This was achieved through farmers being more efficient with their inputs, such as fertiliser and supplements, Doole explained.
A labour shortage in the dairy sector had forced farmers to be more efficient as well, as they had to do more work with fewer workers, Doole said.
Better genetics also came into play, with LIC focusing on milk production growth in the herd, Doole said.
"We're seeing our individual cows improve."
An increase in input prices had encouraged farmers to be careful with the amount used in producing milk, which had had a beneficial effect on the environment, Doole said.
"One thing that we've seen is that emissions have tended to follow that and so we've seen that now when we're producing our milk it's got the lowest emissions footprint in the world.
"So I think that's a very strong outcome as well, alongside the production side."
Ultimately, the "dramatic" results were down to Kiwi farmers' hard work, Doole said.
"I think that's really a testament to the farmers – especially during a pandemic."
Download the New Zealand Dairy Statistics 2020-21 report here.
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Key statistics from the report
• The dairy sector produced 21.7 billion litres of milk containing 1.947 billion kilograms of milksolids – a 2.6 per cent (~560 million litres) increase in litres and a 2.7 per cent (~51 million kg) increase in kilograms of milksolids processed compared with the previous season.
• Average milk production per cow was 397 kg of milksolids, a 3.1 per cent increase from 385 kg last season and the highest on record.
• The total cow population was 4.9 million, a small decrease of 0.36 per cent from the previous season.
• A total of 3.735 million cows were herd tested (76.2 per cent of cows) – the highest on record.
• 3.497 million cows were mated to AB. The percentage of cows mated to AB was 71.3 per cent, which was higher than the previous season (70.8 per cent).
• 49.6 per cent of cows are Holstein-Friesian/Jersey crossbreed, a 0.5 per cent increase from the previous season. 32.5 per cent of cows are Holstein-Friesian, 8.2 per cent are Jersey cows, 0.4 per cent are Ayrshire cows and 9.3 per cent of cows are other breeds.
• The average dairy co-operative payout of $7.75 per kg milksolids was higher than the previous season ($7.20) and the second-highest average payout in the past 10 seasons.