TITLE:
Production of Methane Emissions from Ruminant Husbandry: A Review
AUTHORS:
Jan Broucek
KEYWORDS:
Methane, Ruminants, Emissions, Dairy Cattle, Beef Cattle, Sheep
JOURNAL NAME:
Journal of Environmental Protection,
Vol.5 No.15,
November
26,
2014
ABSTRACT: The aim of
this review is to summarize the current knowledge of methane (CH4) production
from ruminants. The objectives are to identify the factors affecting CH4 production. Methane is a potent greenhouse gas (GHG). Ruminant livestock constitute
worldwide the most important source of anthropogenic emissions of methane. There
are two main factors influencing global warming change, an increase in greenhouse
gas emissions and depletion of the ozone layer. Methane is associated with both
factors. Ruminants (dairy, beef, goats, and sheep) are the main contributors to
CH4 production. Their CH4 production is a natural and inevitable
outcome of rumen fermentation. Feed is converted into products such as milk and
meat. Many factors influence ruminant CH4 production, including level
of intake, type and quality of feeds, energy consumption, animal size, growth rate,
level of production, and environmental temperature. The methane emissions in dairy
cows represent values from 151 to 497 g·day-1. Lactating cows produced
more CH4 (354 g·day-1) than dry cows (269 g·day-1) and heifers (223
g·day-1).
Dairy ewe generates 8.4 kg·head-1 annually. Holstein produced more CH4 (299 g·day-1) than the Crossbred
(264 g·day-1). Methane emission by heifers grazing on fertilized pasture
was higher (223 g·day-1) than that of heifers on unfertilized pasture (179 g·day-1). The average CH4 emissions are from 161 g·day-1 to 323 g·day-1 in beef cattle. Mature beef cows emit CH4 approximately
from 240 g·day-1 to 396 g·day-1. Suffolk sheep emit 22 - 25 g·day-1. The bison’s annual
CH4 emissions per year were 72 kg·head-1. The CH4 emission from manure depends on the physical form of the feces, the amount of digestible
material, the climate, and the time they remained intact. The annual emissions from
the pens and storage pond at dairy farm were 120 kg·cow-1.