Findings from an AgResearch study shows that dairy sheep appear to have lower nitrogen leaching per hectare than their bovine counterparts.
The genetically modified grass strikes a balance between reductions in greenhouse gas emissions, greater tolerance to drought and farm productivity.
AgResearch principal scientist Dr Greg Bryan recently returned from the United States where the Crown Research Institute is conducting the field trials of the high metabolisable energy (HME) ryegrass.
Bryan says the ryegrass research has generated high levels of public and scientific interest here in NZ and overseas.
“The HME ryegrass has performed well in controlled growing conditions and I’ve recently returned from the US where we are growing the plants in field trials in competition with one another, just as they would in pasture.
“The plants are doing well.
“We’re breeding the best novel traits into ryegrass cultivars that will best suit NZ growing conditions and we’re introducing genes into the plants that have simpler genetic patterns that will make future breeding programmes easier.”
Bryan says the ultimate goal of the US phase of the research is to conduct realistic rather than simulated animal nutrition studies.
“So we can evaluate whether the grass might have the potential environmental benefits, such as reduced methane emissions and reduced nitrogen excretion that our modelling suggests it will.”
While the results have been encouraging, Bryan issues a note of caution.
“This is complex long term research and we are working on a species with challenging genetics. It takes several years to breed the HME trait into elite ryegrass varieties currently used by farmers, and very importantly to test performance every step of the way.
“It’s important to stress that the forecast environmental benefits associated with the grass need to be supported by rigorous research. We have a good understanding of the potential benefits of the grass because of our institutional expertise in animal nutrition, from animal nutrition models and from the biochemical analysis of the grasses in in vitro (test tube) studies.”
Bryan says AgResearch will eventually need to seek regulatory approval for HME ryegrass to be grown in NZ for livestock grazing trials.
“We need to test in NZ conditions using NZ animals to ultimately confirm or refute the potential environmental and productivity benefits of HME ryegrass.”
Farmers invest in research
DairyNZ is investing farmers’ levies alongside AgResearch to support the trials in the US.
Dr Bruce Thorrold, of DairyNZ, says dairy farmers are looking for new ways to reduce their environmental footprint and improve productivity.
“The science done by AgResearch to develop these plants is world leading, and we’re investing to see how these plants perform in the field and test their potential value for our farmers. While there is a long way to go, we’re encouraged by the results to date.”
AgResearch, in support of this project and several other forage related research initiatives, is also investing in new glasshouse facilities on its Grasslands campus in Palmerston North. The glasshouses, designed to precise performance specifications and biosecurity standards, will be used to research novel ryegrass, clover, endophytes and many other forage related species.
Dr Richard Scott, science team leader for the plant biotechnology team, says these glasshouses have very sophisticated climate control and irrigation technology.
“But the big game changer for us is that their design will allow us to grow plants that produce higher quantities of high quality seed.
“This new facility is very important for the HME ryegrass programme as all seed used in the US trials is produced here in these contained glasshouses at Palmerston North and we will need kilograms of seed to plant enough ryegrass to perform meaningful animal nutrition studies.”
Up to a dozen scientists from two teams – plant biotechnology and plant-microbe interactions – will run various experiments in the glasshouses.
“A diverse range of scientists can work together there, including PhD students, so we are expecting to see even greater collaboration between teams, research institutes, universities, and co-funders,” said Scott.
“We also know this new facility will enable us to increase the scope and pace of both our field trials and the fundamental research programmes into understanding the mechanisms underlying the higher growth rates observed in the HME ryegrass.”