GRASS on a Piopio farm under water. The township was among the many King Country communities to experience a sodden summer 2023. PHOTO: SIGRID CHRISTIANSEN
“IT is too soft, and it lacks nutrition.”
That’s the folk wisdom about what prolonged wet weather does to grass.
Farmers expect wet winters. But what about the King Country’s months of heavy La Nina downpours, and the missed sunny days? What are the medium-term impacts on pasture quality and parasite and fungal burdens?
This summer, the King Country has seen many rainfall averages double, triple or more.
In an average January, Te Kūiti recorded 98.2mm. In 2023, the rainfall gauge hit 363.4mm, nearly four times the average. Taumarunui recorded 171mm against an average of 98.2mm in January 2023.
In late 2022, more than double the average was recorded in Port Taharoa and Te Kūiti, with an extra 100mm in Taumarunui.
These statistics are the extremes; several areas around the King Country were closer to the average.
Dairy NZ regional leader North Waikato Phil Irvine sums up the wet weather as “uncharacteristic.”
“[It] has impacted dairy farmers’ ability to operate as they normally would.”
Late last year, King Country dairy farms were down 5% in milk production (on average) compared to last season. Milk production recovered later, but other issues were ongoing. Lower pasture growth in late spring restricted the ability to make silage from surplus grass during September and October, Phil said.
Beef + Lamb NZ has identified that sheep and beef farmers are facing significant issues in terms of preparing feed for the coming winter, according to general manager of farming excellence Dan Brier.
“Rain in summer is usually a good thing, and so we won’t look a gift horse in the mouth. But it also comes with challenges.”
Both sheep and beef and dairy farmers have reported big delays with contractors.
“To cut silage or conserve grass you need a dry spell, and they just can’t even get two days of sunshine in a row to do the work. So, all the silage contractors and agricultural contractors are well behind where they’d like to be, in terms of getting grass cut,” Dan said.
Fertiliser makers Ravensdown have highlighted pasture damage issues.
Many issues have affected both types of farming: like pugging and treading. Even farmers exclusively running sheep will have felt some impacts this year.
“With double the average rainfall, you would see that with both stock classes [sheep and cattle],” said Ravensdown national agronomy manager Will Waddell.
“It’s straightforward. With treading and pugging, you are literally killing plants; you’re reducing the pasture population in the paddock,” Opening pastures up in this way kills tillers. And bare ground means thistles, which will be a bigger than usual challenge through to autumn.
As warm temperatures were observed coming into January and February, a new problem arose. Many farm businesses brought in feed and retained numbers, but farmers who had destocked faced a perfect storm: grass growing too fast with not enough mouths to eat it. Last year’s late flush exacerbated this.
“The downside of that dramatic increase in supply, and not enough demand to eat it all, is that we come into a quality issue … we don’t make as much meat or milk from the low-quality grass,” Will said.
“We will have a quality issue, and this is driven by seedhead extent. Seedhead and stem is high with lignin, a structural carbohydrate. That is what holds the seedhead and stem up. High lignin is very low quality. Low-quality results in less meat and milk,” Will said.
Facial eczema (FE) is well-known to thrive in moist conditions.
High growth rates build up trash at the base of the grass, which becomes a “hotbed” for fungi.
“FE is another animal disease we’re likely to see more of this season. FE needs, again, warm moist conditions with lots of dead material in the pasture, and we’ve certainly got those conditions at the moment. When the spores start to climb – the fungus will be growing now and we’ll see the FE spores from now and in February, March,” Will said.
What isn’t a problem? Nutrients, because these are relatively easy to control for.
Common wisdom has it that grass after long rainy periods would be lacking in nutrients, but this shouldn’t be a problem for farmers following a nutrient plan.
An exception is the possible washing away of nitrogen and potassium.
“There is the potential in those high rainfall areas that nitrogen and potassium have leached through the root system … if they’ve had those massive mainfalls,” Will said, although he stressed that other factors had a bigger impact.
‘Stock don’t do well when they are in inclement, rainy or wet weather. They’re solar powered to a certain extent.”
B+LNZ’s Dan Brier reminds farmers that parasite burdens in pastures have been high this season.
“For parasites to grow and survive, they need warm, moist conditions. So, this has been sensational weather for those parasites in our lambs. [And] At any one time, most of the parasites we’re dealing with on our farms are actually on the pasture rather than in the animals.”
“We’re likely to see a strong fly challenge, and there’s already been reports of more flystrike occurring than what would be expected.”
In an online webinar, senior developer farm systems at Dairy NZ Phillipa Hedley reminds dairy farmers that different systems have big impacts: standing cattle off on feed pads for up to 20 hours a day means minimal damage to grass, while block grazing is preferable to strip grazing in terms of damage to pastures in wet conditions.
Pasture damage, as always, was important to avoid. Weeds grew where grass cover was lost and anything helped, Phillipa said. Farmers should have as many exits to paddocks and breaks as possible and consider sacrificing paddocks. Extra teat spraying would be necessary in this case, and magnesium must be on point.
Ravensdown advises farmers to undersow any pastures that remain damaged in autumn.
“That’s a cost-effective fix in raising the population of favourable pasture species up again,” Will said. He also stresses that broadleaf crops do not build up dead material at the base of the plants and are a useful tool in FE management.
B+LNZ reminds farmers to talk to their stock agents early about getting animals processed, because of problems with staffing at the freezing works. Farmers who struggled to get contractors in to cut silage and hay, may find having more stock on the farm may be a bigger issue in 2023 than in other years.
