At a field day at Southern Dairy Hub in Wallacetown last week, DairyNZ senior scientist Dawn Dalley spoke about a project studying the behaviour of cows in different types of weather and soil conditions.
During a month in winter 2020, mobs of cows were fitted with behaviour devices.
Herds grazed on either fodder beet or kale.
Rainfall during the month was "not very significant" but it affected the average lying times of the cows.
"Once the soils get saturated it doesn’t take that much rain to really change conditions and significantly impact on lying times."
Water pooling on the surface of paddocks had a much bigger impact on lying times than the pugging depth, Dr Dalley said.
Paddocks could be pugged to about 20cm and it remained light and easily crumbled and "not saturated".
"The surface pooling and liquefaction of the soil surface had the biggest effect on the lying time."
Options farmers could have in their winter contingency plan when lying times were impacted was moving cows grazing on brassica crops to a bigger area.
This was not an option for cows grazing on fodder beet because it could cause animal health issues.
Farmers could move the fence back to allow cows access to drier ground previously grazed.
At the hub, cereal straw was introduced to the paddocks, which was "incredibly effective".
"It gives the animals somewhere to rest."
This year they also introduced grass breakout strips within crop paddocks, Dr Dalley said.
Hub general manager Louise Cook said when a "nasty spate" of weather hit this winter, two bales of cereal straw were introduced to a herd of cows grazing on swedes.
The straw allowed about 20 cows at a time to take turns lying down.
Grass strips allowed "way more" cows the opportunity to lie down at the same time, she said.
