In Vitro Ruminal Fermentation and Methane Output of Monospecific, Binary, and Multispecies Pastures Under Two...

Area of Science:

• Animal Science
• Agronomy
• Environmental Science

Background:

• Pastures are crucial for grazing systems, influencing ruminal fermentation and by-products.
• Botanical composition and pasture management significantly affect animal digestion and emissions.

Purpose of the Study:

• To assess how pasture type and defoliation frequency affect in vitro ruminal fermentation kinetics.
• To evaluate the impact of pasture management on methane and ammonia production.

Main Methods:

• Four pasture types (Bromus valdivianus, Lolium perenne, mixtures, multispecies) were evaluated.
• Defoliation frequencies of 150 and 300 growing degree days (GDDs) were applied across four seasons.
• In vitro ruminal fermentation, gas production (including methane), volatile fatty acids, and ammonia were measured using the ANKOM RF system.

Main Results:

• Methane production varied with defoliation frequency and season interactions.
• Pasture type and defoliation frequency influenced methane intensity.
• Total gas production was higher for Lolium perenne and at 300 GDD.
• Ammonia concentration decreased with longer defoliation intervals (300 GDD).

Conclusions:

• No single treatment consistently reduced methane output.
• Extending defoliation intervals can lower ruminal ammonia levels.
• Environmental benefits require balancing methane responses with forage quality and animal performance.