The addition of 3-nitrooxypropanol (3-NOP) to the feed of dairy cows reduced their enteric methane emissions by about 25% in a recently published study — one in a series of studies by The Pennsylvania State University into the investigational substance in the U.S. — which might be an early step toward it being approved for use in this country, according to an announcement from Penn State.
Three-NOP inhibits an enzyme that is crucial to the final stage of methane synthesis in a cow’s rumen, and when 3-NOP is fed to cattle, their methane production is inhibited, explained researcher Alex Hristov, distinguished professor of dairy nutrition in the Penn State College of Agricultural Sciences.
In addition to exploring the effect of 3-NOP on enteric methane emissions, the 15-week study conducted at the Penn State Dairy Teaching & Research Center examined the influence the substance had on rumen fermentation, lactational performance, sensory properties of milk and the resumption of ovarian cycles in 56 lactating dairy cows, Penn State said. The results, which were published in the Journal of Dairy Science, confirmed those of other 3-NOP trials conducted at Penn State and around the world, according to Hristov.
Compared with a control group, cows ingesting 3-NOP had 26% lower daily methane emissions, 21% lower methane yield and 25% less methane emission intensity. Significantly, the investigational substance did not affect lactational performance of the cows and, in fact, increased their feed efficiency per unit of milk yield, Hristov reported. The sensory properties of milk from cows fed 3-NOP and cheese made from that milk were not affected by treatment.
Cows release methane — a natural byproduct of digestion in ruminants — into the atmosphere mostly through belching. So, many scientists view the results of 3-NOP trials as critical if the carbon footprint of dairy and beef cattle production is to be reduced to help slow climate change, Hristov noted.
He said, “3-NOP is the only substance that has worked significantly in reducing enteric methane in cattle and not had unacceptable effects on milk production or quality. We have tried many things in recent years — including essential oils, oregano and seaweeds — and they either have been ineffective in the long term or need to be investigated further.”
The Penn State research, including other studies completed or currently underway, is a critical step in the approval process for 3-NOP use in the U.S. and around the world, Hristov argued. “We have credibility because of our excellent facilities and our reputation for generating accurate, reliable data,” he said.
Netherlands-based health and nutrition firm DSM, which has a patent on 3-NOP, already has applied to European regulators for authorization to sell the compound as a cattle feed additive. The company hopes to launch the product in the European Union by early 2021, followed by registrations in other regions such as Brazil, Australia, New Zealand and Canada.
The climate change contribution of methane from cows burping — often incorrectly characterized as cow flatulence — has been the subject of considerable derision within the U.S., conceded Hristov, who is recognized as an international leader in assessing greenhouse gas emissions from animal agriculture. It is taken seriously in other countries, he explained, because the average dairy cow belches approximately 350 lb. of the potent greenhouse gas each year.
Hristov noted that, in contrast, “methane from animal agriculture is just 5% of the total greenhouse gases produced in the United States. Much, much more comes from the energy and transportation sectors. So, I think it’s a fine line with the politics surrounding this subject. Do we want to look at this? I definitely think that we should, and if there is a way that we can reduce emissions without affecting profitability on the farm, we should pursue it.”
Three-NOP is expected to be economical, so farmers could afford to use it, Hristov pointed out. “It could be a game changer, but the question is, will the public accept it? It’s a very small synthetic molecule that is metabolized very quickly and falls apart into compounds that are naturally present in the rumen of the cow,” he said. “Consumer insight studies in the U.S., New Zealand and the Netherlands are showing considerable support for implementing 3-NOP.”
Others involved in the research at Penn State were Troy Ott, professor of reproductive physiology; Audino Melgar, doctoral candidate in animal science, in charge of the research; M.T. Harper, former graduate student; J. Oh, former postdoctoral scholar; F. Giallongo, former graduate student, and M.E. Young, former graduate student. Also part of the research team was Stephane Duval with DSM Nutritional Products in Basel, Switzerland.
The U.S. Department of Agriculture’s National Institute of Food & Agriculture supported this work. DSM Nutritional Products provided partial financial support and 3-NOP for the project.