By Tim Cronshaw
Many dairy farmers have entered feed deficit in Canterbury, with the window for pasture surpluses rapidly compressing as summer approaches.
The silage choppers are usually in full swing at this time of the year, but a large number of the region's farmers have below-target pasture cover because of low growth rates after the cold winter.
Dexcel consulting officer Dr Mary Kinston said maintaining pasture quality was critical for Canterbury farmers during the next few weeks.
She said the window of surplus was becoming compressed and growth rates needed to improve.
"A few farmers are showing surpluses, especially where they have maintained a longer (grazing) round, but it depends on the individual.
"There are quite a few who have substantial deficits, and those in the middle are in a marginal deficit situation.
"They are just on the knife edge of growth rate equalling feed demand.
"The surplus situation is dependent on the growth rate exceeding demand, and normally we would be in a surplus situation."
She said a few farmers with mastitis problems might be downsizing their herds, otherwise stocking rates were unlikely to change at this stage.
Silage contractors have reported a slow start to the season because of the shortage of grass surpluses.
Dairy farmers hope that with rising soil temperatures, warmer weather and refreshing rains, pasture cover will soon exceed cow demand.
In the last week, several farmers have indicated daily growth rates of 60kg to 70kg of dry matter per hectare.
A farm Kinston monitored reported a growth rate of 50kg, while the Lincoln dairy farm showed about 80kg.
Kinston said most farmers were grazing pastures in a rotation of 18 to 24 days. Farmers were maintaining grazing-round frequencies above 18 days to ensure feed deficits were not exacerbated.
By maintaining a longer round length and achieving targeted grass residual levels, farmers are expected to reap the rewards of having high-quality and well-established pastures when growth rates accelerate.
In the last two months, Kinston has overseen five Dexcel Pasture Plus discussion groups from North Rangitata to Waimakariri, attended by more than 100 farmers.
She said growth rates varied at each farm according to its circumstances, such as average pasture cover, stocking rates, weather conditions and irrigation.
Farmers were constantly monitoring grass growth. "In the next few weeks, they will monitor the situation, so when surpluses do become apparent, they will be identified earlier," she said.
"For many farmers, it is still a case of holding average pasture covers and round speeds to maintain the present situation of feed going forward, rather than exacerbating the deficit."
Surpluses will become apparent when grass residual levels are greater than 1500kg of dry matter a hectare.