Are animals disgusted with their own fires

Cattle farming: cows should emit less methane

A dairy cow's methane emissions can also be reduced by a very simple measure: by letting them live longer. This has been shown in studies by scientists in which the metabolism of dairy cows of different ages was examined. Michael Kreuzer, Professor of Animal Nutrition at the ETH Zurich explains why this is the case and why there are nevertheless serious reasons for farmers that speak against a long life for dairy cows.

WORLD ON SUNDAY: Mr. Kreuzer, you placed dairy cows in the metabolic chamber in two large-scale studies. This recorded the quantities the animals ate and excreted - and how much methane they emitted. The youngest cows had just had their first calf. How has the metabolism changed?

Michael Kreuzer: We actually feared that the cows would have an increasingly poor balance with increasing age. That they eat a lot as old cows, but may be able to utilize their feed less well, for example because their teeth are worn out. So they might give less milk than young cows, but still eat a lot and produce a lot of methane. But that was not the case.

WORLD ON SUNDAY: Rather?

Cruiser: It was amazing: the cows actually excreted less methane as they got older. The ratio was worst in three to four year old animals. In contrast, cows older than six years produced a quarter to a third less methane. Even more important for the life cycle balance of the cow is that it only starts to give milk after three years. As a rearing cattle, it also consumes a lot of feed, but does not produce any milk. The older she gets, the less methane is released in relation to the amount of milk the cow will provide in her life because she balances the methane-rich period of her youth.

WORLD ON SUNDAY: Did the milk yield stay the same in old age?

Cruiser: Yes, in our attempt it did. For the climate and the farmer, it is theoretically better to let a cow live longer.

WORLD ON SUNDAY: Why only theoretically?

Cruiser: Because there are sometimes unforeseen developments in agriculture. In Switzerland, for example, the price of minced beef, which normally comes from disused dairy cows, is currently very high - this is due to the high demand for burger meat of Swiss origin for fast food. This makes giving away the cows early on from an economic point of view.