Author(s)

Jan Broucek^*

National Agricultural and Food Centre, Research Institute of Animal Production Nitra, Luzianky, Slovakia.

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.

Methane, Ruminants, Emissions, Dairy Cattle, Beef Cattle, Sheep

Broucek, J. (2014) Production of Methane Emissions from Ruminant Husbandry: A Review. Journal of Environmental Protection, 5, 1482-1493. doi: 10.4236/jep.2014.515141.