Aug 29, 2025
Raphno pre-grazing in summer at Invermay
Back in late July, the DINZ Research Advisory Panel visited AgResearch Invermay to look over facilities, discuss resourcing and get a general lay of the land. While Invermay is a research facility, it still operates as a functional farm, and lessons that might come from operations don’t necessarily mean they came from a dedicated research project.
One such conversation turned to Raphno Pallaton – a hybrid kale-radish brassica. The initial trial was covered in Deer Industry News back in 2023, which can be read here.
To sum up that experience, 15ha of Raphno was undersown with Italian ryegrass, prairie grass, plantain and red and white clover, though AgResearch scientist David Stevens says the prairie grass did not perform well. After a spraying of glyphosate six weeks before drilling to preserve moisture and again immediately before drilling, half the area was drilled in mid-November and the other half in mid-December.
“We started grazing it with first calving hinds and some mixed age hinds in early January, and they were set stocked on it until weaning at the end of February. Live weight gains of the calves were about 490 g/d, compared with 330 g/d for the rest of the mob, which was on drought-affected pasture.”
“The benefits [of Raphno] came in rapid regrowth, no maturity requirements, and with the undersowing, so no transition requirements,” says Stevens. “We didn’t have to spray it for pests or weeds, and it grew an estimated 15t DM/ha, much more than our kale and rape crops. The benefits of sowing it as part of a multi-graze mix were evident as we continued to graze those paddocks into the following summer”
When asked for tips for farmers, Stevens says, “Raphno needs to be grazed early and often to maximise yield and keep quality/palatability up. That then means that you don’t take very big yields into winter and so have to rethink your wintering policies. If you have a big area in mind, then sow it in stages so that it doesn’t all go off. And make sure you have a target for its use.”
The importance of grazing early to maintain palatability was further emphasised during the RAP visit, with the Invermay farm manager saying, “You have to graze it like you hate it.”
The timing of the RAP visit and discussions around Raphno were timed well to align with Next Generation, where Marlborough deer farmers Jason Rentoul and Geoff Hayes talked on their experience growing Raphno. DINZ spoke with Jason Rentoul about his experiences post-event to see if that was in line with AgResearch’s findings.
Rentoul started growing Raphno in 2021, planting 8ha over two paddocks. He also planted 11ha of Spitfire rape as a control. The crops were used to finish lambs in a rotational grazing system, with 20-25 lambs per hectare, with a 3-5 week return time to each paddock. He says that he would use Raphno to finish deer on if venison prices were higher.
“Grazing started 60 days from sowing, and we grazed using the Pallaton road cone method, where you start at the top of the cone, around knee height, and then graze it down to the reflector line on the cone, or around ankle height. The first three grazings, the Raphno and the rape grew the same. After that, the rape ran out and the Raphno continued to grow for another three or four grazings.”
“In the end, I got seven grazings over twelve months over the life of the Raphno versus three grazings for rape. Rape only lasts seven months.”
The biggest cost saving, Rentoul says, is that there is only one drilling and glyphosate spray for 12 months.
"You would need to sow two traditional brassica crops to last this long. That's two drilling costs and two spray outs.”
When asked for tips for farmers considering Raphno, Rentoul says, “We cut the sowing rate back and added Italian ryegrass one year to save on sowing costs. So, 12.5kg per hectare Italian to 5-6kg per hectare Raphno, which worked well. And remember to give the Raphno a nitrogen application in the autumn to help it grow as the soil temperatures start to cool.”
