Navigation Links
New strategy aims to reduce agricultural ammonia
Date:5/11/2011

As concerns about air pollution from large dairies and other concentrated animal feeding operations (CAFOs) continue to mount, scientists are reporting a practice that could cut emissions of an exceptionally abundant agricultural gasammoniaby up to 30%.

In the May-June 2011 issue of the Journal of Environmental Quality, a team led by Mark Powell, a soil scientist with the USDA Agricultural Research Service's U.S. Dairy Forage Research Center in Madison, WI, describes how natural plant compounds known as tannins can reduce both the amount of nitrogen cows excrete in urine, and the action of a microbial enzyme in manure that converts the nitrogen into ammonia on the barn floor.

The U.S. EPA already monitors ammonia emissions from large animal operations under the "Superfund" act, and in April a coalition of citizen groups petitioned the agency to begin regulating ammonia under the Clean Air Act, as well. Besides its pungent smell, ammonia that volatilizes from cattle manure is highly reactive in the atmosphere, forming particulates that travel long distances and contribute to environmental problems such as acid rain, nutrient pollution, and smog.

Feeding tannins to cattle could not only help dairy farmers reduce these impacts and meet regulatory standards, Powell says, but tannins could also boost nitrogen use efficiency in cows, thereby decreasing the need for expensive protein supplements. Only 20 to 35% of feed nitrogen ends up in milk on commercial dairy farms, with the remainder excreted about equally in manure and urine as the compound, urea.

Urea is produced when nitrogen-rich proteins break down mainly in the cow rumen, forming ammonia gas that's eventually converted to urea before being excreted. Tannins are thought to cut urea production by somehow allowing more protein to escape digestion in the rumen and enter the cow intestine, where it's used more efficiently to produce milk protein.

Tannins are perhaps best known for their role in leather tanning, but Powell began investigating them in ruminant feed more than two decades ago in West Africa. In the communities where he worked, tannin-rich shrubs were grown as windbreaks, and to amend the soil and feed livestock. Tannins in the diets of cattle, sheep and goats are in fact well-studied in the tropics, where the vegetation tends to be naturally higher in the astringent plant chemicals, Powell explains. "But tannin research, in terms of ruminant nutrition, is relatively new in temperate environments."

In the new study, Powell and dairy scientists from the University of Wisconsin-Madison fed tannin extracts from red quebracho and chestnut trees to dairy cows that also received two concentrations of crude protein: a low level of 15.5% protein, and a higher one of 16.8%. What they found is that dietary tannin cut ammonia emissions from the cows' manure by an average of 30% at the low protein level, 16% at the high level, or 23% overall. In other words, cows that consumed tannin expelled significantly less urea, thus making less available for conversion to ammonia.

But a drop in urea production wasn't the only effect. To his surprise, Powell discovered that tannins also appear to inhibit urease, the enzyme that converts urea to ammonia. Urease activity in the feces of tannin-fed cows was significantly lower than in the feces of control animals, resulting in an 11% drop in emitted ammoniaor one-third of tannin's total impact on emissions at the high protein level. And when the researchers applied tannin directly to manure on the barn floor (rather than feeding it to cows), the effect was even greater: Ammonia emissions declined by nearly 20%.

The tannin sources investigated in the study are already approved for animal feed, and "the levels we used amount to pennies per cow per day," Powell says, suggesting they could offer a cost-effective means to cut ammonia losses from the barn floor, as well as from manure that's applied to farm fields as fertilizer. Powell is now working with chemists to determine exactly which compounds in the tannin mixtures produce the effect, with an eye toward manufacturing a synthetic substitute later on.

In the meantime, he has his sights on another important air pollutant that is prodigiously produced by cows. "We have another experiment looking at higher doses of tannin in dairy cattle," he says. "We want to see if it can reduce methane emissions."


'/>"/>

Contact: Sara Uttech
suttech@agronomy.org
608-268-4948
American Society of Agronomy
Source:Eurekalert

Related biology news :

1. Effects of anthropogenic sound on marine mammals -- a research strategy
2. GUMC researchers hone in on new strategy to treat common infection
3. Mitochondria could be a target for therapeutic strategy for Alzheimers disease patients
4. Hope for a rabies eradication strategy in Africa
5. RNA research strategy for Europe takes shape
6. Therapeutic hypothermia is promising strategy to minimize tissue damage
7. New therapeutic strategy could target toxic protein in most patients with Huntingtons disease
8. A combined tooth-venom arsenal revealed as key to Komodo dragons hunting strategy
9. New strategy for inhibiting virus replication
10. Science Coalition commends Presidents strategy for innovation
11. IEEE-USA President endorses national innovation strategy
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/15/2016)... March 15, 2016 --> ... by Transparency Market Research "Digital Door Lock Systems Market - ... - 2023," the global digital door lock systems market in ... 2014 and is forecast to grow at a CAGR of ... small and medium enterprises (MSMEs) across the world and high ...
(Date:3/11/2016)... http://www.apimages.com ) - --> http://www.apimages.com ) - ... ( http://www.apimages.com ) - Germany . The ... refugee identity cards. DERMALOG will be unveiling this device, and a ... next week.   --> Germany . ... new refugee identity cards. DERMALOG will be unveiling this device, and ...
(Date:3/9/2016)... NEW YORK , March 9, 2016 ... current and future states of the RNA Sequencing (RNA ... in segments such as instruments, tools and reagents, data ... Analyze various segments of the RNA-Sequencing market such ... RNA-Sequencing services Identify the main factors affecting each segment ...
Breaking Biology News(10 mins):
(Date:4/29/2016)... ... April 29, 2016 , ... Intelligent Implant Systems announced today that the two-level ... sale in the United States. These components expand the capabilities of the system ... sales beginning in October of 2015, the company has seen significant sales growth in ...
(Date:4/28/2016)... Rocky Hill, Conn. (PRWEB) , ... April 28, ... ... source of financing and ongoing support for Connecticut's innovative, growing companies, today announced ... early-stage digital health and financial technology (fintech) companies. , “VentureClash looks ...
(Date:4/27/2016)... ... April 27, 2016 , ... Cambridge Semantics, the ... technology, today announced that it has been named to The Silicon Review’s “20 Fastest ... and other markets, Cambridge Semantics serves the needs of end users facing some of ...
(Date:4/27/2016)... April 27, 2016 NanoStruck ... (OTCPink: NSKQB) ( Frankfurt : 8NSK) ... Pressemitteilung vom 13. August 2015 die Genehmigung von ... um zusätzliche 200.000.000 Einheiten auf 400.000.000 Einheiten zu ... bringen. Davon wurden 157.900.000 Einheiten mit dem ersten ...
Breaking Biology Technology: