Having only recently escaped drought, a mild winter on the Hauraki Plains is now creating a different challenge for farmers; grass staggers.
Prolonged gentle rain, combined with mild temperatures and very few frosts has resulted in rapid pasture growth in recent weeks.
That means many farms have increased their pasture rotation, exposing the cows to younger grasses which were high in potassium and non-protein nitrogen, and low in magnesium. That's a classic recipe for the condition known as grass staggers.
The metabolic disease is caused by magnesium deficiency in cows and when untreated, results in seizures and death.
A rural vet based near Kopu, Dr Greg Lindsay, from Franklin Vets said in the last fortnight there had been a spike in calls about grass staggers.
Lindsay believed this was a combination of drought, which had lead to cows being a bit lighter at calving and rapid pasture growth, which was prompting farmers to use it as a source of feed more than they usually would this time of year.
Significant numbers of herds on the plains are suffering milking cow deaths due to low magnesium (grass staggers). Rapidly growing pastures, combined with higher production and higher pasture intakes are to blame. Issues mostly seen on farms relying on trough treatment alone..1/3— Bart van de Ven (@bartjevandeven) August 21, 2020
"This year it seems to be coming home to bed. So we're seeing multiple deaths and all of a sudden, so it'll be going along fine and then a farmer just gets two dead cows all of a sudden and the majority of those have come back as hypo-mag or low magnesium issues."
Lindsay said farmers who suspected that their stock were at risk should speak to their vet.
"Really just looking at the whole farm system, what's going into the cows? Is it enough to compensate that risk of grass staggers overall?," he said.