Feed supplement reduces methane emissions by livestock.
Cattle, buffalo, sheep and goats in India emit between 9.25 and 14.2 million tonnes of methane annually, a considerable proportion of the approximately 90 tonnes of methane emitted by livestock worldwide. This is of great concern, since methane is a very powerful greenhouse gas.
With this in mind, an institute of the Indian Council for Agricultural Research (ICAR) has developed an anti-methanogenic food supplement, called ‘Harit Dhara’. When administered to cattle and sheep, it not only reduces their methane emissions by 17-20%, but also results in increased milk production and increased body weight.
“An average lactating cow or buffalo in India emits around 200 liters of methane per day, whereas it is 85 to 95 liters for young growing heifers and 20 to 25 liters for adult sheep. Feeding Harit Dhara can reduce these by a fifth. For a cow producing 200 liters (143 g) of methane, this translates into 0.714 kg less CO2 equivalent emissions per day or 261 kg per year (1 liter of methane = 0.714 g; 1 kg of methane = 25 kg of CO2 ), ”Said Dr. Raghavendra Bhatta. , director of ICAR’s National Institute of Animal Nutrition and Physiology (NIANP) in Bengaluru, told The Indian Express.
Methane is produced by animals that have a rumen, in the first of their four stomachs, where the plant material they eat (cellulose, fiber, starch and sugars) is fermented or degraded by microorganisms before its subsequent digestion and absorption of nutrients. The fermentation of carbohydrates leads to the production of CO2 and hydrogen. These are used as a substrate by archaea, microbes in the rumen with a similar structure to bacteria, to produce methane, which the animals then expel through burps.
Harit Dhara works by reducing the population of protozoan microbes in the rumen, responsible for the production of hydrogen and making it available to the archaea for the reduction of CO2 to methane. Tropical plants that contain tannins (bitter and astringent chemicals) are known to suppress or eliminate protozoa from the rumen.
“Our product has been prepared using condensed and hydrolyzable vegetable sources rich in tannins available in abundance in the country. Harit Dhara costs approximately Rs 6 / kg and should be administered only to animals older than three months that have a fully functional rumen. Our RDA is 500 g for adult cattle and buffalo, 150 g for growing cattle and 50 g for adult sheep, ”said Bhatta.
However, reducing enteric methane emissions may not be a sufficient economic justification for farmers to feed Harit Dhara. What the NIANP anti-methanogenic food supplement also does is change the composition of the volatile fatty acids that are the end products of ruminal fermentation (along with hydrogen and CO2).