Methane emission by camelids.

Area of Science:

• Agricultural Science
• Environmental Science
• Animal Science

Background:

• Ruminant livestock are significant sources of enteric methane, contributing to the greenhouse effect.
• Camelids share digestive similarities with ruminants, prompting comparisons of their methane production.
• Accurate greenhouse gas budgets require precise methane emission data, especially for countries with large camelid populations.

Purpose of the Study:

• To quantify methane emissions from key camelid species.
• To compare methane production in camelids versus ruminants on a per-body-mass and per-intake basis.
• To inform greenhouse gas accounting for countries with substantial camelid populations.

Main Methods:

• Respiration chamber measurements were conducted on 16 individuals across three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus).
• All animals were maintained on a consistent diet of alfalfa-based feed.
• Methane emissions were analyzed relative to body mass and digestible neutral detergent fiber intake.

Main Results:

• Camelids emitted significantly less methane per unit of body mass (0.32±0.11 L kg⁻¹ d⁻¹) compared to domestic ruminants (0.58±0.16 L kg⁻¹ d⁻¹).
• No significant difference in methane emission was observed when normalized to digestible neutral detergent fiber intake (92.7±33.9 L kg⁻¹ in camelids vs. 86.2±12.1 L kg⁻¹ in ruminants).
• Lower methane output in camelids is attributed to their lower relative food intake.

Conclusions:

• Camelid and ruminant foregut digestion pathways are similar regarding methanogenesis.
• Methane emission estimates for countries with large camelid populations, if based on ruminant models, likely overestimate actual emissions.
• Feral camel methane emissions in Australia are estimated to be only 1-2% of domestic ruminant methane production.