Country Life: Inside Pāmu's methane measurement barn

Inside a large barn in St Kilda, just outside Taupō, a herd of heifers lead a pampered life.

For over two months they'll call the barn home, enjoying access to 10 feeder bins which they can graze from freely and a soft, sheltered space to bed down.

It's part of a trial being run at Pāmu's methane measurement facility, run by Diane Karaitiana-Bryant.

"That's why I call it the "Animal Hilton", that [on tap] feed, they're sheltered from the weather, they have their bedding changed twice a week, and they only exercise once a week when we weigh them," she told Country Life.

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The purpose-built barn was completed in late 2024 to help measure feed efficiency and how much methane the cows emit in relation to the amount of feed they consume.

Special equipment from United States helps measure the cows' burps emitted while they graze pellets from a feed bin - they put their head through the gate while a sensor reads their electronic ear tag to tell staff if they're ready for their pellet allocation.

The heifers will get six lots of pellets to keep there long enough to measure their methane outputs.

"It correlates to the feed conversion efficiency as well, so less feed, higher growth which naturally means less methane output," Karaitiana-Bryant told Country Life.

"The other thing is if you have another animal that's eating more and emitting more, but not converting that feed into meat or product, then that's what we're trying to find here."

The cows can eat as much as they like as the purpose of the trials is to see how much feed they eat and how its converted, she explained.

The trial runs for 64 days, during which time the stock are carefully monitored to see how they're doing.

Karaitiana-Bryant said lucerne baleage was chosen as it is high in both protein and metabolisable energy (ME).

"It has the optimum nutrients that it needs for cattle being in this facility for the amount of time that they're in here for."

An app helps monitor how much feed is in each bin and they're checked both morning and night by staff.

"We try and give them enough feed during the day so that in the evenings they're eating less and this carries them over through to the morning. By the time we get around in the morning they've still got some feed left in their feeders and we just top them off."

The heifers - many of which weigh more than 530 kilograms or half a tonne - can eat up to 50 kilograms of lucerne baleage per day.