With mating due to start in about a month, farmers are being advised to slow paddock rotations to build up cow condition and allow a feed surplus to develop.
DairyNZ consulting officer Caroline Hadley told a series of field days around Otago last week that the logical reaction when paddocks were wet was to speed up rotation to avoid pugging, but that would not assist pasture cover.
She recommends a rotation of between 20 and 30 days, which could include a sacrifice paddock well away from waterways, until average pasture cover lifts to at least 2000kg dry matter a hectare (DM/ha).
Mrs Hadley said farmers quite correctly focused during and after the storm on animal welfare, but this meant eating into feed reserves, leaving low pasture cover, but she said this did not mean the season was over.
"They have got to look at the big picture. They can still achieve a lot out of the season yet."
There was a risk that when the sun came out farmers would forget about the looming problem, so monitoring pasture growth was crucial.
My Farm supervisor and Clydevale farmer Terry Carr said farmers should look at back fencing cows to stop them trampling areas already eaten off and to look at applying urea at 60-80kg a ha.
If residue pasture after grazing was 1300kg DM/ha or less, paddocks would be slow to respond, but at 1500kg DM/ha, they would respond in fine weather, he said.
Another tactic was to get neighbours together and have a weekly walk through each other's herd to assess cow condition.
"When you see cows each day, you do not notice as quickly if they have lost condition."
Mr Carr said there was still time to build up cow condition for mating and to take advantage of the season's peak milk flow, but much of that depended on management in the few weeks immediately following the storm.
DairyNZ information said the use of supplements was another option, but it recommended enough to provide each cow with at least 10kg DM a cow each day and suggested ordering enough to last two weeks, because the weather and conditions remained volatile.
Supplement options were to feed cows pasture during the day and supplements on a sacrifice paddock at night, under a wire on fresh pasture or to offer palm kernel on a new break while also using a sacrifice paddock.
Palm kernel can also be fed with baleage on silage for 10 to 14 days to boost the quality of feed.
Supplementing cows with magnesium was crucial when they were not being fully fed, and if feeding large volumes of grain to milking cows, lime flour should be added.
Palm kernel can be fed in bins or with silage and cows can eat 3kg each a day, but they need water.
Cows can eat up to 3.5kg of grain each milking but this should ideally be fed in the shed where there is some control. If they are allowed to gorge themselves, they can get acidosis. For this reason, pasture, silage or straw should be offered first. Molasses also has the same acidosis risk.
DairyNZ information said once-a-day milking took pressure off people and cows but it also led to lower production, so 16-hourly milking may be a better option for reducing workload and impact on milk production.
Milking once a day for a week will reduce milk production by 15 to 20% and 1% to 2% over the full lactation. To do so for six weeks will immediately cost 25-30%, and 12-20% of full lactation production.