Implications of dairy systems on enteric methane and postulated effects on total greenhouse gas emission

Abstract

The effects of feeding total mixed ration (TMR) or pasture forage from a perennial sward under a management intensive grazing (MIG) regimen on grain intake and enteric methane (EM) emission were measured using chambers. Chamber measurement of EM was compared with that of SF 6 employed both within chamber and when cows grazed in the field. The impacts of the diet on farm gate greenhouse gas (GHG) emission were also postulated using the results of existing life cycle assessments. Emission of EM was measured in gas collection chambers in Spring and Fall. In Spring, pasture forage fiber quality was higher than that of the silage used in the TMR (47.5% v. 56.3% NDF; 24.3% v. 37.9% ADF). Higher forage quality from MIG subsequently resulted in 25% less grain use relative to TMR (0.24 v. 0.32 kg dry matter/kg milk) for MIG compared with TMR. The Fall forage fiber quality was still better, but the higher quality of MIG pasture was not as pronounced as that in Spring. Neither yield of fat-corrected milk (FCM) which averaged 28.3 kg/day, nor EM emission which averaged 18.9 g/kg dry matter intake (DMI) were significantly affected by diet in Spring. However, in the Fall, FCM from MIG (21.3 kg/day) was significantly lower than that from TMR (23.4 kg/day). Despite the differences in FCM yield, in terms of EM emission that averaged 21.9 g/kg DMI was not significantly different between the diets. In this study, grain requirement, but not EM, was a distinguishing feature of pasture and confinement systems. Considering the increased predicted GHG emissions arising from the production and use of grain needed to boost milk yield in confinement systems, EM intensity alone is a poor predictor of the potential impact of a dairy system on climate forcing.

Methane and nitrous oxide emissions from Canadian dairy farms and mitigation options: An updated review

“…Treatment means related to supplementation of nonconventional dietary ingredients (e.g., monensin and 3-nitrooxypropanol) were excluded. Furthermore, the data set included diverse dairy diets in Canada that range from a grass-legume forage-based diet dominant in Atlantic Canada (Fredeen et al 2013), to corn silage and corn grain diet used in central Canada (Odongo et al 2007a(Odongo et al , 2007bBenchaar et al 2013Benchaar et al , 2014Hassanat et al 2013) and barley silage and small grainbased diet used in western Canada (Beauchemin et al 2009b;Holtshausen et al 2009;Chung et al 2012;Haisan et al 2014). The metaregression was conducted following the approach described in Viechtbauer (2010).…”

Production performance, nutrient use efficiency, and predicted enteric methane emissions in dairy cows under confinement or grazing management system

“…Our meta-analysis revealed only a small difference in predicted CH 4 production between confinement and grazing systems, and no changes in CH 4 yield and CH 4 intensity ( Table 4 ). However, a fair comparison and evaluation of dairy management systems should also consider greenhouse gas emissions from crop production, transportation, and manure management, as well as ecosystem services provided by grazing dairies ( Fredeen et al, 2013 ; Tittonell, 2021 ), which was beyond the scope of our study. Nevertheless, results from studies that have compared the carbon footprint of grazing and confinement dairy systems are not consistent.…”

Evaluación del impacto ambiental de una planta de lácteos en Costa Rica

“…Las respuestas de los funcionarios entrevistados y las visitas de campo realizadas evidencia que esta percepción de olor es permanente, además no se dispone de sistema de tratamiento de olores. Según la actividad del sector agroindustrial, la fabricación de productos lácteos presenta intrínsecamente emisiones de gases como el amoniaco y el metano [12].…”