Dairy cow greenhouse gas emissions reduced by adjusting feed formula

Taipei, Sept. 16 (CNA) The Taiwan Livestock Research Institute has found that adjusting feed formula reduces dairy cows' greenhouse gas (GHG) emissions without affecting the amount of milk produced.

In a news release issued on Sept. 12, the institute said the annual carbon dioxide equivalent produced by lactating dairy cows feeding on the new formula was 4.5 percent lower, dropping from 6,259 kilograms to 5,975kg.

The reduction was calculated using methods specified by the Intergovernmental Panel on Climate Change in 2006, the institute said.

The institute said it adjusted the ratio of corn and soybean oil meal in the feed concentration -- without changing the proportions of herbage, agricultural processing by-products, and feed concentration of the general feed -- and gradually reduced the protein content of the general feed from 18 percent to 15 percent.

Reducing protein intake decreases discharge of undigested nitrogen and cuts production of nitrous oxide -- also a GHG -- as the cattle dung is fermented into compost, the institute said.

Furthermore, the change lowered the cows' blood urea nitrogen and improved their health, the institute added.

The institute explained that using agricultural by-products in cattle feed, such as brewer's grains, pineapple skins and lemon peels, allows agricultural waste to be circulated and reused.

Moreover, in vitro experiments showed that the amount of methane produced by the cows' rumens decreased when the proportion of the agricultural by-products was raised, the statement said.

The rumen is one of the cow's stomachs. It produces methane -- the second most important GHG contributor to climate change -- in the process of feed fermentation.

Earlier this year, the Ministry of Economic Affairs revised the national standard of "Formula Feeds (for Livestock and Poultry)," also with the goal of reducing carbon emissions in livestock farming.

By adding maximum and minimum amounts of crude protein used in chicken and pig feed, the new feed standards were found to effectively reduce annual carbon emissions for each chicken and pig by 0.025kg and 7.24kg, respectively, without impacting their growth, according to the institute.