Cows give us milk, cheese, yoghurt and meat. Their hides become a handbag, a saddle or violin strings, depending on your fancy. And they are a source of critical medicines such as insulin.
Cows also produce methane. Bucket loads of it. Or to be more precise, 250 to 500 litres of methane per cow per day.
Why do cows produce methane and does it matter?
Cattle are ruminants, herbivorous animals that are able to digest grass and weeds - even shrubs and trees in a drought - turning plants that we humans have no appetite for into foods and other products that we relish.
They achieve this by having a special stomach, a hefty muscular sack the size of a cement mixer.
It has four chambers, the largest of which - the rumen - is a fermentation vat, full of microorganisms, bacteria, protozoa and fungi that break down the plants that the cow eats.
Methane is produced as a by-product of that process and is belched up as cows ruminate and chew their cud.
As a vet, I operated on cows that stopped eating and ruminating for no good reason. Through an incision in their flank, I inserted my arm into the rumen up to my armpit, to remove nails, wire, washers, string and even deer teeth that they'd eaten along with a mouthful of grass.
I'd remove the foreign object, stitch her up and the cow would soon be eating and producing methane again.
Methane from cows contributes to greenhouse gas emissions. Although produced in much smaller amounts than carbon dioxide (CO2), methane is about 25 times more effective than CO2 at trapping heat in the atmosphere.
Methane is broken down in the atmosphere to produce CO2 and water. CO2 is re-used by all plants to form sugars and grow via photosynthesis.
The side product is oxygen that humans and animals breathe to stay alive.
The plants are eaten again by cattle and other animals.
That is a quick summary of what is known as the short carbon cycle. It is a natural cycle that has gone around for millions of years, involving plants and animals, and oxygen.
The "froth on the milkshake" is that scientific research is discovering ways to reduce ruminant methane production through improved pastures, selective breeding and feed supplements.
Veterinarians for Climate Action commends the livestock industry in Australia for its determination to reduce ruminant emissions.
We can be sure that vets in rural areas will help to deliver the results of this work to livestock farmers nationwide.
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