Obtaining accurate estimates of methane (CH₄) output across life stages is important to assess how CH₄ output changes throughout the production cycle in pasture-based sheep production systems. This study investigated the factors associated with CH₄ output at each life stage (lambs, hoggets, pregnant, lactating, and dry ewes), the relationship between CH₄ output measured across life stages and the relationship between CH₄ output and dry matter intake (DMI) in an Irish lowland sheep production system. Methane and carbon dioxide (CO₂) output and DMI were measured on 266 purebred Suffolk and Texel females across their lifetime. Lactating ewes produced the highest CH₄ and CO₂ output, along with having the highest DMI. Across all life stages, CH₄ output increased with increasing live weight while CH₄ output decreased as body condition score increased. Weak to moderate relationships were found between CH₄ output measured across life stages, with the strength of the relationship decreasing as the time between life stages increased. A positive relationship was found between DMI and CH₄ output. Results from this study lead to the development of a profile of CH₄ output across the production cycle of a pasture-based sheep system.

Read the full article in the Journal of Animal Science.