Farty Cows At The Frontline of Climate Change

Our cute cows are a major contributor to global warming. Why? Because they are flatulent, meaning they fart constantly. They burp a lot too. One would almost think they are lactose intolerant (forgive the pun).

The world houses many cows, about 1.5 billion of them (2021) and they are the number one agricultural source of greenhouse gases worldwide. Cows collectively produce 7 giga-tonnes of greenhouse gases each year, 40% of which are methane. Although it does not live as long as other greenhouse gases, methane is – say scientists – 28 times more potent and therefore worthy of some serious attention.

If us humans are gassy, we know immediately this must be because of something we ate and we would change our diet to get rid of this nasty side effect. When cows digest their food, the enzymes in their gut needed to breakdown grass (and some unsavoury cheap food mixes added to this) produce methane. So – for cows too - a change in diet would be obvious.

Why then – if there is such a clear cause-and-effect - has the diet of cows not been adjusted? Possibly, because methane emissions were not considered urgent enough to deal with and cows were fed a little bit whatever, despite the burping.

How to reduce methane: a new diet and face masks for cows?

With global warming and climate change now on everyone’s radar, cows and what they eat are on the frontline of an agricultural revolution. Cows’ diets are being experimented with to reduce methane; from seaweed to garlic, cows are working their way through some dietary novelties. And about time.

Munching seaweed

Ermias Kebreab, a highly respected Professor at UCDavis (US) and Director of the World Food Center, recently published a study, stating that adding small amounts of seaweed to a cow’s diet dramatically diminished her methane output. In his paper he says that: “we saw a reduction of over 80% or more when adding just one or two ounces of seaweed. That was a big surprise to us. Reducing methane could help in the short-term to reverse some of the climate effects and may bring a chance to slow down global warming.”

Seaweed, by the way, is easy to grow, inexpensive and it would be a great help to make cows greener.


In the UK, meanwhile, some dairy farmers have been adding garlic and citrus pellets to cows’ feed, invented by the UK-Swiss Agri-tech business Mootral. It is claimed that even a small amount of 15 grams of the food supplement reduces methane emissions by at least 38%. Eating garlic also appeared to make cows happier and less stressed as the garlic keeps annoying flies away (it must bother cows as much as it does us). Cattle farmers using garlic also found that cows taking it, produced more milk, 8% more milk to be precise.

Face masks, really?

A UK based start-up, Zelp, has designed a face mask for cows. This mask sits over the cow’s nostrils and catches a large amount of its methane emissions and reduces these by 60%, without interfering with or changing a cow’s diet, the company claims. Zelp also captures an individual cow’s data via the mask and says to be able to measure a cow’s or a herd’s efficiency. It is yet to be established what the mask effect on cows is. Given humans are not too happy with them, it is debatable cows would. And cows will have to wear them for life. Suffice to say not many cows have been spotted with the moo-mask yet.

It is clear that cows’ diets (and wellbeing) have been an afterthought for too long; because happy and healthy cows, eating better and easier to digest food, is keeping burps at bay and footprints lighter.

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