DIETARY SEAWEED SUPPLEMENTATION REDUCES ENTERIC METHANE EMISSIONS AND IMPROVES FEED EFFICIENCY IN TROPICAL BEEF CATTLE
Abstract
Enteric methane emissions from ruminant livestock represent a major contributor to agricultural greenhouse gas outputs and global climate change. Climate-smart feeding strategies are increasingly being explored to mitigate methane emissions without compromising productivity. This study evaluated the effect of Asparagopsis taxiformis supplementation on methane production, rumen fermentation characteristics, growth performance, and feed efficiency in tropical beef cattle. Thirty-six Brahman crossbred steers (280 ± 15 kg) were randomly assigned to three dietary treatments: Control (0% seaweed), 0.5% seaweed (dry matter basis), and 1.0% seaweed (dry matter basis) over 90 days. Methane emissions were measured using open-circuit respiration chambers, and performance parameters were recorded weekly. Results indicated methane reductions of 18% and 32% in the 0.5% and 1.0% treatments, respectively (p < 0.05). Average daily gain increased significantly in supplemented groups, while feed conversion ratio improved by 9% in the 1.0% treatment. No adverse health or behavioral effects were observed.
Introduction
Livestock production contributes approximately 14–18% of total anthropogenic greenhouse gas emissions globally, with enteric methane accounting for nearly 40% of agricultural emissions. Methane has a global warming potential approximately 28 times greater than carbon dioxide over a 100-year period, making mitigation a critical priority for sustainable agriculture. Tropical beef systems are particularly important in developing regions where livestock contribute significantly to food security, livelihoods, and economic stability. However, these systems often exhibit lower feeding.