A comparison of milk yields and methane production from three contrasting high‐yielding dairy cattle feeding regimes: Cut‐and‐carry, partial grazing and total mixed ration

Abstract

There have been reductions in grazing cattle and corresponding increases in mixed diets across many regions. Mixed diets consist of silage, grains, legumes and other herbaceous plants (termed total mixed ration, TMR). TMR has been associated with increased milk yields but has also been linked to increased enteric methane production. We measured milk yields and methane production from high‐yielding Holstein‐Friesian cattle after substituting 29%–36% of a TMR diet with grass. Two feeding treatments were compared with a diet of TMR: grass grazed at pasture and grass cut in the field and delivered to housed cattle (termed cut‐and‐carry). Each feeding treatment was fed to 15 cattle, and the experiment was conducted in South‐west Scotland. Using a laser methane detector, we measured a twofold and fourfold decline in enteric methane production for the cut‐and‐carry and grazing groups, respectively, when the animals consumed grass. TMR was consumed by both grass‐fed groups overnight, so daily values were adjusted to include elevated methane production during this period. This revealed that methane production for the cut‐and‐carry and grazing groups was 17% and 39% lower than for the TMR‐fed group respectively. Milk yields were maintained for all three groups, and the efficiency of milk production per unit of methane was substantially greater for the two grass‐fed groups. A shift away from exclusively feeding TMR by adding fresh grass to the diets of cattle could contribute to meeting emissions targets and could also represent an economically sustainable climate change mitigation strategy.

Greenhouse Gas Emissions and Technical Efficiency in Alberta Dairy Production: What Are the Trade-Offs?

“…As expected, increased butterfat percentage is positively related to technical efficiency; however, it does not have a significant effect on environmentally adjusted technical efficiency. The nonsignificance for environmentally adjusted technical efficiency may be at least in part because of the lack of availability of detailed nutrition management information in the data set (e.g., forage quality, use of mixed rations) and the potential importance of these factors in explaining methane emissions (e.g., Cameron et al, 2018;Eckard, Grainger, and de Klein, 2010). Years of farming (i.e., experience) is negatively related to technical efficiency.…”

N- en P-excretie melkvee: achtergronden en bronnen voor de berekening

“…LG. Bijvoorbeeld, vergelijkingen tussen TMR systemen (stalvoedering met ruwvoer) en weidegang laten een hoger gemiddeld LG zien bij TMR systemen dan bij weidegang (Fontaneli et al, 2005;O'Neill et al, 2011;Hofstetter et al, 2014;O'Callaghan et al, 2016;Cameron et al, 2018;Frey et al, 2018 Koeien nemen ook gedurende de derde lactatie (Koenen et al, 1999) en latere lactaties (Zom, 2014) nog in gewicht toe. De gewichtstoename is deels te verklaren door een hogere voeropname en grotere vulling van het maagdarmkanaal als gevolg van een grotere voeropnamecapaciteit.…”

Enteric methane emission of the Dutch dairy herd : Average and variation of enteric methane emission among the Dutch dairy herd

“…Some research shows a reducing potential of both partial grazing and cut-and-carry on both CH4 yield and CH4 intensity. Cameron et al (2018) found reductions of CH4 production of 17% (cut-and-carry) and 39% (partial grazing) when around 33% of the total mixed ration diet was replaced with fresh grass. The percentage of fresh grass in the diet did not explain any of the observed variation in enteric CH4 intensity in this inventory.…”