Ø Indian Council of Agricultural Research (ICAR) institute has developed an anti-methanogenic feed supplement ‘Harit Dhara’. When given to bovines and sheep, it not only cuts down their methane emissions by 17-20%, but also results in higher
milk production and body weight gain. Methane’s global warming potential – 25 times of carbon dioxide (CO2) over 100 years, making it a more potent greenhouse gas – that’s cause for concern.
Ø Harit Dhara has been made from tannin-rich plant-based sources. Tropical plants containing tannins, bitter and astringent chemical compounds, are known to suppress or remove protozoa from the rumen.
Ø “An average lactating cow or buffalo in India emits around 200 litres of methane per day, while it is 85-95 litres for young growing heifers and 20-25 litres for adult sheep. Feeding Harit Dhara can reduce these by a fifth.
Ø Methane is produced by animals having rumen, the first of their four stomachs where the plant material they eat – cellulose, fibre, starch and sugars – gets fermented or broken down by microorganisms prior to further digestion and nutrient absorption. Carbohydrate fermentation leads to production of CO2 and hydrogen. These are used as substrate by archaea – microbes in the rumen with structure similar to bacteria – to produce methane, which the animals then expel through burping.
Ø Harit Dhara acts by decreasing the population of protozoa microbes in the rumen, responsible for hydrogen production and making it available to the archaea for reduction of CO2 to methane. Tropical plants containing tannins – bitter and astringent chemical compounds – are known to suppress or remove protozoa from the rumen.
Ø The 2019 Livestock Census showed India’s cattle population at 193.46 million, along with 109.85 million buffaloes, 148.88 million goats and 74.26 million sheep. Being largely fed on agricultural residues – wheat/paddy straw and maize, sorghum or bajra stover – ruminants in India tend to produce 50-100% higher methane than their industrialised country counterparts.