammell, S. B., Dhanoa, M. S., ... France, J. (2003). Alternative approaches to predicting methane emissions from dairy cows. Journal of Animal Science , 81(12), 3141-3150. doi: 10.2527/2003.81123141x. https://doi.org/10.2527/2003.81123141x.... ) Linear 1	$C H_{4} (M J d^{- 1}) = 5.93 + 0.92 D M I (k g d^{- 1})$
Mills et al. (2003Mills, J. A. N., Kebreab, E., Yates, C. M., Crompton, L. A., Cammell, S. B., Dhanoa, M. S., ... France, J. (2003). Alternative approaches to predicting methane emissions from dairy cows. Journal of Animal Science , 81(12), 3141-3150. doi: 10.2527/2003.81123141x. https://doi.org/10.2527/2003.81123141x.... ) Linear 2	$C H_{4} (M J d^{- 1}) = 8.25 + 0.07 M E I (k g d^{- 1})$
Moe and Tyrrel (1979Moe, P. W., & Tyrrell, H. F. (1979). Methane production in dairy cows. Journal of Dairy Science , 62(10), 1583-1586. doi: 10.3168/jds.S0022-0302(79)83465-7. https://doi.org/10.3168/jds.S0022-0302(7... )	$C H_{4} (M J d^{- 1}) = 0.341 + 0.511 N F C I (k g d^{- 1}) + 1.75 H E M I (k g d^{- 1}) + 2.65 C E L I (k g d^{- 1})$

Variable	Mean	SD	CV (%)	Minimum	Maximum
LW, kg	332	35.3	10.6	225	409
DMI, kg d^-1	7.49	0.77	10.3	5.41	9.14
OMI, kg d^-1	7.04	0.739	10.5	5.05	8.64
MEI, MJ d^-1	72.6	7.32	10.1	53.1	87.4
GEI, MJ d^-1	1.35	0.13	9.66	0.989	1.61
CPI, kg d^-1	1.08	0.107	9.64	0.795	1.3
EEI, kg d^-1	0.269	0.048	17.7	0.185	0.367
NDFIap, kg d^-1	4.32	0.449	10.4	3.11	5.29
ADFI, kg d^-1	2.09	0.244	11.7	1.46	2.66
LIGI, kg d^-1	0.413	0.046	11.2	0.319	0.504
CELI, kg d^-1	1.69	0.229	13.5	1.15	2.2
HEMI, kg d^-1	2.48	0.252	10.1	1.79	3.0
TCHI, kg d^-1	5.69	0.63	11.0	4.02	7.08
NFCI, kg d^-1	1.38	0.209	15.2	0.909	1.79
TDNI, kg d^-1	4.58	0.471	10.3	3.32	5.56
Methane emission
CH₄, MJ d^-1	8.17	1.47	18.0	5.07	12.2
CH₄, g d^-1	148	26.6	18.0	92.0	222
CH₄, g kg^-1 DMI	19.9	3.13	15.7	11.8	26.8
CH₄, % GEI	6.10	1.13	18.6	3.57	9.49

Variable	CH₄ (MJ d^-1)	P-value
DMI, kg d^-1	0.40	0.005
OMI, kg DM d^-1	0.43	0.002
MEI, MJ d^-1	0.37	0.010
DEI, MJ d^-1	0.37	0.010
CPI, kg DM d^-1	0.40	0.005
EEI, kg DM d^-1	-0.40	0.005
NDFIap, kg DM d^-1	0.36	0.011
ADFI, kg DM d^-1	0.50	0.0003
LIGI, kg DM d^-1	-0.009	0.952
CELI, kg DM d^-1	0.58	<0.0001
HEMI, kg DM d^-1	0.35	0.015
TCHI, kg DM d^-1	0.47	0.0007
NFCI, kg DM d^-1	0.63	<0.0001
TDNI, kg DM d^-1	0.41	0.004

Equation		RMSPE
Equation 1	$C H_{4} (M J d^{- 1}) = 4.41 (\pm 1.86) + 0.50 (\pm 0.227) D M I (k g d^{- 1})$	17.00
Equation 2	$C H_{4} (M J d^{- 1}) = 5.26 (\pm 2.78) + 2.53 (\pm 0.792) D M I (k g d^{- 1}) - 59.7 (\pm 22.3) E E I (k g d^{- 1})$	29.73
Equation 3	$C H_{4} (M J d^{- 1}) = 4.97 (\pm 1.71) - 1.31 (\pm 0.507) D M I (k g d^{- 1}) + 7.69 (\pm 1.70) C E L I (k g d^{- 1})$	19.61
Equation 4	$C H_{4} (M J d^{- 1}) = 4.08 (\pm 1.65) + 11.6 (\pm 2.34) D M I (k g d^{- 1}) - 33.4 (\pm 7.21) H E M I (k g d^{- 1})$	14.34
Equation 5	$C H_{4} (M J d^{- 1}) = 5.26 (\pm 1.69) - 6.30 (\pm 1.47) D M I (k g d^{- 1}) + 8.80 (\pm 1.81) T C H I (k g d^{- 1})$	14.05
Equation 6	$C H_{4} (M J d^{- 1}) = 4.55 (\pm 1.89) + 0.050 (\pm 0.024) M E I (M J d^{- 1})$	17.11
Equation 7	$C H_{4} (M J d^{- 1}) = 5.16 (\pm 1.72) - 0.130 (\pm 0.048) M E I (M J d^{- 1}) + 7.37 (\pm 1.53) C E L I (k g d^{- 1})$	14.26
Equation 8	$C H_{4} (M J d^{- 1}) = 4.06 (\pm 1.65) + 2.42 (\pm 0.926) C E L I (k g d^{- 1})$	15.73
Equation 9	$C H_{4} (M J d^{- 1}) = 4.75 (\pm 1.92) + 8.26 (\pm 3.95) L I G I (k g d^{- 1})$	18.83
Equation 10	$C H_{4} (M J d^{- 1}) = 4.32 (\pm 1.72) + 1.85 (\pm 0.760) A D F I (k g d^{- 1})$	16.26
Equation 11	$C H_{4} (M J d^{- 1}) = 4.55 (\pm 1.83) + 0.838 (\pm 0.383) N D F I_{a p} (k g d^{- 1})$	17.12
Equation 12	$C H_{4} (M J d^{- 1}) = 4.35 (\pm 1.84) + 0.543 (\pm 0.241) O M I (k g d^{- 1})$	16.74
Equation 13	$C H_{4} (M J d^{- 1}) = 4.50 (\pm 1.94) + 3.40 (\pm 1.66) C P I (k g d^{- 1})$	16.84
Equation 14	$C H_{4} (M J d^{- 1}) = 4.27 (\pm 1.80) + 0.685 (\pm 0.292) T C H I (k g d^{- 1})$	16.48
Equation 15	$C H_{4} (M J d^{- 1}) = 3.14 (\pm 1.48) + 3.65 (\pm 1.05) N F C I (k g d^{- 1})$	14.73
Equation 16	$C H_{4} (M J d^{- 1}) = 4.44 (\pm 1.87) + 0.813 (\pm 0.374) T D N I (k g d^{- 1})$	16.87
Equation 17	$C H_{4} (M J d^{- 1}) = 4.75 (\pm 1.87) + 1.45 (\pm 0.683) H E M I (k g d^{- 1})$	17.21
Equation 18	$C H_{4} (M J d^{- 1}) = 4.53 (\pm 1.88) + 0.042 (\pm 0.020) D E I (M J d^{- 1})$	17.28

Brasil

Brasil

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

ABSTRACT.

Equation	Mean bias¹		Linear bias²		RMSPE³	PC⁴
Equation	Exp (MJd^-1)	P	Exp (MJ d^-1)	P	(% Obs)
Ellis et al. (2009Ellis, J. L., Kebreab, E., Odongo, N. E., Beauchemin, K., McGinn, S., Nkrumah, J. D., ... McBride, B. W. (2009). Modeling methane production from beef cattle using linear and nonlinear approaches. Journal of Animal Science, 87(4), 1334-1345. doi: 10.2527/jas.2007-0725. https://doi.org/10.2527/jas.2007-0725.... ) Eq. A	0.861	<0.0001	0.136	0.724	19.42	0.399**
Ellis et al. (2009Ellis, J. L., Kebreab, E., Odongo, N. E., Beauchemin, K., McGinn, S., Nkrumah, J. D., ... McBride, B. W. (2009). Modeling methane production from beef cattle using linear and nonlinear approaches. Journal of Animal Science, 87(4), 1334-1345. doi: 10.2527/jas.2007-0725. https://doi.org/10.2527/jas.2007-0725.... ) Eq. B	-1.163	<0.0001	-0.003	0.990	20.31	0.579***
Ellis et al, (2009Ellis, J. L., Kebreab, E., Odongo, N. E., Beauchemin, K., McGinn, S., Nkrumah, J. D., ... McBride, B. W. (2009). Modeling methane production from beef cattle using linear and nonlinear approaches. Journal of Animal Science, 87(4), 1334-1345. doi: 10.2527/jas.2007-0725. https://doi.org/10.2527/jas.2007-0725.... ) Eq. D	1.631	<0.0001	11.596	<0.0001	26.85	0.630***
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 1b	-0.467	0.023	0.250	0.600	17.54	0.366*
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 2b	0.0086	0.965	0.353	0.446	16.39	0.399**
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 4b	0.0361	0.866	-1.043	0.127	18.23	-0.009^ns
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 5b	-1.072	<0.0001	0.400	0.455	21.21	0.363*
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 6b	-0.471	0.015	1.114	0.047	17.11	0.496**
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 7b	-1.034	<0.0001	-0.149	0.645	20.86	0.365*
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 8b	-0.106	0.585	0.201	0.587	16.11	0.433**
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 11b	0.071	0.701	0.125	0.652	15.27	0.516**
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 12b	1.033	<0.0001	-0.019	0.910	18.36	0.662***
Ellis et al. (2007Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of methane production from dairy and beef cattle. Journal of Dairy Science, 90(7), 3456-3466. 10.3168/jds.2006-675. https://doi.org/10.3168/jds.2006-675... ) Eq. 14b	-0.304	0.105	0.161	0.576	15.74	0.513**
Axelsson (1949Axelsson, J. (1949). The amount of produced methane energy in the European metabolic experiments with adult cattle. Annals of the Royal Agricultural College of Sweden, 16, 404-419.)	-3.552	<0.0001	-0.336	0.160	46.59	0.383**
Mills et al. (2003Mills, J. A. N., Kebreab, E., Yates, C. M., Crompton, L. A., Cammell, S. B., Dhanoa, M. S., ... France, J. (2003). Alternative approaches to predicting methane emissions from dairy cows. Journal of Animal Science , 81(12), 3141-3150. doi: 10.2527/2003.81123141x. https://doi.org/10.2527/2003.81123141x.... ) Linear 1	-4.650	<0.0001	-0.176	0.532	59.23	0.399**
Mills et al. (2003Mills, J. A. N., Kebreab, E., Yates, C. M., Crompton, L. A., Cammell, S. B., Dhanoa, M. S., ... France, J. (2003). Alternative approaches to predicting methane emissions from dairy cows. Journal of Animal Science , 81(12), 3141-3150. doi: 10.2527/2003.81123141x. https://doi.org/10.2527/2003.81123141x.... ) Linear 2	-5.167	<0.0001	0.046	0.907	65.38	0.366*
Moe and Tyrrel (1979Moe, P. W., & Tyrrell, H. F. (1979). Methane production in dairy cows. Journal of Dairy Science , 62(10), 1583-1586. doi: 10.3168/jds.S0022-0302(79)83465-7. https://doi.org/10.3168/jds.S0022-0302(7... )	-1.686	<0.0001	-0.319	0.061	26.01	0.516***