PROTEIN: the real culprit behind ammonia emissions



It’s no secret that dairy farms are one of the major sources of ammonia emissions.

The toxic gas is linked to respiratory problems in humans and damage to terrestrial and aquatic ecosystems.

But the smelly gas isn’t just hazardous to people and the environment; research shows that high levels of ammonia in confined farm barns may also pose a threat to animals.

A 2015 study by the US Environmental Protection Agency estimated that in the same year, dairy farms contributed more than 20 per cent of the ammonia emitted from animal husbandry operations.

A more recent study published in the American Society of Agronomy journal that analysed the data from this study along with the results of 25 earlier studies aimed to better understand the problem.

By determining which factors most influence ammonia emissions in dairy barns, researchers hope to eventually lower the amount of ammonia being released from dairy facilities.

The study provides practical help to farmers in how to manage emissions.

”Our work is important because it provides key information to farmers and farm advisers about potential ways to lower ammonia emissions,” says Adeline Bougouin, one of the authors of the paper.

However, Bougouin remains aware that reducing the amount of ammonia emitted from dairy farms isn’t easy. Farms are economic enterprises and it’s important any solutions found won’t compromise the bottom line.

“Farmers need concrete strategies that reduce the environmental impact of their farms but not their economic output,” she says.

Some of the factors influencing ammonia emissions—such as seasons—are beyond a farmer’s control. However, factors such as diet, are very much within their control.

Specifically, how much crude protein is in an animals’ diet. Crude protein is a measurement of the total amount of nitrogen in feed. As cattle cannot metabolise nitrogen efficiently, it is excreted as urea which when combined with fecal waste is converted into ammonia.

Bougouin found that reducing the amount of crude protein slightly in a dairy cow’s diet simultaneously reduced the amount of ammonia produced by the animal’s waste without affecting milk yield.

Other factors that influence the amount of ammonia being released from dairy barns include the type of flooring system used, the amount of dry matter in dairy cattle feed, and milk yield per cow.

Although these findings are valuable, it’s important to bear in mind not every farm functions in the same way and therefore may have different results when trying to manage ammonia emissions.

But this is just the start. In time, Bougouin hopes to study whole-farm ammonia losses. “Then we can better understand how various systems in farms contribute to total ammonia emissions.”

To read the whole study, click here.


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