Increasing the dairy herd's size and improving its condition score is a byproduct of a trial on a South Taranaki research farm.
The Waimate West Demonstration Farm near Manaia is the venue for a three-year trial which is investigating whether growing crops on the dairy platform can increase milksolids production and profitability. Three commercial dairy farms in South Taranaki are also part of the trial, which is in its second season.
Details of the trial were presented to more than 100 people at a field day on the farm and on one of the trial's commercial farms, the Powell family farm near Hawera, where Martin and Christine Powell are 50/50 sharemilkers.
The 36ha demonstration farm was established in 1917 and scientific research had been conducted there since the 1960s, supervisor Joe Clough told the crowd.
The trial follows the increase in milk production on New Zealand farms in recent years, which had been achieved by bringing extra feed on to farms and was studying whether growing crops on the dairy platform was cost-effective.
Before the current trial, the demonstration farm had a high stocking rate of 3.7 jersey cows/hectare and achieved moderate per-cow production of about 320kg milksolids (MS).
A lower stocking rate with a focus on higher per-cow production was one of the trial's objectives.
To increase production, more liveweight and condition needed to be put on the herd. "And this does take a year or two to achieve," Clough said.
Last season the drought affected production and the per-cow target of 340kg milksolids (MS) was 10kg below that, but still higher than the traditional figure of 320kg. This season's target is 360kg MS per cow, with a jump to 380kg MS next season. The cows are now being milked as one herd instead of in several herds during recent trials on the farm.
DairyNZ scientist Kevin Macdonald said the aim of the trial was to grow high value feeds that would raise productivity through extra intake and better average feed quality.
Production to date from 127 jersey cows - the same as last season - was 5.07kg MS/cow, compared with 3.6kg MS/cow last season. Daily milk production was 13.1kg/cow (9.5kg/cow). Average pasture cover this season was 2813kg dry matter/hectare (2640kg) and conserved pasture silage had almost doubled from 110kg DM/cow last season to 192kg DM/cow. Macdonald said the target liveweight of the herd this season was more than 400kg.
For the trial, 10 of the demonstration farm's 40 paddocks have been planted in crops - seven in maize, two in chicory and one in turnips. Oats and Italian ryegrass are planted as a winter crop.
The chicory was ready to graze before Christmas and the turnips, sown in November, were ready in mid-January. Half the turnip paddock was grazed before the herd was returned to the chicory paddock, setting the rotation pattern that will continue until April.
The two crops provide the herd with 2-3kg DM and replace the pasture not available in the seven maize paddocks that are out of the round between October and April. Clough said three maize hybrids were planted this season for harvesting at different times - a strategy that protected yield and quality. "But it's been a nightmare for the contractor."
At the contractor's suggestion, the plant population in one maize paddock was varied from the standard 110,000 plants/ha.
Three paddocks of maize would be harvested by mid-March. In a season like last year, maize was needed early to supplement pasture.
"The longer-maturing varieties grow well in this area and that drives the yield. Staggering the harvest gets more yield from the paddocks at the end of the day," Clough said.
Foundation for Arable Research scientist Mike Parker said nitrogen was generally not needed for maize grown in dairy paddocks that had been in long- term pasture. Not applying nitrogen to maize in those paddocks saved money and was also better for the environment.
When maize in dairy paddocks was monitored, it had shown no response to nitrogen fertiliser because up to 300kg N/ha released by the soil was enough to meet crop requirements, he said.
Ballance Agri-Nutrients science extension officer Jeff Morton said the trial was valuable to the Taranaki dairy industry because farmers took more notice of research done locally than in another region.
PGG Wrightson Seeds agronomist Latham Gibbins said ground preparation, soil fertility and pH were key to growing turnips successfully. Turnip crops needed to be monitored for insects after planting and once the plants were established they should be monitored weekly for weeds.
To date the research showed high yields from the crops without excessive use of nitrogen.
Clough said the trials couldn't take place without sponsors' support and funding from DairyNZ, Ministry for Primary Industries Sustainable Farming Fund, Taranaki Regional Council and the Foundation for Arable Research.
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