Lachlan Godson, Pasture Agronomist and Researcher, Agrimix
Every unit of methane is lost energy your cattle didn’t convert to production. Around 6–10% of the gross energy a ruminant eats goes out as methane (Johnson & Johnson 1995) — feed you paid for that never became beef.
Progardes® Desmanthus is a pasture legume that cuts that loss. Less methane per kg of feed means more of the feed becomes product. Low methane and feed efficiency aren’t two goals — they’re the same number read from different ends.
The numbers
The trial was run with CSIRO as our science partner on Cungelella, a Northern Australia Pastoral Company property, with funding from the Department of Climate Change, Energy, the Environment and Water and co-investment from Agrimix and CSIRO.
16-month commercial grazing trial at Cungelella, central Queensland — 400 heifers, four 300 ha paddocks, buffel grass with or without Progardes Desmanthus (Charmley et al. 2025):
- Methane yield down 8% and methane intensity down 9% in the wet seasons, when Desmanthus made up 30–50% of what the cattle were eating.
- Hot carcase weight 10 kg heavier (+5 kg per side), worth about $70/head at the grid. Final liveweight 565 vs 550 kg.
- Faster growth when the legume was growing — wet season 1 gain was 1.08 vs 0.90 kg/day.
Total methane per animal per day was only 3% lower across the trial, too small a difference to call. Where Desmanthus made the difference was efficiency: less methane for every kilogram of feed eaten and every kilogram of liveweight.
Respiration chamber work backs it up: methane yield fell in a straight line as Desmanthus rose to 31% of the diet, about 10% lower at that inclusion (Suybeng et al. 2020).
Less methane, heavier carcases, same paddock. The methane figure is the signal the system is leaking less. The carcase figure is where the energy went.
How Progardes does it
Tannins are the main suspect. The three Progardes species carry 1.5–4.5% condensed tannins plus hydrolysable tannins, and in the lab all three produced less methane than Rhodes grass, up to 26–36% less per gram fermented for D. bicornutus and D. leptophyllus (Vandermeulen et al. 2018). At rumen pH the tannin binds plant protein so microbes can’t break it down and waste it as ammonia. In the acidic true stomach the complex falls apart and the protein is absorbed like any other. Tannins also knock back the methane-producing microbes.
Dose is everything. Above about 5% condensed tannin, intake drops and the feed is locked up. Progardes sits under that line (Vandermeulen et al. 2018) — enough to protect protein and dampen methane, not so much it stops digestion. That’s reducing methane by improving efficiency, not by starving the animal. Better rumen turnover and a better energy supply on a grass-only diet play a part too (Charmley et al. 2025).
The take-home
Don’t sow Progardes Desmanthus to cut emissions. Sow it because you’re paying for feed energy that’s going up as gas and you’d rather have it as beef. The lower methane comes with it.
Our thanks to Dr Ed Charmley and the CSIRO team, who led the science, and to the Collins family and the Northern Australia Pastoral Company for hosting the trial at Cungelella.
It works below ground too. We also funded research into whether Desmanthus builds soil carbon. Read the findings.
References
- Charmley E, Bishop-Hurley G, Matthews M, Simington J, Stanford J, Gardiner C, Godson L, Geldof Z, Kempe N (2025). A longitudinal study of methane emissions by cattle grazing buffel grass or buffel grass–Desmanthus pastures. Animal Production Science 65, AN25329. doi:10.1071/AN25329
- Vandermeulen S, Singh S, Ramírez-Restrepo CA, Kinley RD, Gardiner CP, Holtum JAM, Hannah I, Bindelle J (2018). In vitro assessment of ruminal fermentation, digestibility and methane production of three species of Desmanthus for application in northern Australian grazing systems. Crop & Pasture Science 69, 797–807. doi:10.1071/CP17279
- Suybeng B, Charmley E, Gardiner CP, Malau-Aduli BS, Malau-Aduli AEO (2020). Supplementing northern Australian beef cattle with Desmanthus tropical legume reduces in-vivo methane emissions. Animals 10, 2097.
- Johnson KA, Johnson DE (1995). Methane emissions from cattle. J. Anim. Sci. 73, 2483–2492.
