Milking Trojan for all it’s worth

Getting the best out of a top growing perennial ryegrass at this time of the year comes down to one simple step: graze it three to four days earlier than other paddocks.


That’s the advice from Barenbrug this month as thousands of dairy farmers head into peak pasture growth and mating for the current season, many of them using Trojan NEA2 to keep their cows performing well.

Trojan NEA2 is the only perennial ryegrass with maximum winter to summer ratings in the DairyNZ Forage Value Index (FVI).


On farm, that translates to much higher daily DM growth rates and subsequently faster return times for Trojan NEA2 paddocks compared to others, especially at key times of the season like now.

“Trojan is a beast. If you don’t tame it, by grazing it when it’s ready to graze, it will get the better of you,” says Will Henson, Barenbrug pasture systems specialist.

He says plate meter readings from one Bay of Plenty dairy farm tell the story. From June through to November, Trojan NEA2 paddocks outgrew the farm average by as much as 50 per cent, or 31 kg DM/ha/day, and reached as high as 99 kg DM/ha/day.

“Managing Trojan is no different from managing other perennial ryegrasses. It can just happen faster, because Trojan grows faster.”

To turn Trojan NEA2 pastures into the most milksolids at this time of the year, he encourages farmers to follow three golden rules.


“Rule one: graze at the 2.5 to 3 leaf stage. Rule two: graze (or mow) to a consistent, even residual, which is ideally 1500-1600 kg DM/ha. Rule three: repeat the first two rules.”

Consistent residual management makes a huge difference to future pasture quality, Henson says.

Grass left behind after one grazing will be past its use-by date at the next grazing, and the results will show in the vat because cows won’t want to eat it.


Farmers can prevent any potential quality issues before they happen by managing extra growth proactively.

“Identify surpluses early, book your silage contractor and/or spray out other less productive paddocks for summer cropping.”


Strategic nitrogen application (moisture permitting) can also often be useful.

Between November and January, ryegrass plants go through massive changes.

About 75 per cent of each plant’s tillers die, and are replaced, during this time.

Henson says 25-30 kg N/ha can help promote this change, and give the plants a boost through late November and into December.


“This along with consistent good grazing residuals will mean a higher tiller density, which helps with pasture production and persistence into summer and autumn.”

Keeping pastures leafy and green over summer with minimal build up of dead plant material in the base also helps reduce the incidence of rust.


“We have put together a booklet on how to get the best out of the all-star Trojan, which is on our website.”


For more information on Trojan contact your local Barenbrug area manager.