Thai researchers tested Leucaena leucocephala pellets containing 0–15% crude glycerin in 32 male Boer × Thai native goats for 90 days. Intake fell slightly, but gain-to-feed ratio, fermentation indicators, and modeled economics improved. Methane and greenhouse-gas reductions were estimated from a stoichiometric model rather than direct emissions measurements.
Key findings
- Dry-matter intake fell from 1.19 to 1.12 kg/day, while gain-to-feed ratio rose from 0.088 to 0.108 kg/kg; nutrient digestibility did not change.
- Rumen propionate increased from 18.3 to 28.1 mol/100 mol and the acetate-to-propionate ratio fell from 3.76 to 2.23, while ammonia nitrogen was unchanged.
- Nitrogen intake and fecal nitrogen declined without a change in nitrogen retention; microbial nitrogen supply rose from 11.23 to 12.99 g/day.
- The model predicted 25% lower methane and a decline in emissions intensity from 35.69 to 27.17 kg CO2e/kg gain. Net profit rose 87%, and modeled ROI increased from 12.9% to 25.4%.
Why this matters globally
The study links a tropical forage with a biodiesel by-product, offering circular-economy and feed-cost potential. Climate claims require direct methane measurements, lifecycle assessment, and multi-farm testing that captures variation in crude-glycerin quality.
Thai researcher contribution
Corresponding author Nirandorn Nakdaeng and Kanok Chaovapasee of Princess of Naradhiwas University, with Sirirat Buaphan of Kasetsart University, tested a feed strategy relevant to Thai tropical goat production.
Limitations to consider
The 32-animal, 90-day, single-setting trial covered growing males only, not long-term health, carcass quality, reproduction, or commercial farms. Methane was modeled rather than measured by chamber or tracer methods, and economic estimates depend on input prices; the ration should not yet be labeled low-carbon.