Tabu+ from Agriseeds has been launched for sowing this autumn and company marketing manager Graham Kerr says the results surprised even his staff.
They have it ranking as the only ryegrass with five stars for the six- to eight-month winter feed period throughout New Zealand.
DairyNZ’s FVI is an independent region-specific, profit-based indexed assessment providing farmers with a ranking of annual and perennial rye grass performance based on four geographic regions.
The FVI data has Tabu+ achieving FVI values for drymatter yield of $300-$386 a hectare of farm profit, significantly ahead of another type achieving $40 a hectare.
“And this is a huge difference in profit for seed which only costs about $25 a hectare more,” Kerr said.
While classed as an annual Italian ryegrass, Kerr said farmers in more southern regions could expect at least two to four years grazing from the cultivar while Northland farmers would typically get just one season’s grazing from it.
“But we can see this becoming a grass that has a lot of uses for farmers, depending on their farm systems.
“Farmers down south may choose to take advantage of its excellent winter growth capacity for finishing high-value lambs on contract.
“In Northland it fits well with the farm system changes going on up there where more and more dairy herds are splitting calving into spring and autumn.”
The FVI trials showed the grass delivers very rapid early establishment growth.
With shifts in climate patterns and increasingly hot summers, winter months were likely to become even more valuable for farmers seeking reliable, consistent pasture growth, he said.
Many farmers are reporting lower summer pasture grass growth this season as soil temperatures soar and air temperatures exceeding 28C bring ryegrass growth to a halt.
“Work has shown that trying to boost summer grass growth involves using tropical grasses and there is often a trade-off there with lower feed values. Kikuyu is a good example of that.
“The use of more crops over summer like chicory or plantain can fill that feed gap while a grass like Tabu+ will deliver quality ryegrass feed once those crops have done their job over summer.”
The grass also offered farmers the capacity to mop up and reduce their winter nitrogen losses.
“Typically winter is the period of highest nitrogen leaching, particularly over May, June and July. But if you have a grass that is growing well, it will be absorbing that nitrogen that would otherwise be leached.”
Kerr said there had been a degree of luck in hitting on a grass cultivar with exceptional winter growth and Tabu+’s ability seemed to stem from a good genetic combination rather than any single, specific plant feature.
“But we have also thrown out 500 different crosses before we arrived at this one. This is 14 years on from the original Tabu cultivar so it does not happen quickly.
“It can be quite hard to predict in biologic systems what grasses will stand out and then, occasionally, you get one like this that just makes a really big jump in performance.”
