Soaring temperatures may be welcome news for holidaymakers, but it's a headache for many dairy farmers milking at the hottest time of the day.
However, results of a trial on a Manawatu dairy farm suggests adjusting herds' milking schedule has major benefits for cows and farmers.
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The season trial was carried out by Hayley Hoogendyk who manages Aron-Amy Farm in Kairanga, Manawatu.
The 200-hectare (ha) property, owned by Craig and Raewyne Passey, has 520 cows in two herds.
A mid-January heatwave prompted Ms Hoogendyk to pull afternoon milking from 2.00pm to 11.30am as part of her twice-a-day (TAD) milking schedule (her morning milking time was 5.00am).
The one-week trial was extended to the end of the season.
The old TAD pattern was reinstated at the start of the new season, when heat stress issues were no longer an issue.
The summer schedule change saw improvements in production and milk quality.
"In the first few days of the heatwave, we were crashing from 1.8 to 1.6 kilograms of milksolids per cow per day (kg MS/cow/ day), but after we pulled the afternoon milking time back to 11.30am, it went back up to 1.8," said Ms Hoogendyk.
"We didn't see any negative effects on the quality of the milk, and there was no change in the somatic cell count (SCC), so we were happy," she said.
During the trial, the cows ate a small amount of grass (or crops like turnips) between the two milkings, plus a similar amount of PKE during the second milking."
They ate the remainder (80 percent) of their daily grass or crop allocation in their night paddock.
"We found that the less digesting of food they do during hot days, the better, as digestion raises their body temperature."
She said cows moving themselves between the paddocks, shed and shady areas not only saved time, it minimised lameness issues.
The adjustment in milking times also meant life became more enjoyable for Ms Hoogendyk, her team and their families.
"It had been taking us an hour to get the cows up to the shed, then another hour to push them away afterwards because they didn't want to leave its shade," she said.
Instead, the cows moved themselves by their own free will to a nearby shady paddock between milkings, while staff carried out other on-farm jobs and maintenance, saving staff time.
Hayley Hoogendyk, who was New Zealand Dairy Manager of the Year at last year's Dairy Industry Award is looking at making the change each summer
"Many people don't like change or trying something new, but I think you've just got to look at your animal and staff welfare, this approach is good for both."